(multi-coated)

OM-1 with mirror lock up
Vignetting = B
Distortion = slight pincushion
Aperture Center Corner
f/2.8    B-     B-
f/4      C+     B-
f/5.6    C+     C+
f/8      B-     B-
f/11     B      B-
f/16     B+     B
f/22     B      B-
f/32     B      C+
Notes: High contrast, except at f/32 where moderate; contrast is at the expense of resolution. Exceptional ease of focusing. Probable harmonic vibration from auto diaphram mechanics, as evidenced by the drop in SQF grades when stopping down (sse notes on the following lens/teleconverter combo).

OM-2000 with mirror and aperture prefire and Bogen Telephoto Lens
Support, same lens as above
Aperture Center Corner
f/2.8    B      B
f/4      B      B
f/5.6    B      B
f/8      A-     B
f/11     A-     B
f/16     A      B
f/22     A-     B
f/32     B      C+
Notes: Moderate contrast at f/2.8 to f/22, moderately low at f/32.

180mm f/2.8 Zuiko (multicoated) with Olympus 1.4X Teleconverter
OM-1 with mirror lock up
Vignetting = B+ @ f/2.8, A @ f/4
Distortion = moderate pincushion
Aperture  Center Corner
f/2.8 (4) B      B-
f/4 (5.6) B      B-
f/5.6 (8) B      B
f/8 (11)  B+     B
f/11 (16) A-     B+
f/16 (22) B      B-
f/22 (32) B-     C+
f/32 (64) B-     B-
Notes: Moderate contrast; exceptional ease in handholding. SQF grades exceed those without teleconverter due to use of a lens support. Without additional lens support, the shutter and auto diaphram mechanisms in the OM-1n test camera probably induced harmonic vibrations which impaired image quality.