Canon FD 50mm f/1.4 bayonet mount
Canon AE-1 with self-timer only

Vignetting = B @ f/1.4, A- @ f/2 and beyond
Distortion = slight barrel

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

Note:
moderately high contrast, except f/1.4 to f/2.8,
where corners are moderately low in contrast.

Canon EF with mirror and diaphragm prefire
Vignetting = C+ @ f/1.4, B+ @ f/2, A thereafter
Distortion = barrel

Aperture Center Corner
f/1.4    B      B-
f/2      A-     B
f/2.8    A-     A
f/4      A      A-
f/5.6    A-     A-
f/8      A-     A-
f/11     B+     A-
f/16     B+     B
f/22     B      B

Notes:
different sample than above.
Very high contrast, except moderately high at f/1.4.