Just re-checked with my 50 Art, 85 Art & 70-200 2.8L IS II
Normally wide open they should be tack sharp (like with my Canon 6D).
But now with the A7 III + Metabones 5 (latest firmware) they don't seem to be so sharp wide open.
I took some pics of my wife's face close and further away, but her pupils aren't sharp/full of detail anymore.
I focused with AF-ON centre (single AF) and also tested the Eye-AF in advanced mode on the Metabones 5 adaptor.
Yesterday I saw a video with wide angle lens on youtube that the corners had bad quality.
But this can't be true that the centre with the sharpest lenses isn't sharp anymore ?
Metabones has no glass in it, it would be strange that I can't shoot wide open anymore with those lenses and still keep my maximum sharpness ?
Found it : software problem : all windows photoviewers show the ARW files unsharp (even with Sony's latest raw drivers), in PS/LR they are sharp