Sigma 17mm F4 DG | Contemporary (L-Mount)

Testers found it sharp from f/4, very good in the centre and good to the corners wide open, with the best overall results around f/5.6 and diffraction softening from f/11. Barrel distortion is partly left to the lens profile, and corner shading is visible at f/4 but small and easily corrected. Colour fringing and coma are not a concern, while the out-of-focus rendering from the seven-blade diaphragm can look busy.

The all-metal build, clicked aperture ring and small size get consistent praise, as does the 12cm close focus. Autofocus is quiet and accurate for static subjects and video, though one test on Lumix bodies found it slow to start when subjects moved into the frame. The criticisms are the f/4 maximum aperture, sealing only at the mount and an aperture ring that cannot be declicked.