From: Ruth A. Kramer (rhkramer_at_fast.net)
Date: Mon Apr 05 2004 - 03:35:52 EDT
Hubert Figuiere wrote:
> On Mon, 2004-04-05 at 08:07, Randy Kramer wrote:
> > * One way of trying to enhance the focus of the entire pen point is
> > by use of a longer focal length lens (telephoto) and more light (to use
> > a smaller aperture).
> For the first point, you are wrong.
> The depth of (DOF) in *inversely proportionnal* of the focal lenght
> of the lens. So if you want to get the longer DOF with the same focus
> distance and the same aperture, you must take a shorter lens (ie wider
> angle). Off course this lead to some geometry concerns...
> That said, this is getting off-topic, so if you want to discuss
> photography techinque, do this privately :-)
Sorry, I did reply to Hub privately, with, in essence this same
response: Hub is absolutely right about the depth of field, but I still
think (am quite convinced) that a telephoto lens will help solve the
problem -- at a greater distance you will minimize the depth of field
required and avoid the geometry concerns Hubert mentions.
And, I won't post on the subject (photography) again.
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