Laowa 15mm f/5 Cookie FF (Canon RF)

Owners buy it for the size above all: one says portability is the whole reason they bought it, and another finds it so light that they keep reaching for it despite the slow f/5 aperture and only moderate resolution. Manual focus is easy with focus peaking and a clear distance scale, and the corner falloff is seen as part of a pleasing character.

The 39mm filter thread works, but with the hood fitted only one filter can be stacked before the corners vignette, and the tiny lens cap is fiddly to remove with the hood in place. These reports come from Sony E and Nikon Z owners; the RF version shares the optics but has a manual aperture ring.