I may be outside my league here but I can't imagine that any error in
the thickness of the adapter can lead to backfocus on a manually focused
lens. I would look first to your eyes or a problem with the mirror or
screen position. In fact, problems with the screen or mirror position
would probably also lead to autofocus problems... so we're left with
your eyes. Problems with the thickness of the adapter (assuming they
are significant) would manifest themselves as inability to focus as
close as the spec states if the adapter was too thin or inability to
focus to infinity if the adapter was too thick. In between there would
be no indication of a problem other than the focusing scale on prime
lenses might not agree with the actual distance. But even that I think
would require a truly gross error since those distance scales are
themselves rather gross indicators.
The thing that could easily prove me wrong here is if you can
consistently focus correctly with a DZ lens set for manual focus but
can't do it with an OM Zuiko on your adapter.
The difference in thickness reported for the MA-1 and MF-1 was 0.01 mm
or 0.0004 inches. First of all, I'm not sure that that difference is
significant. Is the machining spec really down to a tolerance less than
that? I rather doubt it given that film thickness variations and film
curl while on the pressure plate probably dwarf that dimension.
Chuck Norcutt
Richard Man wrote:
> 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?
>
>
> // richard (This email is for mailing lists. To reach me directly,
> please use richard at imagecraft.com)
>
>
>
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