RE: [Leica] how can the 75 Lux focus go bad?

["Austin Franklin" <austin@darkroom.com>]

> austin@darkroom.com jotted down the following:
>
> > 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.
>
> This is only true if you don't assume that the lens is
> supposed to cover the
> whole film format.  Most people will make this assumption.
> Few people will
> put a 35mm f/1.4 ASPH on a 4x5" camera and expect it to cover
> the film.

Martin, as both Jim and I have pointed out, the film size is completely
irrelevant, and so is completely covering the film format.  It is not an
assumption, it is a fact.  You are confusing optical DOF with printed DOF.

> > I don't disagree that if you change the distance, to
> re-frame the image so it
> > is the same composition you will get different DOF, but
> that is not part of
> > the discussion...the DOF calculator keeps the same
> distance, just changes in
> > the film format change the resultant DOF it gives you.  I
> believe that is
> > wrong.
>
> Well, basically, you believe wrong... ;)

Want to bet pink slips on this ?