pinhole-discussion:: RE: pinhole film flatness, depth of focus,

From: George L Smyth <glsmyth_at_domain.name.suppressed>
Date: Mon 26 Jul 2004 - 05:34:22 PDT

Murray -

Actually, I have put filters in front of and behind pinholes and not seen a difference, so I would not make the second assumption. With the first assumption, I have seen that objects far away will be "less sharp" than very close objects, probably because of atmospheric effects. Just my observations, not something measurable.

I am guessing that one will not be able to detect much as far as focus is concerned when dealing with film flatness. I would imagine that it does make a difference becuase the F stop will be different, but then again theoretically you have that situation with a perfectly flat sheet of film since the edges will be further than the center. As far as this being measurable or noticeable, I doubt it.

Cheers -

george

-----
http://www.GLSmyth.com
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--- On Sat 07/24, Uptown Gallery < murray@uptowngallery.org > wrote:
From: Uptown Gallery [mailto: murray@uptowngallery.org]
To: pinhole-discussion@spitbite.org
Date: Sat, 24 Jul 2004 22:15:48 -0400
Subject: [pinhole-discussion] pinhole film flatness, depth of focus, etc

depth of field is said to be for, all practical purposes, infinite with typical large f-number pinholes. we also know that depth of focus (behind the aperture) is 'less critical' because filter defects, dust etc., that show up in front of a pinhole, do not if placed BEHIND the pinhole. Since pinhole is 'afocal', is there any problem with film flatness and pinhole, especially large and thin film? Thanks Murray _______________________________________________ Post to the list as PLAIN TEXT only - no HTML pinhole-discussion mailing list pinhole-discussion_at_spitbite.org FAQ at http://spitbite.org/pinhole-discussion/list.html

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Received on Mon Jul 26 05:34:58 2004

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RE: pinhole film flatness, depth of focus, etc