Sigma 20mm F/2 DG DN | C

This Sigma prime is a 20mm wide angle for full-frame mirrorless cameras. It comes in Leica L and Sony E mounts, and you pick the version made for your system. Sigma released it in 2022, and it remains in production.

The focal length suits landscapes, architecture and interiors, where you want to fit a broad scene into the frame. The f/2 aperture also helps in dim rooms and evening streets. Street photographers who like a fixed wide view can work with it all day.

The trade-off is the single focal length. You frame by moving, not zooming, and distant subjects stay small in the picture.

It weighs 13.1 oz (370 g) and measures 2.85 in (72.4 mm) long, so it stays light on a mirrorless body. At 2.76 in (70 mm) across, it also sits slim beside the camera.

The front takes 62mm screw-in filters. Any filter attached directly to the lens must match that thread.

At 20mm, the lens frames a wide view in one shot. That helps in tight alleys and small rooms, where backing up is often impossible. When a subject sits far away, it appears small, so you move closer to make it larger.

The f/2 aperture lets in plenty of light at dawn and dusk. That gives you room to keep ISO settings low when the light falls.

The lens focuses as near as 0.7 ft (22 cm), so you can get close to a foreground rock or doorway detail. A strong near element adds depth to wide scenes. Maximum magnification reaches 0.15x, so the frame still holds plenty of surrounding context.

Background blur stays modest, though. A 20mm view holds much of the scene in focus even at f/2, so the lens builds depth through composition rather than blur. For strong subject isolation, a longer focal length serves better. Stopped down to f/8, more of the scene from foreground to horizon comes into focus.

A seal around the barrel helps keep dust and moisture away from the internals during outdoor shoots. That suits landscape work on dusty trails and in light rain.

There is no built-in stabilisation, so dim-light handheld work needs a fast enough shutter speed or steady support. At 20mm, small handheld movements show less than they would on a long lens, which helps.

The front element has no fluorine coating, so water spots and fingerprints need more patient cleaning. A soft cloth in the pocket covers most of it.

The design includes aspherical elements, whose shaped surfaces help correct distortion. Distortion can bow straight edges, and these elements help limit that in architecture frames.

Low-dispersion glass helps reduce chromatic aberration, the coloured fringes that can appear along high-contrast edges such as branches against a bright sky. Focusing happens internally, so the barrel does not extend as focus changes.