Archived posting to the Leica Users Group, 2004/02/17

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Subject: Re: [Leica] Oh god please no! Not DOF again
From: "Jacques Bilinski & Barbara Bradbury" <jbilin@axionet.com>
Date: Tue, 17 Feb 2004 09:10:42 -0800
References: <47A5E9D4-60DD-11D8-AAF0-0050E42E6E0B@shaw.ca> <005801c3f508$c6f38f20$6501a8c0@jbilinsk> <10DE00DE-6101-11D8-9109-0050E42E6E0B@shaw.ca> <002c01c3f51d$cbfcb9a0$6501a8c0@jbilinsk> <8A52C68F-614C-11D8-A0F2-0050E42E6E0B@shaw.ca>

> Sorry mate, this is the same person with the same reasoning. DOF varies
> because he is allowing objects equidistant from the plane of focus but
> at different magnifications to be directly compared.

Okay I understand your point. This is getting a bit pedantic. My point was
just that "a short-focus lens will irrefutably offer more DOF than a
long-focus lens at the same F-number and image magnification."  This is
using the generally accepted definition of DOF, and when comparing different
focal length lenses the magnification will be identical at the plane of
sharpest focus but different at the near and far points of acceptable focus.
I was wrong in stating that this rebutes your statements.


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In reply to: Message from John Collier <jbcollier@shaw.ca> ([Leica] Oh god please no! Not DOF again)
Message from "Jacques Bilinski & Barbara Bradbury" <jbilin@axionet.com> (Re: [Leica] Oh god please no! Not DOF again)
Message from John Collier <jbcollier@shaw.ca> (Re: [Leica] Oh god please no! Not DOF again)
Message from "Jacques Bilinski & Barbara Bradbury" <jbilin@axionet.com> (Re: [Leica] Oh god please no! Not DOF again)
Message from John Collier <jbcollier@shaw.ca> (Re: [Leica] Oh god please no! Not DOF again)