Sigma 20mm f/2 DG DN Contemporary: Beautifully Crafted

The seventh of Sigma’s I series of prime lenses, the Sigma 20mm f/2 DG DN Contemporary follows the same exquisite design language. Does it also inherit the excellent performance of the others in this series? K Madhavan Pillai puts it to the test.

The Sigma 20mm f/2 DG DN | C, available for the Sony E-mount and the L-mount (shared by Leica, Panasonic and Sigma) is the latest in Sigma’s I series of lenses. Designed distinctively to be premium, compact primes for full-frame (the ‘DG’ in the nomenclature) mirrorless cameras (denoted by ‘DN’), the I series itself is a part of the Sigma Global Vision’s ‘Contemporary’ line of lenses, or lenses that balance quality, compactness and practicality.

By its very nature, 20mm is a fascinating focal lengths and among my personal favourites. It delivers a useful 30mm equivalent on an APS-C sensor, and is great for videos. This is a challenging focal length for manufacturers to maintain optical finesse in a compact size for full-frame sensors, far more than the next focal length standard of 24mm. Going any wider involves significant optical design challenges, but every lens makers I know has at least one prime offering at 20mm or in that vicinity.

Features

The Sigma 20mm C is made of thirteen elements in eleven groups. This includes three glass-moulded aspherical lens elements, one SLD element, and one FLD element to suppress optical aberrations including sagittal coma flare, for a high level of overall detail. It also features Super Multi-Layer Coating and Nano Porous Coating (NPC), to control flare and ghosting.

A feature that I appreciate is the aperture ring, with one-third click stops, and a clearly separated ‘A’ position for when the aperture control is through the camera body. The ring can’t be declicked for video users. There is an easily accessible AF / MF switch to the side.

The maximum aperture of f/2 is fairly large. Sigma also has a more expensive Art series 20mm lens with f/1.4. This lens is larger and almost thrice as heavy. Silent AF is actuated by a stepped motor. The MF and aperture rings are deeply ridged and raised, allowing easy access. L-mount lenses have the advantage of setting the MF ring for linear or non-linear focus on rotation. The L-mount version can also be updated for firmware, and customise certain aspects of settings and focus, using the Sigma USB Dock UD-11, sold separately. There is no image stabilisation.

Bundled with the lens is an exceedingly well-crafted petal-shaped metal lenshood that attaches resolutely. The 20mm C also comes with a separate, metal lens cap that snaps on magnetically, apart from the regular, pinchtype plastic cap.

Handling

The all-metal lens is superbly made, both ergonomically and aesthetically. The milling, engraving, painting, and metal work all are of an appreciably high quality. It is both comfortably compact and light. The lens has a gasket at the mount for protection against dust and splashes. The MF ring is welldampened, similar to a manual focus lens, even though the lens is fly-by-wire.

The aperture ring, sadly missing in many AF lenses nowadays, is a prominent feature of the Sigma 20mm C, and extremely useful, especially in a lens of this focal length. I often prefer to set the lens at hyperfocal distances, limit the Auto ISO, and concentrate on the framing and the moment.

With a 20mm, one needs to be right in the middle of the action. The excellent optics shows its prowess with excellent contrast and flare control even against the light. Photograph/K Madhavan Pillai

Performance

The AF performance of the Sigma 20mm C is excellent too, with the lens snapping into focus at the selected focus point without hunting, almost instantly. It allows functionality with all the focus modes of the newest cameras. With video, AF actuates smoothly between near and far subjects, but there is some noticeable focus breathing.

The lens is able to produce considerable focus blurs at f/2. The blurs are soft and mellow. Bokeh shows some coma towards the edges, seen with specular highlights, but not prominently so. There is vignetting wide open, which radically improves on stopping down to f/4 and f/5.6 . While this is easily corrected at low ISO, with evening scenes and boosted ISO, or with shadows, correcting this may bring in some noise. There is also some expected barrel distortion which is corrected by the camera or by software.

The biggest advantages of this lens are its excellent sharpness from center to edge even wide open (that improves to outstanding levels on stopping down to f/5,6), exemplary control over flare even against the light, and extremely well-controlled chromatic aberrations. In combination, they allow excellent detail and contrast.

Conclusion

Sharp, optically sound, all-metal, compact, and with superb design and handling, the Sigma 20mm f/2 DG DN Contemporary is a desirable lens at Rs. 77,000. Sony users may want to equally consider the rather wellreceived Sony FE 20mm F/1.8 G for a slightly higher price (in India), but L-mount users from Leica, Panasonic and Sigma will find the Sigma 20mm f/2 DG DN Contemporary to be quite an exceptional deal.

This article originally appeared in the April 2022 issue of Better Photography.