From: "John A. Lind" <jlind@xxxxxxxxxxx>
The rectilinear lens is what we are most accustomed to. It maps flat
fields in space to a flat field of film...
The "spherical" (equidistant?) lens is the theoretical fisheye. It maps
spherical fields in space to a flat field of film...
Actually, the way I think of it is that a rectilinear lens records
true angles, while the fisheye records proportional areas. (Until
holograms come way down in price, you can't record both. :-)
That face in the corner of the 24mm shot that looks so "distorted?"
Put your eye where the lens is, and the face will look goofy in real
life, too! That's because (for example) the angular width (from the
center of the frame, the lens's axis) of the chin is the same as that
of the forehead, so the rectilinear lens has to stretch the forehead
out to preserve the angular relationship.
It's ironic that a face in the corner of a full-frame fisheye will
look more "natural" than a face in the corner of a rectilinear,
because the fisheye preserves areal relationships. The chin will be
in proper size proportion to the forehead, for example. So in this
case, the fisheye is less "distorted" than the rectilinear lens! But
our eyes and brain are more upset when lines aren't straight than
when areal proportions are wrong, thus the bad "distortion" rap for
fisheyes.
I've grown to really love the Zuiko 16/3.5 fisheye, and have dozens
of images that no one would ever guess were taken with such a
"distorted" lens. :-)
: Jan Steinman <mailto:Jan@xxxxxxxxxxxxxx>
: Bytesmiths <http://www.bytesmiths.com>
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