Sharpness at 70mm

For this test, the OM System M.Zuiko Digital ED 50-200mm F2.8 IS PRO lens was attached to a OM System OM-1 Mark II body, which was in turn mounted to a sturdy tripod. Exposure delay mode was activated. Tonal and colour variance across the crops are due to change in natural light during the session.

The full frame at 70mm

Centre sharpness is outstanding from wide-open at f/2.8 all the way through to f/8, with f/16 being slightly affected by diffraction, and f/22 even more so.

The edges aren't as sharp as the centre, with the best results obtained from f/4 through to f/11.

Aperture	Centre Crop	Edge Crop
f/2.8
f/4
f/5.6
f/8
f/11
f/16
f/22