Perspective is a function of distance, but the distance one stands from
the subject is a function of FOV. An example makes this relationship
quite obvious: I frequently shoot front 3/4 or 7/8 pics of cars with a
400mm lens. Art directors like that with long cars because it bunches
them up, bringing the back wheels forward. I used to use it with my LX.
I now use it with my *istD. Because the *istD FOV is tighter, I'm
further away from the subject when I shoot. The same distance from the
subject I would be if using a 600mm lens on the LX. So, in effect, I
get the same perspective with the 400 on the *istD that I would get
with a 600 mm lens on the LX.
Paul
On Jul 13, 2005, at 11:52 PM, Godfrey DiGiorgi wrote:
On Jul 13, 2005, at 8:50 PM, Tom Reese wrote:
I suspect that the perspective would be different too. I think a
cropped 18mm image will still show the exaggerated perspective of
that lens. The background will appear to be much further behind the
subject than it will in the image taken with the 28mm lens. That's my
theory anyway.
Citing "Basic Photography" published by Focal Press, ca. 1968-73
Edition:
"Perspective is a function of distance, not focal length. ... Focal
length along with format dimensions determines field of view."
I think you are confusing perspective with "wide angle distortion",
which is the effect in a rectilinear corrected lens of causing circles
to become ovoid when off the lens axis as you increase field of view.
An 18mm lens on a 16x24 format will present the same field of view as
a 28mm lens will on 35mm format, and wide angle distortion will be
constrained to be the same due to the fact that the field of view is
identical (presuming equal rectilinear correction, of course).
Godfrey
