(single-coated)

OM-1 with mirror lockup

Vignetting = C
Distortion = slight pincushion

Aperture  Center    Corner
f/1.4     D         C-
f/2       C-        C
f/2.8     C         B-
f/4       B-        B
f/5.6     B         B
f/8       B+        B
f/11      A-        B
f/16      A-        B+

Notes: Serial number unknown.