Shooting with Canon’s EOS Ra Camera


IC 1805 in Cassiopeia (Traveler and EOS Ra)

I had the chance to test out an early sample of Canon’s new EOS Ra camera designed for deep-sky photography. 

Once every 7 years astrophotographers have reason to celebrate when Canon introduces one of their “a” cameras, astronomical variants optimized for deep-sky objects, notably red nebulas.

In 2005 Canon introduced the ground-breaking 8-megapixel 20Da, the first DLSR to feature Live View for focusing. Seven years later, in 2012, Canon released the 18-megapixel 60Da, a camera I still use and love.

Both cameras were cropped-frame DSLRs.

Now in 2019, seven years after the 60Da, we have the newly-released EOS Ra, the astrophoto version of the 30-megapixel EOS R released in late 2018. The EOS R is a full-frame mirrorless camera with a sensor similar to what’s in Canon’s 5D MkIV DSLR.

Here, I present a selection of sample images taken with the new EOS Ra.

Details on its performance is at my “first-look” review at Sky and Telescope magazine’s website.

IC 1805 in Cassiopeia (Traveler and EOS Ra)
The large emission nebula IC 1805 in Cassiopeia, aka the Heart Nebula. The round nebula at top right is NGC 896. The large loose star cluster at centre is Mel 15; the star cluster at left is NGC 1027. The small cluster below NGC 896 is Tombaugh 4. This is a stack of 8 x 6-minute exposures with the Canon EOS Ra mirrorless camera at ISO 1600 through the Astro-Physics Traveler apo refractor at f/6 with the Hotech field flattener. Stacked, aligned and processed in Photoshop.

Both versions of the EOS R have identical functions and menus.

The big difference is that the EOS Ra, as did Canon’s earlier “a” models, has a factory-installed filter in front of the sensor that transmits more of the deep red “hydrogen-alpha” wavelength emitted by glowing nebulas.

Normal cameras suppress much of this deep-red light as a by-product of their filters cutting out the infra-red light that digital sensors are very sensitive to, but that would not focus well.

NGC 7000 North America Nebula (105mm Apo & Canon EOS Ra)
The North America Nebula, NGC 7000, in Cygnus, taken with the new Canon EOS Ra factory-modified “astronomical” version of the Canon EOS R mirrorless camera. This is a stack of 4 x 6-minute exposures, with LENR on and at ISO 1600, through the Astro-Physics Traveler 105mm f/6 apo refractor with the Hutech field flattener.

I was sent an early sample of the EOS Ra, and earlier this autumn also had a sample of the stock EOS R.

Both were sent for testing so I could prepare a test report for Sky and Telescope magazine. The full test report will appear in an upcoming issue.

IC 1396 in Cepheus (Traveler and EOS Ra)
The large emission nebula IC 1396 in Cepheus with the orange “Garnet Star” at top, and the Elephant Trunk Nebula, van den Bergh 142, at bottom as a dark lane protruding into the emission nebula. This is a stack of 5 x 6-minute exposures with the Canon EOS Ra mirrorless camera at ISO 1600 through the Astro-Physics Traveler apo refractor at f/6 with the Hotech field flattener. Stacked, aligned and processed in Photoshop.

But my “first-look” review can be found here on the Sky and Telescope website.

Please click thru for comments on:

• How the Ra compares to previous “a” models and third-party filter-modified cameras

• How the Ra works for normal daylight photography

• Noise levels compared to other cameras

• Features unique to the EOS Ra, such as 30x Live View focusing

Messier 52 and the Bubble Nebula (Traveler and EOS Ra)
Messier 52 open cluster, at left, and the Bubble Nebula, NGC 7635 below and to the right of it, at centre, plus the small red nebula NGC 7538 at right. The open cluster at lower right is NGC 7510. All in Cassiopeia. This is a stack of 8 x 6-minute exposures at ISO 1600 with the Canon EOS Ra camera and Astro-Physics Traveler apo refractor at f/6 with the Hotech field flattener. No LENR dark frame subtraction employed as the temperature was -15° C.

For most of my testing I shot through my much-prized Astro-Physics Traveler, a 105mm aperture f/6 apochromatic refractor on the Astro-Physics Mach1 mount.

To connect the EOS Ra (with its new RF lens mount) to my existing telescope-to-camera adapter and field flattener lens I used one of Canon’s EF-EOS R lens adapters.

EOS Ra on Scope

EOS Ra on Scope CU

The bottom line is that the EOS Ra works great!

It performs very well on H-alpha-rich nebulas and has very low noise. It will be well-suited to not only deep-sky photography but also to wide-field nightscape and time-lapse photography, perhaps as Canon’s best camera yet for those applications.

EOS Ra Front View-Face On

WHAT ABOUT THE PRICE?

The EOS Ra will sell for $2,500 US, a $700 premium over the cost of the stock EOS R. Some complain. Of course, if you don’t like it, you don’t have to buy it. This is not an upgrade being forced upon you.

As I look at it, it is all relative. When Nikon’s astronomy DSLR, the 36 Mp D810a, came out in 2015 it sold for $3,800 US, $1,300 more than the EOS Ra. It was, and remains a fine camera, if you can find one. It is discontinued.

A 36 Mp cooled and dedicated CMOS astro camera, the QHY367, with the same chip as the D810a, goes for $4,400, $1,900 more than the Ra. Yes, it will produce better images I’m sure than the EOS Ra, but deep-sky imaging is all it can do. At a cost, in dollars and ease of use.

And yes, buying a stock EOS R and having it modified by a third party costs less, and you’ll certainly get a good camera, for $300 to $400 less than an Ra. But …

• The EOS Ra has a factory adjusted white balance for ease of “normal” use — no need to buy correction filters. So there’s a $$ saving there, even if you can find clip-in correction filters for the EOS R — you can’t.

• And the Ra retains the sensor dust cleaning function. Camera modifier companies remove it or charge more to reinstall it.

• And the 30x live view is very nice.

• The EOS Ra also has the full factory warranty.

Do I wish the EOS Ra had some other key features? Sure. A mode to turn all menus red would be nice. As would an intervalometer built-in, one that works with the Bulb Timer to allow sequences of programmed multi-minute exposures. Both could be added in with a firmware update.

And providing a basic EF-EOS R lens adapter in the price would be a welcome plus, as one is essential to use the EOS Ra on a telescope.

That’s my take on it. I’ll be buying one. But then again I bought the 20Da, twice!, and the 60Da, and I hate to think what I paid for those much less capable cameras.

Canon EOS Ra and 15-35mm

BONUS TEST — The RF 15-35mm L Lens

Canon is also releasing an impressive series of top-class RF lenses for their R mirrorless cameras. The image below is an example astrophoto with the new RF 15-35mm f/2.8 L zoom lens, an ideal combination of focal lengths and speed for nightscape shooting.

Orion and Winter Stars Rising
Orion and the winter stars rising on a late October night, with Sirius just clearing the horizon at centre bottom, Capella and the Pleiades are at top. M44 cluster is at far left. Taken with the Canon 15-35mm RF lens at 15mm and f/2.8 and the EOS Ra camera at ISO 800 as part of testing. A stack of 4 x 2-minute exposures on the Star Adventurer tracker.

Below is a further set of stacked and processed images with the RF 15-35mm L lens, taken in quick succession, at 15mm, 24mm, and 35mm focal lengths, all shot wide open at f/2.8. The EOS Ra was on the Star Adventurer tracker (as below) to follow the stars.

EOS Ra on Star Adventurer

Click or tap on the images below to view a full-resolution version for closer inspection.

Autumn Milky Way (15-35mm RF at 15mm + EOS Ra).jpg
15mm — Northern autumn Milky Way with RF 15-35mm at f/2.8 and at 15mm focal length. Taken with the EOS Ra at ISO 800 for a stack of 4 x 2-minute exposures.
Autumn Milky Way (15-35mm RF at 24mm + EOS Ra).jpg
24mm — Northern autumn Milky Way with RF 15-35mm at f/2.8 and at 24mm focal length. Taken with the EOS Ra at ISO 800 for a stack of 2 x 2-minute exposures.
Autumn Milky Way (15-35mm RF at 35mm + EOS Ra).jpg
35mm — Northern autumn Milky Way with RF 15-35mm at f/2.8 and at 35mm focal length. Taken with the EOS Ra at ISO 800 for a stack of 2 x 2-minute exposures.

The RF 15-35mm lens performs extremely well at 15mm exhibiting very little off-axis aberrations at the corners.

Off-axis aberrations do increase at the longer focal lengths but are still very well controlled, and are much less than I’ve seen on my older zoom and prime lenses in this focal length range.

The RF 15-35mm is a great complement to the EOS Ra for wide-field Milky Way images.

I was impressed with the new EOS Ra. It performs superbly for astrophotography.

Again, click through to Sky and Telescope for “first look” details on the test results.

— Alan, November 6, 2019 / UPDATED Nov 7, 2019 / © 2019 AmazingSky.com 

 

How to Shoot and Stitch Nightscape Panoramas


The Milky Way over Writing-on-Stone

Panoramas featuring the arch of the Milky Way have become the icons of dark sky locations. “Panos” can be easy to shoot, but stitching them together can present challenges. Here are my tips and techniques.

My tutorial complements the much more extensive information I provide in my eBook, at right. Here, I’ll step through techniques for simple to more complex panoramas, dealing first with essential shooting methods, then reviewing the workflows I use for processing and stitching panoramas. 

What software works best depends on the number of segments in your panorama, or even on the focal length of the lens you used. 


PART 1 — SHOOTING 

What Equipment Do You Need?

Nightscape panoramas don’t require any more equipment than what you likely already own for shooting the night sky. For Milky Way scenes you need a fast lens and a solid tripod, but any good DSLR or mirrorless camera will suffice. 

1-Camera with Leveling Head and L-Bracket
Pano Gear
A tripod head with a scale marked in degrees is essential. Here it sits on a levelling head with its own bubble level that makes it easy to level the camera. An L-bracket allows the camera to rotate directly above the vertical axis, handy when shooting in portrait mode, as here with a 15mm full-frame fish-eye lens, one option for horizon-to-zenith panoramas. The tripod accessories here are by Acratech. 

The tripod head can be either a ball head or a three-axis head, but it should have a horizontal axis marked with a degree scale. This allows you to move the camera at a correct and consistent angle from segment to segment. I think that’s essential. 

What you don’t need is a special, and often costly, panorama head. These rotate the camera around the so-called “nodal point” inside the lens, avoiding parallax shifts that can make it difficult to align and stitch adjacent frames. Parallax shift is certainly a concern when shooting interiors or any scenes with prominent content close to the camera. However, in most nightscapes our scene content is far enough away that parallax simply isn’t an issue. 

Though not a necessity, I find a levelling base a huge convenience. As I show above, this specialized ball head goes under the usual tripod head and makes it easy to level the main head. It eliminates all the fussing with trial-and-error adjustments of the length of each tripod leg. 

Canon 6D Mk II Level
On the Level
Most cameras now have an electronic level built in that is handy for ensuring the panorama does not end up tilted. This is from a Canon 6D MkII.

Then to level the camera itself, I use the electronic level now in most cameras. Or, if your camera lacks that feature, an accessory bubble level clipped into the camera’s hot shoe will work.

Having the camera level is critical. It can be tipped up, of course, but not tilted left-right. If it isn’t level the whole panorama will be off kilter, requiring excessive straightening and cropping in processing, or the horizon will wave up and down in the final stitch, perhaps causing parts of the scene to go missing.

NOTE: Click or tap on the panorama images to open a high-res version for closer inspection.  

Panorama of the Northern Lights and Winter Stars
Aurora in the Winter Sky
To capture this panorama I used a Sigma 14mm lens on a Nikon D750, mounted in portrait orientation with the gear shown above, to shoot eight segments 45° apart, each 13 seconds at f/2 and ISO 3200. Stitching was with Adobe Camera Raw. The aurora lies to the north at left, while Orion and the winter Milky Way are to the south at right. 

Shooting Horizon Panoramas

While panoramas spanning the entire sky might be what you are after, I suggest starting simpler, with panos that take in just a portion of the 360° horizon and only a part of the 180° of the sky. These “partial panos” are great for auroras (above) or noctilucent clouds, (below), or for capturing just the core of the Milky Way over a landscape. 

The key to all panorama success is overlap. Segments should overlap by 30 to 50 percent, enabling the stitching software to align the segments using the content common to adjacent frames. Contrary to some users, I’ve never found an issue with having too much overlap, where the same content is present on several frames. 

Noctilucent Cloud Panorama over OId Barns on June 19, 2019
Noctilucent Clouds in Summer
NLCs are good panorama subjects. I captured this display on June 19, 2019 using a Sony a7III camera at ISO 400, and a Sigma 50mm lens at f/2 for a set of six segments stitched with Adobe Camera Raw

For a practical example, let’s say you shoot with a 24mm lens on a full-frame camera, or a 16mm lens on a cropped-frame camera. Both combinations yield a field of view across the long dimension of the frame of roughly 80°, and across the short dimension of the frame of about 55°. 

That means if you shoot with the camera in “landscape” orientation, panning the camera by 40° between segments would provide a generous 50 percent overlap. The left half of each segment will contain the same content as the right half of the previous segment, if you take your panos by turning from left to right. 

TIP: My habit is to always shoot from left to right, as that puts the segments in the correct order adjacent to each other when I view them in browser programs such as Lightroom or Adobe Bridge, with images sorted in chronological order (from first to last images in a set) as I typically prefer. But the stitching will work no matter which direction you rotate the camera. 

In the example of a 24mm lens and a camera in landscape orientation you could turn at a 45° or 50° spacing and yield enough overlap. However, turning the camera at multiples of 15° is usually the most convenient, as tripod heads are often graduated with markings at 5° increments, and labeled every 15° or 30°. 

Some will have coarser and perhaps unlabeled markings. If so, determine what each increment represents, then take care to move the camera consistently by the amount that will provide adequate overlap. 

Harvest Moon Rising over the Red Deer River
Moonrise over the Red Deer River
Not all panoramas have to be of the Milky Way. This captures the sweeping arc of Earth’s blue shadow rising in the eastern sky as the Harvest Moon comes up amid the shadow. This is a 7-section single-tier panorama with the 20mm Sigma lens and Nikon D750 at ISO 100. It stitched fine with Adobe Camera Raw.

To maximize the coverage of the sky while still framing a good amount of foreground, a common practice is to shoot panoramas with the camera in portrait orientation. That provides more vertical but less horizontal coverage for each frame. In that case, for adequate overlap with a 24mm lens and full-frame camera shoot at 30° spacings.

TIP: When shooting a partial panorama, for example just to the south for the Milky Way, or to the north for the aurora borealis, my practice is to always shoot a segment farther to the left and another to the right of the main scene. Shoot more than you need. Those end segments can get distorted when stitching, but if they don’t contain essential content, they can be cropped out with no loss, leaving your main scene clean and undistorted.

Shooting with a longer lens, such as a 50mm (or 35mm on a cropped frame camera), will yield higher resolution in the final panorama, but you will have much less sky coverage, unless you shoot multiple tiers, as I describe below. You would also have to shoot more segments, at 15° to 20° spacings, taking longer to complete the shoot.

Night Train in the Moonlight at Morant's Curve
Morant’s Curve in the Moonlight
Not all panoramas have to be shot under dark skies, or encompass 360°. Moonlight illuminates the famous viewpoint called Morant’s Curve in Banff National Park, with Orion setting over the peaks of the Continental Divide, as a train speeds east through the March night. This is a panorama of 12 segments, each with a 24mm Sigma lens and Nikon D750 in portrait orientation, stitched with PTGui. 

As the number of segments goes up shooting fast becomes more important, to minimize how much the sky moves from segment to segment, and during each exposure itself, to aid in stitching. Remember, the sky appears to be turning from east to west, but the ground isn’t. So a prolonged shoot can cause problems later as the stitching software tries to align on either the fixed ground or the moving stars. 

Panoramas on moonlit nights, as I show above, are relatively easy because exposures are short.

Milky Way over Dry Island Buffalo Jump
Milky Way over the Buffalo Jump
A moonless night in early May was perfect for a panorama of the Milky Way arching over the Badlands of Dry Island Buffalo Jump in Alberta. This is a multi-tier panorama of 3 tiers of 7 segments each, with exposures of 30 seconds at f/2 with a 20mm Sigma Art lens and Nikon D750 at ISO 6400.

Milky Way panoramas taken on dark, moonless nights are tougher. They require fast apertures (f/2 to f/2.8) and high ISOs (ISO 3200 to 6400), to keep individual exposures no more than 30 to 40 seconds long.

Histogram Example
Expose to the Right
Minimize noise in the shadows by exposing so the histogram is shifted to the right, and not slammed to the left. Underexposure is the most common cardinal sin of newbie nightscape photographers. 

Noise lives in the dark foregrounds, so I find it best to err on the side of overexposure, to ensure adequate exposure for the ground, even if it means the sky is bright and the stars slightly trailed. It’s the “Expose to the Right” philosophy I espouse at length in my eBook. 

Advanced users can try shooting in two passes: one at a low ISO and with a long exposure for the fixed ground, and another pass at a higher ISO and a shorter exposure for the moving sky. But assembling such a set will take some deft work in Photoshop to align and mask the two stitched panos. None of the examples here are “double exposures.”


Shooting 360° Panoramas

The Milky Way over Maskinonge Lake
Milky Way at Waterton Lakes
While covering 360° in azimuth, this panorama from July 2018 goes only partway up the sky, to capture the Milky Way core to the south and the solstice twilight glow to the north. This is a 10-segment panorama, with each segment 30 seconds at f/2 with a Sigma 24mm Art lens and Nikon D750 at ISO 6400. Adobe Camera Raw stitched this nicely.

More demanding than partial panoramas are full 360° panoramas, as above. Here I find it is best to start the sequence with the camera aimed toward the celestial pole (to the north in the northern hemisphere, or to the south in the southern hemisphere). That places the area of sky that moves the least over time at the two ends of the panorama, again making it easier for software to align segments, with the two ends taken farthest apart in time meeting up in space.

In our 24mm lens example, to cover the entire 360° scene shooting with a 45° spacing would require at least eight images (8 x 45 = 360). I used 10 above. Using that same lens with the camera in portrait orientation will require at least 12 segments to cover the entire 360° landscape. 


Shooting 360° by 180° Panoramas

"Steve," the Strange Auroral Arc
Capturing STEVE This 360° panorama captures the infamous STEVE auroral arc across the south, with a normal auroral display to the north at right. This was from six segments, each 10 seconds at ISO 2500, with a Sigma 14mm lens at f/1.8 and Nikon D750 in portrait orientation.

More demanding still are 360° panoramas that encompass the entire sky, from the ground below the horizon to the zenith overhead. Above is an example.

To do that with a single row of images requires shooting in portrait orientation with a very wide 14mm rectilinear lens on a full-frame camera. That combination has a field of view of about 100° across the long dimension of the sensor. 

That sounds generous, but reaching up to the zenith at an altitude of 90° means only a small portion of the landscape will be included along the bottom of the frame.

To provide an even wider field of view to take in more ground, I use full-frame fish-eye lenses on my full-frame cameras, such as Canon’s old 15mm lens (as shown at top) or Rokinon’s 12mm. Even a circular-format fish-eye will work, such as an 8mm on a full-frame camera or 4.5mm on a cropped-frame camera. 

All such fish-eye lenses produce curved horizons, but they take in a wide swath of sky, making it possible to include lots of foreground while reaching well past the zenith. Conventional panorama assembly programs won’t work with such wide and distorted segments, but the specialized programs described below will. 


Shooting Multi-Tier Panoramas

Bow Lake by Night Panorama
Bow Lake by Night
The summer Milky Way arches over iconic Bow Lake in Banff on a perfect night in July 2018. This is a stitch, using PTGui, of three tiers of 7 segments each, with a 20mm Sigma lens and Nikon D750, with a Genie Mini automating the horizontal panning and shutter release, as shown above. Each frame was 30 seconds at f/2 and ISO 6400. I used this same set to test the programs described below.

The alternative technique for “all-sky” panos is to shoot multiple tiers of images: first, a lower row covering the ground and partway up the sky, followed by an upper row completing the coverage of just the sky at top. 

The trick is to ensure adequate overlap both horizontally and vertically. With the camera in landscape orientation that will require a 20mm lens for full-frame cameras, or a 14mm lens for cropped-frame cameras. Either combination can cover the entire sky plus lots of foreground in two tiers, though I usually shoot three, just to be sure!.

Shooting with longer lenses provides incredible resolution for billboard-sized “gigapan” blow-ups, but will require shooting three, if not more, tiers, each with many segments. That starts to become a chore to do manually. Some motorized assistance really helps when shooting multi-tier panoramas. 


Automating the Pan Shooting

The dedicated pano shooter might want to look at a device such as the GigaPan Epic models or the iOptron iPano, (shown below), all about $800 to $1000. 

5A-iPano Aimed High
iPano Panorama Machine
The iOptron iPano automates all shooting and movement, making even the most complex panoramas easy to shoot. It can also be used for two-axis motion-control time-lapses. 

I’ve tested the latter and it works great. You program in the lens, overlap, and angular sweep desired. The iPano works out how many segments and tiers will be required, and automates the shooting, firing the shutter for the duration you program, then moving to the new position, firing again, and so on. I’ve shot four-tier panos effortlessly and with great success. 

5B-iPano Screen-Shooting Info
iPano Control
The iPano’s on-board screen provides all the menus and options for setting up a shoot. This screen shows that this multi-tier pano will take 6m37s to complete. 

However, these devices are generally bigger and heavier than I care to heft around in the field.

Instead, I use the original Genie Mini from SYRP, (below), a $250 device primarily for shooting motion control time-lapses. But the wireless app that programs the Genie also has a panorama function that automatically slews the camera horizontally between exposures, again based on the lens, overlap, and angular sweep you enter. The just-introduced Genie Mini II is similar, but with even more capabilities for camera control. 

6A--SYRP Genie Mini
The SYRP Genie Mini
A lower-cost option for automated shooting, the Genie Mini also provides time-lapse motion control. Here, I show it with a conventional 3-axis head on top, for shifting the camera up in altitude manually for multi-tier panos, while the Mini handles the horizontal motion and exposures. 

While combining two Genie Minis allows programming in a vertical motion as well, I’ve been using just a regular tripod head atop the Mini to manually move the camera vertically between each of the horizontal tiers. I don’t feel the one or two moves needed to go from tier to tier too arduous to do manually, and I like to keep my field gear compact and easy to use.

6B-Genie App
Wireless Control
The original Genie App (Apple iOS or Android) connects to the Genie via Bluetooth. This screen shows a 360° panorama programmed for a 20mm lens with 37% percent overlap, requiring eight segments. The shutter will fire after each move for 40 seconds.

The Genie Mini (now replaced by the Mini II) works great and I highly recommend it, even if panoramas are your only interest. But it is also one of the best, yet most affordable, single-axis motion control devices on the market for time-lapse work. 


When to Shoot the Milky Way

While the right gear and techniques are important, go out on the wrong night and you won’t be able to capture the Milky Way as the great sweeping arch you might have hoped for.

In the northern hemisphere the Milky Way arches directly overhead from late July to October for most of the night. That’s fine for spherical fish-eye panoramas, but in rectangular images when the Milky Way is overhead it gets stretched and distorted across the top of the final panorama. For example, in the Bow Lake by Night panorama above, I cropped out most of this distorted content.

The Milky Way over Writing-on-Stone
Capturing the Arch
I captured this 360° pano of the summer Milky Way arching over the sandstone formations of Writing-on-Stone Provincial Park in southern Alberta in early June 2018. At that time of year the Milky Way is still confined to the eastern sky. This is a 21-panel panorama, shot in three tiers of seven panels each, with the Nikon D750 and Sigma 20mm Art lens on the Genie Mini, with each segment 30 seconds at f/2 and ISO 6400.

The prime season for Milky Way arches is therefore before the Milky Way climbs overhead, while it is still across the eastern sky, as above. That’s on moonless nights from March to early July, with May and June best for catching it in the evening, and not having to wait up until dawn, as is the case in early spring. 

8B-Starry Night Simulation
Simulating the Scene
I often use Starry Night™ (shown here) to simulate the sky for the place and date I want, to preview where and when the Milky Way will appear and how it will move. The red box shows the field of view of a rectilinear 14mm lens in portrait orientation, showing it covering from the zenith (at top) to just below the horizon.

TIP: The best way to figure out when and where the Milky Way will appear is to use a desktop planetarium program such as Starry Night or Sky Safari  or the free Stellarium. All can realistically depict the Milky Way for your location and date. You can then step through time to see how the Milky Way will move through the night, and how it will frame with your camera and lens combination using the “field of view” indicators the programs provide. 

Southern Sky Panorama at OzSky Star Party
The Great Southern Sky
A 360° panorama from April 2017 captures the arc of the southern Milky Way over the OzSky star party near Coonabarabran, NSW, Australia. This is 8 segments, each 30 seconds at ISO 6400 and f/2.5 with a Rokinon 14mm lens on a Canon 6D in portrait orientation, and stitched with PTGui.

When shooting in the southern hemisphere I like the April to June period for catching the sweep of the southern Milky Way and the galactic core rising in late evening. By contrast, during mid austral winter in July and August the galactic centre shines directly overhead in the evening, a spectacular sight to be sure, but tough to capture in a panorama except in a spherical or fish-eye scene. 

Spring Sky Panorama at Dinosaur Park
The Other Milky Way
This 360° panorama, shot in a single tier with a 14mm Sigma lens and Nikon D750 in portrait orientation, captures the winter Milky Way arching across the western sky on an early spring night at Dinosaur Provincial Park in Alberta. Also in the pano is the sweep of the faint Zodiacal Light. This is a stitch, using PTGui, of 12 segments, each 30 seconds at f/2.8 and ISO 4000.

That said, I always like to put in a good word for the often sadly neglected winter Milky Way (the summer Milky Way for those “down under”). While lacking the spectacle of the galactic core in Sagittarius, the “other” Milky Way has its attractions such as Orion and Taurus. The best months for a panorama with that Milky Way in an arch across a rectangular frame are January to March. The Zodiacal Light can be a bonus at that season, as it was above.

TIP: Always shoot raw files for the widest dynamic range and flexibility in recovering details in the highlights and shadows. Even so, each segment has to be well exposed and focused out in the field.

And unless you are doing a “two-pass” double exposure, always shoot each segment with identical exposure settings. This is especially critical for bright sky scenes such twilights or moonlit scenes. Vary the exposure and you might get unsightly banding at the seams.

There’s nothing worse than getting home only to find one or more segments was missed, or was out of focus or badly exposed, spoiling the set.


PART 2 — STITCHING

Developing Panorama Segments

Once you have your panorama segments, the next step is to develop and assemble them. For my workflow, the process of assembling a panorama from its constituent segments begins with developing each of those segments identically.

NOTE: Click or tap on the software screen shots to open a high-res version for closer inspection. 

11A-Adobe Camera Raw Before-After
Developing with Adobe Camera Raw
This shows one segment of the multi-tier example before (on the left) and after applying development settings in the Basic panel of Adobe Camera Raw. By selecting all the images, the Sync Settings command (at top left) will apply the settings of one image to the rest of the set.

I like to develop each segment’s raw file as fully as possible at this first stage in the workflow, applying noise reduction, colour correction, contrast adjustments, shadow and highlight recovery, and any special settings such as dehaze and clarity that can make the Milky Way pop. 

I also apply lens corrections to each raw image. While some feel doing so produces problems with stitching later on, I’ve never found that. I prefer to have each frame with minimal vignetting and distortion when going into stitching. I use Adobe Camera Raw out of Adobe Bridge, but Lightroom Classic has identical functions. 

There are several other raw developers that can work well at this stage. In other tests I’ve conducted, Capture One and DxO PhotoLab stand out as producing good results on nightscapes. See my blog from 2017 for more on software choices.

DxO Photo Lab Example
Developing with DxO
Among a host of programs competing with Adobe, DxO PhotoLab does a good job developing raw files, with the ability to copy and paste settings from one image to many. It has excellent noise reduction and shadow detail recovery. However, it cannot layer images.

The key is developing each raw file identically, usually by working on one segment, then copying and pasting its settings to all the others in a set. Not all raw developers have this “Copy Settings” function. For example, Affinity Photo does not. It works very well as a layer-based editor to replace Photoshop, but is crude in its raw developing “Persona” functions. 

While panorama stitching software will apply corrections to smooth out image-to-image variations, I find it is best to ensure all the segments look as similar as possible at the raw stage for brightness, contrast, and colour correction. 

Do be aware that among social media groups and chat rooms devoted to nightscape imaging a lot of myth and misinformation abounds about how to process and stitch panoramas, and why some don’t work. Someone having a problem with a particular pano will ask why, and get ten different answers from well-meaning helpers, most of them wrong!


Stitching Simple Panoramas

For example, if your segments don’t join well it likely isn’t because you needed to use a panorama head (one oft-heard bit of advice). I never do. The issue is usually a lack of sufficient overlap. Or perhaps the image content moved too much from frame to frame as the photographer took too long to shoot the set. 

Or, even when quickly-shot segments do have lots of overlap, stitching software can still get confused if adjoining segments contain featureless content or content that changes, such as segments over rippling water with no identifiable “landmarks” for the software to latch onto. 

The primary problems, however, arise from using software that just isn’t up to the task. Programs that work great on simple panoramas (as the next three examples show) will fail when trying to stitch a more demanding set of segments.

11B-Adobe Camera Raw Panorama
Stitching with Adobe Camera Raw
The panorama function in all recent versions of Adobe Camera Raw (Lightroom Classic has the same feature) can do a superb job on simple panoramas, such as the moonlit Morant’s Curve pano, with the magical Boundary Warp option allowing you to fill the frame without cropping and losing content.

For example, for partial horizon panos shot with 20mm to 50mm lenses, I’ll use the panorama function now built into Adobe Camera Raw (ACR) and Adobe Lightroom Classic, and also in the mobile-friendly Lightroom app. As I show above, ACR can do a wonderful job, yielding a raw DNG file that can continue to be edited non-destructively. It’s by far the easiest and fastest option, and is my first choice.

Another choice, not shown here, is the Photomerge function from within Photoshop, which yields a layered and masked master file, and provides the option for “content-aware” filling of missing areas. It can sometimes work on panos that ACR balks at. 

12-ON1 PhotoRAW
Stitching with ON1 PhotoRAW
The Adobe competitor ON1 PhotoRAW also provides a good panorama stitching feature that can work with both simple and many multi-tier panos. It provides a flattened result, even when exporting as a .PSD Photoshop file.

Two programs popular as Adobe alternatives, ON1 PhotoRAW (above) and the aforementioned Affinity Photo (below), also have very capable panorama stitching functions.

However, in testing both programs with the demanding Bow Lake multi-tier panorama I used below with other programs, ON1 2019.5 did an acceptable job, while Affinity 1.7 failed. It works best on simpler panoramas, like this partial scene with a 24mm lens.

13-Affinity Photo
Stitching with Affinity Photo
Another program vying to unseat Adobe products is Affinity Photo. It, too, does a fine job on simple panos, but tends to fail on multi-tier panoramas. There is no choice of panorama projections or option to export a layered master.

Even if they succeed when stitching 360° panoramas, such general-purpose editing programs, Adobe’s included, provide no option for choosing how the final scene gets framed. You have no control over where the program puts the ends of the scene.

Or the program just fails, producing a result like this.

14A-Camera Raw Multi-Tier Fail
When Stitching Goes Awry
Throw a multi-tier pano at Adobe Camera Raw and you might end up with this type of unsalvageable result. Here’s where you have to turn to specialized panorama software
14B-Adobe Camera Raw 14mm Fail
Warp Factor
Even single-tier panos but shot with 14mm rectilinear (in this case) or fish-eye lenses will create warped results with ACR, only partly correctable with Boundary Warp.

Far worse is that multi-tier panoramas or, as I show above, even single-tier panos shot with very wide lenses, will often completely befuddle your favourite editing software, with it either refusing to perform the stitch or producing bizarre results.

Some photographers attempt to correct such wild distortions with lots of ad hoc adjustments with image-warping filters. But that’s completely unnecessary if you use the right software to begin with. 


Stitching Complex Panoramas

When conventional software fails, I turn to the dedicated stitching program PTGui, $150 for MacOS or Windows. The name comes from “Panorama Tools – Graphical User Interface.” 

15-PTGui-Rectangular
Stitching with PTGui
PTGui handles whatever complexity of panorama you can throw at it, either single or multi-tier (in this example), offering an accurate preview, a choice of projection modes (this is “equirectangular”), and the ability to quickly move the pano around to frame it as you like before exporting either a flattened or a layered master.

While PTGui can read raw files from most cameras, it will not read any of the development adjustments you made to those files using Lightroom, Camera Raw, or any other raw developers. 

So, my workflow is to develop all the raw segments, export them out as 16-bit TIFFs, then import those into PTGui. It can detect what lens was used to take the images, information PTGui needs to stitch accurately. If you used a manual lens you can enter the lens focal length and type (rectilinear or fish-eye) yourself. 

18A-PTGui-Spherical
Spherical Scene with PTGui
PTGui makes it easy to re-project the same set of images into other map projections, in this case as a circular fish-eye scene which can be rotated as desired.

I include a full tutorial on using PTGui in my eBook linked to above, but suffice to say that the program usually does a superb job first time and very quickly. You can drag the panorama around to frame the scene as you like, and change the projection at will to create rectangular or spherical format images, as above, and even so-called “little planet” projections that appear as if you were looking down at the scene from space. 

Occasionally PTGui complains about some frames, requiring you to manually intervene to pick the same stars or horizon features in adjacent frames to provide enough matching alignment points until it is happy. Its interface also leaves something to be desired, with essential floating windows disappearing behind other mostly blank panels. 

15B-Layered Photoshop
Adjusting Layers
The layered output from PTGui produces a massive image but one that allows fine adjustments to the masks (by using a white paint brush) to correct mismatches like we see see here along the mountain peak.

When exporting the finished panorama I usually choose to export it as a layered 16-bit Photoshop .PSD or, with big panos, as a Photoshop .PSB “big” document. 

The reason is that in aligning the moving stars PTGui (indeed, all programs) can produce a few “fault lines” along the horizon, requiring a manual touch up to the masks to clean up mismatched horizon content, as I show above. Having a layered and masked master makes this easy to do non-destructively, though that’s best done in Photoshop. 

Affinity Photo Layers
Opening with Affinity
Affinity Photo is one of the few non-Adobe programs that can open large Photoshop .PSB files, and honour the layers, keeping them and the masks that PTGui exports intact.

However, Affinity Photo (above) can also read layered .PSD and .PSB Photoshop files, preserving the layers. By comparison, ON1 PhotoRAW flattens layered Photoshop files when it imports them, one deficiency that prevents this program from being a true Photoshop alternative. 

The Milky Way over Writing-on-Stone
Compressing the Milky Way
A common final step is to compress the long dimension of the image to change its aspect ratio to one better suited to publication. But doing so highly distorts the grand sweep of the Milky Way.

Once a 360° panorama is in a program like Photoshop, some photographers like to “squish” the panorama horizontally to make it more square, for ease of printing and publication. I prefer not to do that, as it makes the Milky Way look overly tall, distorted, and in my opinion, ugly. But each to their own style.

You can test out a limited trial version of PTGui for free, but I think it is worth the cost as an essential tool for panorama devotees. 


Other Stitching Options

16-Microsoft ICE
Stitching with Microsoft ICE
Image Composite Editor, for Windows only but free from Microsoft Research, also does a superb job on all panoramas (as it did with this test case), with accurate stitching and preview, a choice of projections, cropping, and the option for a layered output.

However, Windows users can also try Image Composite Editor (ICE), free from Microsoft Research. As shown above in my test 3-tier pano, ICE works very well on complex panoramas, has a clean, user-friendly interface, offers a choice of geometric projections, and can export a master file with each segment on its own layer, if desired, for later editing. 

17A-HugIn Software
Stitching with HugIn
The open-source program HugIn is free, but suffers from an inaccurate preview, complex interface and workflow, and technical displays and functions only a programmer will love.

The free, open source program HugIn is based on the same Panorama Tools root software that PTGui uses. However, I find HugIn’s operation clunky and overly technical. Its export process is arcane yet renders out only a flattened image.

17B-Bow Lake from Hugin
HugIn Fail
The export of the same multi-tier pano that worked fine with PTGui and ICE failed with HugIn, with missing content and numerous mis-aligned areas of the landscape, tough to fix in the flattened output. 

In testing it with the same three-tier 21-segment pano that PTGui and ICE handled perfectly, HugIn failed to properly include one segment. However, it is free for MacOS and Windows, and so the price is right and is well worth a try. 

Bow Lake by Night Panorama (Spherical)
Fish-Eye Milky Way
In summer with the Milky Way overhead, a spherical projection is often best for presenting the Milky Way as your eye saw it, as a majestic band of light from horizon to horizon across the sky passing through the zenith.

With the superb tools now at our disposal, it is possible to create detailed panoramas of the night sky that convey the majesty of the Milky Way – and the night sky – as no single image can. Have fun!

— Alan, June 25, 2019 / © 2019 Alan Dyer / AmazingSky.com  

Testing the Nikon Z6 for Astrophotography


Nikon Z Title

I put the new Nikon Z6 mirrorless camera through its paces for astrophotography. 

Following Sony’s lead, in late 2018 both Nikon and Canon released their entries to the full-frame mirrorless camera market. 

Here I review one of Nikon’s new mirrorless models, the Z6, tested solely with astrophotography in mind. I did not test any of the auto-exposure, auto-focus, image stabilization, nor rapid-fire continuous mode features. 

For full specs and details on the Z-series cameras see Nikon USA’s website.

Sony a7III vs Nikon Z6 copy

In my testing I compared the Nikon Z6 (at right above) to two competitive cameras, the relatively new Sony a7III mirrorless (at left above) and 2015-vintage Nikon D750 DSLR.

All three are “entry-level” full-frame cameras, with 24 megapixels and in a similar $2,000 price league, though the older D750 now often sells at a considerable discount.


Disclosure

I should state at the outset that my conclusions are based on tests conducted over only three weeks in mid-winter 2019 while I had the camera on loan from Nikon Canada’s marketing company. 

I don’t own the camera and didn’t have many moonless nights during the loan period to capture a lot of “beauty” shots under the stars with the Z6.

Auroral Arc (January 10, 2019)
An arc of the auroral oval across the northern horizon on the night of January 10-11, 2019. With the Sigma 14mm lens and Nikon Z6 for testing.

However, I think my testing was sufficient to reveal the camera’s main traits of interest — as well as deficiencies it might have — for astrophotography.

I should also point out that I do not participate in “affiliate links,” so I have no financial motivation to prompt you to buy gear from merchants. 

But if you buy my ebook (at right), which features reams of sections on camera and time-lapse gear, I would be very pleased! 


TL;DR Conclusions

In short — I found the Nikon Z6 superb for astrophotography. 

Nikon Z6 Screens copy

Summary:

• It offers as low a noise level as you’ll find in a 24-megapixel full-frame camera, though its noise was not significantly lower than the competitive Sony a7III, nor even the older Nikon D750. 

• The Z6’s ISO-invariant sensor proved excellent when dealing with the dark underexposed shadows typical of Milky Way nightscapes.

• The Live View was bright and easy to enhance to even brighter levels using the Movie mode to aid in framing nightscapes. 

• When shooting deep-sky images through telescopes using long exposures, the Z6 did not exhibit any odd image artifacts such as edge vignetting or amplifier glows, unlike the Sony a7III. See my review of that camera in my blog from 2018. 

Recommendations: 

• Current owners of Nikon cropped-frame cameras wanting to upgrade to full-frame would do well to consider a Z6 over any current Nikon DSLR. 

• Anyone wanting a full-frame camera for astrophotography and happy to “go Nikon” will find the Z6 nearly perfect for their needs. 


Nikon Z6 vs. Z7

Nikon Front View copy

I opted to test the Z6 over the more expensive Z7, as the 24-megapixel Z6 has 6-micron pixels resulting in lower noise (according to independent tests) than the 46 megapixel Z7 with its 4.4 micron pixels. 

In astrophotography, I feel low noise is critical, with 24-megapixel cameras hitting a sweet spot of noise vs. resolution.

However, if the higher resolution of the Z7 is important for your daytime photography needs, then I’m sure it will work well at night. The Nikon D850 DSLR, with a sensor similar to the Z7, has been proven by others to be a good astrophotography camera, albeit with higher noise than the lesser megapixel Nikons such as the D750 and Z6.

NOTE: Tap or click on images to download and display them full screen for closer inspection.


High ISO Noise

Comparison - Noise at 3 ISOs
The three 24-megapixel cameras compared at three high ISO levels in a close-up of a dark-sky nightscape.

To test noise in a real-world situation, I shot a dark nightscape scene with the three cameras, using a 24mm Sigma Art lens on the two Nikons, and a 24mm Canon lens on the Sony via a MetaBones adapter. I shot at ISOs from 800 to 12,800, typical of what we use in nightscapes and deep-sky images. 

The comparison set above shows performance at the higher ISOs of 3200 to 12,800. I saw very little difference among the trio, with the Nikon Z6 very similar to the Sony a7III, and with the four-year-old Nikon D750 holding up very well against the two new cameras. 

The comparison below shows the three cameras on another night and at ISO 3200.

Noise at 3200-3 Cameras
The three cameras compared for noise at properly exposed moonlit scenes at ISO 3200, a typical nightscape setting.

Both the Nikon Z6 and Sony a7III use a backside illuminated or “BSI” sensor, which in theory is promises to provide lower noise than a conventional CMOS sensor used in an older camera such as the D750. 

In practice I didn’t see a marked difference, certainly not as much as the one- or even 1/2-stop improvement in noise I might have expected or hoped for.

Nevertheless, the Nikon Z6 provides as low a noise level as you’ll find in a camera offering 24 megapixels, and will perform very well for all forms of astrophotography. 


ISO Invariance

Comparison - ISO Invariancy
The three cameras compared for ISO invariance at 0EV (well exposed) and -5EV (5 stops underexposed then brightened in processing).

Nikon and Sony both employ an “ISO-invariant” signal flow in their sensor design. You can purposely underexpose by shooting at a lower ISO, then boost the exposure later “in post” and end up with a result similar to an image shot at a high ISO to begin with in the camera. 

I find this feature proves its worth when shooting Milky Way nightscapes that often have well-exposed skies but dark foregrounds lit only by starlight. Boosting the brightness of the landscape when developing the raw files reveals details in the scene without unduly introducing noise, banding, or other artifacts such as magenta tints. 

That’s not true of “ISO variant” sensors, such as in most Canon cameras. Such sensors are far less tolerant of underexposure and are prone to noise, banding, and discolouration in the brightened shadows.

See my test of the Canon 6D MkII for its performance under the differing demands of nightscape photography and deep-sky imaging.

To test the Z6’s ISO invariance (as shown above) I shot a dark nightscape at ISO 3200 for a properly exposed scene, and also at ISO 100 for an image underexposed by a massive 5 stops. I then boosted that image by 5 stops in exposure in Adobe Camera Raw. That’s an extreme case to be sure. 

I found the Z6 provided very good ISO invariant performance, though with more chrominance specking than the Sony a7III and Nikon D750 at -5 EV.

Below is a less severe test, showing the Z6 properly exposed on a moonlit night and at 1 to 4 EV steps underexposed, then brightened in processing. Even the -4 EV image looks very good.

Comparison-ISO Invariancy in Moonlight
This series taken under moonlight shows that even images underexposed by -4 EV in ISO and boosted later by +4 EV in processing look similar for noise and image quality as an image properly exposed in the camera (at ISO 800 here).

In my testing, even with frames underexposed by -5 EV, I did not see any of the banding effects (due to the phase-detect auto-focus pixels) reported by others. 

As such, I judge the Z6 to be an excellent camera for nightscape shooting when we often want to extract detail in the shadows or dark foregrounds. 


Compressed vs. Uncompressed / Raw Large vs. Small 

Comparison - Z6 Large vs Medium RAW
Comparing Z6 images shot at full resolution and at Medium Raw size. to show resolution and noise differences.

The Z6, as do many Nikons, offers a choice of shooting 12-bit or 14-bit raws, and either compressed or uncompressed. 

I shot all my test images as 14-bit uncompressed raws, yielding 46 megabyte files with a resolution of 6048 x 4024 pixels. So I cannot comment on how good 12-bit compressed files are compared to what I shot. Astrophotography demands the best original data. 

Z6 Menu - Raw Formats

However, as the menu above shows, Nikon now also offers the option of shooting smaller raw sizes. The Medium Raw setting produces an image 4528 x 3016 pixels and a 18 megabyte file (in the files I shot), but with all the benefits of raw files in processing.

Nikon with Card Slot copy
The Z cameras use the XQD style memory cards and in a single card slot. The fast XQDs are ideal for recording 4K movies at high data rates but are more costly than the more common SD cards.

The Medium Raw option might be attractive when shooting time-lapses, where you might need to fit as many frames onto the single XQD card as possible, yet still have images large enough for final 4K movies. 

However, comparing a Large Raw to a Medium Raw did show a loss of resolution, as expected, with little gain in noise reduction. 

This is not like “binning pixels” in CCD cameras to increase signal-to-noise ratio. I prefer to never throw away information in the camera, to allow the option of creating the best quality still images from time-lapse frames later. 

Nevertheless, it’s nice to see Nikon now offer this option on new models, a feature which has long been on Canon cameras. 


Star Image Quality

Orion Nebula, M42 and M43, with Nikon Z6
The Orion Nebula with the Nikon Z6
The Orion Nebula in Moonlight
The Orion Nebula with the Nikon D750

Above is the Orion Nebula with the D750 and with the Z6, both shot in moonlight with the same 105mm refractor telescope.

I did not find any evidence for “star-eating” that Sony mirrorless cameras have been accused of. (However, I did not find the Sony a7III guilty of eating stars either.) Star images looked as good in the Z6 as in the D750. 

M42 Blow-up in ACR
A single Orion Nebula image with the Z6 in a 600% blow-up in Adobe Camera Raw, showing clean artifact-free star images with good, natural colours.

Raw developers (Adobe, DxO, ON1, and others) decoded the Z6’s Bayer-array NEF files fine, with no artifacts such as oddly-coloured or misshapen stars, which can arise in cameras lacking an anti-alias filter. 


LENR Dark frames 

Z6 Dark Frame- No LENR
A blank long exposure with no LENR applied – click or tap to open the image full screen
Z6 Dark Frame-With LENR
A blank long exposure with LENR – tap or click to open the image full screen

Above, 8-minute exposures of nothing, taken with the lens cap on at room temperature: without LENR, and with LENR, both boosted a lot in brightness and contrast to exaggerate the visibility of any thermal noise. These show the reduction in noise speckling with LENR activated, and the clean result with the Z6. At small size you’ll likely see nothing but black!

For deep-sky imaging a common practice is to shoot “dark frames,” images recording just the thermal noise that can then be subtracted from the image. 

The Long Exposure Noise Reduction feature offered by all cameras performs this dark frame subtraction internally and automatically by the camera for any exposures over one second long. 

I tested the Z6’s LENR and found it worked well, doing the job to effectively reduce thermal noise (hot pixels) without adding any other artifacts. 

Z6 iMenu Screen
The rear screen “i” menu as I had it customized for my testing, with functions for astrophotography such as LENR assigned to the 12 boxes.

NOTE:

Some astrophotographers dismiss LENR and never use it. By contrast, I prefer to use LENR to do dark frame subtraction. Why? Through many comparison tests over the years I have found that separate dark frames taken later at night rarely do as good a job as LENR darks, because those separate darks are taken when the sensor temperature, and therefore the noise levels, are different than they were for the “light” frames. 

I’ve found that dark frames taken later, then subtracted “in post” inevitably show less or little effect compared to images taken with LENR darks. Or worse, they add a myriad of pock-mark black specks to the image, adding noise and making the image look worse.

The benefit of LENR is lower noise. The penalty of LENR is that each image takes twice as long to shoot — the length of the exposure + the length of the dark frame. Because …


As Expected on the Z6 … There’s no LENR Dark Frame Buffer

Only Canon full-frame cameras offer this little known but wonderful feature for astrophotography. Turn on LENR and it is possible to shoot three (with the Canon 6D MkII) or four (with the Canon 6D) raw images in quick succession even with LENR turned on. The Canon 5D series also has this feature. 

The single dark frame kicks in and locks up the camera only after the series of “light frames” are taken. This is excellent for taking a set of noise-reduced deep-sky images for later stacking without need for further “image calibration.” 

No Nikon has this dark frame buffer, not even the “astronomical” D810a. And not the Z6.

ANOTHER NOTE: 

I have to mention this every time I describe Canon’s dark frame buffer: It works only on full-frame Canons, and there’s no menu function to activate it. Just turn on LENR, fire the shutter, and when the first exposure is complete fire the shutter again. Then again for a third, and perhaps a fourth exposure. Only then does the LENR dark frame lock up the camera as “Busy” and prevent more exposures. That single dark frame gets applied to each of the previous “light” frames, greatly reducing the time it takes to shoot a set of dark-frame subtracted images. 

But do note that Canon’s dark frame buffer will not work if…:

a) You leave Live View on. Don’t do that for any long exposure shooting.

b) You control the camera through the USB port via external software. It works only when controlling the camera via its internal intervalometer or via the shutter port using a hardware intervalometer.


Sensor Illumination 

M35 with Z6 & Traveler (4 Minutes)
A single 4-minute exposure of Messier 35 in moonlight at ISO 400 with the Z6 and 105mm apo refractor, with no flat fielding or lens correction applied, showing the clean edges and lack of amp glows. The darkening of the corners is inherent in the telescope optical system and is not from the camera.

With DSLRs deep-sky images shot through telescopes, then boosted for contrast in processing, usually exhibit a darkening along the bottom of the frame. This is caused by the upraised mirror shadowing the sensor slightly, an effect never noticed in normal photography. 

Mirrorless cameras should be free of this mirror box shadowing. The Sony a7III, however, still exhibits some edge shadows due to an odd metal mask in front of the sensor. It shouldn’t be there and its edge darkening is a pain to eliminate in the final processing. 

As I show in my review of the a7III, the Sony also exhibits a purple edge glow in long-exposure deep-sky images, from an internal light source. That’s a serious detriment to its use in deep-sky imaging.

Happily, the Z6 proved to be free of any such artifacts. Images are clean and evenly illuminated to the edges, as they should be. I saw no amp glows or other oddities that can show up under astrophotography use. The Z6 can produce superb deep-sky images. 


Red Sensitivity

M97 with Z6 & Traveler (4 Minutes)
Messer 97 planetary nebula and Messier 108 galaxy in a lightly processed single 4-minute exposure at ISO 1600 with the 105mm refractor, again showing a clean field. The glow at top right is from a Big Dipper star just off the edge of the field.

During my short test period, I was not able to shoot red nebulas under moonless conditions. So I can’t say how well the Z6 performs for recording H-alpha regions compared to other “stock” cameras. 

However, I would not expect it to be any better, nor worse, than the competitors. Indeed, the stock Nikon D750 I have does a decent job at picking up red nebulas, though nowhere near as well as Nikon’s sadly discontinued D180a. See my blog post from 2015 for an example shot with that camera. 

With the D810a gone, if it is deep red nebulosity you are after with a Nikon, then consider buying a filter-modified Z6 or having yours modified. 

Both LifePixel and Spencer’s Camera offer to modify the Z6 and Z7 models. However, I have not used either of their services, so cannot vouch for them first hand. 


Live View Focusing and Framing 

Z6 Live View Screen
An image of the back of the camera with a scene under moonlight, with the Z6 set to the highest ISO speed in the movie mode, to aid framing the scene at night.

For all astrophotography manually focusing with Live View is essential. And with mirrorless cameras there is no optical viewfinder to look through to frame scenes. You are dependent on the live electronic image (on the rear LCD screen or in the eye-level electronic viewfinder, or EVF) for seeing anything.

Thankfully, the Z6 presents a bright Live View image making it easy to frame, find, and focus on stars. Maximum zoom for precise focusing is 15x, good but not as good as the D750’s 20x zoom level, but better than Canon’s 10x maximum zoom in Live View. 

The Z6 lacks the a7III’s wonderful Bright Monitoring function that temporarily ups the ISO to an extreme level, making it much easier to frame a dark night scene. However, something similar can be achieved with the Z6 by switching it temporarily to Movie mode, and having the ISO set to an extreme level.

As with most Nikons (and unlike Sonys), the Z6 remembers separate settings for the still and movie modes, making it easy to switch back and forth, in this case for a temporarily brightened Live View image to aid framing. 

That’s very handy, and the Z6 works better than the D750 in this regard, providing a brighter Live View image, even with the D750’s well-hidden Exposure Preview option turned on. 


Video Capability 

Comparison - Movie Noise Levels
Comparing the three cameras using 1/25-second still frames grabbed from moonlit night movies (HD with the D750 and 4K with the Z6 and a7III) shot at ISO 51200, plus a similarly exposed frame from the a7III shot with a shutter speed of only 1/4 second allowing the slower ISO of 8000.

Where the Z6 pulls far ahead of the otherwise similar D750 is in its movie features.

The Z6 can shoot 4K video (3840 x 2160 pixels) at either 30, 25, or 24 frames per second. Using 24 frames per second and increasing the ISO to between 12,800 to 51,200 (the Z6 can go as high as ISO 204,800!) it is possible to shoot real-time video at night, such as of auroras.

But the auroras will have to be bright, as at 24 fps, the maximum shutter speed is 1/25-second, as you might expect. 

The a7III, by comparison, can shoot 4K movies at “dragged” shutter speeds as slow as 1/4 second, even at 24 fps, making it possible to shoot auroras at lower and less noisy ISO speeds, albeit with some image jerkiness due to the longer exposures per frame. 

The D750 shoots only 1080 HD and, as shown above, produces very noisy movies at ISO 25,600 to 51,200. It’s barely usable for aurora videos.

The Z6 is much cleaner than the D750 at those high ISOs, no doubt due to far better internal processing of the movie frames. However, if night-sky 4K videos are an important goal, a camera from the Sony a7 series will be a better choice, if only because of the option for slower dragged shutter speeds.

For examples of real-time auroras shot with the Sony a7III see my music videos shot in Yellowknife and in Norway. 


Battery Life

Nikon Z6 Battery copy

The Z6 uses the EN-EL15b battery compatible with the battery and charger used for the D750. But the “b” variant allows for in-camera charging via the USB port. 

In room temperature tests the Z6 lasted for 1500 exposures, as many as the D750 was able to take in a side-by-side test. That was with the screens off.

At night, in winter temperatures of -10 degrees C (14° F), the Z6 lasted for three hours worth of continuous shooting, both for long deep-sky exposure sets and for a test time-lapse I shot, shown below. 

A time-lapse movie, downsized here to HD from the full-size originals, shot with the Z6 and its internal intervalometer, from twilight through to moonrise on a winter night. Processed with Camera Raw and LRTimelapse. 

However, with any mirrorless camera, you can extend battery life by minimizing use of the LCD screen and eye-level EVF. The Z6 has a handy and dedicated button for shutting off those screens when they aren’t needed during a shoot.

The days of mirrorless cameras needing a handful of batteries just to get through a few hours of shooting are gone. 


Lens and Telescope Compatibility 

Nikon with Sigma and FTZ copy
A 14mm Sigma Art lens with the Nikon FTZ lens adapter needed to attach any “legacy” F-mount lens to the Z6.

As with all mirrorless cameras, the Nikon Z cameras use a new lens mount, one that is incompatible with the decades-old Nikon F mount. 

The Z mount is wider and can accommodate wider-angle and faster lenses than the old F mount ever could, and in a smaller package. While we have yet to see those lenses appear, in theory that’s the good news.

The bad news is that you’ll need Nikon’s FTZ lens adapter to use any of your existing Nikon F-mount lenses on either the Z6 or Z7. As of this writing, Nikon is supplying an FTZ free with every Z body purchase. 

I got an FTZ with my loaner Z6 and it worked very well, allowing even third-party lenses like my Sigma Art lenses to focus at the same point as they normally do (not true of some thIrd-party adapters), preserving the lens’s optical performance. Autofocus functions all worked fine and fast.

Nikon with Scope Adapter and FTZ copy
The FTZ adapter needed to attach the Z6 to a telescope camera adapter (equipped with a standard Nikon T-ring) and field flattener lens for a refractor.

You’ll also need the FTZ adapter for use on a telescope, as shown above, to go from your telescope’s camera adapter, with its existing Nikon T-ring, to the Z6 body. 

T-rings are becoming available for the Z-mount, but even these third-party adapters are actually extension tubes, not just rings.

The reason is that the field flattener or coma corrector lenses often required with telescopes are designed to work best with the longer lens-to-sensor distance of a DSLR body. The FTZ adapter provides the necessary spacing, as do third-party adapters. 

Nikon Z6 FTZ Foot copy
The FTZ lens adapter has its own tripod foot, useful for balancing front-heavy lenses like the big Sigma here.

The only drawback to the FTZ is that any tripod plate attached to the camera body itself likely has to come off, and the tripod foot incorporated into the FTZ used instead. I found myself often having to swap locations for the tripod plate, an inconvenience. 


Camera Controller Compatibility 

Nikon with Ports copy
The port side of the Z6, with the DC2 shutter remote jack at bottom, and HDMI and USB-C ports above. There’s also a mic and headphone jack for video use.

Since it uses the same Nikon-type DC2 shutter port as the D750, the Z6 it should be compatible with most remote hardware releases and time-lapse motion controllers that operate a Nikon through the shutter port. An example are the controllers from SYRP.

On the other hand, time-lapse devices and external intervalometers that run Nikons through the USB port might need to have their firmware or apps updated to work with the Z6.

For example, as of early May 2019, CamRanger lists the Z6 as a supported camera; the Arsenal “smart controller” does not. Nor does Alpine Labs for their Radian and Pulse controllers, nor TimeLapse+ for its excellent View bramping intervalometer. Check with your supplier.

For those who like to use laptops to run their camera at the telescope, I found the Windows program Astro Photography Tool (v3.63) worked fine with the Z6, in this case connecting to the camera’s USB-C port using the USB-C to USB-A cable that comes with the camera. This allows APT to shift not only shutter speed, but also ISO and aperture under scripted sequences. 

However, BackyardNikon v2.0, current as of April 2019, does not list the Z6 as a supported camera. 


Raw File Compatibility 

Z6 Raw open in Raw Therapee
A Z6 Raw NEF file open in Raw Therapee 5.6, showing good star images and de-Bayering.

Inevitably, raw files from brand new cameras cannot be read by any raw developer programs other than the one supplied by the manufacturer, Nikon Capture NX in this case. However, even by the time I did my testing in winter 2019 all the major software suppliers had updated their programs to open Z6 files. 

Adobe Lightroom and Photoshop, Affinity Photo, DxO PhotoLab, Luminar 3, ON1 PhotoRAW, and the open-source Raw Therapee all open the Z6’s NEF raw files just fine. 

Z6 Raw in PixInsight
PixInsight 1.8.6 failing to open a Z6 raw NEF file.

Specialized programs for processing astronomy images might be another story. For example, as of v1.08.06, PixInsight, a favourite program among astrophotographers, does not open Z6 raw files. Nor does Nebulosity v4. But check with the developers for updates. 


Other Features for Astrophotography 

Here are other Nikon Z6 features I found of value for astrophotography, and for operating the camera at night. 

Nikon with Looking Right copy

Tilting LCD Screen 

Like the Nikon D750 and Sony A7III, the Z6 offers a tilting LCD screen great for use on a telescope or tripod when aimed up at the sky. However, the screen does not flip out and reverse, a feature useful for vloggers, but seldom needed for astrophotography. 

Nikon Z6 Top Screen copy
Showing the top OLED screen and dedicated ISO button that is easy to access in the dark. It works in conjunction with the top dial.

OLED Top Screen (Above)

The Sony doesn’t have one, and Canon’s low-cost mirrorless Rp also lacks one. But the top-mounted OLED screen of the Z6 is a great convenience for astrophotography. It makes it possible to monitor camera status and battery life during a shoot, even with the rear LCD screen turned off to prolong battery life.

Z6 Menu - Quick Menu

Touch Screen 

Sony’s implementation of touch-screen functions is limited to just choosing autofocus points. By contrast, the Nikon Z6 offers a full range of touchscreen functions, making it easy to navigate menus and choose settings. 

I do wish there was an option, as there is with Pentax, to tint the menus red for preserving night vision.

Z6 Menu - Intervalometer

Built-in Intervalometer

As with other Nikons, the Z6 offers an internal intervalometer capable of shooting time-lapses, just as long as individual exposures don’t need to be longer than 30 seconds. 

In addition, there’s the Exposure Smoothing option which, as I have found with the D750, is great for smoothing flickering in time-lapses shot using auto exposure. 

Sony has only just added an intervalometer to the a7III with their v3 firmware update, but with no exposure smoothing. 

Z6 Menu - Silent Shooting

Custom i Menu / Custom Function Buttons 

The Sony a7III has four custom function buttons users can assign to commonly used commands, for quick access. For example, I assign one Custom button to the Bright Monitoring function which is otherwise utterly hidden in the menus, but superb for framing nightscapes, if only you know it’s there! 

The Nikon Z6 has two custom buttons beside the lens mount. However, I found it easier to use the “i” menu (shown above) by populating it with those functions I use at night for astrophotography. It’s then easy to call them up and adjust them on the touch screen.

Thankfully, the Z6’s dedicated ISO button is now on top of the camera, making it much easier to find at night than the awkwardly placed ISO button on the back of the D750, which I am always mistaking for the Image Quality button, which you do not want to adjust by mistake. 

Nikon Z6-My Menu

My Menu 

As most cameras do, the Z6 also has a “My Menu” page which you can also populate with favourite menu commands. 

Nikon D750 and Z6 copy
The D750 (left) compared to the smaller and lighter Z6 (right). This shows the wider Z lens mount compared to Nikon’s old F-mount standard.

Lighter Weight / Smaller Size

The Z6 provides similar imaging performance, if not better (for movies) than the D750, and in a smaller and lighter camera, weighing 200 grams (0.44 pounds) less than the D750. Being able to downsize my equipment mass is a welcome plus to going mirrorless.

Comparison - Z6 Mech vs Silent Shutter
Extreme 800% blow-ups of the Moon show a slightly sharper image with the Z6 set to Silent Shutter.

Electronic Front Curtain Shutter / Silent Shooting 

By design, mirrorless cameras lack any vibration from a bouncing mirror. But even the mechanical shutter can impart vibration and blurring to high-magnification images taken through telescopes. 

The electronic front curtain shutter (lacking in the D750) helps eliminate this, while the Silent Shooting mode does just that — it makes the Z6 utterly quiet and vibration free when shooting, as all the shutter functions are now electronic. This is great for lunar and planetary imaging. 


What’s Missing for Astrophotography (not much!)

Bulb Timer for Long Exposures

While the Z6 has a Bulb setting, there is no Bulb Timer as there is with Canon’s recent cameras. A Bulb Timer would allow setting long Bulb exposures of any length in the camera, though Canon’s cannot be combined with the intervalometer. 

Instead, the Nikon must be used with an external Intervalometer for any exposures over 30 seconds long. Any number of units are compatible with the Z6, through its shutter port which is the same type DC2 jack used in the D750.

Z6 Menu - Multiple Exposures

In-Camera Image Stacking to Raws

The Z6 does offer the ability to stack up to 10 images in the camera, a feature also offered by Canon and Pentax. Images can be blended with a Lighten (for star trails) or Average (for noise smoothing) mode. 

However, unlike with Canon and Pentax, the result is a compressed JPG not a raw file, making this feature of little value for serious imaging. Plus with a maximum of only 10 exposures of up to 30-seconds each, the ability to stack star trails “in camera” is limited. 

Illuminated Buttons 

Unlike the top-end D850, the Z6’s buttons are not illuminated, but then again neither are the Z7’s.


As a bonus — the Nikon 35mm S-Series Lens

Nikkor 35mm Lens Test
The upper left frame corner of a tracked star image shot with the 35mm S lens wide open at f/1.8 and stopped down at third stop increments.

With the Z6 I also received a Nikkor 35mm f/1.8 S lens made for the Z-mount, as the lens perhaps best suited for nightscape imaging out of the native Z-mount lenses from Nikon. See Nikon’s website for the listing. 

If there’s a downside to the Z-series Nikons it’s the limited number of native lenses that are available now from Nikon, and likely in the future from anyone, due to Nikon not making it easy for other lens companies to design for the new Z mount. 

In testing the 35mm Nikkor on tracked shots, stars showed excellent on- and off-axis image quality, even wide open at f/1.8. Coma, astigmatism, spherical aberration, and lateral chromatic aberration were all well controlled. 

However, as with most lenses now offered for mirrorless cameras, the focus is “by-wire” using a ring that doesn’t mechanically adjust the focus. As a result, the focus ring turns continuously and lacks a focus scale. 

So it is not possible to manually preset the lens to an infinity mark, as nightscape photographers often like to do. Focusing must be done each night. 

Until there is a greater selection of native lenses for the Z cameras, astrophotographers will need to use the FTZ adapter and their existing Nikon F-mount or third-party Nikon-mount lenses with the Zs.


Recommendations 

I was impressed with the Z6. 

The Owl Nebula and Messier 108 Galaxy
The Owl Nebula, Messier 97, a planetary nebula in our galaxy, and the edge-on spiral galaxy Messier 108, paired below the Bowl of the Big Dipper in Ursa Major. This is a stack of 5 x 4-minute exposures at ISO 1600 with the Nikon Z6 taken as part of testing. This was through the Astro-Physics Traveler refractor at f/6 with the Hotech field flattener and FTZ adapter.

For any owner of a Nikon cropped-frame DSLR (from the 3000, 5000, or 7000 series for example) wanting to upgrade to full-frame for astrophotography I would suggest moving to the Z6 over choosing a current DSLR. 

Mirrorless is the way of the future. And the Z6 will yield lower noise than most, if not all, of Nikon’s cropped-frame cameras.

Nikkor 35mm S Lens copy
The Z6 with the Nikkor 35mm f/1.8 S lens native for the Z mount.

For owners of current Nikon DSLRs, especially a 24-megapixel camera such as the D750, moving to a Z6 will not provide a significant improvement in image quality for still images. 

But … it will provide 4K video and much better low-light video performance than older DSLRs. So if it is aurora videos you are after, the Z6 will work well, though not quite as well as a Sony alpha. 

In all, there’s little downside to the Z6 for astrophotography, and some significant advantages: low noise, bright live view, clean artifact-free sensor images, touchscreen convenience, silent shooting, low-light 4K video, all in a lighter weight body than most full-frame DSLRs. 

I highly recommend the Nikon Z6. 

— Alan, April 30, 2019 / © 2019 Alan Dyer / AmazingSky.com 

 

 

Testing the Venus Optics 15mm Lens


Laowa Test Title

I test out a fast and very wide lens designed specifically for Sony mirrorless cameras. 

In a previous test I presented results on how well the Sony a7III mirrorless camera performs for nightscape and deep-sky photography. It works very well indeed.

But what about lenses for the Sony? Here’s one ideal for astrophotography.


TL;DR Conclusions

Made for Sony e-mount cameras, the Venus Optics 15mm f/2 Laowa provides excellent on- and off-axis performance in a fast and compact lens ideal for nightscape, time-lapse, and wide-field tracked astrophotography with Sony mirrorless cameras. (UPDATE: Venus Optics has announced versions of this lens for Canon R and Nikon Z mount mirrorless cameras.)

I use it a lot and highly recommend it.


Size and Weight

While I often use the a7III with my Canon lenses by way of a Metabones adapter, the Sony really comes into its own when matched to a “native” lens made for the Sony e-mount. The selection of fast, wide lenses from Sony itself is limited, with the new Sony 24mm G-Master a popular favourite (I have yet to try it).

However, for much of my nightscape shooting, and certainly for auroras, I prefer lenses even wider than 24mm, and the faster the better.

Auroral Swirls over Båtsfjord, Norway Aurora over Båtsfjord, Norway. This is a single 0.8-second exposure at f/2 with the 15mm Venus Optics lens and Sony a7III at ISO 1600.

The Laowa 15mm f/2 from Venus Optics fills the bill very nicely, providing excellent speed in a compact lens. While wide, the Laowa is a rectilinear lens providing straight horizons even when aimed up, as shown above. This is not a fish-eye lens.

Laowa 15mm Front View with Filter Though a very wide lens, the 15mm Laowa accepts standard 72mm filters. The metal lens hood is removable. © 2019 Alan Dyer

The Venus Optics 15mm realizes the potential of mirrorless cameras and their short flange distance that allows the design of fast, wide lenses without massive bulk.

Sigma 14mm vs Laowa 15mm Sigma 14mm f/1.8 Art lens (for Nikon mount) vs. Venus Optics 15mm f/2 lens (for Sony mount). © 2019 Alan Dyer

While compact, at 600 grams the Laowa 15mm is quite hefty for its size due to its solid metal construction. Nevertheless, it is half the weight of the massive 1250-gram Sigma 14mm f/1.8 Art. The Laowa is not a plastic entry-level lens, nor is it cheap, at $850 from U.S. sources.

For me, the Sony-Laowa combination is my first choice for a lightweight travel camera for overseas aurora trips

Laowa 15mm Back View The lens mount showing no electrical contacts to transfer lens metadata to the camera. © 2019 Alan Dyer

However, this is a no-frills manual focus lens. Nor does it even transfer aperture data to the camera, which is a pity. There are no electrical connections between the lens and camera.

However, for nightscape work where all settings are adjusted manually, the Venus Optics 15mm works just fine. The key factor is how good are the optics. I’m happy to report that they are very good indeed.


Testing Under the Stars

To test the Venus Optics lens I shot “same night” images, all tracked, with the Sigma 14mm f/1.8 Art lens, at left, and the Rokinon 14mm SP (labeled as being f/2.4, at right). Both are much larger lenses, made for DSLRs, with bulbous front elements not able to accept filters. But they are both superb lenses. See my test report on these lenses published in 2018.

Sigma and Rokinon 14mm The Sigma 14mm f/1.8 Art lens (left) vs. the Rokinon SP 14mm f/2.4. © 2019 Alan Dyer

The next images show blow-ups of the same scene (the nightscape shown in full below, taken at Dinosaur Provincial Park, Alberta), and all taken on a tracker.

I used the Rokinon on the Sony a7III using the Metabones adapter which, unlike some brands of lens adapters, does not compromise the optical quality of the lens by shifting its focal position. But lacking a lens adapter for Nikon-to-Sony at the time of testing, I used the Nikon-mount Sigma lens on a Nikon D750, a DSLR camera with nearly identical sensor specs to the Sony.


Vignetting

Laowa 15mm @ f2 A tracked image with the Venus Optics Laowa 15mm at f/2. Click or tap on an image to download a full-resolution JPG for closer inspection.

Above is a tracked image (so the stars are not trailed, which would make it hard to tell aberrations from trails), taken wide open at f/2. No lens correction has been applied so the vignetting (the darkening of the frame corners) is as the lens provides.

As shown above, when used wide open at f/2 vignetting is significant, but not much more so than with competitive lenses with much larger lenses, as I compare below.

And the vignetting is correctable in processing. Adobe Camera Raw and Lightroom have this lens in their lens profile database. That’s not the case with current versions (as of April 2019) of other raw developers such as DxO PhotoLab, ON1 Photo RAW, and Raw Therapee where vignetting corrections have to be dialled in manually by eye.

Laowa 15mm @ f2.8 A tracked image with the Venus Optics Laowa 15mm stopped down 1 stop to f/2.8.

When stopped down to f/2.8 the Laowa “flattens” out a lot for vignetting and uniformity of frame illumination. Corner aberrations also improve but are still present. I show those in close-up detail below.

Lens Comparison - Vignetting 15mm Laowa vs. Rokinon 14mm SP vs. Sigma Art 14mm – Comparing the left side of the image for vignetting (light fall-off), wide open and stopped down. ©2018 Alan Dyer

Above, I compare the vignetting of the three lenses, both wide open and when stopped down. Wide open, all the lenses, even the Sigma and Rokinon despite their large front elements, show quite a bit of drop off in illumination at the corners.

The Rokinon SP actually seems to be the worst of the trio, showing some residual vignetting even at f/2.8, while it is reduced significantly in the Laowa and Sigma lenses. Oddly, the Rokinon SP, even though it is labeled as f/2.4, seemed to open to f/2.2, at least as indicated by the aperture metadata.


On-Axis Performance

Lens Comparison - Centre 15mm Laowa vs. Rokinon 14mm SP vs. Sigma Art 14mm – Comparing the centre of the image for sharpness, wide open and stopped down. Click or tap on an image to download a full-resolution JPG for closer inspection. © 2018 Alan Dyer

Above I show lens sharpness on-axis, both wide open and stopped down, to check for spherical and chromatic aberrations with the bright blue star Vega centered. The red box in the Navigator window at top right indicates what portion of the frame I am showing, at 200% magnification in Photoshop.

On-axis, the Venus Optics 15mm shows stars just as sharply as the premium Sigma and Rokinon lenses, with no sign of blurring spherical aberration nor coloured haloes from chromatic aberration.

Laowa 15mm Side with Focus Point This is where this lens reaches sharpest focus on stars, just shy of the Infinity mark. © 2019 Alan Dyer

Focusing is precise and easy to achieve with the Sony on Live View. My unit reaches sharpest focus on stars with the lens set just shy of the middle of the infinity symbol. This  is consistent and allows me to preset focus just by dialing the focus ring, handy for shooting auroras at -35° C, when I prefer to minimize fussing with camera settings, thank you very much!


Off-Axis Performance

Lens Comparison - Upper Left 15mm Laowa vs. Rokinon 14mm SP vs. Sigma Art 14mm – Comparing the centre of the image for sharpness, wide open and stopped down. Click or tap on an image to download a full-resolution JPG for closer inspection. © 2018 Alan Dyer
Lens Comparison - Upper Right 15mm Laowa vs. Rokinon 14mm SP vs. Sigma Art 14mm – Comparing the upper right corner of the image for aberrations, wide open and stopped down. © 2018 Alan Dyer

The Laowa and Sigma lenses show similar levels of off-axis coma and astigmatism, with the Laowa exhibiting slightly more lateral chromatic aberration than the Sigma. Both improve a lot when stopped down one stop, but aberrations are still present though to a lesser degree.

However, I find that the Laowa 15mm performs as well as the Sigma 14mm Art for star quality on- and off-axis. And that’s a high standard to match.

The Rokinon SP is the worst of the trio, showing significant elongation of off-axis star images (they look like lines aimed at the frame centre), likely due to astigmatism. With the 14mm SP, this aberration was still present at f/2.8, and was worse at the upper right corner than at the upper left corner, an indication to me that even the premium Rokinon SP lens exhibits slight lens de-centering, an issue users have often found with other Rokinon lenses.


Real-World Examples – The Milky Way

Sweep of the Autumn Milky Way This is a stack of 8 x 2-minute exposures with the Venus Optics Laowa 15mm lens at f/2 and Sony a7III at ISO 800, on the Sky-Watcher Star Adventurer tracker. A single exposure taken through the Kenko Softon A filter layered in with Lighten mode adds the star glows, though exaggerates the lens distortion on the bright stars.
Mars and the Milky Way over Writing-on-Stone This is a stack of 12 exposures for the ground, mean combined to smooth noise, and one exposure for the sky, all 30 seconds at f/2 with the Laowa 15mm lens on the Sony a7III camera at ISO 6400. These were the last frames in a 340-frame time-lapse sequence.

The fast speed of the Laowa 15mm is ideal for shooting tracked wide-field images of the Milky Way, and untracked camera-on-tripod nightscapes and time-lapses of the Milky Way.

Image aberrations are very acceptable at f/2, a speed that allows shutter speed and ISO to be kept lower for minimal star trailing and noise while ensuring a well-exposed frame.


Real World Examples – Auroras

Coloured Curtains over CNSC (Feb 9, 2019) Aurora over the Churchill Northern Studies Centre, Churchill, Manitoba. This is 6 seconds at f/2 with the 15mm Venus Optic lens and Sony a7III at ISO 3200.
Sky-Filling Aurora at Tibbitt Lake Aurora from near Yellowknife, NWT, September 8, 2018. This is 2.5-seconds at f/2 with the Venus Optics 15mm lens and Sony a7IIII at ISO 3200.
Aurora from at Sea Near Lofotens #1 The Northern Lights from at sea when leaving the Lofoten Islands, Norway heading toward the mainlaind, from Stamsund to Bodo, March 3, 2019. This was from the Hurtigruten ship the ms Trollfjord. This is a single 1-second exposure for at f/2 with the 15mm Venus Optics lens and Sony a7III at ISO 6400.

Where the Laowa 15mm really shines is for auroras. On my trips to chase the Northern Lights I often take nothing but the Sony-Laowa pair, to keep weight and size down.

Above is an example, taken from a moving ship off the coast of Norway. The fast f/2 speed (I wish it were even faster!) makes it possible to capture the Lights in only 1- or 2-second exposures, albeit at ISO 6400. But the fast shutter speed is needed for minimizing ship movement.


Video Links

The Sony also excels at real-time 4K video, able to shoot at ISO 12,800 to 51,200 without excessive noise.

Aurora Reflections from Alan Dyer on Vimeo.

The Sky is Dancing from Alan Dyer on Vimeo.

The Northern Lights At Sea from Alan Dyer on Vimeo.

Examples of my aurora videos shot with the Sony and Venus Optics 15mm lens are in previous blogs from Yellowknife, NWT in September 2018, from Churchill, Manitoba in February 2019, and from at sea in Norway in March 2019.

Click through to see the posts and the videos shot with the Venus Optics 15mm.

As an aid to video use, the aperture ring of the Venus Optics 15mm can be “de-clicked” at the flick of a switch, allowing users to smoothly adjust the iris during shooting, avoiding audible clicks and jumps in brightness. That’s a very nice feature indeed.

In all, I can recommend the Venus Optics Laowa 15mm lens as a great match to Sony mirrorless cameras, for nightscape still and video shooting. UPDATE: Versions for Canon R and Nikon Z mount mirrorless cameras will now be available.

— Alan, April 20, 2019 / © 2019 Alan Dyer / AmazingSky.com

Testing ON1 Photo RAW for Astrophotography


ON1 Testing Title

Can the new version of ON1 Photo RAW match Photoshop for astrophotography? 

The short TL;DR answer: No.

But … as always, it depends. So do read on.


Released in mid-November 2018, the latest version of ON1 Photo RAW greatly improves a non-destructive workflow. Combining Browsing, Cataloging, Raw Developing, with newly improved Layers capabilities, ON1 is out to compete with Adobe’s Creative Cloud photo suite – Lightroom, Camera Raw, Bridge, and Photoshop – for those looking for a non-subscription alternative.

Many reviewers love the new ON1 – for “normal” photography.

But can it replace Adobe for night sky photos? I put ON1 Photo RAW 2019 through its paces for the demanding tasks of processing nightscapes, time-lapses, and deep-sky astrophotos.


The Conclusions

In my eBook “How to Photograph and Process Nightscapes and Time-Lapses” (linked to at right) I present dozens of processing tutorials, including several on how to use ON1 Photo RAW, but the 2018 edition. I was critical of many aspects of the old version, primarily of its destructive workflow when going from its Develop and Effects modules to the limited Layers module of the 2018 edition.

I’m glad to see many of the shortfalls have been addressed, with the 2019 edition offering a much better workflow allowing layering of raw images while maintaining access to all the original raw settings and adjustments. You no longer have to flatten and commit to image settings to layer them for composites. When working with Layers you are no longer locked out of key functions such as cropping.

I won’t detail all the changes to ON1 2019 but they are significant and welcome.

The question I had was: Are they enough for high-quality astrophotos in a non-destructive workflow, Adobe Photoshop’s forté.

While ON1 Photo RAW 2019 is much better, I concluded it still isn’t a full replacement of Adobe’s Creative Cloud suite, as least not for astrophotography.

NOTE: All images can be downloaded as high-res versions for closer inspection. 


ON1 2019 is Better, But for Astrophotography …

  1. Functions in Layers are still limited. For example, there is no stacking and averaging for noise smoothing. Affinity Photo has those.
  2. Filters, though abundant for artistic special effect “looks,” are limited in basic but essential functions. There is no Median filter, for one.
  3. Despite a proliferation of contrast controls, for deep-sky images (nebulas and galaxies) I was still not able to achieve the quality of images I’ve been used to with Photoshop.
  4. The lack of support for third-party plug-ins means ON1 cannot work with essential time-lapse programs such as Timelapse Workflow or LRTimelapse.
ON1 Final Composite
A finished nightscape composite, with stacked exposures for the ground and stacked and tracked exposures for the sky, layered and blended in ON1.

Recommendations

Nightscapes: ON1 Photo RAW 2019 works acceptably well for nightscape still images:

  1. Its improved layering and excellent masking functions are great for blending separate ground and sky images, or for applying masked adjustments to selected areas.

Time-Lapses: ON1 works is just adequate for basic time-lapse processing:

  1. Yes, you can develop one image and apply its settings to hundreds of images in a set, then export them for assembly into a movie. But there is no way to vary those settings over time, as you can by mating Lightroom to LRTimelapse.
  2. As with the 2018 edition, you still cannot copy and paste masked local adjustments from image to image, limiting their use.
  3. Exporting those images is slow.

Deep-Sky: ON1 is not a program I can recommend for deep-sky image processing:

  1. Stars inevitably end up with unsightly sharpening haloes.
  2. De-Bayering artifacts add blocky textures to the sky background.
  3. And all the contrast controls still don’t provide the “snap” and quality I’m used to with Photoshop when working with low-contrast subjects.

Library / Browse Functions

ON1 Browse Module
ON1 cannot catalog or display movie files or Photoshop’s PSB files (but then again with PSBs neither can Lightroom!).

ON1 is sold first and foremost as a replacement for Adobe Lightroom, and to that extent it can work well. Unlike Lightroom, ON1 allows browsing and working on images without having to import them formally into a catalog.

However, you can create a catalog if you wish, one that can be viewed even if the original images are not “on-line.” The mystery seems to be where ON1 puts its catalog file on your hard drive. I was not able to find it, to manually back it up. Other programs, such as Lightroom and Capture One, locate their catalogs out in the open in the Pictures folder.

For those really wanting a divorce from Adobe, ON1 now offers an intelligent AI-based function for importing Lightroom catalogs and transferring all your Lightroom settings you’ve applied to raw files to ON1’s equivalent controls.

However, while ON1 can read Photoshop PSD files, it will flatten them, so you would lose access to all the original image layers.

ON1’s Browse module is good, with many of the same functions as Lightroom, such as “smart collections.” Affinity Photo – perhaps ON1’s closest competitor as a Photoshop replacement – still lacks anything like it.

But I found ON1’s Browse module buggy, often taking a long while to allow access into a folder, presumably while it is rendering image previews.

There are no plug-ins or extensions for exporting directly to or synching to social media and photo sharing sites.


Nightscape Processing – Developing Raw Images

ON1 Before and After Processing
On the left, a raw image as it came out of the camera. On the right, after developing (with Develop and Effects module settings applied) in ON1.

For this test I used the same nightscape image I threw at Adobe competitors a year ago, in a test of a dozen or more raw developers. It is a 2-minute tracked exposure with a Sigma 20mm Art lens at f/2 and Nikon D750 at ISO 1600.

ON1 did a fairly good job. Some of its special effect filters, such a Dynamic Contrast, Glow, and Sunshine, can help bring out the Milky Way, though do add an artistic “look” to an image which you might or might not like.

Below, I compare Adobe Camera Raw (ACR) to ON1. It was tough to get ON1’s image looking the same as ACR’s result, but then again, perhaps that’s not the point. Does it just look good? Yes, it does.

ON1 & ACR Raw Image Comparison
On the left, a single raw image developed with Adobe Camera Raw. On the right, the same image with ON1 and its basic Develop and more advanced Effects settings.

Compared to Adobe Camera Raw, which has a good array of basic settings, ON1 has most of those and more, in the form of many special Effects, with many combined as one-click Presets, as shown below.

ON1 Presets
ON1 offers a huge array of Presets that apply combinations of its filters with one click from the Browse module.

A few presets and individual filters – the aforementioned Dynamic Contrast and Glow – are valuable. However, most of ON1’s filters and presets will not be useful for astrophotography, unless you are after highly artistic and unnatural effects.

Noise Reduction and Lens Correction

ON1 Noise Reduction
On the left, an image in ON1 without any Noise Reduction. On the right, with noise reduction and sharpening (under Details) applied with the settings shown.

Critical to all astrophotography is excellent noise reduction. ON1 does a fine job here, with good smoothing of noise without harming details.

Lens Correction works OK. It detected the 20mm Sigma art lens and automatically applied distortion correction, but not any vignetting (light “fall-off”) correction, perhaps the most important correction in nightscape work. You have to dial this in manually by eye, a major deficiency.

By comparison, ACR applies both distortion and vignetting correction automatically. It also includes settings for many manual lenses that you can select and apply in a click. For example, ACR (and Lightroom) includes settings for popular Rokinon and Venus Optics manual lenses; ON1 does not.

Hot Pixel Removal

Hot Pixel Removal Comparison
On the left, ACR with noise reduction applied (it offers no user-selectable Hot Pixel Removal tool). In the middle, ON1 with Remove Hot Pixels turned on; on the right, with it turned off – showing more hot pixels than ACR does.

I shot the example image on a warm summer night and without using in-camera Long Exposure Noise Reduction (to keep the gap between exposures short when shooting sets of tracked and untracked exposures for later compositing).

However, the penalty for not using LENR to expedite the image taking is a ground filled with hot pixels. While Adobe Camera Raw does have some level of hot pixel removal working “under the hood,” many specks remained.

ON1 showed more hot pixels, until you clicked Remove Hot Pixels, found under Details. As shown at centre above, it did a decent job getting rid of the worst offenders.

But as I’ll show later, the penalty is that stars now look distorted and sometimes double, or you get the outright removal of stars. ON1 doesn’t do a good job distinguishing between true sharp-edged hot pixels and the softer images of stars. Indeed, it tends to over sharpen stars.

A competitor, Capture One 11, does a better job, with an adjustable Single Pixel removal slider, so you can at least select the level of star loss you are willing to tolerate to get rid of hot pixels.

Star Image Quality

ON1 & ACR Star Image Comparison
On the left, a 700% blow-up of the stars in Adobe Camera Raw. On the right, the same image processed in ON1 and exported out as a PSD.

Yes, we are pixel peeping here, but that’s what we do in astrophotography. A lot!

Stars in ON1 don’t look as good as in Camera Raw. Inevitably, as you add contrast enhancements, stars in ON1 start to exhibit dark and unsightly “sharpening haloes” not present in ACR, despite me applying similar levels of sharpening and contrast boosts to each version of the image.

Camera Raw has been accused of producing images that are not as sharp as with other programs such as Capture One and ON1.

There’s a reason. Other programs over-sharpen, and it shows here.

We can get away with it here in wide-field images, but not later with deep-sky close-ups. I don’t like it. And it is unavoidable. The haloes are there, albeit at a low level, even with no sharpening or contrast enhancements applied, and no matter what image profile is selected (I used ON1 Standard throughout).

De-Bayering Artifacts

ON1-Debayer
ON1, with contrast boosts applied but with no sharpening or noise reduction, shows star haloes, while the sky shows a blocky pattern at the pixel level in high ISO shots.
ACR-Debayer
Adobe Camera Raw, with similar settings but also no sharpening or noise reduction, shows a smooth and uniform sky background.

You might have to download and closely inspect these images to see the effect, but ON1’s de-Bayering routine exhibits a cross-hatched blocky pattern at the pixel-peeping level. ACR does not.

I see this same effect with some other raw developers. For example, the free Raw Therapee shows it with many of its choices for de-Bayering algorithms, but not all. Of the more than a dozen raw developers I tested a year ago, ACR and DxO PhotoLab had (and still have) the most artifact-free de-Bayering and smoothest noise reduction

Again, we can get away with some pixel-level artifacts here, but not later, in deep-sky processing.


Nightscape Processing — Layering and Compositing

ON1 Perfect Brush
ON1’s adjustable “Perfect Brush” option for precise masking around edges and objects isn’t quite as effective as Photoshop’s Quick Selection Tool.

Compositing

The 2018 version of ON1 forced you to destructively flatten images when bringing them into the Layers module.

The 2019 version of ON1 improves that. It is now possible to composite several raw files into one image and still retain all the original Develop and Effects settings for non-destructive work.

You can then use a range of masking tools to mask in or out the sky.

For the example above, I have stacked tracked and untracked exposures, and am starting to mask out the trailed stars from the untracked exposure layer.

To do this with Adobe, you would have to open the developed raw files in Photoshop (ideally using “smart objects” to retain the link back to the raw files). But with ON1 we stay within the same program, to retain access to non-destructive settings. Very nice!

To add masks, ON1 2019 does not have the equivalent of Photoshop’s excellent Quick Selection Tool for selecting the sky or ground. It does have a “Perfect Brush” option which uses the tonal value of the pixels below it, rather than detecting edges, to avoid “painting over the lines.”

While the Perfect Brush does a decent job, it still requires a lot of hand painting to create an accurate mask without holes and defects. There is no non-destructive “Select and Mask” refinement option as in Photoshop.

Yes, ON1’s Refine Brush and Chisel Mask tools can help clean up a mask edge but are destructive to the mask. That’s not acceptable to my non-destructive mindset!

Local Adjustments 

ON1 Masking Adjustments
Local Adjustments can be painted in or out with classic and easy-to-adjust and view masks and layers, rather than adjustment pins used by many raw developers such as ACR.

The masking tools are also applicable to adding “Local Adjustments” to any image layer, to brighten or darken regions of an image for example.

These work well and I find them more intuitive than the “pins” ACR uses on raw files, or DxO PhotoLab’s quirky “U-Point” interface.

ON1’s Local Adjustments work more like Photoshop’s Adjustment Layers and are similarly non-destructive. Excellent.

Luminosity Masks

ON1 Luminosity Masking
ON1 has one-click Luminosity masking, an excellent feature.

A very powerful feature of ON1 is its built-in Luminosity masking.

Yes, Camera Raw now has Range Masks, and Photoshop can be used to create luminosity masks, but making Photoshop’s luminosity masks easily adjustable requires purchasing third-party extension panels.

ON1 can create an adjustable and non-destructive luminosity mask on any image or adjustment layer with a click.

While such masks, based on the brightness of areas, aren’t so useful for low-contrast images like the Milky Way scene above, they can be very powerful for merging high-contrast images (though ON1 also has an HDR function not tested here).

Glow Effect
ON1’s handy Orton-style Glow effect, here with a Luminosity mask applied. The mask can be adjusted with the Levels and Window sliders, and applied to a range of colors as well.

ON1 has the advantage here. Its Luminosity masks are a great feature for compositing exposures or for working on regions of bright and dark in an image.

Final Composite

ON1 Final Composite
A finished nightscape composite, with stacked exposures for the ground and stacked and tracked exposures for the sky, layered and blended in ON1.

Here again is the final result, above.

It is not just one image each for the sky and ground, but is instead a stack of four images for each half of the composite, to smooth noise. This form of stacking is somewhat unique to astrophotography, and is commonly used to reduce noise in nightscapes and in deep-sky images, as shown later.

Stacking

ON1-Layer Opacities
This shows an intermediate step in creating the final composite shown above: Four sky layers are stacked, with opacities as shown, which has the effect of smoothing noise. But to continue working on the image requires making a single “New Stamped Layer” out of the group of four – in this case, the sky layers. The same can be done for the four ground layers.

Here I show how you have to stack images in ON1.

Unlike Photoshop and Affinity Photo, ON1 does not have the ability to merge images automatically into a stack and apply a mathematical averaging to the stack, usually a Mean or Median stack mode. The averaging of the image content is what reduces the random noise.

Instead, with ON1 you have perform an “old school” method of average stacking – by changing the opacity of the layers, so that Layer 2 = 50%, Layer 3 = 33%, Layer 4 = 25%, and so on. The result is identical to performing a Mean stack mode in Photoshop or Affinity.

Fine, except there is no way to perform a Median stack, which can be helpful for eliminating odd elements present in only one frame, perhaps an aircraft trail.

Copy and Paste Settings

ON1 Pasting Settings
ON1 allows easy copying and pasting of settings from one raw image to others, with the annoying exception of Local Adjustments and their masks.

Before we even get to the stacking stage, we have to develop and process all the images in a set. Unlike Lightroom or Camera Raw, ON1 can’t develop and synchronize settings to a set of images at once. You can work on only one image at a time.

So, you work on one image (one of the sky images here), then Copy and Paste its settings to the other images in the set. I show the Paste dialog box here.

This works OK, though I did find some bugs – the masks for some global Effects layers did not copy properly; they copied inverted, as black instead of white masks.

However, Luminosity masks did copy from image to image, which is surprising considering the next point.

The greater limitation is that no Local Adjustments (ones with masks to paint in a correction to a selected area) copy from one image to another … except ones with gradient masks. Why the restriction?

So as wonderful as ON1’s masking tools might be, they aren’t of any use if you want to copy their masked adjustments across several images, or, as shown next, to a large time-lapse set.

While Camera Raw’s and Lightroom’s Local Adjustment pins are more awkward to work with, they do copy across as many images as you like.


Time-Lapse Processing

ON1 Copy & Paste
ON1 does allow developing one image in a set, then copying and pasting its settings to perhaps hundreds of other images in a time-lapse set.

A few Adobe competitors, such as Affinity Photo (as of this writing) simply can’t do this.

By comparison, with the exception of Local Adjustments, ON1 does have good functions for Copying and Pasting Settings. These are essential for processing a set of hundreds of time-lapse frames.

ON1 Export
This is ON1’s Export dialog box, set up here to export the developed raw files into another “intermediate” set of 4K-sized JPGs for movie assembly.

Once all the images are processed – whether it be with ON1 or any other program – the frames have to exported out to an intermediate set of JPGs for assembly into a movie by third-party software. ON1 itself can’t assemble movies, but then again neither can Lightroom (as least not very well), though Photoshop can, through its video editing functions.

For my test set of 220 frames, each with several masked Effects layers, ON1 took 2 hours and 40 minutes to perform the export to 4K JPGs. Photoshop, through its Image Processor utility, took 1 hour and 30 minutes to export the same set, developed similarly and with several local adjustment pins.

ON1 did the job but was slow.

A greater limitation is that, unlike Lightroom, ON1 does not accept any third party plug-ins (it serves as a plug-in for other programs). That means ON1 is not compatible with what I feel are essential programs for advanced time-lapse processing: either Timelapse Workflow (from https://www.timelapseworkflow.com) or the industry-standard LRTimelapse (from https://lrtimelapse.com).

Both programs work with Lightroom to perform incremental adjustments to settings over a set of images, based on the settings of several keyframes.

Lacking the ability to work with these programs means ON1 is not a program for serious and professional time-lapse processing.


Deep-Sky Processing

ON1-Tracked Milky Way
A tracked 2-minute exposure of the Cygnus Milky Way, with a Sony a7III camera at ISO 800 and Venus Optics Laowa 15mm lens at f/2, developed in ON1.
ACR-Tracked Milky Way
The same Milky Way image developed in Adobe Camera Raw. It looks better!

Wide-Angle Milky Way

Now we come to the most demanding task: processing long exposures of the deep-sky, such as wide-angle Milky Way shots and close-ups of nebulas and galaxies taken through telescopes. All require applying generous levels of contrast enhancement.

As the above example shows, try as I might, I could not get my test image of the Milky Way to look as good with ON1 as it did with Adobe Camera Raw. Despite the many ways to increase contrast in ON1 (Contrast, Midtones, Curves, Structure, Haze, Dynamic Contrast and more!), the result still looked flat and with more prominent sky gradients than with ACR.

And remember, with ACR that’s just the start of a processing workflow. You can then take the developed raw file into Photoshop for even more precise work.

With ON1, its effects and filters all you have to work with. Yes, that simplifies the workflow, but its choices are more limited than with Photoshop, despite ON1’s huge number of Presets.

Deep-Sky Close-Ups

ON1 Processed M31
The Andromeda Galaxy, in a stack of six tracked and auto-guided 8-minute exposures with a stock Canon 6D MkII through an 80mm f/6 refractor.
Photoshop Processed M31
The same set of six exposures, stacked and processed with ACR and Photoshop, with multiple masked adjustment layers as at right. The result looks better.

Similarly, taking a popular deep-sky subject, the Andromeda Galaxy, aka M31, and processing the same original images with ON1 and ACR/Photoshop resulted in what I think is a better-looking result with Photoshop.

Of course, it’s possible to change the look of such highly processed images with the application of various Curves and masked adjustment layers. And I’m more expert with Photoshop than with ON1.

But … as with the Cygnus Milky Way image, I just couldn’t get Andromeda looking as good in ON1. It always looked a little flat.

Dynamic Contrast did help snap up the galaxy’s dark lanes, but at the cost of “crunchy” stars, as I show next. A luminosity “star mask” might help protect the stars, but I think the background sky will inevitably suffer from the de-Bayering artifacts.

Star and Background Sky Image Quality

ON1 Processed M31-Close-Up
A 400% close-up of the final Andromeda Galaxy image. It shows haloed stars and a textured and noisy sky background.
Photoshop Processed M31-Close-Up
The same area blown up 400% of the Photoshop version of the Andromeda Galaxy image. Stars and sky look smoother and more natural.

As I showed with the nightscape image, stars in ON1 end up looking too “crunchy,” with dark halos from over sharpening, and also with the blocky de-Bayering artifacts now showing up in the sky.

I feel it is not possible to avoid dark star haloes, as any application of contrast enhancements, so essential for these types of objects, brings them out, even if you back off sharpening at the raw development stage, or apply star masks.

ON1 Processed M31-With & Without
On the left, the image before any processing applied; on the right, after the level of processing needed for such deep-sky images. What starts out looking OK, turns messy.

ON1 is applying too much sharpening “under the hood.” That might “wow” casual daytime photographers into thinking ON1 is making their photos look better, but it is detrimental to deep-sky images. Star haloes are a sign of poor processing.

Noise and Hot Pixels

ON1 With & Without NR and Hot Pixels
With and without noise reduction and hot pixel removal shows stars becoming lost and misshapen with the Remove Hot Pixel option.

ON1’s noise reduction is quite good, and by itself does little harm to image details.

But turn on the Remove Hot Pixel button and stars start to be eaten. Faint stars fade out and brighter stars get distorted into double shapes or have holes in them.

Hot pixel removal is a nice option to have, but for these types of images it does too much harm to be useful. Use LENR or take dark frames, best practices in any case.

Image Alignment and Registration

ON1 Auto-Alignment
The six Andromeda images stacked then “Auto-Aligned” in ON1, with just the top (first) and bottom (last) images turned on here. with the top image switched to Difference blend mode to show any mis-alignment.
Photoshop Auto-Alignment
The same set stacked and “Auto-Aligned” in Photoshop, with the same first and last images turned on and blended with Difference. PS’s alignment is much better, indicated by the image “blacking out” as the two registered frames cancel out.

Before any processing of deep-sky images is possible, it is first necessary to stack and align them, to make up for slight shifts from image to image, usually due to the mount not being perfectly polar aligned. Such shifts can be both translational (left-right, up-down) and rotational (turning about the guide star).

New to ON1 2019 is an Auto-Align Layers function. It worked OK but not nearly as well as Photoshop’s routine. In my test images of M31, ON1 didn’t perform enough rotation.

Once stacked and aligned, and as I showed above, you then have to manually change the opacities of each layer to blend them for noise smoothing.

By comparison, Photoshop has a wonderful Statistics script (under File>Scripts) that will automatically stack, align, then mean or median average the images, and turn the result into a non-destructive smart object, all in one fell swoop. I use it all the time for deep-sky images. There’s no need for separate programs such as Deep-Sky Stacker.

In ON1, however, all that has to be done manually, step-by-step. ON1 does do the job, just not as well.


Wrap-Up

M31 from ON1
The final M31, Andromeda Galaxy image processed with ON1.

ON1 Photo RAW 2019 is a major improvement, primarily in providing a more seamless and less destructive workflow.

Think of it as Lightroom with Layers! 

But it isn’t Photoshop.

Dynamic Contrast
ON1’s useful Dynamic Contrast filter. A little goes a long way.

True to ON1’s heritage as a special effect plug-in, it has some fine Effect filters, such as Dynamic Contrast above, ones I sometimes use from within Photoshop as plug-in smart filters.

Under Sharpen, ON1 does offer a High Pass option, a popular method for sharpening deep-sky objects.

Missing Filters and Adjustments

But for astrophoto use, ON1 is missing a lot of basic but essential filters for pixel-level touch-ups. Here’s a short list:

• Missing are Median, Dust & Scratches, Radial Blur, Shake Reduction, and Smart Sharpen, just to mention a handful of filters I find useful for astrophotography, among the dozens of others Photoshop has, but ON1 does not. But then again, neither does Lightroom, another example of how ON1 is more light Lightroom with layers and not Photoshop.

ON1 Color Adjustment
ON1’s selective Color Adjustment. OK, but where’s the Black and Neutrals?

• While ON1 has many basic adjustments for color and contrast, its version of Photoshop’s Selective Color lacks Neutral or Black sliders, great for making fine changes to color balance in astrophotos.

• While there is a Curves panel, it has no equivalent to Photoshop’s “Targeted Adjustment Tool” for clicking on a region of an image to automatically add an inflection point at the right spot on the curve. This is immensely useful for deep-sky images.

• Also lacking is a basic Levels adjustment. I can live without it, but most astrophotographers would find this a deal-breaker.

• On the other hand, hard-core deep-sky photographers who do most of their processing in specialized programs such as PixInsight, using Photoshop or Lightroom only to perform final touch-ups, might find ON1 perfectly fine. Try it!

Saving and Exporting

ON1 saves its layered images as proprietary .onphoto files and does so automatically. There is no Save command, only a final Export command. As such it is possible to make changes you then decide you don’t like … but too late! The image has already been saved, writing over your earlier good version. Nor can you Save As … a file name of your choice. Annoying!

Opening a layered .onphoto file (even with ON1 itself already open) can take a minute or more for it to render and become editable.

Once you are happy with an image, you can Export the final .onphoto version as a layered .PSD file but the masks ON1 exports to the Photoshop layers may not match the ones you had back in ON1 for opacity. So the exported .PSD file doesn’t look like what you were working on. That’s a bug.

Only exporting a flattened TIFF file gets you a result that matches your ON1 file, but it is now flattened.

Bugs and Cost

I encountered a number of other bugs, ones bad enough to lock up ON1 now and then. I’ve even seen ON1’s own gurus encounter bugs with masking during their live tutorials. These will no doubt get fixed in 2019.x upgrades over the next few months.

But by late 2019 we will no doubt be offered ON1 Photo RAW 2020 for another $80 upgrade fee, over the original $100 to $120 purchase price. True, there’s no subscription, but ON1 still costs a modest annual fee, presuming you want the latest features.

Now, I have absolutely no problem with that, and ON1 2019 is a significant improvement.

However, I found that for astrophotography it still isn’t there yet as a complete replacement for Adobe.

But don’t take my word for it. Download the trial copy and test it for yourself.

— Alan, November 22, 2018 / © 2018 Alan Dyer/AmazingSky.com 

 

My 2019 Amazing Sky Calendar


2019 Amazing Sky Calendar Cover

My annual Amazing Sky Calendar is out!

My 2019 Amazing Sky Calendar is now out and available for FREE download as a PDF from my website page.

Once you’re on that page, scroll down for the link to the PDF.

Each month includes many dates and diagrams for celestial sights and space exploration events and anniversaries.

You can then print the PDF locally if you wish.

Do share the web page URL or this blog post. However, the PDF itself is for your personal use only. Enjoy!

— Alan, October 1, 2018 / © 2018 Alan Dyer / www.amazingsky.com

 

 

Testing the Sony a7III for Astrophotography


Milky Way Rising at Dino Park

I put the new Sony a7III mirrorless camera through its paces for the features and functions we need to shoot the night sky.

Sony’s a7III camera has enjoyed rave reviews since its introduction earlier in 2018. Most tests focus on its superb auto exposure and auto focus capabilities that rival much more costly cameras, including Sony’s own a7rIII and a9. 

For astrophotography, none of those auto functions are of any value. We shoot everything on manual. Indeed, the ease of manually focusing in Live View is a key function. 

In my testing I compared the Sony a7III to two competitive DSLRs, the Canon 6D MkII and Nikon D750.

All three are “entry-level” full-frame cameras, with 24 to 26 megapixels and in a similar price league of $1,500 (Nikon) to 2,000 (Sony). 

I tested a Sony a7III purchased locally. It was not supplied to me by Sony in return for an “influential” blog post.

I did this testing in preparation for the new third edition of my Nightscapes and Time-Lapse eBook, which includes information on Sony mirrorless cameras, as well as many, many other updates and additions!

NOTE: Click or Tap on most images to bring them up full-frame for inspection.

Milky Way Rising at Dino Park
MILKY WAY AT DINOSAUR PARK A stack of 2 x 90-second exposures for the ground, to smooth noise, and at f/2.8 for better depth of field, plus a single 30-second untracked exposure at f/2 for the sky. All with the Laowa 15mm lens and Sony a7III at ISO 3200.

Mirrorless vs. DSLR

Sony a7III with Loawa 15mm
COMPACT CAMERA and LENS
The Sony a7III with the compact but fast Laowa Venus Optics 15mm f/2 lens.

 

As with Sony’s other popular Alpha 7 and 9 series cameras, the new Alpha 7III is a full-frame mirrorless camera, a class of camera Canon and Nikon have yet to offer, though models are rumoured or promised. 

In the meantime, Sony commands the full-frame mirrorless market.

As its name implies, a mirrorless camera lacks the reflex mirror of a digital single lens reflex camera that, in a DSLR, provides the light path for framing the scene though the optical viewfinder. 

Sony Live View
SONY LIVE VIEW
The Sony a7III’s excellent Live View screen display. You can see the Milky Way!

In a mirrorless, the camera remains in “live view” all the time, with the sensor always feeding a live image to either or both the rear LCD screen and electronic viewfinder (EVF). While you can look through and frame using the EVF as you would with a DSLR, you are looking at an electronic image from the sensor, not an optical image from the lens. 

The advantage of purely electronic viewing is that the image you are previewing matches the image you’ll capture, at least for short exposures. The disadvantage is that full-time live view draws more power, with mirrorless cameras notorious for being battery hungry. 

Other mirrorless advantages include:

  • Compact size and lighter weight, yet offering all the image quality of a full-frame DSLR.
  • The thinner body allows the use of lenses from any manufacturer, albeit requiring the right adapter, an additional expense.
  • Lenses developed natively for mirrorless models can be smaller and lighter. An example is the Laowa 15mm f/2 I used for some of the testing.
  • The design lends itself to video shooting, with many mirrorless cameras offering 4K as standard, while often in DSLRs only high-end models do.
  • More rapid-fire burst modes and quieter shutters are a plus for action and wedding photographers, though they are of limited value for astrophotography.

Points of Comparison

Camera Trio-Sony, Nikon, Canon
CAMERA TRIO
The Sony a7III, Nikon D750, and Canon 6D Mark II. Note the size difference.

In testing the Sony a7III I ignored all the auto functions. Instead, I concentrated on those points I felt of most concern to astrophotographers, such as:

  • Noise levels
  • Effectiveness of Long Exposure Noise Reduction (LENR) 
  • Quality of Raw files, such as sharpness of stars
  • Brightness of Live View for framing and focusing
  • Uniformity of sensor illumination
  • Compatibility for time-lapse imaging
  • Battery life

TL;DR Conclusions

Sony a7III and Meade 70mm
DEEP-SKY TEST
The North America Nebula with the Sony a7III and a Meade 70mm f/5 astrographic refractor, for a single 4-minute exposure at ISO 1600. The reds have been boosted in processing.

Noise
Levels of luminance and chrominance noise were excellent and similar to – but surprisingly not better than – the Nikon D750.

Star Eater
The Star Eater is gone. Stars are not smoothed out in long exposures. 

ISO Invariance 
The Sony exhibited good – though not great – “ISO invariant” performance.

Dark Frames 
Dark frame subtraction using Long Exposure Noise Reduction removed most – but not all – hot pixels from thermal noise. 

Live View Focusing and Framing
Live View was absolutely superb, though the outstanding Bright Monitoring function is as well-hidden as Sony could possibly make it. 

Sensor Illumination Uniformity
The Sony showed some slight edge-of-frame shadowing from the mask in front of the sensor, as well as a weak purple amp glow.

Features 
• The a7III lacks any internal intervalometer or ability to add one via an app. But it is compatible with many external intervalometers and controllers.

• The a7III’s red sensitivity for recording H-Alpha-emitting nebulas was poor. 

• It lacks the “light-frame” buffer offered by full-frame Canons that allows shooting several frames in quick succession even with LENR turned on.

Video Capability 
The a7III offers 4K video and, at 24 frames-per-second, is full-frame. Shutter speeds can be as slow as 1/4-second, allowing real-time aurora shooting at reasonable ISO speeds. 

Battery Life
Shooting typical 400-frame time-lapses used about 40% of the battery capacity, similar to the other DSLRs. 

Overall Recommendations
The Sony a7III is a superb camera for still and time-lapse nightscape shooting, and excellent for real-time aurora videos. It is good, though not great, for long-exposure deep-sky imaging. 

Liberty Schoolhouse with Star Trails
STAR TRAILS and AURORA With the Laowa 15mm lens and Sony a7III, for 155 exposures, all 20 seconds at f/2.8 and at ISO 800, and taken as part of a 360-frame time-lapse.

Noise

The Sony a7III uses a sensor that is “Backside Illuminated,” a feature that promises to improve low-light performance and reduce noise. 

I saw no great benefit from the BSI sensor. Noise at typical astrophoto ISO speeds – 800 to 6400 – were about equal to the four-year-old Nikon D750. 

That was a bit surprising. I expected the new BSI-equipped Sony to better the Nikon by about a stop. It did not. This emphasizes just how good the Nikon D750 is. 

Nevertheless, noise performance of the Sony a7III was still excellent, with both the Sony and Nikon handily outperforming the Canon 6D MkII, with its slightly smaller pixels, by about a stop in noise levels. 

NOTE: I performed all Raw developing with Adobe Camera Raw v10.3. It is possible some of the artifacts I saw are due to ACR not handling the a7III’s .ARW files as well as it should. But to develop all the images from Sony, Nikon, and Canon equally for comparisons, ACR is the best choice. 

1-Sony vs Nikon vs Canon Noise
COMPARING NOISE
The Sony a7III exhibited noise levels similar to the Nikon D750 at high ISOs, with the Sony and Nikon each about a stop better for noise than the Canon 6D MkII.
2A-Sony vs Nikon vs Canon at 3200
NOISE AT ISO 3200
At ISO 3200, a common nightscape ISO speed, all three cameras performed well in this moonlit scene. The Canon shows a darker sky as its images were taken a few minutes later. The Nikon had the Sigma 14mm Art lens; the Canon and Sony used the same Rokinon 14mm SP lens.
2B-Sony vs Nikon vs Canon at 6400
NOISE AT ISO 6400
At ISO 6400, the Canon begins to show excessive noise, about a stop worse than the Nikon and Sony. No luminance noise reduction was applied to these images. All cameras show an equal number of stars recorded.

ISO Invariance

Both the Sony and Nikon use sensor and signal path designs that are “ISO invariant.” As a result, images shot underexposed at slower ISOs, then boosted in exposure later in processing look identical to properly exposed high-ISO images. Well, almost.

The Sony still showed some discoloration artifacts and added noise when boosting images by +4 EV that the Nikon did not. Even with uncompressed Raws, the Sony was not quite as ISO invariant as the Nikon, though the difference shows up only under extreme push-processing of badly underexposed frames. 

Plus, the Sony was far better than the Canon 6D MkII’s “ISO variant” sensor. Canon really needs to improve their sensors to keep in the game. 

3A-Sony vs Nikon vs Canon ISO Invariancy
ISO INVARIANCE COMPARISON
Here I shot all three cameras at ISO 6400 for a correct exposure for the scene, and also at ISO 1600 and ISO 400, for images 2 and 4 stops underexposed respectively. These were then boosted in Adobe Camera Raw by 2 and 4 stops in Exposure Value (EV) to compensate. With ISO invariant sensors the boosted images should look similar to the well-exposed image.
3B-Sony vs Nikon vs Canon ISO Invariancy CU
ISO INVARIANCE CLOSE-UP
A closeup of the scene shows the ISO variant Canon exhibited more noise and magenta discoloration in the +4 EV boosted image. The Nikon looks very clean, but the Sony also shows discoloration, green here, and an increase in noise. These are all uncompressed 14-bit Raw files.
4-Sony vs Nikon ISO Invariancy
SONY vs. NIKON
Comparing just the two ISO-invariant cameras, the Sony and the Nikon, on another night, shows a similar performance difference when boosting underexposed slow-ISO images later in Camera Raw. The Sony begins to show more noise and now a magenta discoloration in the +3 and +4 EV images, similar to, but not as badly as does the ISO-variant Canon 6D MkII.

Compressed vs. Uncompressed 

Sony-Comp-UnCompThe Sony a7III offers a choice of shooting Uncompressed or Compressed Raw files. Uncompressed Raws are 47 Mb in size; Compressed Raws are 24 Mb. 

In well-exposed images, I saw little difference in image quality. 

But the dark shadows in underexposed nightscapes withstood shadow recovery better in the uncompressed files. Compressed files showed more noise and magenta discoloration in the shadows. 

It is not clear if Sony’s compressed Raws are 12-bit vs. 14-bit for uncompressed files. 

Nevertheless, for the demands of nightscape and deep-sky shooting and processing, I suggest shooting Uncompressed Raws. Use Compressed only if you plan to take lots of time-lapse frames and need to conserve memory card space on extended shoots. 

5A-Sony UnCompressed vs Compressed at -1EV
UNCOMPRESSED vs. COMPRESSED
Here I compare any image degradation from using compressed vs. uncompressed Raws, and from employing Long Exposure Noise Reduction. Images are only slightly underexposed and boosted by +1 EV in Camera Raw. Shadow noise is similar in all images, with the ones taken with LENR on showing elimination of colored hot pixels, as they should.
5B-Sony UnCompressed vs Compressed at -4EV
UNCOMPRESSED vs. COMPRESSED at -4EV
The same scene but now underexposed by 4 stops and boosted by +4 EV later shows greater differences. The compressed image shows more noise and discoloration, and the images taken with LENR on, while eliminating hot pixels, show more random luminance noise. Keep in mind, these are vastly underexposed images. 
6-Sony Comp vs Uncomp + DF
UNCOMPRESSED vs. COMPRESSED DEEP-SKY
A real-world deep-sky example shows the same comparison. All images are well-exposed, for tracked and guided 4-minute exposures. The ones taken with LENR on show fewer hot pixels. The compressed images appear identical to the uncompressed files for noise and star content.

Star Eater (Updated June 3, 2018)

Over the last year or so, firmware updates from Sony introduced a much-publicized penchant for Sony Alphas to “eat” stars even in Raw files, apparently due to an internal noise reduction or anti-aliasing routine users could not turn off. Stars were smoothed away along with the noise in exposures longer than 3.2 seconds in some Sony cameras (longer than 30 seconds in others).

I feel that in the a7III the Star Eater has been largely vanquished.

As the images below show, there is a very slight one-pixel-level softening that kicks in at 4 seconds and longer but it did not eat or wipe out stars. Stars are visible to the same limiting magnitude and close double stars are just as well resolved across all exposures. Indeed, at slower ISOs and longer exposures, more stars are visible.

I saw none of the extreme effects reported by others with other Sonys, where masses of faint stars disappeared or turned into multi-colored blotches.

I did not see any significant “star eating” in any long exposures even up to the 4 minutes I used for some deep-sky shots. In images taken at the same time with other cameras not accused of star eating, the Sony showed just as many faint stars as the competitors. Long exposures showed just as many stars as did short exposures.

This was true whether I was shooting compressed or uncompressed Raws, with or without Long Exposure Noise Reduction. Neither compression nor LENR invoked “star eating.” 

Sony-Star Eater Series @ 200%
STAR EATER SERIES at 200%
This series of tracked images (shown here blown up 200%) goes from 2 seconds to 2 minutes, with decreasing ISO speed to equalize the exposure value across the series. Between 3.2s and 4s a very slight one-pixel-level softening does kick in, reducing noise and very slightly blurring stars. Yet, just as many stars are recorded and are resolved, and at the lower ISOs/longer exposures more stars are visible because faint stars are not lost in the noise.
Sony-Star Eater Series @ 400%
STAR EATER SERIES at 400%
This is the same series as above but now blown up 400% to better reveal the very subtle change in pixel-level sharpness as exposure lengthened from 3.2 to 4 seconds. Noise (most noticeable in the trees) is reduced and stars are very slightly softened. But none are “eaten” or wiped out. And star colors are not affected, though very small stars are sometimes green, an effect seen in other cameras due to de-Bayering artifacts.
7A-Sony vs Canon for Star Eater v1
STAR EATER DEEP-SKY #1
Tracked deep-sky images through a telescope using 4-minute exposures show the Sony a7III recording an equal number of faint stars as the Canon 6D MkII. No luminance noise reduction was applied to these images in processing.
7B-Sony vs Canon for Star Eater v2
STAR EATER DEEP-SKY #2
Another example with 4-minute exposures again demonstrates no problems recording faint stars. The Canon does show more noise than the Sony. No noise reduction was applied in processing. 
7C-Sony vs Nikon for Star Eater
SONY and NIKON COMPARED
For yet more evidence, this is a comparison of the Sony a7III vs. the Nikon D750 in tracked 90-second exposures with 14mm lenses. Again, the Sony records just as many stars as the Nikon.

LENR Dark frames 

Sony-LENRFor elimination of hot pixels from thermal noise I prefer to use Long Exposure Noise Reduction when possible for nightscape and deep-sky images, especially on warm summer nights.

Exceptions are images taken for star trail stacking and for time-lapses, images that must be taken in quick succession, with minimal time gap between frames.

Turning on LENR did eliminate most hot pixels in long exposures, but not all. A few remained. Also, when boosting the exposure a lot in processing, the images taken with LENR on showed more shot and read noise than non-LENR frames. 

The dark frame the camera was taking and subtracting was actually adding some noise, perhaps due to a temperature difference. The cause is not clear. 

Sony advises that when using LENR Raw images are recorded with only 12-bit depth, not 14-bit. This might be a contributing factor. Yet frames taken with LENR on were the same 47 Mb size as normal uncompressed frames.

For those who think this is normal for LENR use, the Nikon D750 shows nothing like this – frames taken with LENR on are free of all hot pixels and do not show more shot or read noise, nor deterioration of shadow detail from lower bit depths.

However, I emphasize that the noise increase from using LENR with the Sony was visible only when severely boosting underexposed images in processing. 

In most shooting situations, I found using LENR provided the overriding positive benefit of reducing hot pixels. It just needs to be better, Sony!

8A-Sony Dark Frames (W and WO LENR)
SONY WITH AND WITHOUT LENR
These are 4-minute exposures of dark frames (i.e. the lens cap on!) taken at room temperature with and without Long Exposure Noise Reduction. In the Sony, LENR did not eliminate all hot pixels nor the magenta amp glow at the left edge. LENR also added a background level of fine noise. These have had exposure and contrast increased to exaggerate the differences.
8B-Nikon Dark Frames (W and WO LENR)
NIKON WITH AND WITHOUT LENR
Dark frames taken with the Nikon D750 under the same circumstances and processed the same show none of the residual hot pixels and added background noise when LENR is employed. Nor is there any amp glow anywhere along the frame edges.
8C-Sony With and Without LENR
SONY REAL-WORLD LENR COMPARISON
A real-world example with the Sony, with a properly exposed nightscape, shows that the ill effects of using LENR don’t show up under normal processing. You do get the benefit of reduced hot pixels in shadows, especially on a warm night like this was. This is a blow-up of the lower corner of the frame, as indicated.

Sensor Illumination 

How evenly an image is illuminated is a common factor when testing lenses. 

But astrophotography, which often requires extreme contrast boosts, reveals non-uniform illumination of the sensor itself, regardless of the optics, originating from hardware elements in front of the sensor casting shadows onto the sensor. 

This is most noticeable – indeed usually only noticeable – when shooting deep-sky targets though telescopes. 

With DSLRs it is the raised mirror which often casts a shadow, produced a dark vignetted band along the bottom of the frame. Its extent varies from camera model to model.

With a mirrorless camera the sensor is not set far back in a mirror box, as it is in a DSLR. As such, I would have expected a more uniformly illuminated sensor. 

Sony a7III - Sensor CU
SENSOR CLOSE-UP showing intruding mask edges.

Instead, I saw a slight shadowing at the top and bottom edges but just at the corners. This is from a thin metal mask in front of the sensor. It intrudes into the light path ever so slightly. It shouldn’t. 

This is an annoying flaw, though applying “flat fields” or ad hoc local adjustments should eliminate this. But that’s a nuisance to do, and should not be necessary with a mirrorless camera.

Worse is that long deep-sky exposures at high ISOs also exhibited a faint purple glow at the left edge, perhaps from heat from nearby electronics, a so-called “amp glow.” Or I’ve read where this is from an internal infrared source near the sensor.

Taking a dark frame with LENR did not eliminate this, and it should, demonstrating again that for whatever reason in the a7III LENR is not as effective as it should be. 

I have not seen such “amp” glows in cameras (at least in the DSLRs I’ve used) for a number of years, so seeing it in the new Sony a7III was another surprise. 

This would be much tougher to eliminate in deep-sky images where the extreme contrast boosts we typically apply to images of nebulas and galaxies will accentuate any odd glows. 

One supplier of filter-modified cameras, Spencer’s Camera, also refuses to modify Sonys, because this glow renders them poor choices for filter modification, for those wanting cameras with deeper red sensitivity.

9A-Sony Full Field
SONY FIELD ILLUMINATION #1
The full field of a deep-sky image taken through an f/5 70mm astrographic refractor shows the minor level of edge darkening at the corners from shadowing of the sensor in the Sony.
New Sony Blog Example
SONY FIELD ILLUMINATION #2 The full field of a deep-sky image taken through an f/6 105mm refractor shows the level of edge darkening at the edges from shadowing of the sensor in the Sony, and the purple “amplifier” glow at the left edge present in all very long exposures.

Red Sensitivity

When shooting deep-sky objects, particularly red nebulas, we like a camera to have a less aggressive infrared cutoff filter, to pick up as much of the deep red Hydrogen-Alpha emission line as possible. 

The Sony showed poor deep-red sensitivity, though not unlike other cameras. It was a little worse than the stock Canon 6D MkII. 

This isn’t a huge detriment, as anyone who really wants to go after deep nebulosity must use a “filter-modified” camera anyway. 

Canon and Nikon both offered factory modified cameras at one time, notably the Canon 60Da and Nikon D810a. Sony doesn’t have an “a” model mirrorless.

To get the most out of the Sony for deep-sky imaging you would have to have it modified by a third-party, though the amp glow described above makes it a poor choice for modification.

10-Canon5D vs 6D vs Sony (Red Nebula)
RED SENSITIVITY COMPARED
Three deep-sky exposures compare cameras for red sensitivity: a filter-modified Canon 5D MkII, a stock Canon 6D MkII, and the stock Sony a7III. As expected the filter-modified camera picks up much more red nebulosity. The Sony doesn’t do quite as well as the Canon 6D MkII.

Live View Focusing and Framing 

Up to now my report on the Sony a7III hasn’t shown as glowing a performance as all the YouTube reviews would have you believe. 

But Live Focus is where the a7III really stands out. I love it!

In Live View it is possible to make the image so bright you can actually see the Milky Way live on screen! Wow! This makes it so easy to frame nightscapes and deep-sky fields.  

Sony-Custom Buttoms
FINDING BRIGHT MONITORING
The excellent Bright Monitoring function is accessible only off the Custom Key menu where it appears as a choice on the Display/Auto Review2 page (below) that can be assigned to a C button.

But this special “Bright Monitoring” mode is as well hidden as Sony could make it. Unless you actually read the full-length 642-page PDF manual (you have to download it), you won’t know about it. Bright Monitoring does not appear in any of the in-camera menus you can scroll through, so you won’t stumble across it.

Instead, you have to go to the Camera Settings 2 page, then select Still Image–Custom Key. In the menu options that appear you can now scroll to one called Bright Monitoring. Surprise! Assign it to one of the hardware Custom C buttons. I put it on C2, making it easy to call up when needed. 

Sony-Bright Monitoring

The other Live View function that works well, but also needs assigning to a C button is the Camera Settings 1 > Focus Magnifier. I put this on C1. It magnifies the Live View by 5.9x or 11.7x, allowing for precise manual focusing on a star. 

Sony-LiveViewDisp

Two other functions are useful for Live View: 

  • Camera Settings 2 > Live View Display > Setting Effect ON. This allows the Live View image to reflect the camera settings in use, better simulating the actual exposure, even without Bright Monitoring on.
  • Camera Settings 1 > Peaking Setting. Turning this ON superimposes a shimmering effect on parts of an image judged in focus. This might be an aid, or an annoyance. Try it. 

In all, the Sony provides superb, if well-hidden, Live View options that make accurately framing and focusing a nightscape or time-lapse scene a joy. 


Great Features for Astrophotography 

Here are some other Sony a7III features I found of value for astrophotography, and for operating the camera at night. 

Sony a7III with Tilt Screen
SONY TILTING SCREEN It tilts up and down but does not flip out as with the Canon 6D MkII’s. Still, this is a neck- and back-saving feature for astrophotography.

Tilting LCD Screen 
Like the Nikon D750, the Sony’s screen tilts vertically up and down, great for use when on a telescope, or on any tripod when aimed up at the sky. As photographers age, this becomes a more essential feature!

Sony-CustomKey

Custom Buttons 
The four C buttons can be programmed for oft-used functions, making them easy to access at night. Standard functions such as ISO and Drive Mode are easy to get at on the thumb wheel, unlike the Nikon D750 where I am forever hunting for the ISO or Focus Zoom buttons, or the Canon 6D MkII which successfully hides the Focus Zoom and Playback buttons at night.

Sony-MyMenu

My Menu 
In new models, Sony now offers the option of a final “My Menu” page which you can populate with often-used functions from the other 35 pages of menu commands!

Adaptability to Many Lenses 
Using the right lens adapter (I use one from Metabones), it is possible to use lenses with mounts made for Canon, Nikon, Sigma and others. Plus there are an increasing number of lenses from third parties offered with native Sony E-mounts. This is good news, as astrophotography requires fast, high-quality lenses, and the Sony allows more choices.

Lighter Weight / Smaller Size
The compact a7III body weighs a measured 750 grams, vs. 900 grams each for the Nikon D750 and Canon 6D MkII. The lower weight can be helpful for use on lightweight telescopes, on small motion control devices, and for simply keeping weight and bulk down when traveling. 

Sony a7III - Dual Slots

Dual Card Slots 
Not essential, but having two card slots is very helpful, for backup, for handling overflows from very long time-lapse shoots, or assigning them for stills vs. movies, or Raws vs. JPGs. Only Slot 1 will work with the fastest UHS II cards that are needed for recording the highest quality 4K video.

USB Power 
It is possible to power the camera though the USB port (indeed that’s how you charge the battery, as no separate battery charger is supplied as standard, a deficiency). This might be useful for long shoots, though likely as not that same USB port will be needed for an intervalometer or motion control device. But if the Sony had a built-in intervalometer…!

Sony-DispInfo

Display Options
To reduce battery drain it is possible to turn off the EVF completely – I find I never use it at night – and to turn off the LCD display when shooting, though the latter is an option you have to activate to add to the Display button’s various modes. 

The downside is that when shooting is underway you get no reassuring indication anything is happening, except for a brief LED flash when an image is written to a card.  

Sony-ECurtain

Electronic Front Curtain Shutter
Most DSLRs do not offer this, but the Sony’s option of an electronic front curtain shutter and the additional Silent Shooting mode completely eliminates vibration, useful for some high-magnification shooting through telephotos and telescopes.

11-Sony Shutter Vibration
LUNAR CLOSE-UPS COMPARED
This trio compares closeups of the Moon taken with and without electronic front curtain shutter. All were taken through a 130mm refractor telescope at f/12 using a Barlow lens. The image with e-shutter and in Silent Mode is a tad sharper, but that could be just as much from variations in seeing conditions as from the lower vibration from using the electronic shutter.

What’s Missing for Astrophotography

Intervalometer — NOW INCLUDED!
UPDATE: In April 2019 Sony issued a v3 Firmware update for the a7III which added an internal intervalometer. I’ve used this new function and it works very well.

I had originally remarked that this useful function was missing. But no more! Thank you Sony!

While a built-in intervalometer is not essential, I find I often do use the Canon and Nikon in-camera intervalometers for simple shoots. So it is great to have one available on the Sony. However, like other brands’ internal intervalometers Sony’s is good only for exposures up to 30 seconds long.

Bulb Timer or Long Exposures
However, while the Sony has a Bulb setting there is no Bulb Timer as there is with the Canon. The Bulb Timer would allow setting long Bulb exposures of any length in the camera. 

Instead, for any exposures over 30 seconds long (or time-lapses with >30-second-long frames) the Sony must be used with an external Intervalometer. I use a $50 Vello unit, and it works very well. It controls the Sony through the camera’s Multi USB port.

In-Camera Image Stacking 
Also missing, and present on most new Canons, are Multiple Exposure modes for in-camera stacking of exposures in a Brighten mode (for star trails) or Averaging mode (for noise smoothing). 

Yes, this can all be done later in processing, but having the camera do the stacking can often be convenient, and great for beginners, as long as they understand what those functions do, or even that they exist!

Time-Lapse Smoothing 
When using its internal intervalometer, the Nikon D750 has an excellent Exposure Smoothing option. This does a fine job smoothing frame-to-frame flickering in time-lapses, something the Canon cannot do. Nor the Sony, as it has no intervalometer at all.

Light Frame Buffer in LENR
This feature is little known and utilized, and only Canon full-frame cameras offer it. Turn on LENR and it is possible to shoot three (with the 6D MkII) or four (with the 6D) Raw images in quick succession even with LENR turned on. The Canon 5D series also has this. 

The dark frame kicks in and locks up the camera only after the series of “light frames” are taken. This is wonderful for taking a set of noise-reduced deep-sky images for later stacking. Nikons don’t have this, not even the D810a, and not Sonys. 

Illuminated Buttons 
The Sony’s buttons are not illuminated. While these might add glows to long exposure images, if they could be designed not to do that (i.e. they turn off during exposures), lit buttons would be very handy at night. 

Limited Touch Screen Functions 
An alternative would be an LCD screen that was touch sensitive. The Sony a7III’s screen is, but only to select an area for auto focus or zooming up an image in playback. The Canon 6D MkII has a fully functional touch screen which can be, quite literally, handy at night.  

Sony a7III with Vello Intervalometer
INTERVALOMETER
For time-lapses, the Sony must be used with an external intervalometer like this Vello unit.

Video Capability 

Here’s another area where the new Sony a7III really shines. 

It offers 4K (or more precisely UltraHD) video recording for videos of 3840 x 2160 pixels. (True 4K is actually 4096 x 2160 pixels.)

With a fast enough UHS-II Class card it can record 4K video up to 30 frames per second and at a bit rate of either 60 or 100 Mbps. 

Sony-MovieSetting

At 24 fps videos are full-frame with no cropping. Hurray! You can take full advantage of wide-angle lenses, great for auroras. At 30 fps, 4K videos are cropped with a 1.2x crop factor.

In Movie Mode ISO speeds go up to ISO 102,400, but are pretty noisy, if unusable at such speeds. 

But when shooting aurora videos I found, to my surprise, I could “drag” the shutter speeds as slow as 1/4-second, fully 4 stops better than the Nikon’s slowest shutter speed of 1/60 second in Full HD, and 3 stops better than the Canon’s slowest movie shutter of 1/30 second. 

Coupled with a fast f/1.4 to f/2 lens, the slow shutter speed allows real-time aurora shooting at “only” ISO 6400 to 12,800, for quite acceptable levels of noise. I am very impressed! 

Real-time video of auroras is not possible with anything like this quality with the Nikon (I’ve used it often), and absolutely not with the Canon. And neither are 4K. 

Is the a7III as good for low-light video as the Sony a7s models, with their larger 8.5-micron pixels? 

I would assume not, but not having an a7s (either Mark I or II) to test I can’t say for sure. But the a7III should do the job for bright auroras, the ones with rapid motion worth recording with video, plus offer 24 megapixels for high-quality stills of all sky subjects. 

I think it’s a great camera for both astrophoto stills and video.

12A-Aurora Video Screen Shot
AURORA VIDEO FRAME
This is a frame grab from a real-time 4K video of a “Steve” aurora.

An example is in a 4K video I shot on May 6, 2018 of an usual aurora known as “STEVE.”

Steve Aurora – May 6, 2018 (4K) from Alan Dyer on Vimeo.


For another example of using the Sony a7III for recording real-time video of the night sky see this video of the aurora shot from Norway in March 2019.

The Northern Lights At Sea from Alan Dyer on Vimeo.


Sony a7III - Buttons and Dials

Battery Life

I found the a7III would use up about about 40% of the battery capacity in a typical 400-frame time-lapse on mild spring nights, with 30-second exposures. This is with the EVF and rear LCD Display OFF, and the camera in Airplane mode to turn off wireless functions to further conserve battery power. I was using the wired Vello intervalometer. 

This is excellent performance on par with the DSLRs I use. At last, we have a mirrorless camera that not only doesn’t eat stars, it also does not eat batteries! 

One battery can get you through a night of shooting, though performance will inevitably decline in winter, as with all cameras. 

Planets Along the Ecliptic
MILKY WAY and PLANETS With the Sony a7III and Laowa 15mm lens at f/2 for a stack of 4 exposures for the ground to smooth noise and one exposure for the sky, all 30 seconds at ISO 3200.

Lens and Telescope Compatibility 

As versatile as a mirrorless camera is for lens choice, making use of that versatility requires buying the right lens adapter(s). They can cost anywhere from $100 to $400. The lowest cost units just adapt the lens mechanically; the more costly units also transfer lens data and allow auto focusing with varying degrees of compatibility. 

Sony a7III with MetaBones
WITH METABONES CANON ADAPTER
The MetaBones Canon EF-to-Sony E mount adapter transfers lens data and allows auto focus to function.

For use on telescopes, the simple adapters will be sufficient, and necessary as many telescope-to-camera adapters and field flatteners are optimized for the longer lens flange-to-sensor distance of a DSLR. Even if you could get a mirrorless camera to focus without a lens adapter to add the extra spacing, the image quality across the field might be compromised on many telescopes. 

I used the Metabones Canon-to-Sony adapter when attaching the Sony to my telescopes using my existing Canon telescope adapters. Image quality was just fine. 

Sony a7III with Telescope Adapter
ADAPTING TO A TELESCOPE
The MetaBones adapter, as will other brands, adds the correct lens flange to sensor distance for telescope field flatteners to work best.

Time-Lapse Controller Compatibility 

Due to limitations set by Sony, controlling one of their cameras with an external controller can be problematic. 

Devices that trigger only the shutter should be fine. That includes simple intervalometers like the Vello, the Syrp Genie Mini panning unit, and the Dynamic Perception and Rhino sliders, to name devices I use. However, all will need the right camera control cable, available from suppliers like B&H. 

And, as I found, the Sony might need to be placed into Continuous shooting mode to have the shutter fire with every trigger pulse from the motion controller. When used with the Genie Mini (below) the Sony fired at only every other pulse if it was in Single shot mode, an oddity of Sony’s firmware.

Some time-lapse controllers are able to connect to a camera through its USB port and then adjust the ISO and aperture as well, for ramped “holy grail” sunset-to-Milky Way sequences. 

For example, the TimeLapse+ View (see http://www.timelapseplus.com) works great for automated holy grails, but the developer recommends that with most Sonys the minimum allowed interval between shots is longer (8 to 14 seconds) than with Canons and Nikons. See http://docs.view.tl/#camera-specific-notes 

With the Alpine Laboratories Radian2, exposure ramping is not possible with a Sony, only basic shutter triggering. See https://alpinelaboratories.com/pages/radian-2-support-get-started_s 

Sony a7III on Genie Mini
SONY WITH THE SYRP GENIE MINI
The Sony A7III worked well with the Syrp Genie Mini motion controller with the right shutter cable but only when placed in Continuous mode.

Recommendations 

In conclusion, here’s my summary recommendations for the three competitive cameras, rating them from Poor, to Fair, to Good, to Excellent. 

Sony a7III - Angled Front

SONY: I deducted marks from the Sony a7III for deep-sky imaging for its lack of a light frame buffer, poor red sensitivity, odd LENR performance, and purple amp glow not seen on the other cameras and that dark frames did not eliminate. 

However, I did not consider “star eating” to be a negative factor, as the Sony showed just as many stars and as well-resolved as did the competitors, and what more could you ask for?

I rate the Sony excellent for nightscape imaging and for real-time aurora videos. I list it as just “good” for time-lapse work only because it will not be fully compatible with some motion controllers and rampers. So beware!

Nikon D750 Angled Front

NIKON: I deducted points for real-time video of auroras – the D750 can do them but is pretty noisy with the high ISOs needed. Its red sensitivity is not bad, but its lack of a light frame buffer results a less productive imaging cycle when using LENR on deep-sky shooting. 

I know … people shoot dark frames separately for subtracting later in processing. However, I’ve found these post-shoot darks rarely work well, as the dark frames are not at the same temperature as the light frames, and often add noise or dark holes. 

Canon 6D MkII Angled Front

CANON: The 6D MkII’s lack of an ISO invariant sensor rears its ugly head in underexposed shadows in dark-sky nightscapes. I like its image stacking options, which can help alleviate the noise and artifacts in still images, but aren’t practical for time-lapses. Thus my Good rating for nightscapes but Fair rating for time-lapses. (See my test at https://amazingsky.net/2017/08/09/testing-the-canon-6d-mark-ii-for-nightscapes/)

While the 6D MkII has HD video, it is incapable of any low-light video work.

But … when well exposed, such as in tracked deep-sky images, the 6D MkII performs well. (See my test at https://amazingsky.net/2017/09/07/testing-the-canon-6d-mkii-for-deep-sky/)

And its light-frame buffer is great for minimizing shooting time for a series of deep-sky images with in-camera LENR dark frames, which I find are the best for minimizing thermal noise. Give me a Canon full-frame any day for prime-focus deep-sky shooting. 

It’s just a pity the 6D MkII has only a 3-frame buffer when using LENR. Really Canon? The 2008-vintage 5D MkII had a 5-frame buffer! Your cameras are getting worse for astrophotography while Sony’s are getting better. 

SONY a7III NIKON D750 CANON 6D Mk II
Nightscapes

Excellent 

Excellent  Good
Time-Lapse Good  Excellent  Fair
Real-Time Video (Auroras) Excellent  Fair  Poor
Wide-field Deep Sky Good  Good  Excellent 
Telescopic Deep Sky Fair  Good  Excellent 

I trust you’ll find the review of value. Thanks for reading!


ADDENDUM as of JUNE 6, 2018

Since publishing the first results a number of people commented with suggestions for further testing, to check claims that:

  1. The Sony would perform better for noise under dark sky conditions, at high ISOs, rather than the moonlit scene above. OK, let’s try that.
  2. The Sony would perform better in an ISO Invariancy “face-off” if its ISOs were kept above 640, to keep all the images within the Sony’s upper ISO range of its dual-gain sensor design, with two ranges (100 to 400, and 640 on up). Fair enough.
  3. What little “star-eater” effect I saw might be mitigated by shooting on Continuous drive mode or by firing the shutter with an external timer. That’s worth a check, too.

For the additional tests, I shot all images within a 3-hour span on the night of June 5/6, using the Sony a7III, Nikon D750, and Canon 6D MkII, with the respective lenses: the Laowa 15mm lens at f/2, the Sigma 14mm Art at f/2, and the Rokinon 14mm SP at f/2.5.

The cameras were on a Star Adventurer Mini tracker to keep stars pinpoints, though the ground blurred in the longer exposures.


DARK SKY NOISE TEST

I show only the Sony and Nikon compared here, shot at the common range of ISOs used for nightscape shooting, 800 to 12800. All images are equally well exposed. The inset image at right in Photoshop shows the scene, the Milky Way above dark trees in my backyard!

To the eye, the Sony and Nikon look very similar for noise levels, just as in the moonlit scene. Both are very good – indeed, among the best performing cameras for high-ISO noise levels. But the Sony, being four years newer than the Nikon, is not better.

BUT … what the Sony did exhibit was better details in the shadows than the Nikon.

And this was with equal processing and no application of Shadow Recovery. This is where the Sony’s Backside Illuminated sensor with presumably higher quantum efficiency in gathering photons might be providing the advantage. With its good shadow details, you have to apply less shadow recovery in post-processing, which does keep noise down. So points to Sony here.

Sony vs Nikon High ISO Noise (Dark Sky)
SONY vs NIKON HIGH ISO under DARK SKIES
Noise levels appeared visually similar but the Sony showed more shadow details. Excellent!

I did put all the high ISO images through the classic noise reduction program Noise Ninja to measure total Luminance and Chrominance noise, and included the Canon 6D MkII’s images.

The resulting values and graph show the Sony actually measured worse for noise than the Nikon at each high ISO speed, 3200 to 12800, though with both performing much better than the Canon.

The higher noise of the Canon is visually obvious, but I’d say the Sony a7III and Nikon D750 are pretty equal visually for noise, despite the numbers.

Noise Ninja Value Graph
COMPARING NOISE WITH NOISE NINJA

DARK SKY ISO INVARIANCY

Again, here I show only the Sony and Nikon, the two “ISO invariant” cameras. The correct exposure for the scene was 30 seconds at ISO 6400 and f/2. The images shown here were shot at lower ISOs to underexposure the dark scene by 2 to 4 stops or EV. Those underexposed images were then boosted later in processing (in Adobe Camera Raw) by the required Exposure Value to equalize the image brightness.

Contrary to expectations, the Sony did not show any great loss in image quality as it crossed the ISO 640 boundary into its lower ISO range. But the Nikon did show more image artifacts in the “odd-numbered” ISOs of 640 and 500. In this test, the Nikon did not perform as well as the Sony for ISO invariancy. Go figure!

Again, the differences are in images vastly underexposed. And both cameras performed much better than the ISO “variant” Canon in this test.

Sony vs Nikon ISO Invariancy (Dark Sky)
DARK SKY ISO INVARIANCY
Here the Sony a7III performed well and better than the Nikon D750.

STAR EATER REVISITED

I shot images over a wide-range of exposures, from 2 seconds to 2 minutes, but show only the ones covering the 2-second to 4-second range, where the “star-eater” anti-aliasing or noise smoothing applied by Sony kicks in (above 3.2 seconds it seems).

I shot with the Sony a7III on Single shot drive mode, on Continuous Low drive mode (with the camera controlling the shutter speed in both cases), and a set with the Sony on Bulb and the shutter speed set by an external Vello intervalometer.

This is really pixel peeping at 400%. In Single drive mode, stars and noise soften ever so slightly at 4 seconds and higher. In Continuous mode, I think the effect is still there but maybe a little less. In shots on Bulb controlled by the External Timer, maybe the stars at 4 seconds are a little sharper still. But this is a tough call. To me, the star eater effect on the Sony a7III is a non-issue. It may be more serious on other Sony alphas.

Sony Star Eater-Shutter Control Series
STAR EATING vs DRIVE MODE
This series shows star sharpness in images taken in Single and Continuous drive modes, and in Externally Timed exposures.

DE-BAYERING STAR ARTIFACTS

An issue that, to me, has a more serious effect on star quality is the propensity of the Sony, and to some extent the Nikon, to render tiny stars as brightly colored points, unrealistically so. In particular, many stars look green, from the dominance of green-filtered photosites on Bayer-array sensors.

Here I compare all three cameras for this effect in two-minute tracked exposures taken with Long Exposure Noise Reduction (i.e. in-camera dark frame subtraction) off and on.

The Sony shows a lot of green stars with or without LENR. The Nikon seems to discolor stars only when LENR is applied. Why would that be? The Canon is free of any such issue – stars are naturally colored whether LENR dark frames are applied or not.

This is all with Raws developed with Adobe Camera Raw.

When opening the same Raws in other programs (ON1 Photo RAW, Affinity Photo, DxO PhotoLab, and Raw Therapee) the results can be quite different, with stars often rendered with fringes of hot, colored pixels. Or rendered with little or no color at all. Raw Therapee offers a choice of de-Bayering, or “de-mosaic,” routines, and each produces different looking stars, and none look great! Certainly not as good as the Canon rendered with Camera Raw.

What’s going on here is a mystery – it’s a combination of the cameras’ unique Raw file formats, anti-alias filter in front of the sensor (or lack thereof in the Sony), and the de-Bayering routines of all the many Raw developers wrestling with the task of rendering stars that occupy only a few pixels. It’s unfair to blame just the hardware or the software.

But this test re-emphasized my thoughts that Canon DSLRs remain the best for long-exposure deep-sky imaging where you can give images as much exposure time as they need, while the ISO invariant Sony and Nikons exceed at nightscape shooting where exposures are often limited and plagued by dark shadows and noise.

Sony vs Nikon vs Canon-LENR Off and On
COLORED STARS COMPARISON
The Sony shows a propensity to render small stars in many vivid and unreal colors. The Nikon can do so after LENR is applied. The Canon is more neutral and natural.

So the pixel-peeping continues!

I hope you found these latest tests of interest.

— Alan, May 31, 2018 / Revised June 6, 2018 & March 27, 2019 / © 2018 Alan Dyer / AmazingSky.com