Nikon Nikkor 50mm f/2 AIS
Nikon F2 w/ mirror lockup and diaphragm prefire

Vignetting = A- @ f/2, A @ f/2.8 and beyond
Distortion = slight waveform

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

Notes: Moderate contrast at f/2, f/11 and f/16; moderately high atf/2.8 to f/8. High resolution at the expense of contrast.