From: Jeff Sumner (jdos2@mindspring.com)
Date: 12/17/02-11:07:39 PM Z
On Tuesday, December 17, 2002, at 11:10 PM, S Wang wrote:
> Shannon,
>
> Pinhole or lens, there is no difference between images made with a
> telephoto or with a long focus, as long as the focal lengths are the
> same. That is, the perspective is determined by the focal length.
> Period.
>
Ack- this can get ugly. I think the problem definitions, as the
perspective (the point from where the shot is taken) doesn't change
with focal length, just the distance to the target. "The Manual of
Photography" says "The perspective of the scene is correctly
reconstructed only by viewing from the principal distance." Also: "
Various points need clarification. By altering the lens to one of
longer focal length v[sic] is increased and the image is enlarged; but
it retains identical perspective. So a charge of focal length for a
given viewpoint for a given viewpoint does not alter perspective but
only image size." Bold was mine. (The Manual of Photography- also "The
Illford Manual of Photography", Eighth Edition, 1988 Butterworth & Co.)
Wide angle pinholes are pretty cool little cameras- especially those
with the curved film holders. I'd like to have one someday. I'm
experimenting with my large format Kodak with aluminum foil taped over
the lens board aperture and a pinhole in the middle. I like Polaroid
materials so I get immediate feedback, though reciprocity is terrible,
and I wasn't terribly accurate about punching the pinhole. I *believe*
it round...
:-)
JD
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