Performance is excellent all the way from f/2.8 through to f/8 ... For this review, the lens was tested on a Canon EOS 5DS R using Imatest. CA (Chromatic Aberration) is virtually non-existent ...

Central sharpness is outstanding from f/2.8 to f/5.6, excellent from f/8 to f/16 and still very good at f/22. The edges do not fare so well, but are very good from f/2.8 to f/5.6, good from f/8 to ...