This has been discussed before, the lens is the weakest part. If one has to
worry, worry about the lens itself. Check an example below for three lenses:
www.accura.com.hk/temp/Leica_M35_50_75.jpg
The field curvature is well over 200 microns towards the edges! The adapter
thickness uneven will be 10 times less!
C.H.Ling
----- Original Message -----
From: "Chuck Norcutt" <chucknorcutt@xxxxxxxxxxxxxxxx>
Ever since I read Mike Hattem's tests of adapters you've described below I
can't figure out what he was carrying on about. Consider that the front
and back mounts are not perfectly parallel. How is that different from
tilting a lens with a tilt/shift adapter? And if it was a truly bad
machining job... maybe only by 0.001-0.002 inch. The image is not
"distorted", only the plane of focus has changed. Unless he's testing
using a perfectly flat object located very close to the lens and with
almost no depth of field and also very precisely parallel with the image
plane I don't see how he could detect it... even at 100%. I don't see
that such a small error in the parallelism of the two mounting faces is
any kind of real world problem.
What's wrong with my logic?
Chuck Norcutt
On 9/25/2014 11:49 PM, Moose wrote:
The genuine Olympus MF-2 seems to be going for $160+, and there are
off-brand options available for ~$40. Do they fit well? Are the
materials and finish sub-par? Do they work? It is hard to justify 4x
the cost when it is just a carefully sized piece of metal and plastic.
I have read that front and back mounts must be very accurately parallel,
perhaps especially for WA lenses? In Mike Hattem's obsessive tests of
various MF lenses on FF Canons, including the 21/2.0 and 21/3.5 Zuikos,
he found that very small errors made a difference - pixel peeping at
100%.
Whether that's a problem with any specific versions, and how noticeable
any effect may be, I don't know.
--
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