Archived posting to the Leica Users Group, 2000/02/28
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Charles Cason <cec@vbe.com> 02/28/00 08:34AM wrote: >>> I'm not sure I understand all the questions about APO lens. I think an APO lens will not resolve any more lines than a non APO, only effect the chromatic color scale??? If you are developing black and white, does it matter if the enlarging lens is APO or not? Can someone, in a few words, correct my thinking on this. Thanks Charles <<< Unless your light source is a single wavelength, light is color whether the film or paper records separate wavelengths or records intensity (as in B & W). You want all wavelengths to focus at the same place otherwise you get a blur instead of a point. An APO lens is defines as one where 3 wavelengths (I forget which 3) at various points in the spectrum focus at the same point. Non-APO lenses don't nessesarily do this. Doug Herr Sacramento http://ourworld.compuserve.com/homepages/telyt