I wrote yesterday:
>The B300 is matched to the 180mm end of the zoom on the IS-3, so the 50/55mm
>focal length may be too wide. With the 85mm/2, the result was acceptable so
>far.
I had a second look at my quick test of the B300 effects on three Zuiko lenses,
85mm/2, 200mm/4, and 200mm/5, which I did Tuesday last week.
I used my Bogen 3205 and 3029 (pan-tilt head) for the support. The camera was
my OM-4T (with a 2-4 screen). I used Velvia for this test. Since I had only
several frames left over from another test, I hope that you should understand
that the results are tentative. I used the aperture set at f8 for speed since a
couple of boys in the neighborhood were moving around in my frame. I metered
the scene with aperture-priority auto or spot metering. A step-up ring of 49-55
was used for the 85mm/2 and the 200mm/5. The slides were projected on the wall
to 22x33 inches or 55.9cm x 83.8cm.
The subject was the next block of my neighborhood shot from the front porch of
my house. The sun was coming out intermittently that afternoon. The area is
about 30m or 100ft away from the corner of my front porch. The farthest house
in the frame with the 200mm tele is estimated to be 90m or more away.
Examining my shots (only two) with the 85mm/2 w/wo the B300, I have now spotted
vignetting at the right-hand corners. I don't see vignetting on the left side,
and I don't understand why. Overall it looks good, so if you are to use this
combo using print film and have a look at the resultant print only, you may not
notice any vignetting.
When I compared my shots of the same area with the 200mm/4 and the 200mm/5 at
f/8 without the B300 attached, it is hard to tell any difference between the
shots.
Now with the B300 attached, the 200mm/4 +B300 shot was somewhat underexposed
than the 200mm/5+B300 shot. The framing got changed slightly as well. I don't
remember what I did at this point.
The overall sharpness of the entire frame is better with the 200mm/4+B300 combo
than with the 200mm/5+B300. The more overexposed 200mm/5+B300 has a street sign
at the bottom edge of the frame which appears a bit softer and the leaves on one
corner are not sharp presumably due to inadequate shutter speed. On the other
hand in the 200mm/5+B300 shot, the same leaves were underexposed so that I could
not tell whether they were sharp or not. Both shots produced sharp images in
the center judged by projection of the slides and the degree of sharpness in the
lettering on the car license plates. No visible vignetting in the 200mm/5+B300
which has a step-up ring to adjust the mount diameter.
I hope that my results would stimulate others to do their own testing.
Tomoko Yamamoto
mailto:tomokoy@xxxxxxxxx
http://www.charm.net/~tomokoy/
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