10mm – The Amazing Sky

May 27, 2026May 28, 2026

Testing Low-Cost Fish-Eye Lenses for Astrophotography

We have a bevy of new and very affordable fish-eye lenses to choose from. They can work great for astrophotography. But which one is best?

Chinese lens makers are showering the market with affordable lenses, and for the most part they’re of quite good quality. Among them are fish-eyes, very special-purpose lenses. One of those purposes is astrophotography — shooting wide swaths of the night sky, if not the entire sky, in one frame. That’s ideal for capturing sky-filling auroras, or the sweep of the Milky Way.

Here I test five low-cost fish-eyes on the night sky:

The AstrHori 6mm at f/2.8 on the Canon R5.

– Two circular format lenses that project a round image taking in a full 360° by 180º within the rectangular frame, plus …

– Three lenses that fill the rectangular frame corner to corner (i.e. they are “full-frame” or “diagonal” fish-eyes) with a field that is about 180º wide across the frame diagonal. They present curved horizons; they are not “zero-distortion” ultra-wide lenses.

All five lenses work well on full-frame (36mm x 24mm sensor) cameras. All have fast f/2.8 or f/2 optics, making them suitable for astrophotography. Slower f/4 and f/5.6 fish-eyes are not so well suited.

I tested them all under a dark starry sky, checking for horizon-to-horizon sharpness and edge artifacts, and on a moonlit night looking for lens flares.

NOTE: My blog features many high-resolution images that may take a while to load.

However, you can CLICK or TAP on a test image to bring it up full screen for closer inspection, and save it as a JPG download.

TL;DR SUMMARY

All five lenses work surprisingly well for such low-cost optics. And all are well made, with smooth, well-dampened manual focusing. None are “plastic-fantastic” junk.

For a full-frame fish-eye the 7Artisans 10mm stands out for astro use, for its optical quality and good features such as the glow-in-the-dark markings, and an excellent storage case. It will be the best lens here for Milky Way images where star sharpness counts most.

For a circular fish-eye, the 6mm AstrHori and the 7.5mm TTArtisan each have unique features: an amazing 220º field of view for the 6mm, and fast f/2 speed for the 7.5mm. Both would be superb for capturing all-sky aurora shows, perhaps for projection in digital planetarium domes.

The five fish-eyes, to compare their relative sizes

THE LENSES

Here are the five lenses under test, in order of increasing focal length, shown above from L to R to compare their sizes —

— 6mm f/2.8 AstrHori circular fish-eye – with an advertised 220º field of view

— 7.5mm f/2 TTArtisan circular fish-eye – 180º field of view (advertised)

— 10mm f/2.8 7Artisans full-frame fish-eye – 185º diagonal field of view (advertised)

— 11mm f/2.8 TTArtisan full-frame fish-eye – 180º diagonal field of view (advertised)

— 12mm f/2.8 AstrHori full-frame fish-eye – 185º diagonal field of view (advertised)

The 6mm, 11mm and 12mm lenses I tested on a 45 megapixel Canon R5.

The 7.5mm and 10mm lenses I tested on a 45 megapixel Nikon Z8.

However, all the lenses are available for a wide range of camera brands, as I list below. All are manual-focus only, with no electrical connections to the camera body. So there is no restriction from Canon in offering them in RF-mount versions. But when using them on any camera, no EXIF metadata is recorded for lens brand, focal length or aperture.

With the exception of the TTArtisan 11mm (which has versions for older Canon EF and Nikon F mounts), the lenses are for mirrorless cameras only — they will not fit on DSLR camera bodies. By virtue of their design, none of the lenses accept filters, either front- or rear-mounted. None feature a rear weather sealing gasket.

But the key factor is that none sell for more than $300; some cost less than $200. At that price, why not have one? Or two?

WHY DIDN’T YOU TEST…?

First, I am not a test lab; I bought these lenses for personal use and out of curiosity. I selected low-cost lenses made for full-frame mirrorless cameras, what I shoot with. Indeed, the short flange distance of mirrorless cameras is what makes these lens designs possible.

I did not test fish-eyes made just for APS-C or Micro4/3rds cameras, for example from the Chinese brands Meike (their 3.5mm and 7.5mm) and Brightin Star (their 7.5mm).

However, despite it being made for full-frame cameras, I chose not to buy and include the new Brightin Star 11mm f/2.8 Mark II ($270), a decision based on expert lens reviewer Christopher Frost’s test here on his YouTube channel. The lens’s edge performance, important for astro work, was shown as poor, even when stopped down. I saved my money.

Nor did I test the new Laowa/Venus Optics 8-15mm f/2.8 zoom fish-eye, which offers a circular-format and full-frame fish-eye in one lens. It might perform well but is $700 US, so not a low-cost option – but you do get two lenses for the price of one. Ditto on the new Canon RF7-14mm f/2.8-f/3.5 L fish-eye – it has autofocus and is $1,900 US.

TESTING NOTES:

— For my aberration tests I shot all the lenses on the same moonless night, with them aimed straight up to take in as much sky as possible to put stars across the frame. The cameras were on a star tracker (not shown) to eliminate star trails that can mask or mimic aberrations.

— In all cases where I show examples shot at different apertures, both images were shot for equal exposure value (by doubling the ISO for the smaller aperture shot), and then processed identically. So any brightness difference you see is from the lens performance, not my exposure or processing.

— I did not apply any lens corrections or brighten the edges to compensate for vignetting. However, none of the diagonal fish-eyes suffer from obvious corner vignetting, unlike rectilinear ultra-wides that can exhibit very dark corners from extreme light fall-off.

— For my lens flare tests I shot all the lenses on the same moonlit night with a waxing Moon in the southwest which I placed off-centre to prompt internal reflections. The cameras were also on a tracker.

— I bought most of these lenses directly from the manufacturers from their on-line stores in China. Delivery in all cases was quick by mail, fulfilled from a North American distribution point. While I had no issues, product quality for bargain lenses can vary, so consider buying from a source where you can easily return the lens for a replacement or a refund.

I will state at the outset that none of these lenses offer pinpoint stars to the edges of their image circles, certainly not at their maximum apertures. You can’t expect aberration-free performance at these prices.

If you wish optical perfection in a fish-eye lens then look at the Sigma 15mm f/1.4 DG DN, for $2,200 US. (See Nico Carver’s test of that lens here on his Nebula Photos YouTube channel.)

Here are the test details, with the five fish-eyes presented in order of increasing focal length.

The AstrHori 6mm f/2.8 Circular Fish-Eye

Available for Sony E, Panasonic L, Canon RF, Nikon Z Lens Mounts

$300 US.

MF 6mm F2.8 Full-frame Circular Fisheye Lens for E/L/RF/Z

The unique selling point of this lens is that it has an amazing 220º field of view across its image circle. It can actually see behind itself! To stay out of the frame, duck!

When aimed straight up it will include not only the entire sky down to the horizon, but also the ground well below the horizon, good for putting the sky in context to the landscape below. Doing so with any other lens requires shooting a multi-segment panorama. While panos have the benefit of higher resolution, the 6mm lens allows for all-sky time-lapses and movies.

Previously, to get such a field of view with such a speed (f/2.8) you had to pay more than $100,000 (!!!) for a rare sample of the massive 6mm f/2.8 Nikkor lens made in limited quantities in the early 1980s. By contrast, the 6mm from AstrHori (it is not AstroHori!) is downright tiny. And cheap!

The lens has a knurled manual focus ring that turns smoothly, and a ribbed aperture ring with firm clicks at each f-stop. Infinity focus, with the stars sharpest, proved to be slightly shy of the centre of the infinity mark, so the lens requires careful manual focusing. The lens can focus past infinity.

The press-on metal lens cap is boldly marked with the lens identity. Like all AstrHori lenses, the 6mm comes with a thick soft cloth pouch.

The short length of the lens makes it difficult to wrap an anti-dew heater coil around it, certainly not without risk of shifting the focus or aperture. That’s a consideration, as aimed straight up its lens is bound to attract dew or frost over long shoots.

IMAGE QUALITY

The 6mm AstrHori doesn’t quite fill the frame across the sensor’s short dimension (24mm). Instead, the lens’s image circle is about 21mm across. The edge of the image circle is soft but clean – it is not rimmed by odd colours or internal reflections.

6mm AstrHori at f/2.8 – In all test images the image on the right is a blow-up of the blue-framed area at left.

Stars in the centre are tack sharp at f/2.8, with some longitudinal chromatic aberration (LoCA) adding small blue halos. The LoCA is gone at f/4. Stars toward the edges show an increasing amount of elongation from astigmatism, and exhibit colour streaks from lateral chromatic aberration (LaCA). Both diminish at f/4 but are still present.

6mm AstrHori at f/4 – Note the brighter edge and ground compared to f/2.8

By comparison, Sigma’s old 8mm f/3.5 circular fish-eye, now long discontinued but that I used for many years on my Canon DSLRs, had smaller but still noticeable levels of astigmatism and lateral chromatic aberration at the edges, even when stopped down to f/4 or f/4.5. So the $300 AstrHori is not far below the classic but much more costly Sigma 8mm for edge sharpness.

The main benefit to stopping down the AstrHori 6mm is the reduced vignetting that brightens the field overall, but especially the horizon around the edges. So if the horizon content is important, stop the lens down. Otherwise, this lens works well at f/2.8.

LENS FLARES

A 30-second exposure at f/2.8 with the Moon in the frame (if it’s in the sky it’ll be in the frame with this lens!) showed only a small lens flare (arrowed) opposite the Moon. It tightened up at f/4 (not shown) but was still present. In all, this is a good performance.

But for all-sky time-lapses with the Moon up, expect to see a lens flare moving opposite the Moon. The same might be true of all-sky images of a total solar eclipse. The eclipse of August 2, 2027 with the Sun at the zenith from Egypt would be a great use-case for this lens!

The TTArtisan 7.5mm f/2 Circular Fish-Eye

Available for Sony E, Leica L, Canon RF, Fuji X, Nikon Z Lens Mounts

$140 US.

Link to the TTArtisan 7.5mm web page

The unique selling point of this lens is its speed – f/2! All the others are f/2.8. However, technically this is a lens made for APS-C sensor cameras, where it would serve as a full-frame fish-eye. But it works as a near-circular-format fish-eye on full-frame cameras, though with the image truncated at the top and bottom, as I show. You don’t get a full circle. But you do get a much wider field than with the full-frame fish-eyes that follow.

The 7.5mm does not come with a case or pouch, unlike lenses from TTArtisan’s competitors. (The case I show above is one I bought extra for this lens.) The lens has a metal front cap with a thread-on central disk, as shown above. With the disk removed, the remaining ring acts as an iris that mechanically vignettes the image to a 24mm-wide circle, but with much less than 180° horizon-to-horizon coverage. I’ve never used this lens that way; I prefer to record as much of the image as the lens projects, then mask down the image later if needed.

I like this lens so much I bought it twice – for Canon RF and for Nikon Z. The Nikon copy I test here has better optics with less tilt (or “decentering”) in the lens elements. The Canon copy is notably soft on the left side. I asked TTArtisan about this, hoping to get a replacement for my Canon RF unit, but their rep said that’s within their acceptable level of performance. That’s the drawback of low-cost lenses like these; expect unit-to-unit variations.

The best focus, with the stars sharpest, proved to be well short of the infinity mark, requiring manual focusing. But I suspect that, too, will vary from unit to unit, likely true of most of these lenses.

With its f/2 speed, the 7.5mm is great for rapid-fire time-lapses of fast-moving auroras, or even real-time 4K or 8K aurora movies where fast lens speed is essential, to keep the ISO lower for less noise.

IMAGE QUALITY

The image circle is fairly cleanly defined, but does show two small dark shadows protruding into both the top and bottom of the frame from some mechanical vignetting. A dark blue glow also rims the periphery of the image circle. Keep in mind, on the APS-C cameras the lens is designed for you wouldn’t see the outer part of the image circle.

At f/2 stars are quite sharp at the centre, but begin to soften and elongate from what looks like coma as well as astigmatism in the outer third of the image circle.

Star sharpness improves at f/2.8, and more at f/4, by which point stars now look very sharp almost to the edge of the image circle.

As the examples show, the image also brightens and becomes more evenly illuminated as you stop down. In all, shooting at f/2.8 will work best for most astrophoto situations. Shoot at f/2 if you need the extra speed for rapid time-lapses or movies. Shoot at f/4 if star sharpness is paramount, such as for projection in a digital planetarium dome.

LENS FLARES

The TTArtisan 7.5mm proved surprisingly immune to lens flares. I didn’t see any in the sky itself. What you do get is a flare around the periphery from an internal reflection off bright lights, like the Moon here. This might need masking out in the final images.

The 7Artisans 10mm f/2.8 Mark II Full-Frame Fish-Eye

Available for Sony E, Leica L, Canon RF, Nikon Z Lens Mounts

$280 US.

MF 10mm f/2.8 Mark II Ultra Wide-angle Full-frame Fisheye Lens for E/L/R/Z

This is the first, and so far only, lens I have used from the China-based company 7Artisans. I am impressed with it. The 10mm came with both a cloth lens pouch and a hard-sided zippered lens case, both shown above. Very nice! Nikon should take note and be so generous with their premium S-line lenses.

The lens is solid, with all-metal construction and a metal press-on lens cap. The rear cap is plastic, true of all the lenses. The focus movement is smooth with a good level of resistance or dampening. Infinity focus, with the stars sharpest, proved to be left of the infinity mark. The lens focuses past infinity, so careful manual focusing is needed. The aperture ring is click-less, preferred for video use, but a bit of a nuisance for photography.

An added bonus, clearly showing this lens has been designed for night use in mind, is that the focus and depth of field markings are fluorescent. Hit the lens with white light and they will glow in the dark for a while, as above. Nice!

I tested the new Manual Focus Mark II model, advertised as having “enhanced performance” over the original lens – with two of the 11 lens elements being ED glass, versus the original model’s single ED element. I never used the original 10mm, so I can’t comment on how the Mark II version has improved. And don’t confuse this new MkII 10mm with another 10mm f/2.8 AF lens 7Artisans also sells. That 10mm has auto-focus but is only for APS-C cameras.

IMAGE QUALITY

I aimed all the full-frame fish-eyes straight up to the zenith, to put stars in all corners. However, I am zooming in on the edge of the long dimension in these samples. Click or tap on an image to download a high-resolution JPG for closer inspection of all parts of an image.

The 7Artisans 10mm proved very sharp at the centre and toward the edges of the frame, showing only a small level of astigmatism and lateral colour at the edges at f/2.8. Bright stars at the very corners did show “wings” from astigmatism.

Stars tightened up at f/4, but still had some astigmatism at the pixel-peeping level. The 10mm also had the widest field of view of the three full-frame fish-eyes, by a slight margin.

The image edges brightened with the lens at f/4, as expected from the reduced vignetting all wide-angle lenses show when stopped down. But unless you are very fussy about star shapes, the 7Artisans 10mm will work very well when shot wide-open at f/2.8.

LENS FLARES

I didn’t see any noticeable flares in my moonlight test shots, quite remarkable! What slight halo you can see around the Moon, here shot at f/2.8, is in the sky, from the thin clouds this night.

The TTArtisan 11mm f/2.8 Full-Frame Fish-Eye

Available for Sony E, Leica L, Panasonic/Olympus M43, Canon RF, Fuji X, Nikon Z Lens Mounts plus for Nikon F and Canon EF DSLR cameras in a different model.

$235 US.

Link to the TTArtisan 11mm web page

I’ve owned this lens for several years during which time it has served me well for many aurora shows. As best I can tell the lens sold today is the same as the one I bought some 5 years ago. Like the 7.5mm, the 11mm does not come with a case or pouch, a shortcoming of TTArtisan lenses. The case I show above is an extra one I had on hand that works well for this lens.

Note, this is the one lens of the group that is available for DSLR cameras – for Canon EF and Nikon F – though in a different optical design than the lens I tested.

The lens is compact, solid and dense, with all-metal construction, including the front lens cap. The focus turns smoothly with just the right amount of dampening. Infinity focus, with the stars sharpest, proved to be actually at the infinity mark with the focus at the extreme end. The lens does not focus past infinity, making it the easiest lens of the group to focus in the field. The aperture ring is click-less, again not ideal for photography.

IMAGE QUALITY

The 11mm TTArtisan’s test images proved to be about 1/2-stop darker than images with the 10mm 7Artisans and 12mm AstrHori, when all were shot at the same camera settings.

The 11mm also had the narrowest field of the three diagonal fish-eyes, even compared to the 12mm AstrHori, though the difference was slight.

Stars were sharp in the centre of the frame with minimal LoCA. Astigmatism increasingly elongated the stars into streaks toward the edges of the frame at f/2.8, though with minimal lateral colour. Stars tightened up at f/4 but still showed more aberration than did the 10mm 7Artisans.

Stopping down brightened the frame edges. But overall, this lens can work well at f/2.8, which is how I’ve used it for most shooting, mostly of auroras. If Milky Way nightscapes are your priority, look at the 7Artisans 10mm.

LENS FLARES

11mm TTArtisan at f/2.8 – a small lens flare is arrowed.

The TTArtisan 11mm was fairly immune to lens flares, showing only a slight coloured flare (arrowed) opposite the Moon in my test images. So its coatings must be performing fairly well, despite the overall lower level of light transmission of this older lens.

The Astrhori 12mm f/2.8 Full-Frame Fish-Eye

Available for Sony E, Leica L, Canon RF, Nikon Z Lens Mounts

$260 US.

MF 12mm F2.8 Full-frame Fisheye Lens for E/Z/R/L

AstrHori offers a 12mm as their diagonal fish-eye for full-frame cameras. It is solidly made, but larger than the others with a bulbous front lens element. It is also the heaviest lens of the group, weighing 830 grams with lens caps, compared to 700 grams for the 7Artisans 10mm, and 550 grams for the much smaller TTArtisan 11mm.

While the 12mm came with AstrHori’s standard lens pouch it is far too small for this lens. What were they thinking? The lens has a smoothly-turning manual focus ring and, similar to the others, with a good level of dampening. Infinity focus with the stars sharpest was shy of the infinity mark, between 1 metre and infinity. The lens focused past infinity, so careful manual focusing is required, true of all the lenses except the TTArtisan 11mm.

The aperture ring has firm click stops at 1/2-stop intervals from f/2.8 to f/8, and one each for f/11 and f/16. This is the only lens of the group with a plastic front cap, but it is deep and presses on very securely. The aperture values have large white figures making them easy to read in the dark.

IMAGE QUALITY

Stars are sharp in the centre with only slight LoCA-induced blue halos at f/2.8 that disappear at f/4. Stars begin to soften and elongate from astigmatism at the outermost edges of the field at f/2.8.

They tighten somewhat at f/4 but not by much compared to f/2.8. The entire field, not just the field edges, brightens at f/4 from the more uniform illumination.

12mm AstrHori at f/4 – Note the brighter field at f/4.

Of the three full-frame fish-eyes I’d rank the 12mm as #2 for across-the-field star sharpness, behind the 10mm 7Artisans but ahead of the 11mm TTArtisan.

LENS FLARES

I don’t need to add an arrow to point out the lens flares here! Wow! They are extreme.

12mm AstrHori lens flare at three f/ratios – Gone at f/4 – The white ring around the Moon is a natural ice halo.

Wide open at f/2.8 the lens shows rainbows of internal lens reflections, with an odd split appearance. Stopping down to the click stop halfway between f/2.8 and f/4 (about f/3.2) eliminates half the reflections. Stopping down to f/4 gets rid of all of them. Very odd.

Either the lenses are not properly edge blackened, or the lens hood is inducing reflections in the bulbous front element, or there is some shiny component inside adding the reflections.

12mm AstrHori at f/2.8 and at f/4, with Moon below centre.

The flares get larger as the light source (the Moon here) moves to the edge of the frame. With the Moon closer to the centre (as shown above), the coloured rings disappear but there are still radial streaks pointing away from the Moon. They disappear at f/4.

I never noticed these flares on dark sky shots of the stars and aurora. But this is not a lens you can shoot the sky with if the Moon or Sun are in it, at least not at f/2.8. If you shoot an eclipse sky time-lapse with this lens, you must stop it down.

This is a serious flaw AstrHori needs to fix in a Mark II version of this lens.

Recommendations

I think every astrophotographer should have a fish-eye lens in their kit, especially true of aurora chasers. The low cost of these new Chinese lenses makes it easy to add one, for the few special nights it’ll be used.

A blend of three exposures – two for the ground and me without the light on, and one for the sky with the headlamp on. Untracked, with the 7Artisans MkII 10mm lens wide-open at f/2.8 on the Nikon Z8 at ISO 3200 for 15 seconds each.

A full-frame fish-eye is the first choice I would recommend. But do note they produce a curved horizon, as above. If that’s not to your liking, buy an ultra-wide rectilinear lens. But none have as a wide a field as a fish-eye, and rectilinears will distort objects much more by stretching them at the corners.

Of the three full-frame fish-eyes I tested I liked the 10mm 7Artisans the best. It offered the best optical quality, nice fittings with its glow-in-the-dark markings, an excellent hard storage case, and it was compact.

The 12mm AstrHori was bright and relatively sharp, but much larger than the others so is not a lens you can tuck away in a bag in case you might need it. And its wild lens flares made it unsuitable for use wth the Sun or Moon in the frame, at least when shot wide open.

The 11mm TTArtisan was compact but darker than the others, showing its older coatings perhaps, and lower light transmission. Again, mine was an older unit.

A single 2.5-second exposure with the TTArtisan 7.5mm fish-eye lens at f/2 on the Nikon Z6III at ISO 1600. From the Churchill Northern Studies Centre, Manitoba.

The f/2 speed of the 7.5mm TTArtisan is great if you intend to take time-lapses or movies of the aurora. It would be good for sequences shot for tilt-dome planetariums.

Otherwise, the unique 220º 6mm AstrHori is perfect for capturing all the sky and ground below on one frame. It would be good for shooting stills or time-lapses of auroras or sky motion for planetarium projection, especially in non-tilt-dome (flat-floor) theatres.

I hope this test has helped you make a choice. We have some fine lenses to pick from now, and at appealing prices, compared to the DSLR days when there were few fish-eyes on offer, all costly.

December 6, 2024February 14, 2025

Testing Wide-Angle Lenses on Nikon Z for Astrophotography

I test a trio of wide-angle, auto-focus lenses for astrophotography, all for Nikon Z mount: the Nikkor 20mm f/1.8 S, the Viltrox 16mm f/1.8, and the Laowa 10mm f/2.8 Zero D.

As a bonus, I also test a fourth lens: the TTArtisan manual-focus 7.5mm f/2 fish-eye.

NOTE: Images are large and may take a while to load.

While the selection of lenses for Nikon Z mirrorless cameras is not as diverse as it is for Sony E-mount, Nikon shooters have more brands of lenses to pick from than do users of Canon R mirrorless cameras. For nightscapes and Milky Way photography we want fast, wide-angle lenses, usually in the 14mm to 24mm range.

Canon, Nikon, and Sony all have excellent zoom lenses that cover the range. I use Canon’s RF 15-35mm L lens a lot, and reviewed it here on my blog from 2022.

But all these wide-angle zooms are f/2.8. While that’s a good speed for most astro work, having an even faster lens can be valuable. An aperture of f/2 or faster allows for:

— Shorter exposures for untrailed stars when shooting just on a tripod with no tracker.

— Capturing fainter and more numerous meteors during a shower.

— Rapid-cadence time-lapses of auroras, freezing the motions of curtains.

— Real-time movies of auroras and satellite passages at lower, less noisy ISO settings.

The Nikkor 20mm at f/1.8 allowed a short 1.3-second exposure for capturing the aurora from a ship off the coast of Norway, to minimize ship motion trailing the stars.

Also, stopping those faster lenses down to f/2.8 can sometimes yield better image quality than shooting with a native f/2.8 lens wide open.

Canon and Sony each have fast f/2 zooms that cover the range from 28mm to 70mm. While those focal lengths can be useful, both lenses are expensive and heavy. And they are still not wide enough for many astro subjects. For fast lenses with even shorter focal lengths we need to turn to “prime” lenses, ones with fixed focal lengths.

As of this writing Canon has few fast, wide primes for their RF lens mount (their new 24mm f/1.4 VCM is a costly choice designed primarily for video use). A few third-party lens makers offer fast (f/2 or faster) primes for Canon full-frame cameras, always as manual focus lenses. For example, Laowa has a 15mm f/2, and TTArtisan has a 21mm f/1.5.

Yes, Sigma now offers auto-focus 16mm and 23mm f/1.4 primes, and Samyang has a new 12mm f/2, but they are only for Canon RF-S cropped-frame cameras. Canon has yet to allow other companies to produce auto-focus lenses for their full-frame cameras.

Nikon has been restrictive as well. Sigma’s much-lauded Art series that includes the 14mm rectilinear (i.e. the horizon remains straight) and 15mm fish-eye (with a curved horizon), both f/1.4 and aimed at astrophotographers, are not offered for Nikon or Canon, only for Sony E-mount and Panasonic/Leica L-mount cameras.

However, while Sigma lenses are missing, there is a wider choice of third-party lenses for Nikon Z-mount compared to Canon RF, plus Nikon itself makes a very fine 20mm prime in their premium S-series.

That’s what I test here — three wide-angle rectilinear primes for Nikon Z: A 20mm Nikkor, and two third-party primes: one from Viltrox, their 16mm; and one from Laowa, their new 10mm.

As a bonus, I add in a test of a fast fish-eye lens, from TTArtisan, their 7.5mm f/2.

NOTE: All test images can be downloaded as full-resolution JPGs for closer inspection. Click or tap on the images.

Prices are from B&H Photo, but will vary with sales and special promotions.

The Nikkor 20mm S-Line Lens ($1,050)

I shot the northern summer Milky Way (below) with the three rectilinear wide-angle lenses (meaning these are not fish-eyes) with the camera on a star tracker, to prevent star trailing. The tracker was the Move-Shoot-Move Nomad, reviewed here on my blog.

The Nikon Z6III and 20mm Nikkor on the MSM Nomad tracker.

I shot with Nikon’s new Z6III, a 24-megapixel full-frame camera I reviewed in the December 2024 issue of Sky & Telescope magazine. It offers a number of excellent features for nightscape photography. Most notably, auto-focus lenses zip to the infinity focus point automatically when the camera is turned on, something I wish Canon cameras would do.

The Nikkor 20mm has a field of view along the long dimension of 84°.

The Nikkor 20mm is the widest prime lens in Nikon’s premium S-Line series. It offers what I consider to be an ideal focal length for most nightscape and wide-field Milky Way images.

While a 14mm lens is often thought of as the default nightscape lens, a 20mm presents less distortion (objects leaning in or stretched out at the corners) and a more natural perspective. Plus the lens can be made faster (in this case f/1.8), smaller, and not cost as much as an ultra-fast 14mm like the Sigma f/1.4 Art lens.

Nikkor 20mm Corner Aberrations

The four panels show the upper left corner, in the area outlined in the inset that shows the full frame.

Sharp stars right to the corners is the ideal for all forms of astro images. We don’t want stars to turn into winged seagulls or coloured streaks. They should remain as pinpoint as possible.

The Nikkor 20mm shows very little aberrations across the frame. Stars are elongated by tangential astigmatism and discoloured by lateral chromatic aberration only slightly and only at the extreme corners.

Stopping down the lens decreased the aberrations, but some residual astigmatism remained, even at f/4. However, the corner aberrations are low enough, and so restricted to the very corners, that this is a lens you can certainly use wide open at f/1.8, or perhaps at f/2, without any penalty of image sharpness.

Nikkor 20mm Vignetting

The four panels show the left side, as outlined in the inset. The inset is the f/1.8 sample.

Ideally, we also want images to be as fully-illuminated across the frame as possible. Light fall-off, or vignetting, creates dark corners with less signal reaching the sensor. Less signal gives rise to more noise, noticeable when brightening the corners in processing. That can reveal unsightly noise, banding, and discolouration in nightscapes, especially in the ground, often the darkest part of a scene, not the starry sky.

The 20mm shows a fair degree of edge and corner darkening when wide open at f/1.8. Stopping the lens down to f/2 improves the field illumination notably. And by f/2.8 the field is fairly uniformly lit. There is little need to go as slow as f/4.

In all, the Nikkor 20mm S is a superb lens ideal for nightscapes and Milky Way images.

The Viltrox AF 16mm STM ASPH ED IF ($580)

The new company Viltrox has been making a name for themselves recently with the introduction of a number of top-quality pro-grade lenses to compete with the best from any brand, and at much more affordable prices.

The horizontal field of view of the Viltrox 16mm is 100°.

Their 16mm is an auto-focus lens that, on the Nikon, can actually auto-focus on stars, as can the Nikkor 20mm. However, it, too, will zip to infinity focus when powered up. Plus two function buttons can be programmed to rack between two preset focus distances, one of which can be infinity.

The buttons at left are for preset distances.

A manual aperture ring (above left) has 1/3rd-stop detents, or it can be set to A for controlling the aperture in the camera.

A colour OLED display (above right) shows the focus distance and aperture, a nice way to confirm your settings at night. The display is too bright on the darkest nights; I cover it with red gel.

An option to turn it red using the Viltrox app would be welcome. Or to turn it off! ….

NOTE ADDED FEB 24, 2025 — I tested all lenses on a stock camera. But when used on an astro-modified camera with greater red and infra-red sensitivity, the Viltrox 16mm can add a noticeable red glow or flare to images, as a colleague has found and reported to me. I did confirm this with very long exposures and high ISOs with my stock Z6III. It barely shows up in dark frames boosted a lot for brightness (see below – it’s the faint magenta band across the centre of the frame).

But in modded cameras it is much more obvious. This comes from the lens’s top OLED display. The trick is to slightly dismount the lens, which turns the display off, but still maintains data contact to the camera. Viltrox is aware of the issue and has said they will fix it in a firmware update.

With Viltrox lens fully engaged and display ON

Uniquely, this and other Viltrox lenses have Bluetooth built in, for direct connection to a mobile device for firmware updates and lens settings, shown above. However, I found the app buggy; it would connect to the lens, but then refuse to allow settings to be changed, claiming the lens was not connected. Or the app would freeze, disconcerting during a firmware update. Luckily, that did not brick the lens.

Viltrox 16mm Corner Aberrations

The four panels show the small corner area outlined in the centre inset that shows the entire image.

At the extreme corners, the Viltrox shows some softness (perhaps from field curvature), but only minimal astigmatism and lateral chromatic aberration when wide open at f/1.8, and slightly sharper corners at f/2. At f/2.8 corner performance is nearly perfect, and certainly is at f/4.

This is a level of aberration correction even the most premium of lenses have a hard time matching.

Viltrox 16mm Vignetting

The panels show the left side outlined in the centre inset, which shows the f/1.8 image.

As is often the case with wider lenses, the Viltrox does show a great deal of vignetting at f/1.8, more so than the Nikkor 20mm. While this can be corrected in processing it will raise noise levels.

Stopping down to just f/2 helps, but the field becomes more uniform only at f/2.8, the sweet spot for this lens for the best all-round performance. But it offers the speed of f/1.8 when needed, such as for auroras.

If you prefer a wider field than a 20mm provides, the Viltrox 16mm (also available for Sony) is a great choice that won’t break the bank. Until Canon changes their third-party lens policy, Canon owners are out of luck getting this excellent lens.

The Venus Optics/Laowa 10mm Zero-D FF ($800)

The Laowa also accepts 77mm filters, unusual for such a wide lens..

The lens maker Venus Optics (aka Laowa) is known for its innovative and often unusual lens designs.

Introduced in 2024, their new 10mm offers the widest field available in a rectilinear (not fish-eye) lens for full-frame cameras. The “Zero-D” label is for the lens’s lack of pincushion or barrel distortion. Horizons remain straight no matter where they fall on the frame. However, objects at the corners become elongated a lot.

The Northern Lights in a superb display on August 11-12, 2024, at Grasslands National Park, Saskatchewan. This is with the Laowa 10mm wide open at f/2.8 on the Nikon Z6III at ISO 6400.

Even so, there’s a lot to be said for having a field that extends for 130° across the long dimension of a full-frame sensor. That’s more than enough to go from well below the horizon to past the zenith when the camera is in portrait orientation. Even in landscape orientation (as above) the lens covers nearly a 90° field across the short dimension, enough to go almost from horizon to zenith.

The f/2.8 speed is slower than the other lenses on test here, but is still faster than most ultra-wide lenses. Remarkably, it accepts common 77mm filters, the same as the Nikkor 20mm and Viltrox 16mm.

The 10mm is available as an auto-focus lens for Sony E and Nikon Z, and in manual focus versions for Canon RF and Panasonic L, oddly all at the same price.

Laowa 10mm Corner Aberrations

The four panels show the corner area outlined in the inset, at four apertures between f/2.8 and f/4.

Corner aberrations are much worse than in the 20mm and 16mm lenses, showing a fair degree of tangential and sagittal astigmatism, elongating stars radially and adding wings to them, respectively. The aberrations are larger and reach deeper into the frame than in the Nikkor and Viltrox lenses.

There’s also some lateral chromatic aberration adding blue and purple fringes to the stars at the corners. Stopping down to f/4 improves, but doesn’t eliminate, the aberrations.

Laowa 10mm Vignetting

The four panels show the left side, as outlined in the inset, which shows the f/2.8 image.

Edge and corner darkening were also worse than in the other lenses and required about a +50 setting to correct in Adobe Camera Raw, far less than the maximum of +100. So it’s still quite acceptable and correctable.

However, while stopping the lens down to f/4 improves vignetting, it does not eliminate it, still requiring a +40 correction. Vignetting will be a factor to deal with in all astrophotos with this ultra-wide lens.

Laowa 10mm Lens Flares

Three panels showing the Moon framed in the left corner (L), centred (C), and in the right corner (R).

With such a wide lens, the Moon or other bright light sources are bound to be within the frame. The Laowa exhibits a prominent internal lens flare when bright objects are in the corners, but just in the corners. Objects near the edge but centered are fine.

Showing the effect of decreasing aperture on the lens flare and bright light source.

Stopping down the lens adds diffraction spikes (or “sunstars”) to bright lights, but doesn’t eliminate the circular internal reflection. None of this is a serious issue for most images, but it is something to be mindful of when framing nightscapes.

With the Laowa 10mm lens at f/2.8 on the Nikon Z6III at ISO 3200. Note the Big Dipper at left and Orion at right.

In Milky Way and starfield images, constellations in the corners can distort into unnatural shapes that look odd, as I show above. While the lens can take in a great swath of sky, its distortion and corner aberrations make it less than desirable for tracked Milky shots.

An aurora in the dawn twilight on September 17, 2024. A 4-second exposure with the Laowa 10mm at f/2.8.

Where the Laowa 10mm really proves its worth is for auroras, as above, which can require as wide a field as you can muster. Note the flat horizon.

For ultra-wide nightscapes in a single image (not a panorama) with a natural looking (not curved) horizon, and for meteor showers, the Laowa is just the ticket.

BONUS TEST: The TTArtisan 7.5mm f/2 Fish-Eye ($140)

The TTArtisan has a fixed lens hood. Front filters are not possible without vignetting.

Technically, this lens is designed to be used on cropped-frame (or APS-sensor) cameras where it fills the frame with a curving horizon. But it works on a full-frame camera where it projects a circular image slightly larger in diameter than the short dimension of the frame, so not a complete circle as with a true circular fish-eye like the old Sigma 8mm f/3.5.

An aurora in the dawn twilight on September 17, 2024 in a 2-second exposure with the TTArtisan 7.5mm fish-eye lens at f/2 on the Nikon Z6III at ISO 800.

For all-sky auroras, this is ideal, where the TTArtisan’s fast f/2 speed is unprecedented in a fish-eye lens. That makes rapid-cadence time-lapses possible, as well as real-time movies. An example is here on my YouTube channel.

A stack of 4 x 4-minute exposures with the TTArtisan 7.5mm f/2 fish-eye lens stopped down to f/2.8 on the Nikon Z6III at ISO 1600, on the MSM Nomad tracker.

Or you can just capture the Milky Way from horizon to horizon, as above. For the latter, having stars sharp across the circular field is still desirable.

I have this lens for Canon RF as well, but that unit shows a noticeable softening of the left edge with defocused stars, likely from lens de-centering. I was told by TTArtisan that was a normal unit-to-unit variation and not a defect warranting replacement. Annoying!

I hesitated to buy one for my Nikon. But this is such a unique lens, and so affordable, I took the chance. The Nikon Z-mount version proved much better.

TTArtisan 7.5mm Edge Performance

There is no corner performance or vignetting to test here.

TTArtisan 7.5mm lens at f/2, showing the left side area shown in the blowups below.

Instead, I’m inspecting the same side on the Nikon Z version that caused a problem on my Canon version.

Comparing f/2 and f/2.8 edge aberrations.

The Nikon version looks fine, with stars sharp along the edge even at f/2, showing just a low level of astigmatism, to be expected in such a fast, wide lens. Stars tighten up a bit more at f/2.8. Most critically, the field was flat and in focus across the frame. There was no evidence of lens de-centering or optical defects.

The edges do show some discolouration and a soft edge to the image area. I also see two odd dark protrusions at the top of the frame. Looking through the lens, there’s nothing obvious intruding into the light path.

Keep in mind when used on a full-frame camera you’re seeing more of the projected image than was intended in the design.

The 7.5mm lens comes with a metal lens cap with a threaded centre disk. Remove it to create an aperture that vignettes the image to a smaller but complete circle.

The TTArtisan 7.5mm is a specialty lens to be sure. But at its low price it isn’t a big outlay to include in your lens arsenal, for unique all-sky images, of auroras, satellite passages, sky colours, and the Milky Way. And it is terrific for time-lapses and movies of the whole sky. It is a no-frills manual lens available for most camera mounts.

Recommendations

The Viltrox 16mm, Laowa 10mm and TTArtisan 7.5mm are all available for Sony E-mount. The Laowa and TTArtisan are available for Canon RF, but the Viltrox 16mm is not, as it is an auto-focus, full-frame lens, the class of lenses Canon has yet to allow on their RF mounts, much to the disdain of all concerned but Canon management it seems.

Viltrox 16mm — For nightscape use, the Viltrox 16mm might be the single best choice, as being the most versatile and affordable of the trio of wide-angle lenses. Its focal length is a good balance between the usual 14mm and what I think is a more useful 20mm.

Nikkor 20mm — I like the Nikkor 20mm for its lower level of vignetting, slightly tighter framing, and very sharp stars. I think a 20mm is an ideal focal length for many nightscapes and Milky Way scenes. But it is the most expensive lens tested here.

Laowa 10mm — While nearly as costly as the Nikkor 20mm, the Laowa 10mm is much more specialized and, I think, not as useful as the others for general nightscape and Milky Way shooting. But it is superb for auroras, if you are in a place where they are common, as they are here in Alberta. Otherwise, I think you’d find the 10mm a costly lens that might not see a lot of use for astrophotography. Its real forté is architecture and real-estate interiors.

TTArtisan 7.5mm — Ditto on its limited use. But it is so affordable it’s easy to justify even if it doesn’t get a lot of use. The astro images, time-lapses, and movies it can produce are unique and impossible to create any other way. Be sure to buy it from a source where you can return it easily if you find your sample defective.

Reason To Go Mirrorless

The quality of these and other premium lenses from Nikon, and also from Canon, Sony and third-party makers like Sigma and Viltrox, is one of the major benefits of migrating to mirrorless cameras. DSLRs, and the lenses made for them, are now effectively dead as new gear choices.

Yes, mirrorless cameras can be better in many aspects of their operation than DSLRs. But it is the lenses made for mirrorless that show the greatest improvement over their DSLR equivalents, many of which date back to the forgiving film days.

— Alan, December 6, 2024 (amazingsky.com)