Archived posting to the Leica Users Group, 2000/08/29

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Subject: Re: [Leica] Re: Bokeh vs. Nukeh, WYSIWYG
From: Krechtz@aol.com
Date: Tue, 29 Aug 2000 15:48:38 EDT

In a message dated 8/29/00 11:21:58 AM Eastern Daylight Time, 
jim_brick@agilent.com writes:

<< DOF preview is intended for just that. Checking DOF and making sure what
 you want in focus IS in focus and what you want out of focus IS out of
 focus. It works. I've been using it on 35mm SLR's and view cameras since
 1959 and on Hasselblads since 1962. This is how these cameras work. What
 can I say. The professional photographic industry is based on this fact and
 principal.
 
 Used properly, WYSIWYG. Exactly.
 
 Jim
 
  >>

First, any damn fool knows that the lens has to be stopped down.  Second, the 
whole matter of depth of field is itself an approximation based upon an 
arbitrary, mathematically derived standard - the so-called circle of 
confusion, which relates only to relative "acceptable" sharpness, not a 
precise determination of greatest possible definition or resolution or even 
finest resolution within a given frame, let alone as compared to areas 
considered out of focus.  Third, you don't even bother to address the issue 
of how to determine the rendering of out of focus areas on the film by 
looking at a groundglass, with the lens either stopped down to shooting 
aperture or wide open.  Fourth, the newer the camera or focusing screen, as 
the case may be, the brighter the screen is likely to be and less likely to 
be capable of rendering clear distinctions between areas in focus and out of 
focus, IME, let alone giving even an approximate idea of what out of focus 
areas will look like on the frame.  Fifth, we were speaking of 35mm 
photography, using lenses of focal lengths most commonly used with RF 
cameras.  In that context, even a lens of a focal length of 80mm, like the 
Hasselblad "standard" lens, will be more likely to show differences between 
areas in and out of focus than the 35-50mm range under discussion.  Sixth, in 
the context of the thread, I was responding to the contention that RF cameras 
were not useful in situations where the rendering of out of focus ares was a 
consideration.  I disagree with that assertion.

Joe Sobel