Archived posting to the Leica Users Group, 2001/04/17

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Subject: RE: [Leica] Was Medium format camera (now pit-bull arena)
From: "Austin Franklin" <darkroom@ix.netcom.com>
Date: Tue, 17 Apr 2001 17:18:54 -0400

>... I believe their leaf-shutter designs were
> consistent
> to more than 99% (meaning that an indicated 1/500" would actually be
> between 1/495" and 1/505") by 1963.  Several Japanese firms were
> working in
> the same area of research then or shortly afterward.  A mechanical
> leaf-shutter design will have, as Austin indicates, some problems with
> accuracy, though less than the error in a focal-plane shutter.  But either
> an electronically-assisted shutter or a pure electronic shutter will be
> immensely accurate.

How did they adjust for the difference in actual speed between fully open to
fully stopped down?  I can't dispute that one can make a VERY accurate leaf
shutter at one aperture, but it's the difference in speed between fully open
and full closed that is the issue...not the accuracy at one particular
aperture.

BTW, this issue of shutter open/close time is the main reason leaf shutters
don't go above 1/500 typically, and very few (I only know of the Rollei PQS
lenses with the linear motors, are there any others?) go to 1/1000.

Replies: Reply from Rob McElroy <idag@pce.net> (Re: [Leica] Was Medium format camera- now shutters)