Archived posting to the Leica Users Group, 2000/01/18

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Subject: Re: [Leica] More fuel on the fire
From: Greg Locke <locke@straylight.ca>
Date: Tue, 18 Jan 2000 17:51:13 -03-30

At 03:01 PM 18/01/00 -0600, you wrote:
>I've read the latest debate about lens quality with great interest, as last
>year about this time my brother and I conducted a similar (concededly
>unscientific) test.  Always using a tripod, we shot about a dozen scenes at
>three prescribed apertures using a variety of cameras:  Leica R4, Leica M6,
>Canon AE-1, Contax G1 and Minox 35GL.  We had all the pictures (shot using
>Kodak color negative film) developed by Kodak, with 4x6 prints.

         Why would you use neg film and prints to judge lens quality?
There are too many variables with the printing process and 35mm colour neg 
film to be reasonable control factor.  I'm sure there are research 
scientists on this list that will tell us that with all experiments you 
must have control factors and that factors that cannot be controlled should 
be quantified or removed.

If I were doing side by side tests I would use the finest transparency film 
I could find.
You get the best resolving power, least grain and don't have the variable 
of printing fluctuations clouding the issue.  Then analyze the results 
through a loupe.

try it again with slide film and let us know  ;^)

cheers,



Greg Locke                         St. John's, Newfoundland
locke@straylight.ca              http://www.straylight.ca/locke
- ------------------------------------------------------------------------------
Touched By Fire: doctors without borders in a third world crisis.
http://www.straylight.ca/touchedbyfire.htm
ISBN#0-7710-5305-3 McClelland & Stewart