Here are the last two Zuikos that I needed to complete my testing of all
the OM System Zuiko lenses which can focus to infinity:
8mm f/2.8 Fisheye Zuiko (multi-coated)
OM-2S with mirror and diaphragm prefire
Vignetting: B @ f/2.8, A- at f/4, A thereafter
Distortion: NA
Aperture Center Corner
f/2.8 B+ B
f/4 B+ B
f/5.6 B B
f/8 B+ B
f/11 B+ B
f/16 B+ B+
f/22 B- B-
Notes: moderate contrast at f/16 and f/22; moderately high contrast at
f/11; very high contrast at f/2.8; extrememly high contrast at f/4 to
f/8. Test subject modification: map was hung in a 180 degree arc with
the lens on a plane with the two ends of the map.
Personal comments: A fun lens to see the world through! Fine image
detail seems secondary to compositional effects, so the B grades don't
really detract much from the quality of this ultra contrasty lens.
Surprisingly easy to focus with the biprism of a 2-14 screen. Drop this
puppy and its toast, since it is very top heavy.
1000mm f/11 Zuiko (multi-coated)
OM-2S with mirror and diaphragm prefire, dual tripods - one on the
camera and one on the tripod mount of the lens
Vignetting: None
Distortion: slight pincushion
Aperture Center Corner
f/11 C- C
f/16 C C+
f/22 B B+
f/32 B B
f/45 B C+
Notes: Very low contrast at f/45, moderately low contrast at f/11,
moderate contrast at f/16 to f/32. Essentially impossible to use with a
2 series focusing screen, apparently due to the optical properties of
those screens.
Difficult to focus due to poor performance wide open (i.e., the aperture
focusing is done at).
Thanks for the recent kudos. I'll add a Zuiko test from time to time to
shed light on production/condition sample variation or replace an old
OM-1 test with one on a more recent body. I'll also be replacing the
flat map 16mm Fisheye test with one of a curved map - as soon as I get
my hands on a 16mm.
Gary Reese
Las Vegas, NV
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