Archived posting to the Leica Users Group, 1997/03/03
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Chris Fortunko wrote: >In my opinion using front-mounted filters on wide-angle lenses, less than >35mm, is a no-no, because of refraction problems. This is a case where thin >gelatin filters may be better than glass. I assume you are talking about dyed in the mass colored filters when speaking about refraction problems, where edge rays would pass through a greater distance of colored material than axial rays? Polarizers do not have this problems as they are made of a thin foil which is sandwiched. They work fine with wide angle lenses; there are of course other issues, such as partial sky polarization, but that is a different issue. I have at times used a polarizer on 17, 18, 20mm etc lenses, and even a few times on the 15mm Hologon. It works fine, as long as you keep in mind what polarization does. For the Hologon, for B&W color filters I've cut gels to fit behind the center filter (which does of course produce varying density, but which is, I believe, produced by vacuum deposition on one surface of glass, which is then sealed by cementing another piece of glass on top). Other wide angles get used with the usual color filter, and as long as they are of good quality, seem to work fine. * /|\ Henning J. Wulff /###\ Architecture |[ ]| henningw@portal.ca