Archived posting to the Leica Users Group, 1998/11/20

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Subject: [Leica] MTF explanation
From: Carsten Bockermann <Carsten_Bockermann@compuserve.com>
Date: Fri, 20 Nov 1998 17:02:57 -0500
 
Dick,

>>original subject is a set of black lines on a white background, which
seems
>>to me to represent an upper contrast bound.  

in reality there is no pefect white and no perfect black, so there is no
upper contrast bound. If the was, the contrast ratio between the two lines
would be infinite. For lens test, contrast ratios of 1:1000 and 1:1.6 are
being used; I donīt know what the actual values are for film tests.

Carsten

http://ourworld.compuserve.com/homepages/Carsten_Bockermann/