Archived posting to the Leica Users Group, 2003/01/15

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Subject: [Leica] To Austin, was RE: I eat crow
From: Herb Kanner <kanner@acm.org>
Date: Wed, 15 Jan 2003 00:00:57 -0800

Austin,

Perhaps putting Henning's statement in different words will help make 
it clear---

The idealized theory in geometric optics is that a "perfect" lens 
transforms an object plane to an image plane.  Consider a plane out 
there in front of the camera, a plane that is parallel to the plane 
of the film.  If the image of any point on that plane is in focus, 
then for a "perfect" lens, the images of all points on that plane 
will be in focus.  Any deviation from this is the defect called 
curvature of field.  Now, it is obvious that points on the plane 
corresponding to the edge of the film are further from the camera 
than the point whose image is at the center.

Herb
- -- 
Herbert Kanner
kanner@acm.org
650-326-8204

Do not meddle in the affairs of cats,
for they are subtle and will pee
on your computer!
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