Archived posting to the Leica Users Group, 2003/04/24

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Subject: RE: [Leica] Digital Aesthetic
From: Henning Wulff <henningw@archiphoto.com>
Date: Thu, 24 Apr 2003 16:07:23 -0700
References: <NABBLIJOIFAICKBIEPJJIEAGFLAB.darkroom@ix.netcom.com>

At 2:54 PM -0400 4/24/03, Austin Franklin wrote:
>Henning,
>
>>  DOF is dependent on focal length and aperture value
>>  alone, and only slightly modified by the different circle of
>>  confusion criteria for different formats.
>
>Good grief, Hemming.  The DOF is HIGHLY dependant on the COC.  The COC
>significantly modifies the DOF for the same focal length, aperture, and
>distance.
>
>Example:
>
>50mm, f2.8, 1M subject distance:
>
>COC of .033 gives a DOF of 0.07M
>COC of .06 gives a DOF of .128M
>
>Clearly, the COC highly modifies the DOF.

I meant that the usual application of COC is a lesser factor than the 
focal length/aperture combination (actually, it's the aperture size 
diameter that is the true determinant alone). I just overstated my 
case to make the point.

The other, somewhat subjective component is: what do you expect from 
the various formats in terms of 'sharpness'? If you expect nothing 
more from a 4x5 shot blown up to 16x20 than from a 35mm shot blown up 
to 16x20, then the COC becomes a much greater factor.

- -- 
    *            Henning J. Wulff
   /|\      Wulff Photography & Design
  /###\   mailto:henningw@archiphoto.com
  |[ ]|     http://www.archiphoto.com
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In reply to: Message from "Austin Franklin" <darkroom@ix.netcom.com> (RE: [Leica] Digital Aesthetic)