Hi,
When using a converter, remember to stop down the apertue to at least = F8.
I have just got back some test shots (taken through my window facing = my
back yard and the brick buildings at the other side, approx 80m away) =
with a Tamron 3.8-4/80-210, a Zuiko 2.8/135 and three different 2x =
converters: a Kenlock, an RMC Tokina and the Adapall Tamron SP. All shot =
with a tripod and a cable release on an OM-2. I could have used MLU but = I
seldomly use it in my photography.
The test images were taken with Sensia 100 and evaluation was carried = out
by just looking at the projected images. No measurements carried = out,
however.
Results are astonishing. Wide-open, all converters are poor performers, =
with the Kenlock being the worst, the Tokina slightly better, and the =
Tamron acceptable. The Kenlock produced images which show extreme blur = on
both the zoom and the 135. Stopping down to F8 improves image = quality,
but the Kenlock still is a dog. F22 produces rather good = results with all
converters on both lenses.
Then, inspired by Olaf's astrophotography (see the thread of some months =
ago), I mounted all three converters onto the Tamron 80-210, resulting = in
a focal lenght of 1680mm! Stopped down to F32 (what theoretically = would
be F256, including the 3 converters), the setup resulted in an = exp. time
of approx 2 seconds. Image quality was OK. Not sharp, but also = not as
distorted as I thought.=20
Maybe I should repeat this under more consistent conditions and perform = a
resolution and sharpness test? I don't have the equipmet for that, =
however. I wonder how the Zuiko 2x performs compared to the others?
Best regards
Bernd Möller
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