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Re: [OM] OH NO! More Alt dot Moose - Again

Subject: Re: [OM] OH NO! More Alt dot Moose - Again
From: Mike Gordon via olympus <olympus@xxxxxxxxxxxxxxxxx>
Date: Tue, 14 Feb 2017 19:06:46 -0500
Cc: usher99@xxxxxxx
The elgant but hard way Moose writes:

<<Well, OK, there is a possible elegant manual solution, using/modifying an Oly 
Bellows (and possibly leaving it so it can be restored.) 


<<Subtract the E-M register distance of 18 mm from the OM of 46, and we have 28 
mm to work with for a focusing mechanism that reaches infinity. The minimum 
flange to flange distance of the Oly Bellows is 35 mm 


<<The actual rear mount is screwed on to the tube that mounts in the bellows 
assembly very simply. The diameters of the male E-Mount, both bayonet and 
overall, are very similar to the OM mount. I believe a mount taken from a cheap 
extension tube could be attached by <<drilling some new holes in the bellows 
piece and attaching the E-Mount. As the locking mechanism of the E-Mount is on 
the camera body, not the lens, it would work without modification - and save 
about 2 mm occupied by the locking mechanism on the bellows. That would <<give 
a total mounting flange to flange depth of about 33 mm. 


<<That leaves about 5 mm of excess length. About 5+ mm could be gained by 
unscrewing the front of the bellows from the fabric and gluing the fabric to 
the front mount. Or, more solidly, and reversibly, by screwing the interior 
fabric mounting plate to new little holes drilled in <<the front standard. My 
measurements aren't exact, but it looks like it would be very close, maybe even 
a tiny bit past, infinity focus. If not quite there, a pleat of the bellows 
could be cut off. 


<<Everything but any bellows shortening would be reversible. There may be 
replacement fabric portions available. Or one could just put up with a small 
limitation to the 7+" of extension it allows. 


<<That would do the job of allowing focusing by moving camera body relative to 
a fixed lens with excellent, smooth control. And yes, the A7 will clear 
everything on the bellows. Looking on Camreasize, is appears the II and RII 
would also work. 

Thanks for the directions and providing food for thought--not sure I have the 
heart to modify my LN bellows from Bill Barber.  Would like to use a very good 
lens in front but wonder if using a longer registration lens like an old 
t-mount or even Mamiya 645 may  be made to work and not require bellows 
surgery.  The Mamiya 35 isn't bad but does have more CA than I would like but 
would also work on my Mirex T-S adapter.  I think Kiron made  a pretty good 
Tmount 28mm perhaps branded as vivitar but don't clearly remember and  it may 
be hard to find.  The problem is then the possible  thin custom adapters 
required--they don't come cheap from Srb griturn if they even  will   fabricate 
them anymore.  I  also wonder what would happen if one mounted a WA on a screw 
macro rail    http://www.reallyrightstuff.com/B150-B-Macro-focusing-rail   
(there are cheaper alternatives) and moved the cam back the same amount the 
helicoid moved the entrance pupil forward?????   perhaps mount a laser to align 
i
 t in front--no clue what happens to the framing and whether one could get the 
images to align  and clean up OK in post.  May be a recipe for madness.

Macro landscaper or mad as a hatter, Mike






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