Distortion in Camera Lens
-
When photographing regular, grid like
forms, as in architectural photography or in copying artwork that
contains square or rectangular elements, you may notice that lines that
are straight or parallel in the subject are reproduced as curves in
characteristic ways. A door or window, or a drawn rectangle, may appear
to have its sides curved inward ("pincushion" distortion) or outward
("barrel" distortion). This aberration, by the way, has no effect on
image sharpness.
-
Any such distortion is inherent in the
lens design and is not correctable. Fast wide-angle lenses are
especially likely to display noticeable barrel distortion. If you are
buying a lens with the intention of using it at least in part for
careful photography of rectilinear forms, beware. Look instead for
low-distortion lenses, such as are designed for architectural work or
for copying, and are advertised as such.
|
