If I understand Gary Reese's reply to a similar question of mine a couple of
months ago, where the focus ring is set makes little difference with lenses
that are not corrected for close ups. For lenses that are corrected for
close ups, it's best to set them at the minimum focusing distance when used
with extension tubes, etc.
And if I remember correctly from something I read in the distant (not to say
close up) past, DOF calculations go wacko where macro photography is
concerned. There's a formula to calculate it, but I don't remember what it
is.
Hope I got that right.
Lex
===
From: "Barry B. Bean" <bbbean@xxxxxxxxxxxxxx>
Subject: [OM] Extension rings and focus - newbie Q
Date: Thu, 14 Sep 2000 11:46:55 -0500 (CDT)
I recently bought a set of extension rings from a list member, and
through experimentation have run into the following question:
Using the extension tubes with a normal (non-macro) lens, should I
set focus to near or infinity for best results? What affect will this
have on actual depth of field?
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