From: Carl Weese (cweese@earthlink.net)
Date: 12/18/02-07:23:54 AM Z
> Hence, in practice (not theory) focal
> length, standing at the same point in space, does change perspective.
No, perspective is determined by camera (actually, lens) to subject
distance. The *indirect* relation is that a short lens may force you to
stand closer to the subject while a long lens forces you to step back. The
stepping in or back, not the lens itself, changes the picture's perspective.
You can demonstrate this easily with a wide-to-tele zoom lens. Shoot wide
and tele views standing in one place. The framing changes (just as it would
if you simply cropped the wide view in the enlarger) but the
perspective--the relationship between objects--remains the same. A greatly
enlarged and severely cropped print from a wide lens will give a "telephoto
look" just like the zoom lens.
Now set the lens at normal and walk way back to take in the framing of the
wide angle length, then walk all the way in to match the framing of the tele
length. The perspective--the size relationships between objects in the
picture--with the normal lens used at near and far distances will be
radically different, and these relationships will also be different from the
single set of perspective relationships obtained by changing focal length
while standing in one spot.
For perspective, camera position rules. Lens changes only affect framing.
---Carl
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