Some wide angle and normal lenses (especially those with floating elements)
have been found to be very sensitive to film to flange distance. Many of the
Zeiss/Contax lenses being used with an adapter on Canon DSLR's can go from
bad to excellent with as little as .1mm difference. Some believe that even
a 0.05mm spec is needed for optimal performance. There has been much
discussion, and results posted, on this topic in the FM forums over the last
year. Here is the latest post:
http://www.fredmiranda.com/forum/topic/492605/2
Paul
-----Original Message-----
From: olympus-owner@xxxxxxxxxx [mailto:olympus-owner@xxxxxxxxxx]On Behalf Of
usher99@xxxxxxx
Sent: Sunday, January 21, 2007 3:27 PM
To: olympus@xxxxxxxxxx
Subject: [OM] The real 24mm finals: Sumo-style monster vs little gem
"I don't understand the adapter variability part. I can understand that
the thickness of the adapter might have an influence in the lens's
ability to reach minimum or infinity focus but the test images are all
taken at medium distances."
Chuck Norcutt
I'm not sure I understand the mechanism. There was an especially marked
effect with a N*kon WA. See below and the subsequent pages. Even the
center frame sharpness was affected. Perhaps some are not machined well and
are not even truly flat.
Mike
http://www.16-9.net/lens_tests/15mm_2/sigma1224vnikon15f.html
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