Sigma 20mm f/1.4 Art Review | A Wide Lens In A League Of Its Own
It seems like we are seeing quite a few “trophy” lenses these days. For example, Sigma has twice broken the f/2.8 zoom barrier, once for APS-C sensors with the 18-35mm f/1.8 Art, and once for full-frame sensors with the 24-35mm f/2 Art. Also, remember that Canon just created a new class of wide lens altogether with the 11-24mm f/4. I find myself asking, what’s next? Anything is possible, even practical. (Except probably not a 24-70mm f/2. Sorry!)
You would think with so much exotic glass hitting the market that Sigma would pause and dial it back a notch, to create a lens for us,mere mortals, like an 85 f/1.8 Contemporary, or of course an 85mm f/1.4 Art. Tamron is up to three new f/1.8 primes now, by comparison.
Instead, we have received another lens with a jaw-dropping set of numbers that should make any nightscape photographer begin to drool immediately: 20mm f/1.4.
Previously, the only lenses to even come close to this have been the Leica 21mm f/1.4, a $6,700 lens, and Sigma’s own 20mm f/1.8 EX, a discontinued (?) $450 lens. (Only recently did we get the $800 Nikon 20mm f/1.8 G, which I reviewed HERE.)
Not including fast 24mm options or f/2.8 zooms, this essentially leaves a total void for any non-Nikon shooters who wish to have decently good image quality, center to corner, at a fast aperture. And Nikon shooters, well, I will leave the f/1.8 versus f/1.4 debate for a later time, or the comment section below. Have at it, all you speed junkies!
Enter the Sigma 20mm f/1.4 Art, a unicorn of a full-frame lens. At $899, it’s pricey enough to incite cries of “it had better be sharp!” Yet in my opinion, if it turns out to be even half decent it will be both an impressive feat and an incredible value.
Sigma 20mm f/1.4 Art Sample Video And Images
Sigma 20mm f/1.4 Art Sample Crops
(I create my 100% crop samples by shooting with the lens diagonal and at infinity, to inspect the entire zone from center to corner.)
F/1.4, Center (Normal details are sharp, highlights bloom a lot!)
F/1.4, Rule-of-Thirds Area
F/1.4, Corner (50 MP)
F/1.4, Corner (24 MP)
F/1.4, Corner (4K)
Sigma 20mm Art, F/2, Center (Normal details very sharp, highlights bloom less!)
Sigma 20mm Art, f/2, Rule-of-Thirds Area
Sigma 20mm Art, f/2, Corner
Sigma 20mm Art, f/2.8, Center (Normal details very sharp, almost no blooming)
Sigma 20mm Art, f/2.8 Rule-of-Thirds Area
Sigma 20mm Art, f/2.8, Corner
Sigma 20mm Art, f/4, Center
Sigma 20mm Art, f/4, Rule-of-Thirds Area
Sigma 20mm Art, f/4, Corner (Finally, decently sharp!)
Sigma 24mm f/1.4 Art Sample Crops For Comparison
Sigma 24mm Art, f/1.4, Center (Normal details sharp, highlights bloom purple)
Sigma 24mm Art, f/1.4, Rule-of-Thirds Area (Slightly less sharp)
Sigma 24mm Art, f/1.4, Corner (Severe coma, softness, and vignetting)
Sigma 24mm Art, f/2, Center (Extremely sharp, blooming & halos mostly gone)
Sigma 24mm Art, f/2, Corner (Coma not improved much, Vignetting improved)
Sigma 24mm Art, f/2.8, Center (Very sharp, very little blooming)
Sigma 24mm Art, f/2.8, Corner (Coma significantly improved, Vignetting almost gone)
Sigma 24mm Art, f/4, Center (Extremely sharp, no blooming or fringing)
Sigma 24mm Art, f/4, Corner (Sharp, no blooming, very little chromatic aberration)
Distortion, Vignetting, Field Curvature, Coma, Etc.
The Sigma 20mm f/1.4 Art has almost no distortion, and Adobe has a profile available to correct it already even if it did.
Vignetting is significant wide open, as you might expect, but decreases greatly at both f/2 and f/2.8; in my opinion becoming basically a non-issue by f/2.8.
Coma, unfortunately, is prevalent starting from the rule-of-thirds area and worsening towards the corners. It doesn’t clean up much at all when stopping down to f/2, but improves greatly at f/2.8. (Then again, plenty of f/2.8 zooms hit this range and do just as good.)
Furthermore, there is some sort of weird field curvature or other blooming effect happening at f/1.4, through the whole image. (See below)
Sigma 20mm Art @ f/1.4, Central Area
Sigma 20mm Art @ f/1.4, Rule-of-Thirds Area
At first, I thought this might be a bad copy, however, based on the differentials of various MTF chart lines, I think it might just be a characteristic of the lens. I’m not an optical engineer, mind you, but whenever I see the lines wobble like that half-way down the chart, I fear for the rule-of-thirds area of the image.
Oh, I almost forgot, sunstars! Sunstars on the Sigma 20mm f/1.4 Art are pretty awesome, but because of the rounded aperture blades (which do create nice soft bokeh) the points are not as sharp as the old manual focus lenses from Nikon and Pentax.
Also, flare is extremely low, (see above) and overall colors and contrast are fantastic.
Okay, let’s get right to the point: Considering the limited scope of what this lens might be useful for, I wish it had slightly less coma, blooming, and vignetting. Don’t get me wrong, for both the price and the weight I am very impressed with the overall image quality.
The center-to-edge image quality is in fact entirely adequate for both print work and 4K timelapse work. However, if you’re going to make a lens as exotic as a 20mm f/1.4, and do it hot on the heels of a 50mm f/1.4 that gives even a Zeiss Otus a run for its money, I feel like it ought to be almost completely flawless, even if it costs double and weighs an extra half-pound. I know dozens of nightscape photographers who would have gladly paid $1.5K or even $2K for this lens if it had been as incredible at f/1.4 as the 35 Art or the 50mm Art.
Based on the MTF charts and the optical formula, though, it almost looks like Sigma just took their 24mm f/1.4 Art and tweaked the light path ever so slightly to make it a 20mm angle of view instead of 24mm.
So, when it comes to image quality, I’ll simply give credit where it is due: Sigma did something amazing, though not perfect.
However, a lens’ performance is not just found in its images. I’m giving the Sigma 20mm f/1.4 Art a four-star rating not just because I feel like it could have been slightly better optically, but also because like its f/1.4 Art siblings, it still seems to be slightly behind both Canon and Nikon’s low-light autofocus consistency. Sigma’s HSM autofocus is impressive, quiet, and snappy, but both Nikon and Canon shooters will find it to be ever-so-slightly more “hit-or-miss” than a ‘name-brand’ lens. Most folks may not notice this in casual situations, but I fear a demanding pro will notice a slightly higher percentage of misfocused shots.
I really hope that Sigma is working day and night to eliminate this slight drawback, as I’m sure Tamron is too, now that they’re developing fast primes.
As an aside, it is a shame that Nikon in particular, has tried to mess with Sigma lens AF performance so much over the years. It seems like Sigma is often having to update the firmware of their lenses just to get them to function properly on new Nikon bodies. So, Kudos to Sigma for fighting the good fight, and shame on Nikon for playing so dirty.
It goes to eleven. Wait, it goes to 1.4. Enough said.
Some might see this lens as a one-trick pony, and even to many general low-light photographers, this single most important feature may not actually be that necessary.
However, the minute you find 24mm isn’t wide enough and f/2.8 isn’t fast enough, this might be your only solid option, period. That’s a feature worth five stars, plain and simple.
It’s got decent autofocus and convenient AF/MF switching, plus the physical switch is solid and impossible to accidentally bump. It’s got a focus indicator window, although the focus throw is so short that even on such a wide lens they barely have room for hyperfocal markings at f/8 and f/16, let alone enough distance markings to make them useful. That’s pretty standard, though, for almost every modern autofocus lens, so I can’t complain.
The Sigma Art lens lineup, lamentably for some, is not fully weather sealed. Even Nikon’s cheapest f/1.8 G primes, like the 50mm f/1.8 G, have at least a rear mount gasket.
Having said that, the Sigma 20mm f/1.4 Art (like its siblings) is made with precise tolerances and seems to be impervious to both moisture and dust. It’s not an L lens, (or a Pentax WR lens) but it’ll certainly get the job done when faced with slight rain or a sand storm.
The design and construction, like the quality, is impressive. The AF/MF switch is slightly recessed and impossible to accidentally switch, as I mentioned, and the fixed hood is just as robust as the rest of the body. This ain’t no Rokinon 14mm f/2.8, that’s for sure.
As I already mentioned, some would dock the Sigma 20mm f/1.4 Art a point for being unsealed, however, I feel like the construction and assembly itself is so tight that it might as well be weather sealed, for all but the worst kinds of weather.
Lastly, that exposed front element, and the overall heft of the lens may be a deal-breaker, especially for a Nikon shooter who has the comparatively dinky 20mm f/1.8 G as an option. However, I simply cannot call this lens’ size or weight a “design flaw” after I already docked a point for the image quality not being even more flawless. That would be an unfair catch-22. So, well done Sigma.
One thing I should note, however, is the greater care needed in keeping the front element moisture and dust-free. If a lens accepts front filters, I can slap on a cheap UV filter and just wipe it down incessantly between every photo, when it’s raining very hard or if there are waves splashing, etc.
However when UV filters are not an option, you must take great care each time you clean the front element. Sometimes, honestly, this inclines me to just leave it alone which can ruin photos as you see here.
I have tested each of Sigma’s new Art lenses over the years, and they are always very impressive right out of the box. They’re rugged, finely crafted tools that one feels proud to mount on their camera. The heft and solid feel of the 20mm f/1.4 Art is as reassuring as it looks.
There have been claims and examples of heavily abused Sigma Art lenses that broke down or fell apart, but in my experience, aside from Sigma’s oldest Art lens, the 35mm f/1.4, build quality has never been a concern at all.
It will take about as much abuse as any modern (largely plastic) Nikon f/1.4 prime, and probably almost as much abuse as any of the legendary Canon (more metal) Canon f/1.4 and f/1.2 L primes.
Let’s get this discussion over as quickly as possible: Ask yourself, if Canon or Nikon were to make a 20mm f/1.4, let alone Zeiss, what do you think it would cost? $1.5-2K? $5K if from Zeiss?
Canon just updated their 35mm f/1.4 L, and it is $1,800. Zeiss just released a Milvus 21mm f/2.8, and it is $1,800 as well. I rest my case.
Simply put, considering the performance and quality of the Sigma 20mm f/1.4 Art, it is an absolute steal at $899.
Who Should Buy The Sigma 20mm f/1.4 Art
Now that we’ve established what an impressive feat of engineering this lens is, the one remaining question is still the most important one: Is this lens right for you?
To be blunt, there’s a chance you might be better off with a Sigma 24mm f/1.4 Art instead of this 20mm behemoth. Why? Because the focal lengths are close enough that in most shooting conditions a single step backward will give you want you want. Also, in my experience, 24mm is simply more practical in the real world than 20mm.
The Sigma 24mm f/1.4 Art also accepts 77mm filters, which is great for photographers who shoot in really dirty conditions, while the 20mm dwarfs all 24mm primes with its gigantic front element.
Furthermore, even if you absolutely must have 20mm instead of 24mm, much of the time an f/2.8 or f/4 zoom (or prime) is probably more than enough for what you’re doing. General photojournalism on a full-frame sensor is very easy at f/2.8 these days, with such amazing high ISO options, and a lens like a Canon 16-35mm f/2.8 or Nikon 14-24mm f/2.8 is a much more versatile tool.
Simply put, you should seriously consider the specific focal length and aperture that you need because more practical alternatives abound.
So, who or what is such a lens perfect for? Nightscapes, of course. When you’re trying to photograph the milky way over a moonless landscape, you can never have enough light, and wider is almost always better.
Hands-down, this is an astro-landscape photographer’s dream lens. The 24mm f/1.4 class of lenses has always been a go-to choice for photographing the milky way, and this is even better.
One other area where both aperture speed and field of view cannot be easily substituted is in videography, as you should have seen in the sample video footage above. Whatever direction your cinematic creativity may be taking you, whether it’s shooting a film by the light of the moon, or just driving around at night, The 20mm f/1.4 has a unique wide angle view that cannot always be easily replicated by simply taking one step back.
From Left To Right: Rokinon 14mm f/2.8, Sigma 20mm f/1.4 Art, Sigma 24mm f/1.4 Art
What Alternatives Should Some Photographers Consider
For most photographers, from wedding journalists to low-light action sports shooters, a 24mm f/1.4 is a great alternative, as is an f/2.8 zoom that hits 20mm. If you need autofocus and rock-solid construction, there is no better choice than the Sigma 24mm f/1.4 Art, which has already proven itself to be a solid optic.
If you’re an astro-landscape photographer who 1.) is on a budget, 2.) doesn’t care about autofocus, and 3.) is okay with mediocre build quality in exchange for slightly less coma, then a Rokinon/Samyang/Bower 24mm f/1.4 has been the go-to lens for nightscape shooters. (However, be warned, none of those budget lenses will hold up to abuse nearly as well as a Sigma Art lens! The Sigma 24mm f/1.4’s slightly higher coma, and slightly lower vignetting, in my opinion, is an extremely worthwhile trade-off if you can afford it. The Rokinon lenses literally fall apart after a while.)
Hey, what about crop-sensor shooters? Tokina did just come out with a 14-20mm f/2.0, which on a 1.5x Nikon DX sensor comes to 21mm equivalent. I suppose this is pretty much your only close alternative, despite the slight loss of high ISO performance and the whole stop difference in aperture. Personally, I’d consider the Tokina 14-20 2.0 on a Nikon D5300 to be a killer “B-roll” astro-landscape timelapse option, while a Sigma 20mm f/1.4 Art on a Nikon D810 by comparison is clearly an all-out flagship choice.
Lastly, if you’re a Nikon shooter, (Or a Sony FE shooter with a Nikon adapter) the Nikon 20mm f/1.8 G does make a killer alternative to the Sigma 20mm f/1.4 Art, just so long as you don’t mind slightly worse corners, or of course the loss of aperture.
Personally, I’m a hiker and a lightweight traveler, so to be honest I’d be happy with the Nikon 20mm f/1.8 G, despite my slight disappointment at its wide-open corner performance. But, if you’re fine with the extra weight, the Sigma sure does beat the Nikon handsomely, especially at f/2.
Just seriously consider both focal length and aperture before deciding to take the plunge on this lens. But if you do decide that 20mm f/1.4 is for you, then you’ll not be disappointed!
It’s hard to sum up the review of such an exotic lens, except to use the term I already chose at the very beginning: a trophy lens. The Sigma 20mm f/1.4 Art is an accomplishment for Sigma, a bragging right, and a specialty tool that is the only show in town if you need what it has to offer.
Having said that, it would be silly to give a “Must Have” recommendation to anyone other than a serious, die-hard astro-landscape photographer, considering how solid the alternatives are, even from Sigma’s own stable. Looking for something more compact and practical? The Sigma 24mm f/1.4 Art is fantastic. Don’t mind the weight, and want something equally exotic but in a more useful range? The Sigma 24-35mm f/2 Art is another trophy on Sigma’s shelf right now.
I also suspect that Sigma will have either a Sport or Art series zoom lens to announce, sooner or later, that is either f/2 or f/2.8, and covers the 20mm range. Just something to think about.
All in all, though, if you’ve got a hankering for wide and fast, it doesn’t get any wider and faster than this! Well done, Sigma, I look forward to seeing what you produce next.
Get the Sigma 20mm 1.4 Art here
Take care and happy clicking,
EDIT: After some discussion, I have added 100% corner crops from a re-sized 24 megapixel version of my 20mm f/1.4 corner test, as well as a 100% crop from a 4K re-sized image. Hopefully this will give astro-landscape photographers and night timelapse photographers a better idea of what to expect in various real-world situations!
Since this is down-sized from a 50 MP image, this is NOT the per-pixel sharpness that you’d expect if you shot on a Nikon D750 or a Sony A7S. However, it is useful for determining how “big” the coma will be.
In my opinion, it’s not bad at all, especially at 4K.
Sigma 20mm f/1.4 Art, 24 MP 100% crop (extreme corner)
Sigma 20mm f/1.4 Art, 4K resolution 100% crop (extreme corner)