Archived posting to the Leica Users Group, 1997/12/03
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]At 04:07 PM 12/3/97 -0800, you wrote: >Your claim that diffraction is less of a problem with longer focal lengths >is incorrect. The limit of resolution (as measured by the Rayleigh >criterion) of a diffraction-limited lens is given by As far as I know, Leica has only two diffraction-limited lenses. So what good are those numbers? Seems to me by what you say is that the limit to resolution is r=L f/D. But who says any lens is at the limit? As I heard it, the angle of light in a wide angle lens is much more severe (light passing over the edge of the aperture). And thus diffraction is increased compared to the light travelling through a telephoto where the light is diffracted less becasue the angle of attack on the edge of the aperture blade was less severe. So please, define what diffraction limted means. Seems to me these numbers don't make sense. ========== Eric Welch St. Joseph, MO http://www.ponyexpress.net/~ewelch Make it idiot proof and someone will make a better idiot.