Archived posting to the Leica Users Group, 1999/04/14
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Hi everybody, I recently acquired an Leica M polarization filter for my M6 and I am a little bit confused about how to use it correctly. According to the manual one turns the filter until the desired level of polarization is obtained, swings it in front of the lens and then determines the exposure normally by metering through the lens (and filter). In this way the exposure is dependent on the amount of polarization imposed by the filter. However, several places in literature I have read that one should treat polarization filters as fixed factor filters (2.5x unpolarized). Thus, one determines the exposure *without* the filter and then multiply by the filter factor (2.5x, always) to get the correct exposure (unless some very dark areas that requires more exposure are "uncovered" at maximum polarization). Leica AG has informed me that 3x is the correct filter factor at maximum polarization. Until now I have determined the exposure without the filter and then increased it by 1 1/2 stop, and usually this method works better than when measuring the exposure through the filter. Any opinions on this? - -- Arne | Arne Helme (arne@acm.org) "We are all in the gutter, but some of us | | http://www.huygens.org/~arne are looking at the stars" - Oscar Wilde | | PHONE: +31-53-4894178, FAX: +31-53-4894590, HOME: +31-53-4309352 | | Informatica/SPA, Univ. Twente, Box 217, 7500 AE Enschede, Netherlands |