Archived posting to the Leica Users Group, 2000/11/08

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Subject: DOF (was: RE: [Leica]Why a 35mm lens?)
From: Douglas Herr <telyt560@cswebmail.com>
Date: 8 Nov 2000 09:44:16 -0800

On Wed, 08 November 2000, "M.E.Berube" wrote:

> 
> At 12:56 AM 11/8/00 +0100, Alan Hull wrote:
> >So I thought "zone focus" and change to a 35mm lens to increase DOF.
> >Which of course is nonsense as DOF has nothing to do with focal length.
> 
> Huh?
> Admittedly, I'm not an expert on photo theory and often confuse it all 
> round, but everything that I was taught, and my brief 20 years experience 
> hath shewn, that lenses of short focal length produce greater depth of 
> field than do standard lenses at the same aperture.
> 
> Or did I misunderstand?
> 
> Carpe Luminem,
> Michael E. Berube

DOF has nothing to do with focal length.  DOF is influenced by image magnification and aperture.  Shorter lenses have greater DOF for a given aperture and working distance because of the reduced image magnification.

Doug Herr
Birdman of Sacramento
http://ourworld.compuserve.com/homepages/telyt
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