Olympus 180mm f/2.0 Zuiko (multi-coated)

(multi-coated)

OM-4T with mirror and diaphragm prefire (sample 1)
Vignetting = B+ @ f/2, A- @ f/2.8
Distortion = slight pincushion
Aperture Center Corner
f/2      A      A-
f/2.8    B+     B
f/4      B+     B+
f/5.6    A-     A-
f/8      B+     B+
f/11     B+     B
f/16     A-     B+
f/22     A      B+
Notes: Extremely high contrast at f/2 and f/22; high contrast at f/2.8 to f/16.

OM-4T with mirror and diaphragm prefire (sample 2)
Distortion: slight pincushion
Aperture Center Corner Vignetting Contrast
f/2      B+     B      B-         mod. high
f/2.8    A-     B+     A?         mod. high
f/4      A-     A-     B+         high
f/5.6    A      A+     A-         very high
f/8      A      A      A-         high
f/11     A+     A-     A          extr. high
f/16     A-     A      A          very high
f/22     A      B+     A          very high

180mm f/2.0 Zuiko (multi-coated) with Olympus 1.4X Teleconverter

OM-4T with mirror and aperture prefire (sample 1)
Vignetting = B+ @f/2 (2.8), A- @f/2.8 (4)
Distortion = none
Aperture  Center Corner
f/2 (2.8) D      B-
f/2.8 (4) A-     B
f/4 (5.6) B+     B+
f/5.6 (8) B-     B
f/8 (11)  A-     B+
f/11 (16) A-     A-
f/16 (22) A-     B
f/22 (32) B+     B
Notes: Moderately low contrast atf/2 (effective f/2.8); very high contrast at f/8 and f/11; high contrast at f/16.

OM-4T with mirror and diaphragm prefire (sample 2)
Distortion: slight pincushion
Aperture  Center Corner Vignetting Contrast
f/2 (2.8) C      B+     A-         high
f/2.8 (4) A+     A-     A          v. high
f/4 (5.6) A+     A-     A          v. high
f/5.6 (8) A-     B+     A          high
f/8 (11)  A      B+     A          high
f/11 (16) A      A      A          v. high
f/16 (22) A      A-     A          v. high
f/22 (32) A      A-     A          v. high

180mm f/2 Zuiko (multi-coated) with Olympus 2x teleconverter
OM-4T with mirror and diaphragm prefire
Distortion: pincushion
Aperture    Center Corner Vignetting Contrast
f/2 (4)     C      C      B          v. low
f/2.8 (5.6) B+     C+     A          high
f/4 (8)     A-     B      A          v. high
f/5.6 (11)  B-     C+     A          moderate
f/8 (16)    B      B-     A          mod. low
f/11 (22)   B      B-     A          mod. low
f/16 (32)   B-     B-     A          mod. low
f/45        C+     C+     A          moderate