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[OM] New affordable Sony FF

Subject: [OM] New affordable Sony FF
From: usher99@xxxxxxx
Date: Wed, 30 Sep 2009 15:46:10 -0400
Ouch,
No mount surgery allowed, I think.
Interesting that the adpater works fine with a shorter registration 
difference with the M42 to alpha.  It is clearly the bayonet
mechanism that is the problem.  It is clearly not easy to construct an 
OM to alpha adapter or it would have been done already.
Mirex came up with an internal release to save space on  the camera 
end. See below---the release is adjacent to the aperture coupling pin.
One has to reach inside and pull up the small pin to remove the 
adapter.  Not clear there would be space for this either as you point 
out, but I'll ask Ian at Srb Griturn--worst  case scenerio is that he 
can't do it. Your link to the M42 adapter was interesting.  The camera 
end of the OM to alpha should be a piece of cake.  I've only seen the 
MD mount and not the MinoltaAF/alpha flavor.

http://www.zoto.com/site/#USR.gordon9213::PAG.detail::d926fa4dcf5d0ce25c5a47d425890207
 


Mike










Here is website which shows how to remove the normal flange (in their 
case a
minolta old lens) and just uses the M42 to alpha adapter with a spacer.
This would be difficult with OM as the stop down mechanism of lens 
would be
removed along with the old OM flange, apart from being sacriligious!

http://www.flickr.com/photos/arkku/1266937278/in/set-72157600018767343/

Tim Hughes

--- On Wed, 9/30/09, Tim Hughes <timhughes@xxxxxxxx> wrote:

From: Tim Hughes <timhughes@xxxxxxxx>
Subject: Re: [OM] New affordable Sony FF
To: "Olympus Camera Discussion" <olympus@xxxxxxxxxxxxxxxxx>
Date: Wednesday, September 30, 2009, 5:44 AM

Mike,
        As discussed before , it may depend more on whether the bayonet 
outer
diameter on the OM flange interferes with the throat diameter of the 
alpha
body.  The flange websites never give the throat diameter needed to 
know the
fit!   The outer diameter of the OM bayonet is 47mm. So the inner 
diameter of
the alpha has to be say ~ 49mm, not to interfere and to provide space 
for an
OM  bayonet

Looking at this website :
http://www.gadgetinfinity.com/product.php?productid=17019
They show an alpha to 42mm adapter which looks like it could be easily 
machined
to have a throat a bit larger than 42mm , maybe 45mm, but on the other 
alpha
adapters they sell, they mention an OD for the barrel part of forward
protruding adapter, of only 49mm. This implies the actual alpha  throat 
is less
than 49mm diameter. So from this estimate , it looks like there is not 
enough
space. If you wanted to hold the OM lens against the camera with a 
1.5mm washer
in between, it might just possibly fit, but it seems there is not quite 
enough
space to make an actual locking OM bayonet mount inside.

We need somebody with access to an alpha to measure the throat diameter 
to
confirm this guestimate, but it does not look too promising

Tim Hughes

--- On Tue, 9/29/09, usher99@xxxxxxx <usher99@xxxxxxx> wrote:

From: usher99@xxxxxxx <usher99@xxxxxxx>
Subject: [OM] New affordable Sony FF
To: olympus@xxxxxxxxxxxxxxxxx
Date: Tuesday, September 29, 2009, 5:03 PM

Thanks for the links.

  Something seems askew with the adapter businness.  The registration
distance for OM is 46mm and the Sony/Minolta AF is 44.5 leaving only
1.5mm.  As mentioned the bayonet release takes up a bunch of space.  I
suspect (but don't know) that the undersurface little pin release
engineered by Mirex might make an adapter sans glass possible.  If
anyone is interested I could contact the technical advisor, Ian, at SRb
Griturn to see if they would machine one and get a price.

Mike


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