Review: SIGMA 20mm F1.4 | A by Qwich

Sigma has done wonders in the world of photography with its Art series of lenses. Initially, the widest focal length was 24mm for the amazingly wide aperture of f/1.4, but that changed with Sigma’s new offering, the Sigma 20mm f/1.4 DG HSM Art lens. The Art series of lenses from Sigma are a part of Sigma’s Global Vision. The lens is quite impressive and the image quality and technical aspects of the lens are quite satisfying as well.

Focal Length / Focal Length Range

If you have yet to click with fixed focal lenses, you my friend are missing out. Be sure to make the focal length your priority when you select a lens as it is this which makes or breaks your picture. How so? Because it is the focal length which will decide the distance you click your subjects from, and thus your entire perspective too will depend on the same. The advantage of using a fixed wide lens such as the Sigma 20mm f/1.4 is to make your subject appear bigger and important and your background much smaller and filling your frame with a lot of it.

I believe that as a focal length, The Sigma 20mm f/1.4 ‘s fixed focal length at 20mm means that it is essentially a SCAPES lens. Now this can include a variety of scapes such as landscapes, cityscapes, nightscapes etc. Clicking nature and people too are an interesting experience with this lens. You can get close to your subjects while trekking in the mountains or while at your kid’s birthday party. Sigma 20mm f/1.4 is an excellent lens for capturing family moments or party et al. I feel this should be pointed out though, since I said early that the lens’s perspective is such that the foreground is much larger compared to the background which seems to cramp into the frame, if you click people such that their distances from the lens vary a lot, the one in foreground will look much bigger than the person in the background.

A great use of the abilities of this lens is in the genre of Wedding photography. Our Indian weddings are an elaborate affair and there are functions and events literally every day for over a week. Family dances, bride’s friends having some fun together, reception and what not, all can be clicked quite easily with this lens in cramped spaces quite efficiently!

This lens makes for a must for your indoor clicking need. From clicking festivities to family dinners, the focal length is perfect to focus on the family members while blurring out the background quite artistically.

However most people out there are still using an entry level DSLR or a mid-range DSLR which has an APS-C sensor with a crop factor of 1.6x. What this means is that your focal length is increased to 1.6 times. Hence, Sigma 20mm f/1.4 on an APS-C/1.6x body will give the angle of view as that of a 32mm lens compared to a full frame camera body. Now 32mm falls close to the uber-popular 35mm focal length which many love to shoot at. So on a crop sensor body, the Sigma 20mm f/1.4 gives you almost as good a perspective as a 35mm focal length lens would give on a full frame sensor body. That means you get quite an artistic yet standard perspective yet it is quite different in its own way. Those 3mm can change the perspective just enough to make it more interesting and appealing.

The 32mm perspective is also incredibly good for photojournalistic ventures. Photographers who are into clicking portraits (be it at a wedding) love the 32mm focal length range for clicking some full to mid body shots and even group photos. The multitude of uses of this focal length goes very deep, I have barely scratched the surface.

Max Aperture

Before the arrival of this Sigma 20mm f/1.4 DG HSM Art Lens, the widest aperture that one could get their hands on for a focal length wider than 24 mm was Sigma’s own 24mm f/1.8.

The Sigma 20mm f/1.4 comes with a rare and loved wider aperture of f/1.4. Wide apertures are much desired by all genres of photographers as they allow more light to fall onto the sensor thus enhancing the low-light handheld shooting capabilities of your DSLR rig.

Another advantage of a wide aperture is the shallow DOF (Depth of Field) that it provides. This would mean that your background will go into a nice blur (even Bokeh) when you are clicking them, But with this lens that you have to make sure that the distance between the foreground and the background is quite large for this to work properly.

I discussed earlier how this lens is great for clicking family functions and marriages etc in cramped spaces. Now added benefit is with its wide aperture is that since most of our houses are not too brightly lit, Sigma 20mm f/1.4 can click great pictures in those bad lighting conditions too.

Image Quality – Sigma 20mm f/1.4

Sigma has made some great progress with their Art series of lenses in terms of image quality. It would not be wrong to call the Sigma 20mm f/1.4 one of the best lenses in its class in terms of image quality.

We know that the lenses are their sharpest in the center, losing their sharpness as they move towards the edges. The Sigma 20mm f/1.4 is very sharp in the middle at f/1.4 but the corners bear the brunt of problems we have faced with even the most expensive lenses out there. Corners of images are and stay soft until you step down your f-stop. The corners also appear soft due to the lateral Chromatic Aberration (CA) of the Sigma 20mm f/1.4 which does not go away till you are at f/2.8. Vignetting also appears evidently in the range of f/1.4-f/2.8. Best results in terms of sharpness are reached at f/4-f/5.6. The shortcomings of the Sigma 20mm f/1.4 are more prominent with full frame body than with APS-C body as the sensor of the APS-C body is smaller and utilizes a smaller portion of the glass of the lens.

Most lenses perform their best in the center of the frame, where light rays pass straight through the optics and in the center of the frame, this lens is very sharp even at f/1.4. A modest improvement, in contrast, is seen at f/2, but with razor sharp results at this aperture, further stopping down results in no visible improvements. The sharpness of this lens will become evident as you go from f/2.8 to f/4 and further to f/5.6 and even f/8.

The Sigma 20mm f/1.4 is an ultra-wide aperture (Yeah, f/1.4 lenses aren’t that common) wide angle lens and thus, prominent vignetting is expected when shooting with a wide open aperture. Technically on a full frame body one can see that at f/1.4 the vignetting at the corners is a good 3.5 stops! Though on a crop body it is down to 1 stop. Fortunately, CA and vignetting are two of the easiest things to be corrected using post processing software. Or you could simply stop down the lens to f/2 and save yourself some processing. Though from f/4 to f/16 the vignetting is almost down to 0.6 stops in full frame bodies and negligible in crop bodies. The Sigma 20mm f/1.4 Art lens is also great for controlling lens flare with quite a little amount of it showing up at even f/16.

The Sigma 20mm f/1.4 also has a modest bit of barrel distortion. Again, one of those easy to correct with post processing software (or even in the camera itself for some models). Nothing which harms the lens’s reputation.

Since the Sigma 20mm f/1.4 comes with an odd number of aperture blades, a point source of light will show a star-like effect with 18 points. That is 2×9 (9 being the blade count here).

Overall, the Sigma 20mm f/1.4 lens is a great performer when comparing its opticals. While clicking at f1.4, if your main subject is in the center of the frame, you would be more than happy with the results, but if your frame involves having the subject at the borders then you better select a narrower aperture somewhere around f2.0.


Not unlike the rest Sigma Art lenses, the Sigma 20mm f/1.4 ‘s AF is driven by Sigma’s own HSM or Hypersonic Motor. I found the Autofocusing to take place with decent speed and is surprisingly very silent. It is certainly not as fast as the STM or even USM on high-grade Canon lenses but it gets the job done well. I still faced a little amount of issued in video recording mode where the lens would keep losing track of subject as it was rotated around at the same distance and would keep focusing on the background. The focusing on the Sigma 20mm f/1.4 is internal and FTM/Full Time Manual focusing is enabled, unless of course it has been disabled using the Sigma Dock function.

The AF performance of the Sigma 20mm f/1.4 is, but not completely reliable. The center point gives a better AF accuracy compared to the points on the periphery. While using this lens if  focus distances are changed by a good amount, Sigma 20mm f/1.4 lens subjects change their size by a small amount. While this characteristic is quite common, photographers who use photo stacking technique WRT focus distance should keep this in mind.f field scale on this lens, though f/8 and f/16 are the only marks provided.

The Sigma 20mm f/1.4 Art’s 40.4mm manual focus ring is very comfortable and ideally positioned. It is ever so slightly raised from the barrel, making it easy to find. The focusing ring of the Sigma 20mm f/1.4 is quite smooth and had no play when I tested the lens.

The Sigma 20mm f/1.4 DG HSM Art Lens can focus as close as 11 inches or 277mm for a 0.14x MM (Maximum Magnification). Following is a chart which compares this attribute in lenses of the same class.

Model MFD MM
Canon EF 20mm f/2.8 USM Lens 9.8″ (250mm) 0.14x
Canon EF 24mm f/1.4L II USM Lens 8.3″ (210mm) 0.16x
Nikon 20mm f/1.8G AF-S Lens 7.9″ (201mm) 0.23x
Nikon 20mm f/2.8D AF Lens 10.2″ (259mm) 0.12x
Nikon 24mm f/1.4G AF-S Lens 9.8″ (250mm) 0.18x
Samyang 24mm f/1.4 US UMC Lens 9.8″ (250mm)
Sigma 20mm f/1.4 DG HSM Art Lens 10.9″ (277mm) 0.14x
Sigma 20mm f/1.8 EX DG Lens 7.9″ (200mm)
Sigma 24mm f/1.4 DG HSM Art Lens 9.8″ (250mm) 0.19x
Zeiss 21mm f/2.8 Distagon T* ZE Lens 8.7″ (220mm) 0.15x

So how can you make better use of this shortcoming of the Sigma 20mm f/1.4 ? Simple. Just use and extension tube which can decrease MFD and increase MM. An extension tube shorter than 12 mm would be an ideal of this lens as a longer one would mean that the focus distance would fall inside the hood, hence unusable.

Build Quality & Features

All the Sigma Art lenses are very much alike in their physical attributes and the Sigma 20mm f/1.4 is no exception.

They have a ‘minimal design’ attribute to them which can be noted by the matt finish high-quality TSC and the broad and similar rubber rings. If you notice closely, you can see that the hood of the Sigma 20mm f/1.4 nowhere has the hood alignment mark or ribs and rubberised rear grip. This clearly points out to the fact that the hood can not be detached. This is so as the hood protects a pretty-to-the-eyes convex lens element which is bulging out.

Sigma has done well to make all their Global Vision lenses have an excellent, classy, high-end look and feel. The Sigma 20mm f/1.4 is no exception to this. The mixture of matte and gloss with sharp and smooth rubber rings gives the lens a great feel and impressive design qualities.

The material used for lens construction of the Sigma 20mm f/1.4 is a Thermally Stable Composite (TSC). The Sigma 20mm f/1.4 has a single physical switch which can be used to enable of disabling the AF can be easily reached by your left thumb while you hold the camera. Sigma has a habit of engraving the product introduction year into the body of the Global Vision lenses. My review unit had 015 engraved at its bottom suggesting it was made in 2015.

It is important to mention that unlike many other Art lenses, the Sigma 20mm f/1.4 is not the weather sealed lens and it would be wise to keep it out of extreme conditions.

My initial reaction to the Sigma 20mm f/1.4 ‘s size was that it seemed too large for a 20mm lens. But the more I used it, the more I got used to it. Somehow a large lens like this one suits my taste better than say, a pancake lens. While talking in terms of weight, less is always better. However, heavy lenses also make for more stable ones. The Sigma 20mm f/1.4 is definitely on the heavy side at 950gms but it also helps to keep the camera stable. Though I would not complain if Sigma would shave off at least 300 grams from this lens! With a camera like Canon 5Diii, paired with this lens, you are almost carrying 2KGS ! Talk about building some muscles.

The basic equation denotes that wider lens = larger glass elements = more weight. Hence, the extra weight also comes as a compensation for the wide f/1.4 aperture of the Sigma 20mm f/1.4. This lens comes with a nonstandard sliding lens hood. Try not to displace it, it will not be easy finding a replacement. It slides onto the hood quite comfortably, though. It is, however, worth mentioning that the lens can not use any type of filters. Those who like to use UV filters to protect their front elements or other filters like ND or CPL etc will be left asking for more.

The Sigma 20mm f/1.4 DG HSM Art Lens comes packed in a good looking zippered, thinly-padded nylon case which also has a belt loop so that you can carry it or attach it to another bag.

Sigma Global Vision and the Dock

Also, present on the barrel of the Sigma 20mm f/1.4 is an “A” symbol in a metal rivet. This is something common to Sigma’s Global Vision lenses. They have various classifications like “A”, “C” or “S” which simply refer to “Artistic”, “Contemporary” and “Sports” respectively.

A really cool and useful feature of the Global Vision lenses is their compatibility with the Sigma Dock. The dock, which works with the Sigma Optimization Pro software, lets the lens’ firmware be updated and leads to precise AF calibration at four distances. FTM can also be disabled/enabled via the Sigma dock.

Image Samples:




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