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.

UPDATE — November 25, 2019

As part of further testing I shot the Heart and Soul Nebulas in Cassiopeia through my little Borg 77mm f/4 astrograph with both the EOS Ra and my filter-modified 5D MkII (modified years ago by AstroHutech) to compare which pulled in more nebulosity. It looked like a draw.

Both images are single 8-minute exposures, taken minutes apart and developed identically in Adobe Camera Raw, but adjusted for colour balance to equally neutralize the sky background. The histograms look similar. Even so, the Ra looks a little redder overall. But keep in mind a sky or nebula can be made to appear any shade of red you like in processing.

The question is which camera shows more faint nebulosity?

The modified 5D MkII has always been my favourite camera for this type of astrophotography, picking up more nebulosity than other “a” models I’ve tested, including the Nikon D810a.

But in this case, I’d say the EOS Ra is performing as well as, if not better than the 5D MkII. How well any third-party modified camera you buy now performs will depend which, if any, filter the modifier installs in front of the sensor. So your mileage will vary.

EOS Ra and 5D MkII Comparison


For most of my other 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 magnification is very nice.

• The EOS Ra also carries a 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 25, 2019 / © 2019 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 

 

 

Touring the Wonders of the Winter Sky


The Wonders of the Winter Sky

I present a tour of the deep-sky wonders of the winter sky.

While some might think the Milky Way is only a summer sight, the winter Milky Way is well worth a look!

In January and February we are looking outward from our location in the Milky Way, toward the Orion Spur, the minor spiral arm we live in. In it, and in the major Perseus Arm that lies beyond, lie hotbeds of star formation.

Artist's impression of the Milky Way (updated - annotated)
Courtesy European Southern Observatory

These star forming areas create a panorama of star clusters and glowing nebulas along the winter Milky Way and surrounding the constellation of Orion. The montage above shows the best of the deep-sky sights at this time or year.

(And yes, for southern hemisphere viewers I know this is your summer sky! But for us northerners, Orion is forever associated with frosty winter nights.)

The closeups below are all with a 200mm telephoto lens providing a field of view similar to that of binoculars. However, most of these nebulas are photographic targets only.


The Belt and Sword of Orion

The Belt and Sword of Orion with Barnard's Loop
This is a stack of 16 x 2- to 3-minute exposures with the filter-modified Canon 5D MkII at ISO 800 to 1250 and 200mm Canon L-Series lens at f/2.8. Taken with the Fornax Lightrack tracker as part of testing. Taken from home on January 8, 2019 during a clear couple of hours between passing haze and cloud.

This is the heart of the star formation activity, in the centre of Orion.

The bright Orion Nebula (or Messier 42 and 43) at bottom in Orion’s Sword is obvious in binoculars and glorious in a small telescope.

The Horsehead Nebula above centre and just below Orion’s Belt is famous but is a tough target to see through even a large telescope.

Barnard’s Loop at left is a wave of nebulosity being blown out of the Orion area by strong stellar winds. Any sighting of this object by eye is considered a feat of observing skill!


The Rosette Nebula and Area

Rosette and Christmas Tree Cluster with 200mm
The area of the Rosette Nebula (bottom) and Christmas Tree Cluster (top) in Monoceros with the Fornax Lightrack tracker and 200mm lens and filter modified Canon 5D MkII. This is a stack of 10 x 3 minute exposures at ISO 800.

The small cluster of hot young stars inside the Rosette Nebula is blowing a hole in the nebula giving it its Rosette name. Above is a loose star cluster called the Christmas Tree, surrounded by more faint nebulosity that includes the tiny Cone Nebula.


Gemini Clusters and Nebulas

The Clusters and Nebulas of Gemini
This is a stack of 10 x 3-minute exposures with the filter-modified Canon 5D MkII at ISO 800 and 200mm Canon L-Series lens at f/2.8. Some light haze passing through in some exposures added the natural star glows. I left those in as part of the stack to add the glows. Taken with the Fornax Lightrack tracker as part of testing. Taken from home on a rare fine and mild winter night, January 4, 2019.

This field of clusters and nebulosity is above Orion in Gemini, with Messier 35 the main open star cluster here at top. Below M35 is the tiny star cluster NGC 2158. The nebulosity at left between Mu and Eta Geminorum is IC 443, a remnant of a supernova explosion, and is aka the Jellyfish Nebula. The nebula at bottom is IC 2174, just over the border in Orion and aka the Monkeyhead Nebula.


Auriga Clusters and Nebulas

The Clusters and Nebulas of Auriga
This is a stack of 5 x 3-minute exposures with the filter-modified Canon 5D MkII at ISO 800 and 200mm Canon L-Series lens at f/2.8. Taken with the Fornax Lightrack tracker as part of testing. Diffraction spikes added with Astronomy Tools actions. Taken from home on January 4, 2019.

Above Gemini and Orion lies Auriga, with its rich field of clusters and nebulosity, with — from left to right — Messier 37, Messier 36, and Messier 38, as the main open star clusters here. Below M38 is NGC 1907. The nebulosity at right is IC 410 and IC 405, the Flaming Star Nebula.

In between them is the colourful asterism known as the Little Fish. Messier 38 is also known as the Starfish Cluster while Messier 36 is called the Pinwheel Cluster. The bright red nebula at top is Sharpless 2-235. The little nebulas at centre are NGC 1931 and IC 417.


The California Nebula

The California Nebula in Perseus
This is a stack of 5 x 3-minute exposures with the filter-modified Canon 5D MkII at ISO 800 and 200mm Canon L-Series lens at f/2.8. An additional exposure taken through the Kenko Softon A filter is layered in to add the star glows to bring out their colours. Taken with the Fornax Lightrack tracker. Taken from home on a rare fine and mild winter night, January 4, 2019.

Now we enter Perseus, more an autumn constellation but well up through most of the winter months. It contains the aptly named California Nebula, NGC 1499, at top left, with the bright star Zeta Persei. at bottom A small region of reflection nebulosity, IC 348, surrounds the star Atik, or Omicron Persei, at bottom right. The star just below NGC 1499 is Menkib, or Xi Persei, and is likely energizing the nebula.


The Pleiades, or Seven Sisters

Pleiades M45 with 200mm Lens
The Pleiades with the Fornax Lightrack tracker and 200mm lens + Canon 5D MkII in a stack of 10 x 3 minute exposures at ISO 800.

Obvious to the eye and central to the sky lore of many cultures is the Pleiades, aka the Seven Sisters, in Taurus the bull. It is also called Messier 45.

This is a newly formed cluster of hundreds of stars, passing through a dusty region of the Milky Way, which adds the fuzzy glows around the stars — an example of a reflection nebula, glowing blue as it reflects the blue light of the young stars.


The Hyades

The Hyades Star Cluster with NGC 1647 in Taurus
This is a stack of 5 x 2-minute exposures with the Canon 5D MkII at ISO 800 and 200mm Canon L-Series lens at f/2.8. An additional exposure taken through the Kenko Softon A filter is layered in to add the star glows to bring out their colours. Taken with the Fornax Lightrack tracker. Diffraction spikes added with Astronomy Tools actions for artistic effect.

Below the Pleiades in Taurus lies the larger Hyades star cluster. The V-shaped cluster stars are all moving together and lie about 150 light years away. Bright yellow Aldebaran, the eye of Taurus, is an intruder and lies at only half that distance, so is not a member of Hyades but is a more nearby star. The smaller, more distant star cluster NGC 1647 appears at left.


Seagull Nebula

Seagull Nebula and Sirius with 200mm
This is a stack of 10 x 3 minute exposures at ISO 800 (with the filter-modified Canon 5D MkII and Canon 200mm lens at f/2.8). The rings of colour around Sirius are an artifact of the sensor filter, I think!

Low in my northern winter sky is the brightest star in the sky of any season, Sirius. Just above and to the east of Sirius lies the Seagull Nebula (at top left), also called IC 2177, on the Canis Major-Monoceros border. Like many of these nebulas. the Seagull is too faint to easily see even with a telescope, but shows up well in photographs.


Lambda Orionis Nebula

Lambda Orionis Nebula with 200mm
With the Fornax Lightrack tracker and 200mm lens and filter-modified Canon 5D MkII. A stack of 10 x 3 minute exposures at ISO 800 with the filter-modified Canon 5D MkII and Canon 200mm lens at f/2.8.

This is the head of Orion, with the red supergiant star Betelgeuse at bottom left and the blue giant star Bellatrix right at bottom right. The brightest star at top is Meissa or Lambda Orionis, and is surrounded by a large and very faint area of hydrogen nebulosity. The open cluster around Meissa is catalogued as Collinder 69.

While the winter Milky Way might not look as bright and spectacular as the summer Milky Way of Sagittarius and Scorpius, it does contains a wealth of wonders that are treats for the eye and telescope … and for the camera.

PS.: The techniques for taking and processing images like these form the content of our new Deep Sky with Your DSLR video course now being promoted on KickStarter until the end of February, and available for purchase once it is published later this spring.

See my previous blog post for details.  Thanks and clear skies!

— Alan, February 17, 2019 / © 2019 Alan Dyer / AmazingSky.com 

 

How to Shoot “Deep-Sky with Your DSLR”


KSPage-Feb7We’ve embarked upon a new project to produce a comprehensive tutorial on deep-sky imaging with DSLR cameras.

This past week we launched a new KickStarter campaign to fund the production of a new multi-hour video course on how to capture deep-sky objects using entry-level telescope gear and DSLR cameras.

The emphasis in the course will be on techniques for taking and processing publication-quality images as simply and easily as possible.

A Frosty Telescope Shooting Andromeda

The final video course will consist of several programs, including a video of one of our annual “Deep-Sky with Your DSLR” workshops presented locally here in Alberta. We’ve often had requests for a video version of those workshops, for those who cannot attend in person.

This is it! Here’s a short preview of some of the content.

 

We include the Workshop video, but we supplement it with much more: with video segments shot in the field by day and by night, showing how to setup and use gear, and shot in the studio showing how to process images.

Deep-Sky Photo Session in the Backyard

While much of the content has been shot and edited, there’s more to do yet. Thus our KickStarter campaign to complete the funding and production. Backers of the project through KickStarter will get the final videos at a substantial discount off the final retail price.

All the details are on the project’s KickStarter page. Click through for the listing of course content, and options for funding levels. An FAQ page answers many of the common questions.

A week into the campaign and we’re just over 50% funded, but we have a way to go yet!

M31 with Orion 80mm Apo and Celestron AVX Mount (Multiple Exposu

We hope you’ll consider backing our project, which we think will be unique on the market.

Clear skies!

— Alan, February 7, 2019 / © 2019 / 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 

 

Testing the Canon 6D Mark II for Deep-Sky


6D MkII on Cygnus

Following up on my earlier tests, I compare the new Canon 6D MkII camera to earlier Canon full-frame models in long, tracked exposures of the Milky Way.

A month ago I published tests of the new Canon 6D MkII camera for nightscape images, ones taken using a fixed tripod in which exposures usually have to be limited to no longer than 30 to 60 seconds, to prevent star trailing.

Despite these short exposures, we still like to extract details from the dark shadows of the scene, making nightscape images a severe test of any camera.

I refer you to my August 9, 2017 blog Testing the Canon 6D MkII for Nightscapes for the results. The 6D MkII did not fare well.

Here I test the 6D MkII for what, in many respects, is a less demanding task: shooting long exposures of deep-sky objects, the Milky Way in Cygnus in this case.

Why is this an easier task? The camera is now on a tracking mount (I used the new Sky-Watcher Star Adventurer Mini) which is polar aligned to follow the rotation of the sky. As such, exposures can now be many minutes long if needed. We can give the camera sensor as much signal as the darkness of the night sky allows. More signal equals less noise in the final images.

In addition, there are no contrasty, dark shadows where noise lurks. Indeed, the subjects of deep-sky images are often so low in contrast, as here, they require aggressive contrast boosting later in processing to make a dramatic image.

While that post-processing can bring out artifacts and camera flaws, as a rule I never see the great increase in noise, banding, and magenta casts I sometimes encounter when processing short-exposure nightscape scenes.


6D MkII at Four ISOs
The Canon 6D MkII at four typical ISO speeds in tracked exposures.

6D at Four ISOs
The original Canon 6D at four typical ISO speeds in tracked exposures.

5D MkII at Four ISOs
A Canon 5D MkII that has been filter-modified at four typical ISO speeds in tracked exposures.
For this test, I shot the same region of sky with the same 35mm lens L-Series lens at f/2.2, using three cameras:

• Canon 6D MkII (2017)

• Canon 6D (2012)

• Canon 5D MkII (2008)

Note that the 5D MkII has been “filter-modified” to make its sensor more sensitive to the deep red wavelengths emitted by hydrogen gas, the main component of the nebulas along the Milky Way. You’ll see how it picks up the red North America Nebula much better than do the two off-the-shelf “stock” cameras. (Canon had their own factory-modified “a” models in years past: the 20Da and 60Da. Canon: How about a 6D MkIIa?)

I shot at four ISO speeds typical of deep-sky images: 800, 1600, 3200, and 6400.

Exposures were 4 minutes, 2 minutes, 1 minute, and 30 seconds, respectively, to produce equally exposed frames with a histogram shifted well to the right, as it should be for a good signal-to-noise ratio.

Noisy deep-sky images with DSLR cameras are usually the result of the photographer underexposing needlessly, often in the mistaken belief that doing so will reduce noise when, in fact, it does just the opposite.

The above set of three images compares each of the three cameras at those four ISO speeds. In all cases I have applied very little processing to the images: only a lens correction, some sharpening, a slight contrast and clarity increase, and a slight color correction to neutralize the background sky.

However, I did not apply any luminance noise reduction. So all the images are noisier than what they would be in a final processed image.

Even so, all look very good. And with similar performance.

All frames were shot with Long Exposure Noise Reduction (LENR) on, for an automatic dark frame subtraction by the camera. I saw no artifacts from applying LENR vs. shots taken without it.

The 6D and 6D MkII perhaps show a little less noise than the old 5D MkII, as they should being newer cameras.

The 6D MkII also shows a little less pixelation on small stars, as it should being a 26 megapixel camera vs. 20 to 21 megapixels for the older cameras. However, you have to examine the images at pixel-peeping levels to see these differences. Nevertheless, having higher resolution without the penalty of higher noise is very welcome.


3 Canons at ISO 1600
The three cameras compared at ISO 1600. Note the histogram and region of the frame we are examining up close.

3 Canons at ISO 3200
The three cameras compared at ISO 3200. Note the histogram and region of the frame we are examining up close.

3 Canons at ISO 6400
The three cameras compared at ISO 6400. Note the histogram and region of the frame we are examining up close.
Above, I show images from the three cameras side by side at ISOs 1600, 3200, and 6400. It is tough to tell the difference in noise levels, the key characteristic for this type of astrophotography.

The new 6D MkII shows very similar levels of noise to the 6D, perhaps improving upon the older cameras a tad.

Because images are well-exposed (note the histogram at right), the 6D MkII is showing none of the flaws of its lower dynamic range reported elsewhere.

That’s the key. The 6D MkII needs a well-exposed image. Given that, it performs very well.


3 Canons Stacked & Processed
The three cameras in stacked and processed final images.
This version shows the same images but now with stacked frames and with a typical level of processing to make a more attractive and richer final image. Again, all look good, but with the modified camera showing richer nebulosity, as they do in deep-sky images.

The lead image at the very top is a final full-frame image with the Canon 6D MkII.


As such, based on my initial testing, I can recommend the Canon 6D MkII (and plan to use it myself) for deep-sky photography.

Indeed, I’ll likely have the camera filter-modified to replace my vintage yet faithful 5D MkII for most of my deep-sky shooting. The 6D MkII’s tilting LCD screen alone (a neck, back, and knee saver when attached to a telescope!) makes it a welcome upgrade from the earlier cameras.

The only drawback to the 6D MkII for deep-sky work is its limited dark frame buffer. As noted in my earlier review, it can shoot only three Raw files in rapid succession with Long Exposure Noise Reduction turned on. The 5D MkII can shoot five; the 6D can shoot four. (A 6D MkIIa should have this buffer increased to at least 4, if not 8 images.)

I make use of this undocumented feature all the time to ensure cleaner images in long deep-sky exposures, as it produces and subtracts dark frames with far greater accuracy than any taken later and applied in post-processing.


I hope you’ve found this report of interest.

With the 6D MkII so new, and between smoky skies and the interference of the Moon, I’ve had only one night under dark skies to perform these tests. But the results are promising.

For more tips on deep-sky imaging and processing see my pages on my website:

Ten Tips for Deep-Sky Images

Ten Steps to Deep-Sky Processing

Thanks and clear skies!

— Alan, September 7, 2017 / © 2017 Alan Dyer / amazingsky.com

 

A Cosmic Christmas Wreath


IC 1396 & Garnet Star in Cepheus

A cosmic Christmas wreath glows in the sky, adorned by a celestial garnet.

This nebula, known as IC 1396, shines in the constellation of Cepheus the king, now high overhead on early winter evenings in the northern hemisphere. It’s a bubble of gas blown by new stars amid the interstellar wreath.

At top, shining like a Christmas light on the wreath, is an orange star. This is Mu Cephei, also known as the Garnet Star. It’s a red supergiant, roughly 1,500 times bigger than our Sun. If it replaced our Sun at the centre of our solar system it would engulf all the planets out to and including Jupiter.

Be happy Mu sits 1,000 light years away!

Happy holidays! And happy solstice. Winter arrives in the northern hemisphere at 6:03 p.m. EST on Sunday, December 21. That’s the shortest day and longest night of the year, for all those north of the equator.

– Alan, December 20, 2014 / © 2014 Alan Dyer