Zuikoholics:
For those of you who always wonder if you really should have picked a
Leica or Leicaflex system, then here is something you might find
interesting. If you trust B+W filters, you might also find this
interesting.
The following 90mm f/2 Zuiko Macro test is a re-evaluation of the
results previously posted and will replace those results.
90mm f/2.0 Zuiko Macro (multi-coated)
OM-2000 with mirror and aperture prefire
Vignetting = C+ @ f/2, B at f/2.8, B @ f/4, A- thereafter
Distortion = none
Aperture Center Corner
f/2 B+ A-
f/2.8 A- B+
f/4 B+ B
f/5.6 A- B+
f/8 A- A-
f/11 A- B+
f/16 A- B-
f/22 A- B-
Notes: Moderately high contrast images at f/22; high contrast images at
f/2, f/2.8 and f/16; very high contrast images at f/4, f/5.6 and f/11;
extremely high contrast images at f/8. Paired SQF grade and contrast
comparisons to the Leitz 90mm f/2 Summicron-R test done on a Leicaflex,
with SQF differences significant at the 1/3 grade level. Lens condition:
9+ (KEH=Ex+).
versus:
Leitz 90mm f/2 Summicron-R (1978 era 3-cam)
Leicaflex with mirror and diaphragm prefire
Vignetting = B @ f/2, A- @ f/2.8, A thereafter
Distortion = slight pincushion
Aperture Center Corner
f/2 w/ filter* C+ C
f/2 B B
f/2.8 B+ B
f/4 B+ A-
f/5.6 A A
f/8 A- A-
f/11 A B
f/16 A B
Notes: * = Tested with a B+W 010 filter. Moderately high contrast images
at f/2; high contrast images at f/2.8 and f/16; very high contrast
images at f/4 and f/11; extremely high contrast images at f/5.6 and f/8.
Lens condition 9+ (KEH=Ex+). Paired SQF grade and contrast comparison to
the 90mm f/2 Zuiko Macro test done on a OM-2000, with SQF differences
significant at the 1/3 grade level.
I can't explain what makes the Zuiko's edge performance improve wide
open. For raw image detail, the Summicron can outperform the Zuiko
stopped down, as well as show less light fall-off (vignetting) at wider
apertures, but the Zuiko has better performance at larger apertures
(esp. f/2) and less distortion.
I had a heck of a time splitting hairs, so 1/3 grade differences (ex. A-
vs. A) are pretty subtle. In fact, I had to cheat and use a 100x
magnifier to be sure. But the grades are still directly comparable to
all the other test results I posted.
Regarding dropping some A grades in this re-evaluation: all posted test
results are subject to revision. That is what the S in SQF stands for:
Subjective.
Gary Reese
Las Vegas, NV
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