Sigma 17mm F4 DG | Contemporary

Testers found it sharp in the centre and corners from f/4, with f/4–f/8 the best range and diffraction setting in from f/11. Barrel distortion and corner vignetting are present before correction but are routine for the class. The stepping-motor AF is quick, quiet and good with face tracking in video.

The usual reservations are the slow aperture, busy out-of-focus rendering, noticeable longitudinal colour fringing in some scenes, and weather sealing that stops at the mount gasket.

Owners use it as a carry-everywhere wide on compact bodies and for walk-around vlogging, and the metal build and click-stopped aperture ring come up often as reasons to choose it over plastic alternatives. The 12cm close focus gets a lot of praise.

Common complaints are f/4 in low light, the fact that the aperture ring cannot be declicked for video, and some focus breathing.