To me the issue you had when testing stars on the Z8 comes from the adapter. You may get a better corner quality by refocusing and it will make the center less good, but that’s not the point. The lens creates an image at a very specific distance behind itself, a fraction of a millimeter is enough to have a bad result especially on a full frame sensor so far from the center of the image, and espacially on a very wide angle lens, and especially on such a fast aperture. Also, there is nothing more critical than a night sky to check for optical flaws, the quality is certainly more than acceptable for everything else.
With astrophotography gear it’s common to adjust this backfocus with very thin shims of 0.1 / 0.2mm and very precise adjustable tilt adapters. I’ve spent hours and hours on these things, for weeks and weeks, and months and months ; on lenses and telescopes. The result with the Z8 shown here is typically from a sensor that’s too close to the imaging train (stars pointing outwards). Considering all this, the results on the Sony body are stunning though.
That’s a great point, and I think you’re right. It especially is a problem with mirrorless lenses adapted across brands. Whenever I’ve tried testing adapted mirrorless lenses in the lab (like a Sony lens on a Nikon body), it has been an issue in the corners every time. But DSLR to mirrorless adapters (even third-party ones) tend to give sharp results through the corners.
Mark Manner
March 29, 2024 7:28 am
Great review Spencer! You’re a wonderful resource.
I haven’t had a chance to test that one yet, hopefully later this year! I’ll put it in the next Sony lens poll for our members.
Chris S.
March 27, 2024 10:29 pm
Spencer, thanks for this review–first rate!–and your equally excellent review, last week, of the Sony 14mm f/1.4 GM. Good lens reviews are harder than most people know, and these where terrific.
And for me, these reviews are timely. I recently purchased a specimen of the Sigma 14mm f/1.4 in Sony E mount, for use with a Megadap adapter on a Nikon Z7II body. My use is astro-landscape photography, updating from the Nikon 14-24mm f/2.8 G lens I’ve been using for this since 2008. (That year, I purchased a Nikon D700, which suddenly made nighttime landscapes, including the Milky way, very attainable.)
I have had only two brief openings of nighttime clear skies since this lens arrived, and I need to make a keep/don’t keep decision before the return period expires. So far, my impressions are decidedly mixed.
Mechanically, this lens is a dream. The tripod collar and focus lock are immensely welcome. How many times, in the past, have I wondered if I bumped the focus ring, and had to zoom in in live view to re-check focus? Far too many times. To focus once, lock the ring, and forget about focus is a big deal. Bumping focus–or thinking you have bumped it –is very easy in the dark (and often in the cold and wind).
Optically, I’m torn. Given that every lens is a compromise, and for this lens, all compromises were made in favor of star photography, I expected less of the distortion you’ve identified, and which I also see. Your demonstration that there is more distortion on a Nikon body is enlightening. Drat! I could add a Sony body to my gear, but this also requires use of a second raw format, second set of memory cards, second set of batteries and chargers, second L-bracket, second remote release, second set of electrical cords, etc. No knock on Sony–I just think simplicity has value in the field; I camp out for months to chase night skies and other photographic subjects, and when camping, a smaller equipment debris field is a good thing. And I’m heavily invested in Nikon, so switching entirely to Sony is not attractive for me.
One thing I’ve seen with the Sigma 14mm f/1.4, that I wonder if you experienced: The lens is very hard for me to focus (even in live view, with maximum magnification, on a tripod). The smallest movements my hands can make on the focus ring whisk the lens clear through the focus point. Worse, even small deviations from perfect focus result in donut-shaped stars. This has never been a problem with my Nikon 14-24mm f/2.8 G, in which OOF stars, while not perfect, simply got a little bigger and fuzzier.
Spencer, did you experience this “donut-ing” of out-of focus stars in your tests? I’m wondering if my sample has an issue. (A friend, who has more knowledge of lens issues than I do, suspected that my lens has a lot of uncorrected spherical aberration; he was unsure whether this is a lens design issue, or an aspect of my particular specimen.
Telescope-using photographers report that donut-shaped OOF stars are routine for them. To acquire perfect focus, they recommend using a Bahtinov mask. Bahtinov masks create a visible pattern that changes when a star in in focus. Such mask can be DIY for telescopes, but are hard hard to make for wide-angle lenses–they require many small lines, at the micron-level. For purchasing such a mask for a wide angle lens, the only source I know is from “focusonstars.com,” a cottage industry by Hungarian photographer Gábor Takács. I like supporting photographers who create solutions for other photographers. I purchased, and have received, a mask from Gábor Takács, but have not had a clear might sky to test it.
Lastly, I’ll mention that the Sigma lens’ f/1.4 seems far brighter than its theoretical two stops more openness from my f/1.8 zoom would imply (already a lot of additional brightness). It is an incredibly bright lens. I suspect that if we measured the various competing lenses in T-stops (which measure actual light transmission), we’d find that the Sigma 14mm F/1.4 transmits light very efficiently, and is therefore brighter than f/stop comparisons suggest.
Summing up, Spencer, could you please comment on whether or not you observed any donut or ring-shaped stars, when slightly out of focus?
I did indeed experience “donut”-like stars when they were slightly out of focus, both on Sony and when adapted to Nikon! Nothing wrong with your copy of the lens. Honestly, it didn’t bother me because I took it as a useful sign that my focus wasn’t perfect.
As to the rest of your comment, I think you summed it up, especially using this lens adapted to Nikon. It’s a joy to use mechanically. On a native Sony (or presumably Leica L mount camera), it’s optically excellent. Adapted, you need to decide if the corners are strong enough for your needs – it could go either way.
mitchell
March 27, 2024 1:17 pm
Is it realistic to compare your lens resolution tests to lenses on different systems? Like the FE 20 1.8 vs the results of the Z 20 1.8 S . Or does the sony have an inherent advantage in resolution readings given the higher megapixel count of the camera used in each respective test? Thank you!
Actually yes, you can compare them – we put a lot of effort into finding a way to make this possible. Here’s our article on the subject: photographylife.com/our-c…e-to-nikon
Steven Sparks
March 27, 2024 12:34 pm
I believe I’d rather have the Nikon Z 20mm f/1.8, wouldn’t you? (for Nikon Z cameras) Much cheaper, much lighter, less distortion, and mostly sharper per your test.
Certainly compared to adapting this lens to the Nikon Z system, absolutely. On the other hand, if you compare the Sigma 14mm f/1.4 Art on its native Leica L or Sony E, against the Z 20mm f/1.8 S on Nikon Z, it could go either way. It’s impossible to answer without knowing the photographer’s priorities.
Pasha
March 27, 2024 6:29 am
I believe that the results in “Test 4: Sigma 14mm f/1.4 Art on Nikon Z8” suggested that the adapter doesn’t have the correct flange distance. You can correct the shape of the stars at the corner by adjusting the focusing (a line like \, on the upper right corner, will become a dot and then a / line, obviously at the centre this will make things worse). To be more precise the flange distance seems to big.
The problem is like you say, Pasha – if you focus differently to improve the corners, then the center will not look good. I don’t think it’s primarily the adapter’s fault. We’ve seen the same thing with different adapters from a variety of brands when adapting mirrorless lenses across cameras.
John
March 27, 2024 6:18 am
Thank you for a thorough and helpful review, Spencer!
The straight comparison with Sony 14mm GM f/1.8 counterpart clearly shows ups and downs of Sigma’s design. It’s a specialty piece of glass for a hard core enthusiasts looking for the brightest possible outcome for night sky and milky way as such. In the end of the day 2 main things are decisive for the buyer: price and weight/optical performance. I suspect majority of people will opt for Sony, since you can get it for a decent price nowadays from mpb.com or second hand in near mint condition online. Plus the compact size and better coma performance are a huge plus. When hiking a few miles up that hill to a remote location, the weight difference counts a lot.
Sigma in my humble opinion will remain as an exotic choice for those who have use for the extra f/1.4 aperture benefit and those nice little lens features it comes with. But in real and practical scenario Sony wins hands down. As a happy owner I can only attest to this.
Choice is great for Sony Alpha shooters nowadays and that’s what matters the most 🙂
Sure thing, John! I think it is a more exotic choice for those who are dedicated solely to Milky Way photography. For daytime landscapes, the Sony 14mm f/1.8 GM, and even an ultra-wide zoom, are just as good. Even at night, the Sony 14mm f/1.8 GM is better in some ways (though worse in others).
The Sigma’s value to me is about more than its pure optical quality, although it’s still excellent there. It is more about the ability to focus (and sometimes shoot) at f/1.4, and the useful features like manual focus locking and a spot for lens heaters. Definitely specialized considering the weight. I think you’re right that most will choose the Sony 14mm f/1.8 GM. But there will be some astrophotographers for whom the Sigma is a dream lens.
Aku Kankaanpää
March 27, 2024 5:55 am
Got a chance to compare this lens against Sony 14/1.8GM. In my opinion there was no idea to switch to Sigma as it had visibly worse coma in corners and stopping down didnt improve it.
I found that stopping down the Sigma did improve things, with comparable coma to the Sony at f/2.8. I wonder if there was some slight decentering on your copy or some other issue at play.
bg5931
March 27, 2024 3:45 am
The Sony appears to be the more balanced package. The Sigma really only offers f/1.4, but I am not sure how important this is, given the possibility of using a star tracker (probably a model with modest size would be sufficient for the Sony) and/or image stacking.
For convenience and maybe even for image quality, I agree. That said, it’s really nice to focus manually with an f/1.4 lens that doesn’t have any focus shift upon stopping down (at least at infinity). That alone could lead to sharper results for many photographers who struggle to focus manually on the night sky. And then there’s the quality-of-life features like a manual focus lock… no easy winner here!
To me the issue you had when testing stars on the Z8 comes from the adapter.
You may get a better corner quality by refocusing and it will make the center less good, but that’s not the point.
The lens creates an image at a very specific distance behind itself, a fraction of a millimeter is enough to have a bad result especially on a full frame sensor so far from the center of the image, and espacially on a very wide angle lens, and especially on such a fast aperture.
Also, there is nothing more critical than a night sky to check for optical flaws, the quality is certainly more than acceptable for everything else.
With astrophotography gear it’s common to adjust this backfocus with very thin shims of 0.1 / 0.2mm and very precise adjustable tilt adapters. I’ve spent hours and hours on these things, for weeks and weeks, and months and months ; on lenses and telescopes.
The result with the Z8 shown here is typically from a sensor that’s too close to the imaging train (stars pointing outwards).
Considering all this, the results on the Sony body are stunning though.
That’s a great point, and I think you’re right. It especially is a problem with mirrorless lenses adapted across brands. Whenever I’ve tried testing adapted mirrorless lenses in the lab (like a Sony lens on a Nikon body), it has been an issue in the corners every time. But DSLR to mirrorless adapters (even third-party ones) tend to give sharp results through the corners.
Great review Spencer! You’re a wonderful resource.
Thank you, Mark!
What about Sigma 14-24/2.8 optically for 60mp Sony body?
I haven’t had a chance to test that one yet, hopefully later this year! I’ll put it in the next Sony lens poll for our members.
Spencer, thanks for this review–first rate!–and your equally excellent review, last week, of the Sony 14mm f/1.4 GM. Good lens reviews are harder than most people know, and these where terrific.
And for me, these reviews are timely. I recently purchased a specimen of the Sigma 14mm f/1.4 in Sony E mount, for use with a Megadap adapter on a Nikon Z7II body. My use is astro-landscape photography, updating from the Nikon 14-24mm f/2.8 G lens I’ve been using for this since 2008. (That year, I purchased a Nikon D700, which suddenly made nighttime landscapes, including the Milky way, very attainable.)
I have had only two brief openings of nighttime clear skies since this lens arrived, and I need to make a keep/don’t keep decision before the return period expires. So far, my impressions are decidedly mixed.
Mechanically, this lens is a dream. The tripod collar and focus lock are immensely welcome. How many times, in the past, have I wondered if I bumped the focus ring, and had to zoom in in live view to re-check focus? Far too many times. To focus once, lock the ring, and forget about focus is a big deal. Bumping focus–or thinking you have bumped it –is very easy in the dark (and often in the cold and wind).
Optically, I’m torn. Given that every lens is a compromise, and for this lens, all compromises were made in favor of star photography, I expected less of the distortion you’ve identified, and which I also see. Your demonstration that there is more distortion on a Nikon body is enlightening. Drat! I could add a Sony body to my gear, but this also requires use of a second raw format, second set of memory cards, second set of batteries and chargers, second L-bracket, second remote release, second set of electrical cords, etc. No knock on Sony–I just think simplicity has value in the field; I camp out for months to chase night skies and other photographic subjects, and when camping, a smaller equipment debris field is a good thing. And I’m heavily invested in Nikon, so switching entirely to Sony is not attractive for me.
One thing I’ve seen with the Sigma 14mm f/1.4, that I wonder if you experienced: The lens is very hard for me to focus (even in live view, with maximum magnification, on a tripod). The smallest movements my hands can make on the focus ring whisk the lens clear through the focus point. Worse, even small deviations from perfect focus result in donut-shaped stars. This has never been a problem with my Nikon 14-24mm f/2.8 G, in which OOF stars, while not perfect, simply got a little bigger and fuzzier.
Spencer, did you experience this “donut-ing” of out-of focus stars in your tests? I’m wondering if my sample has an issue. (A friend, who has more knowledge of lens issues than I do, suspected that my lens has a lot of uncorrected spherical aberration; he was unsure whether this is a lens design issue, or an aspect of my particular specimen.
Telescope-using photographers report that donut-shaped OOF stars are routine for them. To acquire perfect focus, they recommend using a Bahtinov mask. Bahtinov masks create a visible pattern that changes when a star in in focus. Such mask can be DIY for telescopes, but are hard hard to make for wide-angle lenses–they require many small lines, at the micron-level. For purchasing such a mask for a wide angle lens, the only source I know is from “focusonstars.com,” a cottage industry by Hungarian photographer Gábor Takács. I like supporting photographers who create solutions for other photographers. I purchased, and have received, a mask from Gábor Takács, but have not had a clear might sky to test it.
Lastly, I’ll mention that the Sigma lens’ f/1.4 seems far brighter than its theoretical two stops more openness from my f/1.8 zoom would imply (already a lot of additional brightness). It is an incredibly bright lens. I suspect that if we measured the various competing lenses in T-stops (which measure actual light transmission), we’d find that the Sigma 14mm F/1.4 transmits light very efficiently, and is therefore brighter than f/stop comparisons suggest.
Summing up, Spencer, could you please comment on whether or not you observed any donut or ring-shaped stars, when slightly out of focus?
Many thanks, and very best regards.
–Chris S.
I did indeed experience “donut”-like stars when they were slightly out of focus, both on Sony and when adapted to Nikon! Nothing wrong with your copy of the lens. Honestly, it didn’t bother me because I took it as a useful sign that my focus wasn’t perfect.
As to the rest of your comment, I think you summed it up, especially using this lens adapted to Nikon. It’s a joy to use mechanically. On a native Sony (or presumably Leica L mount camera), it’s optically excellent. Adapted, you need to decide if the corners are strong enough for your needs – it could go either way.
Is it realistic to compare your lens resolution tests to lenses on different systems? Like the FE 20 1.8 vs the results of the Z 20 1.8 S . Or does the sony have an inherent advantage in resolution readings given the higher megapixel count of the camera used in each respective test? Thank you!
Actually yes, you can compare them – we put a lot of effort into finding a way to make this possible. Here’s our article on the subject: photographylife.com/our-c…e-to-nikon
I believe I’d rather have the Nikon Z 20mm f/1.8, wouldn’t you? (for Nikon Z cameras) Much cheaper, much lighter, less distortion, and mostly sharper per your test.
Certainly compared to adapting this lens to the Nikon Z system, absolutely. On the other hand, if you compare the Sigma 14mm f/1.4 Art on its native Leica L or Sony E, against the Z 20mm f/1.8 S on Nikon Z, it could go either way. It’s impossible to answer without knowing the photographer’s priorities.
I believe that the results in “Test 4: Sigma 14mm f/1.4 Art on Nikon Z8” suggested that the adapter doesn’t have the correct flange distance. You can correct the shape of the stars at the corner by adjusting the focusing (a line like \, on the upper right corner, will become a dot and then a / line, obviously at the centre this will make things worse). To be more precise the flange distance seems to big.
There’s an extensive discussion on this topic in the comments section of the Sony 14/1.8 review. I suggest reviewing that first.
The problem is like you say, Pasha – if you focus differently to improve the corners, then the center will not look good. I don’t think it’s primarily the adapter’s fault. We’ve seen the same thing with different adapters from a variety of brands when adapting mirrorless lenses across cameras.
Thank you for a thorough and helpful review, Spencer!
The straight comparison with Sony 14mm GM f/1.8 counterpart clearly shows ups and downs of Sigma’s design. It’s a specialty piece of glass for a hard core enthusiasts looking for the brightest possible outcome for night sky and milky way as such. In the end of the day 2 main things are decisive for the buyer: price and weight/optical performance. I suspect majority of people will opt for Sony, since you can get it for a decent price nowadays from mpb.com or second hand in near mint condition online. Plus the compact size and better coma performance are a huge plus. When hiking a few miles up that hill to a remote location, the weight difference counts a lot.
Sigma in my humble opinion will remain as an exotic choice for those who have use for the extra f/1.4 aperture benefit and those nice little lens features it comes with. But in real and practical scenario Sony wins hands down. As a happy owner I can only attest to this.
Choice is great for Sony Alpha shooters nowadays and that’s what matters the most 🙂
Sure thing, John! I think it is a more exotic choice for those who are dedicated solely to Milky Way photography. For daytime landscapes, the Sony 14mm f/1.8 GM, and even an ultra-wide zoom, are just as good. Even at night, the Sony 14mm f/1.8 GM is better in some ways (though worse in others).
The Sigma’s value to me is about more than its pure optical quality, although it’s still excellent there. It is more about the ability to focus (and sometimes shoot) at f/1.4, and the useful features like manual focus locking and a spot for lens heaters. Definitely specialized considering the weight. I think you’re right that most will choose the Sony 14mm f/1.8 GM. But there will be some astrophotographers for whom the Sigma is a dream lens.
Got a chance to compare this lens against Sony 14/1.8GM. In my opinion there was no idea to switch to Sigma as it had visibly worse coma in corners and stopping down didnt improve it.
I found that stopping down the Sigma did improve things, with comparable coma to the Sony at f/2.8. I wonder if there was some slight decentering on your copy or some other issue at play.
The Sony appears to be the more balanced package. The Sigma really only offers f/1.4, but I am not sure how important this is, given the possibility of using a star tracker (probably a model with modest size would be sufficient for the Sony) and/or image stacking.
For convenience and maybe even for image quality, I agree. That said, it’s really nice to focus manually with an f/1.4 lens that doesn’t have any focus shift upon stopping down (at least at infinity). That alone could lead to sharper results for many photographers who struggle to focus manually on the night sky. And then there’s the quality-of-life features like a manual focus lock… no easy winner here!