Archived posting to the Leica Users Group, 2000/07/11

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Subject: Re: [Leica] new leica rangefinder concepts
From: ralph fuerbringer <rof@mac.com>
Date: Tue, 11 Jul 2000 08:55:51 -0400

magnification or the reverse is merely incidental in a diopter: it simply
adjusts your vision to the standard they use generally based on normal 20.20
vision. i believe the contax autofocus  with interchangeable lenses has made
some progress along the lines you suggest,with most content with parallax
compensaton. more valuable than the magnification in my estimation would be
a finder  whose field  gets progressibly smaller as you focus closer. a 90
at 3' for example has a field closer to a 135 at infinity. note that at one
to one the field would be 1/4 the size you have at infinity.  a japanese rf
had a finder for its noninterchangeable lens that automatically and
continuously adjusted for field reduction as well as parallax as you focused
from infinity to 3'. as far as i
know everyone else has ignored this phenonomen in 35 and 120 cameras.for so
called large format  schneider and linhof
introduced a finder( actually 3 optically the same appropriately marked for
23,45,57 lenses )to show the exact field when you set the distance for a
specific focal length. clarifying the famous warning : be careful what you
ask for, you may get it too high a price.
  

> From: Greg Locke <locke@straylight.ca>
> Reply-To: leica-users@mejac.palo-alto.ca.us
> Date: Tue, 11 Jul 2000 09:06:33 -02-30
> To: leica-users@mejac.palo-alto.ca.us
> Subject: [Leica] new leica rangefinder concepts
> 
> Not being a manufacturing engineer, I don't understand the obstacles of
> doing this but.....
> 
> Would not Leica rangefinders be more effective (and popular) if they have a
> "variable" magnification so that the frame area for 90 and 135 lens
> appeared larger in the viewfinder (thus making focusing more accurate and
> over all overall use easier)
> 
> So instead of buying a .85 or .72, the magnification could be user
> adjustable or "simply" change when the lens is applied. I know my F4's have
> variable diopter control... how hard can it be to apply this to the
> magnification issue.
> 
> ...or is this simply one of the benefits of SLR?
> 
> Has this been discussed before, if so what were the conclusions.
> 
> cheers,
> 
> Greg Locke
> St. John's, Newfoundland
> locke@picturedesk.org
> 
> PICTUREDESK INTERNATIONAL     ...news pictures ONLINE
> 1-800-340-4970 / http://www.picturedesk.org
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> 
> 
> 
>