*Sigma 20mm f/1.4 Art Lens on the Sony a7II and Canon 5DII, a user review w/ @adorama


Sigma Art EF 20mm f/1.4 Lens review

Happy new year! I’ve been having a wonderful holiday season, largely thanks to Adorama for lending me this beaut of a lens.  The Sigma Art 20mm f/1.4 is the widest, f/1.4 full frame lens, and is the newest addition to the much vaunted line of f/1.4 Sigma Art Primes available in Canon EF, Nikon F, Sony FE, Leica L and Sigma mounts.  In this article, we’ll explore a bit of the more measurable aspects as well as the more touchy, feely parts of interacting with this lens.  I shot this lens on both the Canon EOS 5D mkII and the Sony a7II via the EF>FE Metabones MkIV smart adapter, and it performed equally as solid on both cameras.  Is this a viable option for full frame system shooters for fast, ultra wide applications?  Well, seeing as there has never been a full frame compatible lens this wide, this fast, it’s forging new ground for many shooters, and that is pretty rare in this day and age.  C’mon in to see some example images and read my rambling thoughts…



SPECS, bells and whistles:

  • Angle of View: 94.5 degrees
  • Max aperture-Min aperture: f/1.4 – f/16
  • Min focusing distance: 10.9″
  • Max magnification: 1:7.1
  • 15 Elements in 11 Groups
  • Two FLD Elements and Five SLD Elements
  • Two Aspherical Elements
  • Diaphragm Blades: 9, rounded
  • Diam x Length: 3.6″ x 5.1″ (91mm x 130mm)
  • Weight: 33.5oz / 2.1lb (950g)

Sigma art 20mm f/1.4 on a7II and 5DII side by side (1)

This lens is not small, by any stretch of the imagination.  Measuring a hefty 3.6″ x 5.1″ and 33.5oz (just over 2lbs at nearly a kilo), this is not a “throw it in the pocket, just in case” type of lens.  This is an intentional tool.  20mm is a very short, wide focal length all things said and done, and when used on a full frame sensor, it provides an ultra wide angle of view (roughly 95 degrees on the horizontal axis in landscape).  

The minimum focusing distance is just shy of 11″ which allows you to get creative with closeups.  The maximum magnification doesn’t start to scrape the macro realms, but really, if you’re looking to shoot macro with an UWA lens, A) it will be tough to find, and B) there’s nothing stoping you from adding some extension tubes, which might actually be kind of fun.

Due to the protruding front element, there is no way to mount a threaded filter, but with current sensors, and modern software, I’m finding less and less need for filters anymore, anyway.  I do like neutral density filters, and if shooting video, having the ability to further eat light when necessary, is handy, so this lens may struggle to appeal directly within those fields, but otherwise, I’m sure someone will be coming up with (or may have already) a filter holder to fit this lens for those who want or need to filter a lens like this.

While the maximum aperture for a 20mm f/1.4 lens will physically measure in at just over 14mm (not physically huge) the optical construction to properly focus and spread light across a large sensor is complex and comparably immense, hence the overall size and heft of this lens, showcasing 15 optical elements in 11 groups with two aspherical, two FLD and 5 SLD elements to help limit distortion, flare, vignetting and chromatic aberration while maintaining contrast and color throughout the aperture range.

Just for giggles, here are two lenses with the exact same focal length, 20mm, side by side.

20mm f/1.7 vs 20mm f/1.4

Granted, one is designed for use on a sensor 1/4 the size of the other, but before you start talking about “fast lenses” requiring a lot more glass just purely based on the physics, the micro 4/3 lens max aperture of f/1.7, still measures in only about 2mm smaller than the max aperture of the Sigma f/1.4 for reference.  Yes, the m4/3 Lumix lens crops to a 40mm equivalent field of view, but a 20mm lens is a 20mm lens as far as math is concerned with the optics needing to properly focus light at a distance of 20mm from the capture medium to the rear nodal point at infinity.  Here in lies perhaps some insight into the lengths Sigma has gone in designing and building this optic, and while both of these 20mm lenses are optical achievements in design and performance, a full frame optic will always have a harder time getting light spread across a larger surface area while properly focused.


sigma art 20mm on sony a7II


With this type of lens, two types of photography immediately jumped to mind.  First, night/astro photography and secondly, interior/architecture.  Of course landscape is a given, but we can shoot landscape with most any lens, really, and when doing so, we’ll normally be stopped down to aperture settings enabling the sharpest results, edge to edge.  Landscape shooting doesn’t normally need fast, large maximum apertures, but that shouldn’t stop one from utilizing them to fun effect for landscape as well. 

Unfortunately for me, the entire month I have had this lens, it has been overcast, raining, snowing, icing and blowing, less two nights where the winds were whipping around at 40+mph and ice made driving, uh, fun which provided a bit of a challenge to get out anywhere to shoot in the later hours.  This limited my ability to do any astro shooting stuff, which is really a bummer as I was hoping to get some good nights in.  I couldn’t send the lens back without some semblance of how this does for stars and the like, so I did get out that one clear, cold night to shoot the night sky from my back yard.  For the second application, I luckily had a job shooting a retail store, so I did get a few shots in with it there.  Outside of that, it is just a fun, creative, story telling focal length that is a lot of fun to shoot with in a variety of situations.

Astro/Night Sky shooting:

We’ll look at the COMA and general night sky shooting on both the Sony a7II and Canon 5DII first.  Coma (in a photographic sense) is an optical aberration where a point of light is distorted in such a way that it appears to have a tail, or wings, normally visible in wider angle optics near the extreme corners and edges.  

All shots below were captured as proprietary RAW files and processed through Aperture.  Both series were shot identically on both the a7II and 5DII.  All examples of the night sky stuff are untouched other than to convert to a resized JPEG for space sake.  The center of the images, even wide open were all great, so I’ll spare you that chart.  What I, and I’m sure many out there are interested in, is seeing how the corners perform with such a wide, fast lens in the night sky.  All shots were taken with the in camera white balance set to Tungsten, ISO 1600, and nothing else done to them in post (no NR, sharpening, et al).  Keep in mind that we’re looking at the extreme corner, and worst part of the lens here.  While the edges also exhibit some of the same coma as these corner shots, it isn’t quite as bad with the exception of the actual edges for the most part.

Click image to see Full Size

COMA on the 20mm f/1.4

Before you claim slow shutter speeds as the culprits, take into consideration that the f/1.4 shot was a mere 1.3 seconds which for night sky stuff is nothing.  Herein lies the beauty of such a fast, wide lens.  The f/5.6 shots were only 15 second exposures, which is hardly enough to pull light trails with a 20mm field of view.  No, unfortunately the gnat like distortion we’re seeing in the corners is coma.  Not great, but also not unique to this lens.  Like I mentioned earlier, I’d have loved to really get some good hours shooting more night sky stuff, but with weather hampering the party (we had the wettest, see: cloudiest, December in recorded history here in the PNW) I was literally limited to a single night which also saw some insane wind and slick roads, not to mention family in town, keeping me close to home.  

Take what you will from this.  I’m not thrilled with the corners, but I’m also not surprised.  What I am happy about though is how well this lens kept up in the corners while adapted to the Sony a7II via the Metabones adapter and actually looks to out perform the lens on the 5DII as far as distortion from this test.



Alright, now onto interior stuff.  The distortion (which is quite apparent when shooting up close, as seen later down the article, as is the case with many a wide angle lens) is actually pretty well corrected for optically as I saw it through the viewfinder.  When composing interior shots especially, it is easy to notice any distortion along frame edges.  With walls, corners, beams and the like, you can pretty easily see any bending and bowing due to the wide spread barrel distortion attributed to wider angled lenses.  That said, when the camera was properly leveled (which having the levels on screen in the case of the a7II is pretty boss) this lens does remarkably well for optically correcting when focusing further than about 10-15′ away from the camera’s position.  That may not sound too impressive, but having done a lot of shooting over the last few years of this type with a 14mm f/2.8 prime and 17-40mm zoom, I find the Sigma’s performance admirable.


Having an ultra wide angle lens with a remarkably fast aperture, in this scenario also adds the ability to shallow up the depth of field (not easy for an UWA lens) providing a new tool for detail shots and vignettes which I found to be very useful, and a pleasant surprise.

I really appreciated this lens on this shoot, and while there were spots where I needed the extra width that my trusty 17-40mm provided, the shots that I used the 20mm for produced shots that were both relatively untouched by optical distortion, and gave me resulting images that I’d not have been able to get with my other wide angle options.  


Resolution/close up optical distortion:

Below I’ve got comparison shots between this lens on the Sony a7II, and the Canon 5DII with the full image files from each first with a squared line overlay, followed by 100% crops from the center (at the point of focus) and the bottom right corner to see how this lens does at near minimum focusing distance with sharpness, distortion and vignetting.  All pieces on the shelves were placed an equal distance from the edge of said shelves, and while the lens and cameras were centered, the further away from the center of the image, the further away from that point of focus due to field curvature.  The point of focus is the teeny red cup, held by Mr. Business, center frame.  At this close a focus distance (~18″), distortion and softness are certainly exaggerated, but this is about as bad as I can get this lens to perform, so there’s that.  If I were doing any personal shooting this close to anything, I’d not be too worried about the corners, myself.  More than the ultimate sharpness in the corners though, have a look at the vignetting as seen in the corner crops below.

First, the frames, as they were captured followed by center crops and corner crops:

Click to see larger

a7full 5Dfull

Click to see larger


The point of focus was the red cup, which I manually focused on.  For those of you who don’t have kids, or don’t still play with legos, that guy there is President Business, and his coffee cup extends beyond his body by about a half of an inch, tops.  The shots wide open aren’t soft, it’s that the depth of field is that thin.  While, to my eye while composing, and according to the on screen levels for the Sony, the shot was entirely squared, I can see here that it was off, just a smidge.  Still evident though is slight mustache distortion through both, but vertical lines, and most horizontal lines are pretty damn straight, considering that this is a 20mm lens, focused at around 18 inches from the focal plane.

Also, this is one of the first times I’ve done a controlled test between my 5DII and my a7II, and this, if nothing else, is showing me how that little extra resolution on the Sony sensor is kind of embarrassing the old Canon here.  Take into consideration that the Sigma is a native EF mount lens too, and has to be adapted to the Sony, so, uh, yeah about that, Canon…

Alright, on to the corners:

Click to see larger


Alright, again my slight miscalculation on leveling is evident here, but look at how friggin’ straight the outside edge of that Canon 70-200mm lens is.  Sure it’s distorted, but that is to be expected in the extreme corner of most any lens anywhere near this wide.  Vignetting isn’t noticeable at f/2.8, and is totally gone by f/4 to my eye, with total sharpness following the same tick.  Again, taking into consideration the field curvature (the plane of focus is not flat) the corners are pretty darn sharp, even wide open where that curvature hits its apex, so if you need this lens to be sharp, corner to corner, stop it down to f/4 or beyond, and try to focus on something further away than about a foot and a half.  You’ll be just fine.


Any of you who’ve been around and read my reviews are probably well aware that I look at lenses to either buy, or keep.  I’m not entirely interested in scientifically testing lenses for shits and giggles (excuse my American).  I have a lot going on with a young family and two jobs, so I’m not going to waste time on something I don’t like playing around with.  This lens is no exception.  It’s very large, and relatively heavy, but those drawbacks come with some pretty impressive quality.  I’m sure that there are those reviews out there that will give you a much better, and more scientific list of results as they pertain to sharpness, distortion and the like, and I whole heartedly suggest you search those out if you’d like to read more about this lens.  For me, that’s about as much as I have in the tank to show you, and I hope it at least gives you a little insight.  Now, onto the fun part of this lens, shooting it.

Here are a few images that I’ve taken over the last month with this lens.  Please let me know if you have any questions, I’d be happy to try and answer them.

a7II – ISO3200 – f/1.4 – 1/40sec


5DII – ISO200 – f/1.4 – 1/320sec


a7II – ISO800 – f/2 – 1/640sec


a7II – ISO200 – f/1.4 – 1/2000sec


a7II – ISO400 – f/2.8 – 1/3200sec


a7II – ISO50 – f/16 – 1.6sec


a7II – ISO100 – f/1.4 – 1/2500sec


a7II – ISO400 – f/1.4 – 1/4000sec


a7II – ISO200 – f/11 – 1/250sec


5DII – ISO400 – f/1.4 – 1/1600sec


5DII – ISO50 – f/16- 1.3sec


a7II – ISO200 – f/2 – 1/800sec


a7II – ISO100 – f/1.4 – 1/3200sec


I really, really enjoyed shooting with this lens, and having had the time with it, it has vaulted up my wish list.  I hope to have one to call my own here soon.  When I first really got into photography, I went wide angle crazy.  I loved playing with odd shooting angles to amplify distortion and perspective to fun and sometimes silly effect.  Since then, I’ve tailed away as I became more enthralled by compositional nuance and various other forms of photographic output.  I’ve come full circle, and I think that 2016 is going to be a renaissance year for me, going back to some more wide angle applications.  This lens re-sparked that excitement, reminding me how much fun I had while starting to explore the world through a wide lens.  

The real magic that this lens brings to the table is firstly its speed.  As has been said, nowhere else can you find a full frame lens this wide, this fast.  Considering that for something like astro photography, most lenses in this range, at best, are f/2.8 with the rare exception of an f/2 or f/1.8 UWA (that is up to two full stops faster!) until you hit the 24mm f/1.4 variants.  It’s not just fast for speed’s sake either, it’s pretty darn sharp wide open too.  That in and of itself is reason to consider it.  Add in the optical quality, and relatively modest price and Sigma has continued to not only pressure the big boys, but is kicking ass in the lens game.  Good on you, Sigma.  Keep it coming.

The Sigma Art Series lenses now offer shooters four classic focal lengths at comparably reasonable prices.  That, and they’re optically killing the competition less a couple of the very expensive Zeiss Otus lenses.  Bang for buck?  There’s nobody really pumping out stellar, fast full frame primes at sub $1000 prices other than Sigma right now.  You can click the links below to see the lenses at Adorama.

Sigma 20mm f/1.4 Art $899 – (bundles currently available)

Sigma 24mm f/1.4 Art $849 – (bundles currently available)

Sigma 35mm f/1.4 Art $899 – (bundles currently available)

Sigma 50mm f/1.4 Art $849 – (bundles currently available)

Thank you again to the team at Adorama for sponsoring this review by way of sending me this lens to test.  Adorama is a trusted and awesome retailer that I buy from often.  You can visit Adorama HERE, and if interested you can find the Sigma ART 20mm f/1.4 Lens via my affiliate link HERE.

I’d love to connect via the socials.  Find me on  Facebook, Twitter, Flickr and Instagram.  If you’d like to receive my reviews, and tutorial posts as I release them, feel free to add your email to the top right of the page here and you’ll get them emailed as soon as they’re posted.  Coming up soon are some fun new software programs and a remarkably fast, standard m4/3 prime lens review…

Thank you for the read, and happy shooting.




8 thoughts on “*Sigma 20mm f/1.4 Art Lens on the Sony a7II and Canon 5DII, a user review w/ @adorama

  1. Even when I have no intention of buying one of the items you review (I’ll stick with my 20mm pancake, thank you very much), I still enjoy reading every word because your posts are so well-considered and well-written, and because you always teach me something new. Thank you for the time and thought you always put into your posts, Tyson.


  2. Pingback: *Sigma 20mm f/1.4 Art Lens on the Sony a7II and...

    • Thanks CDC! I really like this lens. It isn’t small, but it is a stop faster and 5mm wider than the Batis and with a metabones adapter, it’s about a wash cost wise. I’d love to shoot these two side by side, but I know that I really want the Sigma 🙂


  3. Pingback: Sony Tidbits… | sonyalpharumors

  4. Hi Tyson. I read your Sigma 20mm lens review online and had a question for you. I read another review saying that with adapting ultra wide angle lenses to Sony FE you lose a lot of corner sharpness compared to the same lens on its native Canon body. I was wondering what your thoughts are on that after your testing. Thanks for your work!


    • Hi Mark,

      I found the lens adapted to the a7II to be better in the corners than on my 5DII. That may be more to do with my old Canon though and the newer Canon sensors might be better designed for third party ultra wides. All in all, I’m happy with the overall sharpness on either camera to be honest. When stopped down and kept within the range before starting to lose sharpness due to diffraction, the 20mm does well. Wide open, the corners are going to suffer, but that will be the case with just about every optic, but stopped down to between about f/4-f/11 or so, anything that should be sharp (that I’ve paid attention to anyway) is plenty sharp for me. The bigger issue I’ve seen is distortion at the extreme edges when the lens isn’t leveled, or I catch people on the edges, etc. Another reality with wide angles that just needs to be worked around 🙂

      Thanks for the read!



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