7Artisans 9mm F5.6 (Canon RF)

Testers found the centre sharp and contrasty from f/5.6, with the corners at their best around f/8. Results at the frame edges are weaker, especially at close range. Lateral colour and coma are well controlled, flare is hard to provoke for such a wide lens, and the 10-point sunstars are well defined.

Vignetting is the main optical weakness: it is heavy in the corners, does not improve on stopping down, and comes with a slight green corner cast. Distortion is judged differently. One test found a noticeable wavy barrel pattern with no correction profile, while another found it low in normal shooting compared with lenses that rely on in-camera correction. Build quality is praised for its all-metal construction, with no weather sealing and no filter thread as the obvious omissions.

Canon RF owners report that it works well on bodies such as the EOS R6, with solid image quality, very little visible distortion and an impressive field of view for landscape, architecture and creative wide shots. The all-metal barrel mounts without play, the focus ring is smooth and precise, and the 0.2m close focus is useful for near-far compositions.

The caveats are practical. It is fully manual with no contacts, so 'Release shutter without lens' must be enabled on EOS R bodies before it will fire, and one buyer notes the listing does not make the manual operation clear. The f/5.6 aperture makes it more of a daylight lens, and not everyone finds a use for the bundled rear ND filters.