Forgot to add - if you are consistently having backfocus issues with a
manual focus lens, your focus screen is not aligned correctly with your
sensor (different distance). Live view might be sensitive enough to provide
a check with your manual focus. My eyes aren't good enough to trust my
manual focus abilities - I stop down after focusing.
My E-3 seems to have about a 1/2 degree rotation on the sensor. I've been
using a geared leveling head with leveling bubbles for most of my shots.
Most of the time I have to rotate the image about 1/2 degree. Prior to using
the head I mostly had to make a clockwise correction but it wasn't
consistent enough to be sure that it wasn't operator error.
-jeff
-----Original Message-----
From: Jeff Keller [mailto:om-list@xxxxxxxxxxx]
The generic Nikon to EOS adapters can cause big problems.
http://www.16-9.net/lens_tests/15mm_2/sigma1224vnikon15f.html
If the thickness is off it should only affect the lenses having floating
lens elements. If all of the lens elements move together as a single group,
the distance markings would be off but the lens would work fine otherwise.
So for OM lenses: many of the f2 lenses, the big white telephotos, probably
the zooms, and some of the nice third party telephotos such as the Tamron
400/4 may suffer.
The MF-1 and MA-1 looked like they were within measurement tolerances of
each other according to the article Piers posted a link to.
-jeff
-----Original Message-----
From: Richard Man [mailto:richard-lists@xxxxxxxxxxxxxx]
Sent: Saturday, December 06, 2008 1:00 AM
To: Olympus Camera Discussion
Subject: [OM] OM to 4/3 adapter thickness....
Wait a minute, if MF-1 and MA-1 differ in thickness, doesn't that
mean one of them is not optimal? I have a generic adapter, and it
looks to be slightly off (backfocus), could that be the reason?
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