Archived posting to the Leica Users Group, 1999/11/17

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Subject: RE: [Leica] Finders
From: "O'Rourke, Joel, Ctr. OASD/C3I/Y2K" <Joel.O'Rourke@osd.pentagon.mil>
Date: Wed, 17 Nov 1999 17:18:14 -0500

There is a slight fallacy here. The real reason the mirrors are made smaller
("shorter") is to allow them to swing up during exposure, without hitting
the rear of the lens. This is especially important for short-focus lenses at
infinity.

If I recall correctly, Hasselblad had a similar problem with some of their
lenses; hence, the latest "gliding mirror" design which moves the mirror
back towards the film plane, then up to the viewfinder glass, during
exposure.

regards,

Joel

Date: Wed, 17 Nov 1999 11:37:03 EST
From: InfinityDT@aol.com
Subject: Re: [Leica] Finders

In a message dated 11/17/99 8:37:06 AM Eastern Standard Time,
TEAShea@aol.com 
writes:

<< The real reason that all SLR's cut off some of the frame is to enable
them 
to 
 make the mirror smaller - thus allowing a lighter, smaller mechanism.
 
 Tom Shea >>

Interesting.  Just how much lighter can a body be made by making the mirror
a 
couple millimeters smaller?  Are we talking fractions of grams here?