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. (Sorry, Canon and Nikon users, it is not available for other lens mounts.)

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.


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 (it is not available for other lens mounts), for nightscape still and video shooting.

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

Photographing the Total Eclipse of the Moon

Lunar Eclipse CompositeOn the evening of January 20 for North America, the Full Moon passes through the umbral shadow of the Earth, creating a total eclipse of the Moon. 

No, this isn’t a “blood,” “super,” nor “wolf” Moon. All those terms are internet fabrications designed to bait clicks.

It is a   total   lunar  eclipse  — an event that doesn’t need sensational adjectives to hype, because they are always wonderful sights! And yes, the Full Moon does turn red.

As such, on January 20 the evening and midnight event provides many opportunities for great photos of a reddened Moon in the winter sky. 

Here’s my survey of tips and techniques for capturing the eclipsed Moon. 

First … What is a Lunar Eclipse?

As the animation below shows (courtesy NASA/Goddard Space Flight Center), an eclipse of the Moon occurs when the Full Moon (and they can happen only when the Moon is exactly full) travels through the shadow of the Earth. 

The Moon does so at least two times each year, though often not as a total eclipse, one where the entire disk of the Moon enters the central umbral shadow. Many lunar eclipses are of the imperceptible penumbral variety, or are only partial eclipses.

Total eclipses of the Moon can often be years apart. The last two were just last year, on January 31 and July 27, 2018. However, the next is not until May 26, 2021.

For a short explanation of the geometry of lunar eclipses see the NASA/Goddard video at https://svs.gsfc.nasa.gov/11516 

At any lunar eclipse we see an obvious darkening of the lunar disk only when the Moon begins to enter the umbra. That’s when the partial eclipse begins, and we see a dark bite appear on the left edge of the Moon. 

While it looks as if Earth’s shadow sweeps across the Moon, it is really the Moon moving into, then out of, our planet’s umbra that causes the eclipse. We are seeing the Moon’s revolution in its orbit around Earth. 

At this eclipse the partial phases last 67 minutes before and after totality. 

Telescope CU-Stages
This shows the length of the eclipse phases relative to the start of the partial eclipse as the Moon begins to enter the umbra at right. The Moon’s orbital motion takes it through the umbra from right to left (west to east) relative to the background stars. The visible eclipse ends 196 minutes (3 hours and 16 minutes) after it began. Click or tap on the charts to download a high-res version.

Once the Moon is completely immersed in the umbra, totality begins and lasts 62 minutes at this eclipse, a generous length. 

The Moon will appear darkest and reddest at mid-eclipse. During totality the lunar disk is illuminated only by red sunlight filtering through Earth’s atmosphere. It is the light of all the sunsets and sunrises going on around our planet. 

And yes, it is perfectly safe to look at the eclipsed Moon with whatever optics you wish. Binoculars often provide the best view. Do have a pair handy!

Total Lunar Eclipse (December 20/21, 2010)
Total eclipse of the Moon, December 20/21, 2010, taken from home with 130mm AP apo refractor at f/6 and Canon 7D at ISO 400 for 4 seconds, single exposure, shortly after totality began.

At this eclipse because the Moon passes across the north half of the umbra, the top edge of the Moon will always remain bright, as it did above in 2010, looking like a polar cap on the reddened Moon.

Near the bright edge of the umbra look for subtle green and blue tints the eye can see and that the camera can capture.

Where is the Eclipse?

As the chart below shows, all of the Americas can see the entire eclipse, with the Moon high in the evening or late-night sky. For the record, the Moon will be overhead at mid-eclipse at local midnight from Cuba!

All of the Americas can see this eclipse. The eclipse gets underway as the Moon sets at dawn over Europe. Diagram courtesy EclipseWise.com

For more details on times see www.EclipseWise.com and the event page at http://www.eclipsewise.com/lunar/LEprime/2001-2100/LE2019Jan21Tprime.html 

I live in Alberta, Canada, at a latitude of 50 degrees North. And so, the sky charts I provide here are for my area, where the Moon enters the umbral shadow at 8:35 p.m. MST with the Moon high in the east. By the end of totality at 10:44 p.m. MST the Moon shines high in the southeast. This sample chart is for mid-eclipse at my site.

Framing TL-Mid-Eclipse
The sky at mid-eclipse from my Alberta site. Created with the planetarium software Starry Night, from Simulation Curriculum.

I offer them as examples of the kinds of planning you can do to ensure great photos. I can’t provide charts good for all the continent because exactly where the Moon will be during totality, and the path it will take across your sky will vary with your location. 

In general, the farther east and south you live in North America the higher the Moon will appear. But from all sites in North America the Moon will always appear high and generally to the south. 

To plan your local shoot, I suggest using planetarium software such as the free Stellarium or Starry Night (the software I used to prepare the sky charts in this post), and photo planning apps such as The Photographer’s Ephemeris or PhotoPills. 

The latter two apps present the sightlines toward the Moon overlaid on a map of your location, to help you plan where to be to shoot the eclipsed Moon above a suitable foreground, if that’s your photographic goal. 

When is the Eclipse?

While where the Moon is in your sky depends on your site, the various eclipse events happen at the same time for everyone, with differences in hour due only to the time zone you are in. 

While all of North America can see the entirety of the partial and total phases of this eclipse (lasting 3 hours and 16 minutes from start to finish), the farther east you live the later the eclipse occurs, making for a long, late night for viewers on the east coast. 

Those in western North America can enjoy all of totality and be in bed at or before midnight.

Here are the times for the start and end of the partial and total phases. Because the penumbral phases produce an almost imperceptible darkening, I don’t list the times below for the start and end of the penumbral eclipse. 

Eclipse Times Table

PM times are on the evening of January 20.

AM times are after midnight on January 21.

Note that while some sources list this eclipse as occurring on January 21, that is true for Universal Time (Greenwich Time) and for sites in Europe where the eclipse occurs at dawn near moonset. 

For North America, if you go out on the evening of January 21 expecting to see the eclipse you’ll be a day late and disappointed! 

Picking a Photo Technique

Lunar eclipses lend themselves to a wide range of techniques, from a simple camera on a tripod, to a telescope on a tracking mount following the sky. 

If this is your first lunar eclipse I suggest keeping it simple! Select just one technique, to focus your attention on only one camera on a cold and late winter night. 

Lunar Eclipse Closeup with Stars
The total eclipse of the Moon of September 27, 2015, through a telescope, at mid-totality with the Moon at its darkest and deepest into the umbral shadow, in a long exposure to bring out the stars surrounding the dark red moon. This is a single exposure taken through a 92mm refractor at f/5.5 for 500mm focal length using the Canon 60Da at ISO 400 for 8 seconds. The telescope was on a SkyWatcher HEQ5 equatorial mount tracking at the lunar rate.

Then during the hour of totality take the time to enjoy the view through binoculars and with the unaided eye. No photo quite captures the glowing quality of an eclipsed Moon. But here’s how to try it.

Option 1: Simple — Camera-on-Tripod

The easiest method is to take single shots using a very wide-angle lens (assuming you also want to include the landscape below) with the camera on a fixed tripod. No fancy sky trackers are needed here. 

During totality, with the Moon now dimmed and in a dark sky, use a good DSLR or mirrorless camera in Manual (M) mode (not an automatic exposure mode) for settings of 2 to 20 seconds at f/2.8 to f/4 at ISO 400 to 1600. 

That’s a wide range, to be sure, but it will vary a lot depending on how bright the sky is at your site. Shoot at lots of different settings, as blending multiple exposures later in processing is often the best way to reproduce the scene as your eyes saw it. 

Shoot at a high ISO if you must to prevent blurring from sky motion. However, lower ISOs, if you can use them by choosing a slower shutter speed or wider lens aperture, will yield less digital noise.

Focus carefully on a bright star, as per the advice below for telephoto lenses. Don’t just set the lens focus to infinity, as that might not produce the sharpest stars.

Total Lunar Eclipse (December 20/21, 2010)
Total eclipse of the Moon, December 20/21, 2010, with 15mm lens at f/3.2 and Canon 5D MkII at ISO 1600 for a 1-minute tracked exposure. Without a tracker, use shorter exposures (less than 20 seconds) and higher ISOs or wider apertures to avoid trailing,

One scene to go for at this eclipse is similar to the above photo, with the reddened Moon above a winter landscape and shining east of Orion and the winter Milky Way. But that will require shooting from a dark site away from urban lights. But when the Moon is totally eclipsed, the sky will be dark enough for the Milky Way to appear. 

Framing Eclipse Sky
Click or tap on any of the charts to download a high-resolution copy.

The high altitude of the Moon at mid-eclipse from North America (with it 40 to 70 degrees above the horizon) will also demand a lens as wide as 10mm to 24mm, depending whether you use portrait or landscape orientation, and if your camera uses a cropped frame or full frame sensor. The latter have the advantage in this category of wide-angle nightscape. 

Framing Winter Milky Way & Moon

Alternatively, using a longer 14mm to 35mm lens allows you to frame the Moon beside Orion and the winter Milky Way, as above, but without the landscape. Again, this will require a dark rural site.

If you take this type of image with a camera on a fixed tripod, use high ISOs to keep exposures below 10 to 20 seconds to avoid star trailing. You have an hour of totality to shoot lots of exposures to make sure some will work best.

Total Lunar Eclipse, Dec 20, 2010 24mm Wide-Angle
Total eclipse of the Moon, December 20/21, 2010, with Canon 5D MKII and 24mm lens at f2.8 for stack of four 2-minute exposures at ISO 800. Taken during totality using a motorized sky tracker. The eclipsed Moon is the red object above Orion, and the stars appear bloated due to high haze and fog rolling in.

If you have a sky tracker to follow the stars, as I did above, exposures can be much longer — perhaps a minute to pick up the Milky Way really well — and ISOs can be lower to avoid noise. 

Option 1 Variation — Urban Eclipses

Unfortunately, point-and-shoot cameras and so-called “bridge” cameras, ones with non-interchangeable lenses, likely won’t have lenses wide enough to capture the whole scene, landscape and all. Plus their sensors will be noisy when used at high ISOs. Those cameras might be best used to capture moderate telephoto closeups at bright urban sites. 

With any camera, at urban sites look for scenic opportunities to capture the eclipsed Moon above a skyline or behind a notable landmark. By looking up from below you might be able to frame the Moon beside a church spire, iconic building, or a famous statue using a normal or short telephoto lens, making this a good project for those without ultra-wide lenses.

Total Lunar Eclipse, Feb. 20, 2008
Lunar eclipse, Feb 20, 2008 with a 135mm telephoto and Canon 20Da camera showing the Moon’s size with such a lens and cropped-frame camera. This is a blend of 8-second and 3-second exposures to bring out stars and retain the Moon. Both at ISO200 and f/2.8. Saturn is at lower left and Regulus at upper right.

Whatever your lens or subject, at urban sites expose as best you can for the foreground, trying to avoid any bright and bare lights in the frame that will flood the image with lens flares in long exposures. 

Capturing such a scene during the deep partial phases might produce a brighter Moon that stands out better in an urban sky than will a photo taken at mid-totality when the Moon is darkest. 

TIP: Practice, Practice, Practice!

With any camera, especially beginner point-and-shoots, ensure success on eclipse night by practicing shooting the Moon before the eclipse, during the two weeks of the waxing Moon leading up to Full Moon night and the eclipse.

The crescent Moon with Earthshine on the dark side of the Moon is a good stand-in for the eclipsed Moon. Set aside the nights of January 8 to 11 to shoot the crescent Moon. Check for exposure and focus. Can you record the faint Earthshine? It’s similar in brightness to the shadowed side of the eclipsed Full Moon.

The next week, on the nights of January 18 and 19, the waxing gibbous Moon will be closer to its position for eclipse night and almost as bright as the uneclipsed Full Moon, allowing some rehearsals for shooting it near a landmark.

Option 2: Advanced — Multiple Exposures

An advanced method is to compose the scene so the lens frames the entire path of the Moon for the 3 hours and 16 minutes from the start to the end of the partial eclipse. 

Framing TL-Start of Eclipse
This set of 3 charts shows the position of the Moon at the start, middle, and end of the eclipse, for planning lens choice and framing of the complete eclipse path. The location is Alberta, Canada.

Framing TL-Mid-Eclipse

Framing TL-End of Eclipse

As shown above, including the landscape will require at least a 20mm lens on a full frame camera, or 12mm lens on a cropped frame camera. However, these charts are for my site in western Canada. From sites to the east and south where the Moon is higher an even wider lens might be needed, making this a tough sequence to take.

With wide lenses, the Moon will appear quite small. The high altitude of the Moon and midnight timing won’t lend itself to this type of multiple image composite as well as it does for eclipses that happen near moonrise or moonset, as per the example below. 

Lunar Eclipse From Beginning to End, To True Scale
This is a multiple-exposure composite of the total lunar eclipse of Sunday, September 27, 2015, as shot from Writing-on-Stone Provincial Park, Alberta, Canada. For this still image composite of the eclipse from beginning to end, I selected just 40 frames taken at 5-minute intervals, out of 530 I shot in total, taken at 15- to 30-second intervals for the full time-lapse sequence included below.

A still-image composite with the lunar disks well separated will need shots only every 5 minutes, as I did above for the September 27, 2015 eclipse. 

Exposures for any lunar eclipse are tricky, whether you are shooting close-ups or wide-angles, because the Moon and sky change so much in brightness. 

As I did for the image below, for a still-image composite, you can expose just for the bright lunar disk and let the sky go dark.

Exposures for just the Moon will range from very short (about 1/500th second at f/8 and ISO 100) for the partials, to 1/2 to 2 seconds at f/2.8 to f/4 and ISO 400 for the totals, then shorter again (back to 1/500 at ISO 100) for the end shots when the Full Moon has returned to its normal brilliance. 

That’ll take constant monitoring and adjusting throughout the shoot, stepping the shutter speed gradually longer thorough the initial partial phase, then shorter again during the post-totality partial phase.

You’d then composite and layer (using a Lighten blend mode) the well-exposed disks (surrounded by mostly black sky) into another background image exposed longer for 10 to 30 seconds at ISO 800 to 1600 for the sky and stars, shot at mid-totality.

To maintain the correct relative locations of the lunar disks and foreground, the camera cannot move.

Lunar Eclipse Sequence from Monument Valley
The total lunar eclipse of April 4, 2015 taken from near Tear Drop Arch, in western Monument Valley, Utah. I shot the totality images during the short 4 minutes of totality. The mid-totality image is a composite of 2 exposures: 30 seconds at f/2.8 and ISO 1600 for the sky and landscape, with the sky brightening blue from dawn twilight, and 1.5 seconds at f/5.6 and ISO 400 for the disk of the Moon itself. Also, layered in are 26 short exposures for the partial phases, most being 1/125th sec at f/8 and ISO 400, with ones closer to totality being longer, of varying durations.

That technique works best if it’s just a still image you are after, such as above. This image is such a composite, of the April 4, 2015 total lunar eclipse from Monument Valley, Utah.

This type of composite takes good planning and proper exposures to pull off, but will be true to the scene, with the lunar disk and its motion shown to the correct scale and position as it was in the sky. It might be a composite, but it will be accurate.

My Rant! 

That’s in stark contrast to the flurry of ugly “faked” composites that will appear on the web by the end of the day on January 21, ones with huge telephoto Moons pasted willy-nilly onto a wide-angle sky.

Rather than look artistic, most such attempts look comically cut-and-pasted. They are amateurish. Don’t do it!  

Option 3: Advanced — Wide-Angle Time-Lapses

If it’s a time-lapse movie you want (see the video below), take exposures every 10 to 30 seconds, to ensure a final movie with smooth motion.

Unlike shooting for a still-image composite, for a time lapse each frame will have to be exposed well enough to show the Moon, sky, and landscape. 

That will require exposures long enough to show the sky and foreground during the partial phases — likely about 1 to 4 seconds at f/2.8 and ISO 400. In this case, the disk of the partially-eclipsed Moon will greatly overexpose, as it does toward the end of the above time-lapse from September 27, 2015.. 

But the Moon will darken and become better exposed during the late stages of the partial eclipse and during totality when a long exposure — perhaps now 10 to 20 seconds at f/2.8 and ISO 800 to 1600 — will record the bright red Moon amid the stars and winter Milky Way. 

Maintaining a steady cadence during the entire sequence requires using an interval long enough throughout to accommodate the expected length of the longest exposure at mid-totality, with similar camera settings to what you’ve used for other Milky Way nightscapes. If you’ve never taken those before, then don’t attempt this complex sequence. 

After totality, as the Moon and sky re-brighten, exposures will have to shorten again, and  symmetrically in reverse fashion for the final partial phases.

Such a time-lapse requires consistently and incrementally adjusting the camera over the three or more hours of the eclipse on a cold winter night. The high altitude of the Moon and its small size on the required wide angle lenses will make any final time lapse less impressive than at eclipses that occur when the Moon is rising or setting. 

But … the darkening of the sky and “turning on” of the Milky Way during totality will make for an interesting time-lapse effect. The sky and scene will be going from a bright fully moonlit night to effectively a dark moonless night, then back to moonlit. It’s a form of “holy grail” time lapse, requiring advanced processing with LRTimelapse software. 

Again, do not move the camera. Choose your lens and frame your camera to include the entire path of the Moon for as long as you plan to shoot. 

Even if the final movie looks flawed, individual frames should still produce good still images, or a composite built from a subset of the frames. 

Option 4: Simple — Telephoto Close-Ups

The first thought of many photographers is to shoot the eclipse with as long a telephoto lens as possible. That can work, but …

The harsh reality is that the Moon is surprisingly small (only 1/2-degree across) and needs a lot of focal length to do it justice, if you want a lunar close-up.

Telescope FOV-400 & 800mm

You’ll need a 300mm to 800mm lens. Unfortunately, the Moon and sky are moving and any exposures over 1/4 to 2 seconds (required during totality) will blur the Moon badly if its disk is large on the frame and all you are using is a fixed tripod.

If you don’t have a tracking mount, one solution is to keep the Moon’s disk small (using no more than a fast f/2 or f/2.8 135mm to 200mm lens) and exposures short by using a high ISO speed of 1600 to 3200. Frame the Moon beside the Beehive star cluster as I show below.

Take a range of exposures. But … be sure to focus!

TIP: Focus! And Focus Again!

Take care to focus precisely on a bright star using Live View. That’s true of any lens but especially telephotos and telescopes. 

Focus not just at the start of the night, but also more than once again later at night. Falling temperatures on a winter night will cause long lenses and telescopes to shift focus. What was sharp at the start of the eclipse won’t be by mid totality. 

The catch is that if you are shooting for a time-lapse or composite you likely won’t be able to re-point the optics to re-focus on a star in mid-eclipse. In that case, be sure to set up the gear well before you want to start shooing to let it cool to ambient air temperature. Now focus on a star, then frame the scene. Then hope the lens doesn’t shift off focus. You might be able to focus on the bright limb of the Moon but it’s risky.

Fuzzy images, not bad exposures, are the ruin of most attempts to capture a lunar eclipse, especially with a telephoto lens. And the Moon itself, especially during totality, is not a good target to focus on. Use a bright star. The winter sky has lots!

Option 5: Advanced — Tracked Telescopic Close-Ups 

If you have a mount that can be polar aligned to track the sky, then many more options are open to you. 

Sigma on SAM on Stars

You can use a telescope mount or one of the compact and portable trackers, such as the Sky-Watcher Star Adventurer (I show the Mini model above) or iOptron Sky Tracker units. While these latter units work great, you are best to keep the payload weight down and your lens size well under 300mm. 

Framing Telephoto CU

That’s just fine for this eclipse, as you really don’t need a frame-filling Moon. The reason is that the Moon will appear about 6 degrees west of the bright star cluster called the Beehive, or Messier 44, in Cancer.

As shown above, a 135mm to 200mm lens will frame this unique pairing well. For me, that will be the signature photo of this eclipse. The pairing can happen only at lunar eclipses that occur in late January, and there won’t be any more of those until 2037! 

That’s the characteristic that makes this eclipse rare and unique, not that it’s a “super-duper, bloody, wolf Moon!” But it doesn’t make for a catchy headline.

Total Lunar Eclipse, Dec 20, 2010 Total HDR
A High Dynamic Range composite of 7 exposures of the Dec 20/21, 2010 total lunar eclipse, from 1/2 second to 30 seconds, to show the more normally exposed eclipsed Moon with the star cluster M35, at left, in Gemini, to show the scene as it appeared in binoculars. Each tracked photo taken with a 77mm Borg apo refractor at f/4.2 (300mm focal length) and Canon 5D MkII at ISO 1600.

Exposures to show the star cluster properly might have to be long enough (30 to 120 seconds) that the Moon overexposes, even at mid-totality. If so, take different exposures for the Moon and stars, then composite them later, as I did above for the December 20, 2010 eclipse near the Messier 35 star cluster in Gemini. 

If really you want to shoot with even more focal length for framing just the Moon, a monster telephoto lens will work, but a small telescope such as an 80mm aperture f/6 to f/7 refractor will provide enough focal length and image size at much lower cost and lighter weight, and be easier to attach to a telescope mount. 

But even with a 500mm to 800mm focal length telescope the Moon fills only a small portion of the frame, though cropped frame cameras have the advantage here. Use one if it’s a big Moon you’re after! 

No matter the camera, the lens or telescope should be mounted on a solid equatorial telescope mount that you must polar align earlier in the night to track the sky. 

Alternatively, a motorized Go To telescope on an alt-azimuth mount will work, but only for single shots. The rotation of the field with alt-az mounts will make a mess of any attempts to shoot multiple-exposure composites or time-lapses, described below. 

Whatever the mount, for the sharpest lunar disks during totality, use the Lunar tracking rate for the motor. 

Total Lunar Eclipse Exposure Series
This series shows the need to constantly shift exposure by lengthening the shutter speed as the eclipse progresses. Do the same to shorten the exposure after totality. The exposures shown here are typical. 

Assuming an f-ratio of f/6 to f/8, exposures will vary from as short as 1/250th second at ISO 100 to 200 for the barely eclipsed Moon, to 4 to 20 seconds at ISO 400 to 1600 for the Moon at mid-totality. 

It’s difficult to provide a precise exposure recommendation for totality because the brightness of the Moon within the umbra can vary by several stops from eclipse to eclipse, depending on how much red sunlight manages to make it through Earth’s atmospheric filter to light the Moon.

TIP: Shoot for HDR

Total Lunar Eclipse, Dec 20, 2010 Partial HDR
Total eclipse of the Moon, December 20/21, 2010, with 5-inch refractor at f/6 (780mm focal length) and Canon 7D (cropped frame camera) at ISO 400. This is an HDR blend of 9 images from 1/125 second to 2 seconds, composited in Photoshop. Note  the blue tint along the shadow edge.

As I did above, during the deep partial phases an option is to shoot both long, multi-second exposures for the red umbra and short, split-second exposures for the bright part of the Moon not yet in the umbra.

Take 5 to 7 shots in rapid succession, covering the range needed, perhaps at 1-stop increments. Merge those later with High Dynamic Range (HDR) techniques and software, or with luminosity masks. 

Even if you’re not sure how to do HDR processing now, shoot all the required exposures anyway so you’ll have them when your processing skills improve. 

Option 6: Advanced — Close-Up Composites and Time-Lapses

With a tracking telescope on an equatorial mount you could fire shots every 10 to 30 seconds, and then assemble them into a time-lapse movie, as below. 

But as with wide-angle time-lapses, that will demand constant attention to gradually and smoothly shift exposures, ideally by 1/3rd-stop increments every few shots during the partial and total phases. Make lots of small adjustments, rather than fewer large ones.

If you track at the lunar rate, as I did above, the Moon should stay more or less centred while it drifts though the stars, assuming your mount is accurately polar aligned, an absolutely essential prerequisite here.  

Lunar Eclipse Composite
Composite image digitally created in Photoshop of images taken during October 27, 2004 total lunar eclipse, from Alberta Canada. Images taken through 5-inch apo refractor at f/6 with Canon Digital Rebel 300D camera at ISO 200.

Conversely, track at the sidereal rate and the stars will stay more or less fixed while the Moon drifts through the frame from right to left (west to east) as I show above in a composite of the October 27, 2004 eclipse.

But such a sequence takes even more careful planning to position the Moon correctly at the start of the sequence so it remains “in frame” for the duration of the eclipse, and ends up where you want at the end.

In the chart below, north toward Polaris is at the top of the frame. Position the Moon at the start of the eclipse so it ends up just above the centre of the frame at mid-eclipse. Tricky! 

Telescope CU-Stages
Repeated from earlier, this chart shows the path of the Moon through the north half of the umbra, a path that will be the same for any site, as will be the timing. North is up here.

As I show above, for this type of “Moon-thru-shadow” sequence a focal length of about 400mm is ideal on a full frame camera, or 300mm on a cropped frame camera.

From such a time-lapse set you could also use several frames selected from key stages of the eclipse, as I did in 2004, to make up a multiple-image composite showing the Moon moving through the Earth’s shadow. 

Again, planetarium software such as Starry Night I used above, which can be set to display the field of view of the camera and lens of your choice, is essential to plan the shoot. Don’t attempt it without the right software to plan the framing. 

I would consider the telescopic time-lapse method the most challenging of techniques. Considering the hour of the night and the likely cold temperatures, your best plan might be to keep it simple. 

It’s what I plan to do.

I’ll be happy to get a tracked telephoto close-up of the Moon and Beehive cluster as my prime goal, with a wide-angle scene of the eclipsed Moon beside Orion and the Milky Way as a bonus. A few telescope close-ups will be even more of a bonus.

The Astrospheric website, with astronomy-oriented weather predictions. It’s also available as a great mobile app.

However, just finding clear skies might be the biggest challenge!

Try the Astrospheric app for astronomy-oriented weather predictions. The Environment Canada data it uses has led me to clear skies for several recent eclipses that other observers in my area missed. 

It’ll be worth the effort to chase!

The next total eclipse of the Moon anywhere on Earth doesn’t occur until May 26, 2021 in an event visible at dawn from Western North America. The next total lunar eclipse visible from all of North America comes a lunar year later, on May 15, 2022. 

Total Lunar Eclipse from Alan Dyer on Vimeo.

I leave you with a music video of the lunar eclipse of September 27, 2015 that incorporates still and time-lapse sequences shot using all of the above methods. 

Good luck and clear skies on eclipse night!

— Alan, January 1, 2019 / © 2019 Alan Dyer / amazingsky.com 


The Fast 14s Face-Off

Sigma and Rokinon 14mm on Stars

I put two new fast 14mm lenses to the test: the Sigma 14mm f/1.8 Art vs. the Rokinon 14mm f/2.4 SP. 

Much to the delight of nightscape and astrophotographers everywhere we have a great selection of new and fast wide-angle lenses to pick from.

Introduced in 2017 are two fast ultra-wide 14mm lenses, from Sigma and from Rokinon/Samyang. Both are rectilinear, not fish-eye, lenses.

I tested the Nikon version of the Sigma 14mm f/1.8 Art lens vs. the Canon version of the Rokinon 14mm f/2.4 SP. I used a Nikon D750 and Canon 6D MkII camera.

I also tested the new faster Rokinon SP against the older and still available Rokinon 14mm f/2.8, long a popular lens among nightscape photographers.

The Sigma 14mm is a fully automatic lens with auto focus. It is the latest in their highly regarded Art series of premium lenses. I have their 20mm and 24mm Art lenses and love them.

The Rokinon 14mm SP (also sold under the Samyang brand) is a manual focus lens, but with an AE chip so that it communicates with the camera. Adjusting the aperture is done on the camera, not by turning a manual aperture ring, as is the case with many of Rokinon’s lower cost series of manual lenses. The lens aperture is then recorded in each image’s EXIF metadata, an aid to later processing. It is part of Rokinon’s premium “Special Performance” SP series which includes an 85mm f/1.2 lens.

All units I tested were items purchased from stock, and were not supplied by manufacturers as samples for testing. I own these!


For those with no time to read the full review, here are the key points:

• The Sigma f/1.8 Art exhibits slightly more off-axis aberrations than the Rokinon 14mm SP, even at the same aperture. But aberrations are very well controlled.

• As its key selling point, the Sigma offers another full stop of aperture over the Rokinon SP (f/1.8 vs. f/2.4), making many types of images much more feasible, such as high-cadence aurora time-lapses and fixed-camera stills and time-lapses of a deeper, richer Milky Way.

• The Sigma also has lower levels of vignetting (darkening of the frame corners) than the Rokinon 14mm SP, even at the same apertures.

• Both the Sigma Art and Rokinon SP lenses showed very sharp star images at the centre of the frame.

• Comparing the new premium Rokinon 14mm SP against the older Rokinon 14mm f/2.8 revealed that the new SP model has reduced off-axis aberrations and lower levels of vignetting than the lower-cost f/2.8 model. However, so it should for double the price or more of the original f/2.8 lens.

• The Rokinon 14mm SP is a great choice for deep-sky imaging where optical quality is paramount. The Sigma 14mm Art’s extra speed will be superb for time-lapse imaging where the f/1.8 aperture provides more freedom to use shorter shutter speeds or lower ISO settings.

Though exhibiting the lowest image quality of the three lenses, the original Rokinon 14mm f/2.8 remains a superb value, at its typical price of $350 to $500. For nightscapers on a budget, it’s an excellent choice.



For all these tests I placed the camera and lens on a tracking mount, the Sky-Watcher Star Adventurer Mini shown below. This allowed the camera to follow the sky, preventing any star trailing. Any distortions you see are due to the lens, not sky motion.

Sigma on SAM on Stars
Star Adventurer Mini Tracker (with Sigma 14mm on Nikon D750)

As I stopped down the aperture, I lengthened the exposure time to compensate, so all images were equally well exposed.

In developing the Raw files in Adobe Camera Raw, I applied a standard level of Contrast (25) and Clarity (50) boost, and a modest colour correction to neutralize the background sky colour. I also applied a standard level of noise reduction and sharpening.

However, I did not apply any lens corrections that, if applied, would reduce lateral chromatic aberrations and compensate for lens vignetting.

So what you see here is what the lens produced out of the camera, with no corrections. Keep in mind that the vignetting you see can be largely compensated for in Raw development, with the provisos noted below. But I wanted to show how much vignetting each lens exhibited.


Stars are the severest test of any lens. Not test charts, not day shots of city skylines. Stars.

The first concern with any fast lens is how sharp the stars are not only in the centre of the frame, but also across the frame to the corners. Every lens design requires manufacturers to make compromises on what lens aberrations they are going to suppress at the expense of other lens characteristics. You can never have it all!

However, for astrophotography we do look for stars to be as pinpoint as possible to the corners, with little coma and astigmatism splaying stars into seagull and comet shapes. Stars should also not become rainbow-coloured blobs from lateral chromatic aberration.


Sigma 14mm Upper L Corner
Sigma 14mm Art – Upper Left Corner Close-up at 5 Apertures
Sigma 14mm Upper R Corner
Sigma 14mm Art – Upper Right Corner Close-up at 5 Apertures

These images show 200% blowups of the two upper corners of the Sigma 14mm Art lens, each at five apertures, from wide open at f/1.8, then stopped down at 1/3rd stop increments to f/2.8. As you would expect, performance improves as you stop down the lens, though some astigmatism and coma are still present at f/2.8.

But even wide open at f/1.8, off-axis aberrations are very well controlled and minimal. You have to zoom up this much to see them.

There was no detectable lateral chromatic aberration.

Aberrations were also equal at each corner, showing good lens centering and tight assembly tolerances.


Rokinon 14mm Upper L Corner
Rokinon 14mm SP at 3 Apertures
Rokinon 14mm Upper R Corner
Rokinon 14mm SP at 3 Apertures

Similarly, these images show 200% blow-ups of the upper corners of the Rokinon SP, at its three widest apertures: f/2.4, f/2.8 and f/3.2.

Star images look tighter and less aberrated in the Rokinon, even when compared at the same apertures.

But images look better on the left side of the frame than on the right, indicating a slight lens de-centering or variation in lens position or figuring, a flaw noted by other users in testing Rokinon lenses. The difference is not great and takes pixel-peeping to see. Nevertheless, it is there, and may vary from unit to unit. This should not be the case with any “premium” lens.


Rokinon vs Sigma (Corner Aberrations)
Rokinon vs. Sigma Corner Aberrations Compared

This image shows both lenses in one frame, at the same apertures, for a more direct comparison. The Rokinon SP is better, but of course, doesn’t go to f/1.8 as does the Sigma.


We don’t want good performance at the corners if it means sacrificing sharp images at the centre of the frame, where other aberrations such as spherical aberration can take their toll and blur images.

These images compare the two lenses in 200% blow-ups of an area in the Cygnus Milky Way that includes the Coathanger star cluster. Both lenses look equally as sharp.


Sigma 14mm Centre
Sigma 14mm Art – Centre of Frame Close-up

Even when wide open at f/1.8 the Sigma Art shows very sharp star images, with little improvement when stopped down. Excellent!


Rokinon 14mm Centre
Rokinon 14mm SP – Centre of Frame Close-up

The same can be said for the Rokinon SP. It performs very well when wide open at f/2.4, with star images as sharp as when stopped down 2/3rds of an f-stop to f/3.2


Rokinon vs Sigma (Centre Aberrations)
Sigma vs. Rokinon Centre Sharpness Compared

This image shows both lenses in one frame, but with the Sigma wide open at f/1.8 and stopped down to f/2.8, vs. the Rokinon wide open at f/2.4 and stopped to f/2.8. All look superb.


The bane of wide-angle lenses is the light fall-off that is inevitable as lens focal lengths decrease. We’d like this vignetting to be minimal. While it can be corrected for later when developing the Raw files, doing so can raise the visibility of noise and discolouration, such as magenta casts. The less vignetting we have to deal with the better.

As with off-axis aberrations, vignetting decreases as lenses are stopped down. Images become more uniformly illuminated across the frame, with less of a “hot spot” in the centre.


Sigma 14mm Vignetting (5 Apertures)
Sigma 14mm Art – Vignetting Compared at 5 Apertures

This set compares the left edge of the frame in the Sigma SP at five apertures, from f/1.8 to f/2.8. You can see how the image gets brighter and more uniform as the lens is stopped down. (The inset image at upper right show what part of the frame I am zooming into.)


Rokinon 14mm Vignetting (3 Apertures)
Rokinon 14mm SP – Vignetting Compared at 3 Apertures

This similar set compares the frame’s left edge in the Rokinon SP at its three widest apertures, from f/2.4 to f/3.2. Again, vignetting improves but is still present at f/3.2.


Rokinon vs Sigma Vignetting
Rokinon vs. Sigma – Vignetting Compared

This compares both lenses at similar apertures side by side for a direct comparison. The Sigma is better than the Rokinon with a much more uniform illumination across the frame.

Sigma 14mm Vignetting at f1.8
Sigma 14mm Art – Vignetting at f/1.8 Maximum Aperture
Rokinon 14mm Vignetting at f2.4
Rokinon 14mm SP – Vignetting at f/2.4 Maximum Aperture

In these two images, above, of the entire frame at their respectively widest apertures, I’d say the Sigma exhibits less vignetting than the Rokinon, even when wide open at f/1.8. The cost for this performance, other than in dollars, is that the Sigma is a large, heavy lens with a massive front lens element.

ROKINON 14mm f/2.4 SP vs. ROKINON 14mm f/2.8 Standard

Even the Rokinon 14mm SP, though a manual lens, carries a premium price, at $800 to $1000 U.S., depending on the lens mount.

Samyang 14mm Lens
The 14mm Rokinon/Samyang f/2.8 Lens

For those looking for a low-cost, ultra-wide lens, the original Rokinon/Samyang 14mm f/2.8 (shown above) is still available and popular. It is a fully manual lens, though versions are available with a AE chip to communicate lens aperture information to the camera.

I happily used this f/2.8 lens for several years. Before I sold it earlier in 2017 (before I acquired the Sigma 14mm), I tested it against Rokinon’s premium SP version.

The older f/2.8 lens exhibited worse off-axis and on-axis aberrations and vignetting than the SP, even with the SP lens set to the same f/2.8 aperture. But image quality of the original lens is still very good, and the price is attractive, at half the price or less, than the 14mm SP Rokinon.


14mm Rokinons Aberrations (Upper L Corner)
Two Rokinons (Older “Standard” vs. new SP) – Upper Left Corner Close-up
14mm Rokinons Aberrations (Upper R Corner)
Two Rokinons (Older “Standard” vs. new SP) – Upper Right Corner Close-up

Here, in closeups of the upper corners, I show the difference between the two Rokinons, the older standard lens on the left, and the new SP on the right.

The SP, as it should, shows lower aberrations and tighter star images, though with the improvement most marked on the left corner; not so much on the right corner. The original f/2.8 lens holds its own quite well.


14mm Rokinons Aberrations (Centre)
Two Rokinons (Older “Standard” vs. new SP) – Centre of Frame Close-up

At the centre of the frame, the difference is more apparent, with the SP lens exhibiting sharper star images than the old 14mm with its generally softer, larger star images. The latter likely has more spherical aberration.


14mm Rokinons Vignetting
Two Rokinons (Older “Standard” vs. new SP) – Vignetting Compared

The new SP lens clearly has the advantage here, with less vignetting and brighter corners even when wide open at f/2.4 than the older lens does at its widest aperture of f/2.8. This is another reason to go for the new SP if image quality is paramount


The new Sigma 14mm Art lens is costly, at $1600 U.S., though with a price commensurate with its focal length and aperture. Other premium lenses in this focal length range, either prime or zoom, from Nikon and Canon sell for much more, and have only an f/2.8 maximum aperture. So in that sense, the Sigma Art is a bargain.

The new Rokinon 14mm SP sells for $800 to $1000, still a premium price for a manual focus lens. But its optical quality competes with the best.

The older Rokinon 14mm f/2.8 is a fantastic value at $350 to $500, depending on lens mount and AE chip. For anyone getting into nightscape and Milky Way photography, it is a great choice.


With such a huge range in price, what should you buy?

A 14mm is a superb lens for nightscape shooting – for sky-filling auroras, for panoramas along the Milky Way, or of the entire sky. But the lens needs to be fast. All three lenses on offer here satisfy that requirement.

Sigma 14mm & Rokinon 14mm SP (Front)
Sigma 14mm Art (left) and Rokinon 14mm SP (right)

SIGMA 14mm f/1.8 ART

If you want sheer speed, this is the lens. It offers a full stop gain over the already fast Rokinon f/2.5, allowing exposures to be half the length, or shooting at half the ISO speed for less noise.

Its fast speed comes into its own for rapid cadence aurora time-lapses, to freeze auroral motion as much as possible in exposures as short as 1 to 2 seconds at a high ISO. The fast speed might also make real-time movies of the aurora possible on cameras sensitive and noiseless enough to allow video shooting at ISO 25,000 and higher, such as the Sony a7s models.

The Sigma’s fast speed also allows grabbing rich images of the Milky Way in exposures short enough to avoid star trailing, either in still images or in time-lapses of the Milky Way in motion.

While the Sigma does exhibit some edge aberrations, they are very well controlled (much less than I see with some 24mm and 35mm lenses I have) and are a reasonable tradeoff for the speed and low level of vignetting, which results in less noisy corners.

Photographers obsess over corner aberrations when, for fixed-camera nightscape shooting, a low level of vignetting is probably more critical. Correcting excessive vignetting introduces noise, while the corner aberrations may well be masked by star trailing. Only in tracked images do corner aberrations become more visible, as in the test images here.

I’d suggest the Sigma is the best choice for nightscape and time-lapse shooting, with its speed allowing for kinds of shots not possible otherwise.

The Sigma also appears to be the best coated of all the lenses, as you can see in the reflections in the lenses in the opening image, and below. However, I did not test the lenses for flares and ghosting.

As a footnote, none of the lenses allow front-mounted filters, and none have filter drawers.

ROKINON 14mm f/2.4 SP

For less money you get excellent optical quality, though with perhaps some worrisome variation in how well the lens elements are figured or assembled, as evidenced by the inconsistent level of aberration from corner to corner.

Nevertheless, stars are tight on- and off-axis, and vignetting is quite low, for corners that will be less noisy when the shadows are recovered in processing.

I’d suggest the Rokinon SP is a great choice if tracked deep-sky images are your prime interest, where off-axis performance is most visible. However, the SP’s inconsistent aberrations from corner to corner are evidence of lower manufacturing tolerances than Sigma’s, so your unit may not perform like mine.

For nightscape work, the SP’s f/2.4 aperture might seem a minor gain over Rokinon’s lower-cost f/2.8 lens. But it is 1/3 of an f-stop. That means, for example, untracked Milky Way exposures could be 30 seconds instead of 40 seconds, short enough to avoid obvious star trailing. At night, every fraction of an f-stop gain is welcome and significant.

ROKINON 14mm f/2.8 Standard

You might never see the difference in quality between this lens and its premium SP brother in images intended for time-lapse movies, even at 4K resolution.

But those intending to do long-exposure deep-sky imaging, as these test images are, will want the sharpest stars possible across the frame. In which case, consider the 14mm SP.

But if price is a prime consideration, the original f/2.8 Rokinon is a fine choice. You’ll need to apply a fair amount of lens correction in processing, but the lens exists in the Camera Raw/Lightroom database, so correction is just a click away.

Sigma and Rokinon 14mm on Stars

That was a lengthy report, I know! But there’s no point in providing recommendations without the evidence to back them up.

All images, other than the opening “beauty shot,” can be clicked/tapped on to download a full-resolution original JPG for closer inspection.

As I’ve just received the Sigma Art lens I’ve not had a chance to shoot any “real” nightscape images with it yet, just these test shots. But for a real life deep-sky image of the Milky Way shot with the Rokinon SP, see this image from Australia. https://flic.kr/p/SSQm7G

I hope you found the test of value in helping you choose a lens.

Clear skies!

— Alan, September 22, 2017 / © 2017 Alan Dyer / amazingsky.com


Last of the Summer Milky Way

Last of the Summer Milky Way

The summer Milky Way sets into the southwest on a late November night. 

On Saturday, November 28, well into winter here in Alberta, the stars of the Summer Triangle and the summer Milky Way set into the southwest on a clear, though slightly hazy, late November night.

This is the last of the summer Milky Way, with the centre of the Galaxy now long gone, but the Summer Triangle stars remaining in the evening sky well into autumn. Glows from light pollution in the west light the horizon, in a quick series of images shot in my rural backyard.

In the Summer Triangle, Vega is at right, as the brightest star; Deneb is above centre, and Altair is below centre, farthest south in the Milky Way.

I shot this as a test image for the Nikkor 14-24mm lens, here wide-open at f/2.8 and at 14mm, where it performs beautifully, with very tight star images to the corners. It does very well at 24mm, too! This is astonishing performance for a zoom lens. It matches or beats many “prime” lenses for quality.

The camera was the 36-megapixel Nikon D810a, Nikon’s “astronomical DSLR” camera, also on test. Here it shows its stuff by picking up the red nebulas in Cygnus and Cepheus.

Thorough tests of both the camera and lens will appear later in the year. Stay tuned.

Do subscribe to my blog (click below) to get email notices of new entries.

For the even more technically-minded, this image is a stack, mean combined, of five 2-minute tracked exposures, at f/2.8 and ISO 800. The camera was on the iOptron Sky-Tracker. So the stars are not trailed but the ground is! I made no attempt here to layer in an untracked ground shot, as there isn’t much detail of interest worth showing, quite frankly.

At least not in the ground. But the Milky Way is always photogenic.

– Alan, November 28, 2015 / © 2015 Alan Dyer / www.amazingsky.com