> It seems possible (though it doesn't make sense to me) that a shift
> lens indeed works, [...] I thought the very basis of stereo
> is to have two physically different points of view, e.g. like our eyes
> are separated. With a shift lens, the camera is stationary, so the point
> of view is the same, is it not?
No, it is not.
It is the lens that determines the point of view, not the camera. The
camera just holds the film/sensor where the image is recorded. As a matter
of fact, a stereo camera has two lenses and one camera body.
The person whose picture you linked:
http://www.flickr.com/photos/turbguy/2332656395/
is a member of our stereo club here in Ohio, but recently relocated.
The description reads: "Here's a cross view of a macro photograph taken
with a shifted lens and a shifted camera (slide bar) to avoid keystone
distrortion yet obtain a full field view. "
He combined the shift lens and a shifted camera in order to "obtain a full
field of view". It takes some knowlege and experience to understand what
this means. When you take a close up by shifting the camera, you need to
crop the outer edges of the stereo pair, in order to "set the stereo window"
(helps in the presentation). This is not a problem in digital but it can be
a problem with slide film. Cropping the edges results in a smaller image.
This fellow combined the shift of the camera with the shift of the lens, to
reduce the need of cropping. The exact details are not clear to me. I know
that if you shift the camera and *tilt* (not shift) the lens (or camera),
then you don't need to crop.
These are details that don't need to confuse the beginner... The simplest
way to take a stereo picture is to shift one camera (with lens attached :)).
If you have a shift lens, apparently shifting the lens between the two
extremes right and left, will work too, but the "stereo base" might be less
than optimum for anything other than extreme close ups.
George
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