Archived posting to the Leica Users Group, 2001/02/07

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Subject: Re: Re: [Leica] how can the 75 Lux focus go bad?
From: "Jason Hall" <JASON@jbhall.freeserve.co.uk>
Date: Wed, 7 Feb 2001 15:17:31 -0000
References: <200102070811958.SM00756@m2w073>

> I disagree.  If you take the same lense, and use it on ANY size
film, at the same distance, you will get the same DOF.  >Optics
doesn't know what the film size is, and adjust it self accordingly.
3' IS 3', no matter what the film size is.

That is like saying that a 24mm lens @f8 on 35mm has the same depth of
field as a 500mm lens @f8 on 35mm if you enlarge the 24mm image
sufficiently.

In practice a 10x8 negative will not be enlarged to the same degree as
a 35mm negative therefore the COC is different.  These are fundamental
rules accepted by most photographers for calculating depth of field,
you might want to read around the subject and understand the
principles before making such bold statements.  This thread was done
to death on the LUG not long ago.

Jason Hall

In reply to: Message from "austin@darkroom.com" <austin@darkroom.com> (RE: Re: [Leica] how can the 75 Lux focus go bad?)