Is it good to get polarizers multicoated??? The usual reason polarizers are not multicoated is that there is so much reflection at the internal laminated surfaces, where the polarizer sheet is, that multicoating gives no improvement over monocoating! Additionally, multicoating may change the direction of polarization and thus reduces the polarizing effect of a polarizer. Many prominent filter producers do not use multicoating on their polarizing filters.
As the inner reflections at the filter foil are the critical problem, the way to go if you want a higher quality filter is buy a Kaesemann type filter. They are said to be more uniform and especially, they are sealed at the edges, which ensures they are not going to separate after several years. Separation causes deterioration of the material and increasing reflections with time. Although adding multicoating to polarizers adds little and possibly even has disadvantages, some companies sells multicoated polarizers (It clearly has marketing advantages: Who doesn't always want a multicoated filter?). In formal tests by Photomags these multicoated polarizers are usually not surpassed by their single coated counterparts. Knut At 14:48 18.06.02 +0200, you wrote: >Alan wrote: > > >>I don't think the Pentax polarizers are multicoated, at least the Japanese >>web site doesn't say so. > > >Mine isn't. I was quite disappointed considering it's high price. > >Pål >- >This message is from the Pentax-Discuss Mail List. To unsubscribe, >go to http://www.pdml.net and follow the directions. Don't forget to >visit the Pentax Users' Gallery at http://pug.komkon.org . - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
