Sigma's 20mm f/1.4 Art Is Pure Heaven with No Competition (Unless You Shoot Nikon)

Sigma's 20mm f/1.4 Art Is Pure Heaven with No Competition (Unless You Shoot Nikon)

If you don't know Sigma's Art series lenses yet, you're missing out. Their well established 24mm, 35mm, 50mm, and zoom options in the Art lineup shine, but it's hard to believe it took this long for a wide-angle 20mm f/1.4 Art to make it out into the real world. But the moment I began shooting with this beauty is the moment of the past didn't matter anymore. We're in a new world: there's a 20mm to die for; and this is it.

Introduction

We've been very, very patient. Sigma had zero competition, so it's no real surprise that it took this long. Nikon's still-somewhat-new 20mm f/1.8G is a great alternative for Nikon shooters that does feature Nikon's excellent Nano Coating, but it's not as good as the 24mm f/1.8G (which is obviously not as wide) that just got rave review from DxOMark. Both lenses do fall over half a stop short of Sigma's sharp as hell, massively awesome 20mm f/1.4 Art. Thinking of Canon's EF 20mm f/2.8 USM? It may be cheap, but it's a full two stops tighter than the Sigma. And besides, it's so ugly. Just look at it...need I say more? Either way, it's the Nikon 24mm f/1.8G that we'll be considering as the only realistic alternative for Sigma's newest prime lens if image quality is a top concern.

The built-in hood does a great job of shielding the front element from sunlight and bumps alike. Overall, the lens has a great, solid, heavy feel to it.

If you're looking for the short version of this review, here it is: Just buy it -- especially if you're a Canon shooter. Then sell whatever you had before that was somewhat like it. On the other hand, if you're a Nikon shooter and don't absolutely need the f/1.4 aperture (most will find it hard to justify why you need that small difference), then you still have a decision to make. The Nikon is amazingly slightly cheaper, and beats the Sigma on sharpness and a number of other factors, even if just by a bit in both cases, and even if it's just DxOMark that currently says so. Nikon surprised us very pleasantly with their 24mm f/1.8G after their 24-70mm f/2.8E blunder. They may have a long-term chance against Sigma after all, as these are the kinds of results we've been waiting for. But back to this review of the Sigma...

First Impressions

This lens is packaged the same way as all of the other Sigma Art lenses: simply, but with everything you need (the lens and a case). Taking the lens out is when the real magic sets in. It's not small. Compared to the rest of the Sigma Art lineup, the 20mm is closer in size to the 50mm than it is to the 35mm and 24mm. This is in part due to its built-in hood that helps protect its bulbous front element, which brings us to our first and only real point of contention.

Because of its bulbous front element, the Sigma 20mm f/1.4 Art can't accept traditional screw-on filters. Much like Nikon's 14-24mm f/2.8 and Tamron's new-ish 15-30mm f/2.8 VC, you'll need a special, square filter kit like those made by Lee Filters in order to effect any change with polarizing filters, etc. At the same time, it's this feature that allows Sigma to deliver such a superb image. If I were a landscape photographer, I would have invested in an appropriate filter kit long ago anyway...

The Sigma 20mm f/1.4 Art is a very "good" size. The lens cap is a slip-on cover that slides firmly over the built-in leafed lens hood. Thankfully, it doesn't come off unintentionally.

If there's one reason to pay twice as much for more or less the same lens in the 24mm Canon L or Nikon f/1.4G version, it's autofocus (aside from the world of difference between 20mm and 24mm, of course). The Sigma Art lenses do extremely well, but the home-cooked variants tend to perform just slightly faster in my experience. Yes, it's almost imperceptible. But yes, "almost."

Thanks to the wide angle of the 20mm focal length, however, this difference is minimized and perhaps even negated altogether. Because wide-angle lenses have such relatively large depths of field, they don't have to "adjust" as much to get to a particular point of focus. This short throw means that focus is usually lightning-fast on wide-angles. Add to that the fact that this is a prime lens, and you've got focus speeds that won't leave your wanting more.

Either way, if you want proof of how good the Sigma is overall, it's time for our first sample image:

Apart from what you can tell from the general angle and some mild distortion of the circular saucer underneath the cappuccino cup, it's hard to believe you'd get this shallow depth of field from a 20mm lens. The bokeh looks like my 85mm shot at f/2 or so. Granted, this is way too shallow for this particular shot. But it does illustrate the point (just about the only in-focus point is the lip of the cup right where the drink spilled over slightly).

 

That right there is a JPEG saved straight from the raw .NEF file without any changes. 

In any case, if you never thought you'd say, "Bokehlicious," about a 20mm lens, think again. This has enough bokeh to smooth out the Eiffel Tower into an inflatable Air Dancer in the background of your street mime portrait series. In fact, I'm going to go order a second cappuccino right now... For anyone paying close attention: by "bokeh," I of course more accurately mean, "shallow depth of field."

With Nikon's f/1.8G (the 20mm and the 24mm), you still get a decent shallowness to the depth of field, or so I would imagine. I admittedly haven't had the chance to shoot with either yet, but physics is physics. And the cheaper price of either might still win your brain over, especially since we're probably talking about a relatively small perceivable difference in image quality between both of these lenses anyway. Then again, I'm sure you could still tell the difference in light transmission if you really need that extra (almost) stop. But those are all decisions you need to make.

The 20mm focal length is a refreshing one for walking around, as it brings a large section of life into the frame with relatively minimal distortion. I wish I had my tripod and a little more time on my hands to have made a real go of this shot as the clouds turned...(this shot is edited slightly).

Image Quality

I'm not a scientist. I'm not testing this in any special way. But when I take a look at these files taken with my relatively modest Nikon D750, I'm amazed. I've included plenty of samples (plain and not so plain) for you to mull over and form your own opinions. But contrast is punchy, color rendition is fantastic, and there's an air of sharpness surrounding every image in a way that makes me ooh and ahh over the results, regardless of whether or not I like the actual photograph in question.

You can't have a lens this wide without some noticeable distortion. And in the corners, it certainly is there. But if you're smart about shooting your wide-angle shots the way you should be by keeping recognizable objects or corners of clearly rectangular objects out of the corners, you'd be hard pressed to find any distortion that is too distracting.

That said, sharpness in the corners -- even on the edges as a whole -- degrades quite a bit due to just how wide this lens is. Honestly, it's a little more degraded around the edges than I would have expected. On the other hand, it's been a long time since I've shot anything decently wide at all. Although I may be out of touch with the "norm" for a wide-angle lens, everyone else seems to think it performs quite well. So for now, I'll chalk it up to an issue with this copy or perhaps simply an issue with my own perception of what is and is not normal.

You can take all of the "scientific" tests with a grain of salt, but it doesn't hurt that DxOMark and LensRentals like this lens, too. The new Sigma 20mm f/1.4 Art is sharper than the Nikon and Canon 24mm f/1.4 lenses in the center, and at least equal in corner resolution. That should set any last doubts at ease. Those interested in edge sharpness can enjoy the simple street shots below as examples.

This was shot at ISO 100 and f/2.8 just to get a feel for what would be considered a fairly medium depth of field for this lens. If you follow the in-focus area (roughly the middle of the road) to the edges of the frame, you'll notice some loss in sharpness...even continuing up to the trees on the left). Maybe the loss of sharpness in the edges is normal for a lens like this. While it's fine to my "normal" eye, it seems a bit less sharp than the pixel-peeper in me would prefer.

Here's one more shot where the softness in the edges is noticeable. Again, is this normal? You tell me... The rest of the frame looks fantastic, though.

Summary

I already mentioned the short version of this review above: buy this lens. But at the end of the day, we're lucky that one of our only options in the category is a fantastic one at that. The bulbous element should only disappoint the select few who constantly add and remove screw-on filters. And while there is no mention of an oil-, dirt-, and water-shedding fluorine coating like that on the front element of the Tamron 15-30mm VC (and Nikon's and Canon's super-telephotos), that's not a deal-breaker...it simply would have been a nice touch given how large the front element is. And it's not like these lenses are anything alike (though I still wouldn't blame your for having a tough time choosing between the two).

If you're a Nikon shooter, the 24mm f/1.8G offers just what this lens does and then some at a slightly more narrow field of view, except for the picky shooter's desire to get all the way to f/1.4. While I haven't shot with it yet, I would recommend trying it if it's an option for you -- you can even screw filters onto the front of that one.

As far as my needs go, consider them met. I'll be keeping this lens one way or another. Anyone want my 24mm f/1.4 Art?

 

The Sigma 20mm f/1.4 Art can be ordered in Sigma, Nikon, and Canon mounts for $849.00.

 

(Correction: This article originally made references to Nikon's 20mm and 24mm f/1.8G lenses in incorrect orders. These errors have now been fixed.)

Adam Ottke's picture

Adam works mostly across California on all things photography and art. He can be found at the best local coffee shops, at home scanning film in for hours, or out and about shooting his next assignment. Want to talk about gear? Want to work on a project together? Have an idea for Fstoppers? Get in touch! And, check out FilmObjektiv.org film rentals!

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I will gladly take your 24mm 1.4 off your hands, let me know :D

Can you point me in the direction of the filter kit i should already own that will work with this lens? I own a standard 100mm HiTech and it wont i dont think

How is the weathersealing with this one? ;)

I'm afraid I can't comment too much on that. While I have some leeway with what I can do with these lenses, I'm not sure I'll be well liked if I go pouring water all over my gear. I imagine the weather resistance is akin to the rest of the series. With all of my gear, I plan for it to accept light rain or sprinkling. Anything more and I usually break out the plastic cover just in case (sometimes with the D4 and certain Nikon lenses, I wouldn't worry about standard rain alone, though...).

Ok thanks :)
Returned from Iceland 1½ month ago and sometimes my gear was dripping (5dm3 + 16-35mm m2) and didn't have any problems with it - just wondered if this could go through the same conditions ;)

I wouldn't push it too far. But yes, most higher-quality lenses these days can shed rain pretty well. It's just not THAT hard to close seals enough so that water wants to brush by them instead of penetrate through them. So you should be fine similarly with this...

Thanks alot for the answer! :)

as a wedding photographer, I personally prefer the 35mm 1.4 over a 20mm or 24mm 1.4...I definitely agree with Patrick that wide angle primes are geared toward astrophotographers

In the pantheon of ultra wide lenses this one would be highly prized by me. I own a 14-24mm Nikkor 2.8, Zeiss 21mm Distagon 2.8, if anything the reason I own the Distagon is because when I bought the Nikkor (I bought it first), I didn't realize just how limited my filter options would be. The Zeiss accepts threaded filters.
The primary use I would have for the ultra fast 20mm Sigma is night time observations and maybe street photos. For my uses, the 20mm makes plenty of sense to me.
Sigma is the only company that can actually compete with the likes of Zeiss in I.Q. and offer it at highly competitive price. Zeiss on the other hand offers you near unbeatable construction quality in an all metal shell, buttery smooth focus ring action to boot.
Nikon offers you great all around imaging optics in the form of a brick.

Hey @Adam, thanks for this article! You might want to check dxomark it surprisingly agrees with you with regards to edge softness (look under measurements>sharpness>global map http://www.dxomark.com/Lenses/Compare/Side-by-side/Sigma-20mm-F14-DG-HSM...) you'll notice though somehow this is only obvious at f 2.8 whereas it disapears at either f 2.0 or f 4.0... never heard of anything like that I was surprised to see it on DxO... Fantastic wedding pictures by the way @Tony. Truly inspiring. And to those that keep saying this lens is not meant for weddings well... this is how you make images that stand out I guess, doing things out of the ordinary.

Well I got Sigma 35mm 1.4 and 20mm 1.4 for my d810,first they had heavy front focus specially from 1 meter distance and more.After Lens Align system calibration I have very nice sharp images when I focus in a subject which is less than a meter away but more than a meter or 2 is very soft which I expected from a prime lens to be more sharp! I have send my body to Nikon NPS and they checked and said camera is in order and they have checked with Nikon wide angle lenses and focusing is right in body!
I have to check with other friends who has same lens and body or bring it to Sigma to check further!
Any idea or same problem?!

While two of my sigma lenses were perfect, I had the same types of issues with one of them. While it's very frustrating, they did fix it without any questions asked and for free. I had it back in about a week... So I think that'd be the best bet...

I get along fine on my 85mm F1.8. Not as expensive, or heavy.
Great results in many cases. Only drawback is CA, which is easily fixed on most things.

Thanks for the article. It would have been tremendously helpful, had I not been a Nikon user. See, I've been in a bit of a quandary myself. I'm an amateur photographer that recently switched to prime lenses - I had been using zoom lenses for some time and wanted to get sharper images and shallower depth of field. The prices of good photographic gear being what they are, I only got the Sigma 50mm 1.4G as a starter, and have been impressed by its image quality - and its bokeh.

Having no prior experience with prime lenses I soon ran into the usual problem: a 50mm prime lens is ill-suited for architectural photography, especially interiors. So, I've been looking for a good wide-angle prime and the choice soon boiled down between Sigma 20mm 1.4G and Nikon 24mm 1.8G. Both are good in their own way but I'm not sure which one is better for me. I guess a wider angle is better for interiors, but adds more distortion. The wider aperture allows better low-light photography, especially astrophotography, which is certainly something I want to delve into, but takes away sharpness. And Sigma has a protruding bulb that is easy to damage.

Given that at this point I can afford only one of the two, and that I mostly want it for architectural (exterior and interior) photography and astrophotography, which do you think is the better choice?

Thanks for the question, Ioannis. I understand your concern. Honestly, while both the Nikon 24mm and Sigma 20mm lenses you're considering are superb, you actually have a few more options than you may think. For starters, there's the also-superb Nikon 20mm f/1.8G (https://www.bhphotovideo.com/c/product/1082607-REG/nikon_20mm_f_1_8g_fx_...) that came out a little more recently. This doesn't have the bulb that the Sigma does, is around the same price (even a little cheaper), and still features Nikon's excellent Nano coating. Of course, it doesn't open up as wide, but what you give up in half a stop of light you gain in weight savings and a virtual guarantee of autofocus calibration that will already be suited to your Nikon body.

Also, Nikon has their 28mm f/1.8g, as well. That entire f/1.8G lineup is incredibly well-rounded. I would go out and try them, and then see what focal lengths you really love the most. It may be best to one day look into getting the 20mm and 28mm while skipping the 24mm. Or perhaps you'll be drawn more to the 24mm as a perfect compromise for your shooting. Maybe you'll settle on the 20mm with the thinking that you can always crop in a bit, and that a 20mm focal length will give you the most flexibility while sticking with a single lens....

Honestly, though, even I'll admit it's a tough choice. But once you get your one wide-angle, don't be afraid to continue to pull out the 50mm or even buy into something like an affordable 35mm. Mike Kelley (and he's not alone in this) uses a range of focal lengths for given situations. Sure, you're going to need those wide lenses. But there are plenty of shots on every location in which using other focal lengths is even more appropriate.

Best of luck.

Good advice! And yes, I do plan to get a 35mm in the future - it's just that I have to prioritize, I cannot buy everything I'd like to at once.

Your point about using a 20mm lens and cropping when necessary is an excellent one. I'm lucky to be using a D810, and with its 36 megapixel resolution cropping is not a quality-diminishing process.

Also, thanks for pointing out the Nikon 20mm f/1.8, it seems to be a really nice choice, especially as an alternative to the Sigma one. My lack of experience doesn't make me any favors in helping me judge the impact of that half f-stop for what I want to use the lens for, but if I can find a way to try them both and see what I like best, I'm definitely going to.

No problem. And in general, don't look at it as a difference in a half stop. Look at the half stop merely as a sign that one lens is superior to the other in at least one way (for the lenses we're discussing, anyway). Whether those differences result in a sharper image or less distortion or less chromatic aberration or all of those or something entirely different, whether or not the price difference is worth it to you should be the determining factor. Honestly, I'd say all of Nikon's 1.8G lenses are more than adequate to fully support ANYONE's career. The only reason people spend more money on more expensive glass is because they can and it's just nice to have for those few times when it does make a slight difference.

I bought the Sigma 2mm f/1.4 hoping it would be good for astrophotography. While the center is sharp, the corners have significant coma, making the lens poor for astro work unless you want to take 3x3 panoramas to get rid of the corners.

This article paints the opposite picture. Just goes to show that one needs to evaluate it on his/ her own merits.

https://www.dslrbodies.com/lenses/nikon-lens-reviews/third-party-lens-re...