Archived posting to the Leica Users Group, 1998/02/04
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]> > 2) Linear distortion is a direct function of a variation in magnification > across the image field. A true rectilinear lens has zero variation in > magnification, and using the usual definitions, a fisheye has 100 percent > distortion, orthographic or equidistant projection only providing > variations in midfield. > > 3) Optical geometry allows for nothing else. > Danny, intuitively Henning's statements seem to make sense to me. It may be helpful to think of a complex fully corrected lens as a simple pinhole for the purposes of understanding distortion. I can see how a fully corrected telephoto or retrofocus lens could alter the image in the same way that a slight change in camera position would, but I don't understand how a different lens design (eg a mirror lens) could alter the perspective. I'm willing to be convinced otherwise though.