Archived posting to the Leica Users Group, 2001/06/06

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Subject: Re: [Leica] Re: Hexar Back focus
From: Dante Stella <dante@umich.edu>
Date: Wed, 6 Jun 2001 16:46:08 -0400 (EDT)

The pressure plate is not flexible.  It rests on the film, which rests on
the inner guide rails.  When there is no film, it rests on the outer guide
rails (which are slightly raised).  This is pretty conventional with
modern motorized SLRs, at least as far as I can tell.  Too much force
against the film would be hard on the motors, I think.

My M3 has no outer rails, and the plate rests on the film plane rails with
no film in it.

On Wed, 6 Jun 2001, Mark Rabiner wrote:

> John Collier wrote:
> >
> > I can only speculate but perhaps the flange to film distances are the same.
> > The difference may be in the measuring technique. If Hexar measures from the
> > bayonet flange to the pressure plate, this would give a greater distance
> > than Leica's  nominal 27.8mm which is to the front surface of the film.
> >
> > John Collier
> >
> ><Snip>
>
> Is the pressure plate flexible? Under pressure?
>
>
> Mark Rabiner
>
> Portland, Oregon
> USA
>
> http://www.rabiner.cncoffice.com/
>

Replies: Reply from Marshall Hunt <huntmc2@fuse.net> (Re: [Leica] Re: Hexar Back focus)