Sigma 20mm F2 DG DN Contemporary
View from a broad angle
F2 optics (bright)
The focus motor is quick and silent.
Aperture control on the lens
Aluminum in a classic black finish
CONS
Not completely weatherproof
Distortion correction is required for raw captures.
Focused breathing that is noticeable
SIGMA 20MM F2 DG DN CONTEMPORARY SPECS
| Dimensions | 2.9 by 2.8 inches |
| Weight | 13.1 oz |
| Filter Thread | 62 mm |
| Mount | Leica L, Sony E |
| Focal Length (Wide) | 20 mm |
| Optical Stabilization | None |
| Focus Type | Autofocus |
The Sigma 20mm F2 DG DN Contemporary ($699) is the newest lens in the company’s I Series, a collection of retro-styled aluminum lenses. It has the largest angle of view yet—a 20mm view on compatible full-frame cameras—and inherits the series’ on-lens aperture control, sleek appearance, and superb optical performance. It’s available for Sony E-mount bodies, where it competes directly with the $900 Sony FE 20mm F1.8 G, or for L-mount cameras, where it’s currently unrivaled. The Sigma 20mm performs admirably and is a good value, but for Sony photographers, the FE 20mm remains our Editors’ Choice.
Style that is understated
On any compatible camera, the 20mm F2 DG DN Contemporary looks upscale. The matte black finish on the aluminum barrel contrasts with a glossy accent ring that sits between the aperture and focus settings. Given its angle of view and aperture, it’s a small lens—it measures 2.9 by 2.8 inches (HD), weighs 13.1 ounces, and utilizes 62mm front filters.
The lens comes with a metal hood that may be stored by attaching it backwards. The hood contains knurled ridges that match the knurled ridges on the manual focus ring. In the box, Sigma offers two caps: a conventional pinch cap and a flashy magnetic metal cap. At its core, the pinch cap is very practical and easy to grasp. The metal cap is clearly more attractive, but removing it off the lens requires a more deft touch, especially if the hood is attached.
Only the lens mount is protected from dust and splashes. In light precipitation, I wouldn’t worry about using the 20mm, but in umbrella weather, you shouldn’t. The hood is important not only for preventing flare, but also for keeping droplets and stray fingerprints off the front glass. The front element does not have an anti-smudge fluorine coating, thus it should be handled with caution.
The 20mm Contemporary is compatible with Leica, Panasonic, and Sigma L-mount cameras, as well as Sony E-mount mirrorless cameras. The E-mount version of the lens was supplied to us, and we tested it in the lab and in the field using the full-frame a7R IV.
At the time of writing, there are no additional autofocus 20mm primes available for the L-mount system. The Sigma 24mm F2 DG DN Contemporary and Panasonic S 24mm F1.8 are the closest substitutes, however they don’t have the same broad field of view. Sony photographers have a few more alternatives; for example, the FE 20mm F1.8 G (which is more expensive) and the Tamron 20mm F2.8 Di III OSD M1:2 (which is less expensive) both have the same focal length.
Handling and Concentration
On-lens aperture and manual focus adjustments are included on the 20mm F2 DG DN Contemporary. If you prefer to regulate the f-stop from the camera, the aperture ring goes from f/2 to f/22 in third-stop increments and includes an A setting. However, you won’t be able to de-click the ring for silent operation, which is something to keep in mind if you plan to use the lens for video. The Sony 20mm F1.8G takes things a step further by allowing you to effortlessly switch between silent and noisy aperture modes.
If you wish to utilize the lens for video images that move the plane of focus for dramatic effect, the focus breathing effect—in which the angle of view varies along with focus—is noticeable and can be distracting. However, if you plan to use the 20mm as a wide lens for walk-and-talks, vlogging, or other photos where the focus stays on the same subject, this is less of an issue.
The autofocus is driven by a silent STM motor that moves smoothly and fast. The lens on the a7R IV moves from close-up to infinity focus in a fraction of a second. For ordinary wide-angle settings, it’s more than fast enough.
Another option is manual focus, which you may choose between using the AF/MF toggle on the lens. I enjoyed the experience because the ring rotated with a satisfying level of resistance and no latency. On E-mount cameras, the response is nonlinear: a rapid turn radically affects the focus, while slower, careful rotations fine-tune it. Photographers favor this, whereas videographers prefer a linear response, in which the change in focus is determined by the angle of rotation rather than the speed at which it is turned. You can pick between those two settings in the camera interface if you’re using the 20mm for an L-mount model, but E-mount shooters are stuck with nonlinear focus mode.
Close-up focus is accessible up to 8.7 inches (22cm) for a respectable 1:6.7 macro, which is impressive for a wide lens. While you miss out on the extremely small subjects that 1:1 macro alternatives like the Sigma 105mm F2.8 DG DN Macro Art can capture, I’m delighted with the working distance. The Sony FE 20mm F1.8 G focuses a little closer for larger 1:4.5 results if you prefer a little more magnification from a wide angle. With 1:2 macro results, Tamron’s less expensive 20mm F2.8 outperforms both, but its angle of view narrows significantly when you concentrate near, and its autofocus engine is sluggish in comparison.
In the lab with the Sigma 20mm F2 Contemporary
To test the optical performance of the 20mm F2, I used the 60MP Sony a7R IV and Imatest software. It produces remarkable clarity (5,000 lines) in the center of the frame and very good marks (4,000 lines) off-center, even wide open, in lab tests. Edges sharpen at smaller apertures, and at f/4, the lens is sharp from edge to edge for landscapes. At wider apertures, it performs similarly to the more expensive Sony FE 20mm, and while the Sony wins by f/5.6, you’ll need to utilize a high-resolution a7R or a1 body to realize those benefits.
The 20mm F2 softens backgrounds at wide apertures, but smooth bokeh effects require working from closer range. Because of the nine-blade aperture, highlights have a unique cat eye look at edges and corners at f/2, but look more circular by f/2.8.
The sunstar effect, in which the lens produces a multi-point starburst around the sun or other bright points, is a desirable aesthetic for some landscape paintings. The 20mm F2 produces the best defined sunbursts at f/22, but it can also be used at f/16.
Some optical sacrifices, such as significant barrel distortion and a vignette at the frame’s edges, are automatically compensated for by in-camera corrections. If you work in raw format, you’ll have to handle these issues on your own. We didn’t have access to an Adobe correction profile when we evaluated this lens ahead of its official release, but a manual adjustment of +40 on the distortion slider fixed the problem. Every mainstream lens has an Adobe Lightroom profile, so it’ll only be a matter of time before this one gets one.
The I Series Extends Its Horizons
The Sigma 20mm F2 DG DN Contemporary offers the greatest field of view of any I Series lens to date, while maintaining the same design ethos as the rest of the series. The tactile aperture ring, superb manual focus experience, and relatively compact and light design are all features that Sigma emphasizes in these lenses. With a full-frame camera, the 20mm is easy to fit into your shoulder bag and provides for a very affordable kit.
The 20mm angle captures a little more of the world than the more usual 24mm lenses, and the bright aperture comes in helpful for work in low light—think architectural interiors and astrophotography—as well as blurring off the backdrop. You might like the soft backdrops it creates if you’re a vlogger who records handheld video directly to the camera.
The 20mm Contemporary is unrivaled in the L-mount—if you want a 20mm prime with autofocus, this is it. Although the Panasonic Lumix S 20-60mm F3.5-5.6 covers the same focal length as the 20mm, its plastic construction and narrow f-stop don’t match the aluminum structure and F2 optics of the 20mm.
The FE 20mm F1.8 G is a lens for Sony E-mount photographers to consider. It costs around $200 extra, but it offers better weather protection, focuses a touch closer, and has higher optical quality. By a hair, it’s our Editors’ Choice winner, but the Sigma isn’t to be overlooked if you prefer its style and cheaper price.
Sigma 20mm F2 DG DN Contemporary
View from a broad angle
F2 optics (bright)
The focus motor is quick and silent.
Aperture control on the lens
Aluminum in a classic black finish
CONS
Not completely weatherproof
Distortion correction is required for raw captures.
Focused breathing that is noticeable
