Canon FD 50mm f/3.5 Macro S.S.C.
Canon AE-1 with self-timer

Vignetting = B @ f/3.5, A- @ f/5.6
Distortion = moderate pincushion

Aperture Center Corner

f/3.5    B-     B-
f/5.6    A      A
f/8      A+     A
f/11     A      A-
f/16     A-     A-
f/22     B+     B+

Note:
high contrast at f/5.6 to f/16,
moderate contrast at f/3.5 and f/22.