(multi-coated)

OM-2S w/ mirror and diaphragm prefire
Vignetting: B- @ f/3.5, B @ f/5.6, B+ @ f/8, A- thereafter
Distortion: NA
Aperture Center Corner
f/3.5    B      B-
f/5.6    A      B+
f/8      A      B+
f/11     A-     A-
f/16     A-     B+
f/22     B      B
Notes: Contrasty at the expense of resolution. High contrast at f/3.5 and f/22, very high contrast at f/5.6 andf/11 (although only high in corners), very high contrast at f/8 and f/16.

Test subject modification: map was hung in a 180 degree arc with the lens on a plane with the two ends of the map.