Glen, In general, it is not just the autofocus but also metering that may be affected by a linear polarizer. I know that on a ZX-5n, the metering IS affected by a linear polarizer, and I suspect it is the same story with ZX-M. I hope somebody on the list will be able to confirm this. I do not know about the other, older cameras.
Having been looking for polarizers myself, I found a shop that seems to have a reasonable price for various filters: http://hvstar.net/ aka besteastern on e-bay. I was not able to find much of additional external feedback about this store beyond that on e-bay. Igor Wed Aug 29 13:03:17 EDT 2007 Glen Tortorella wrote: Hi All, I am looking for a polarizing filter for my cameras. I have a ZX-M, a KX, and a Super Program. Would a linear polarizing filter be a good choice for these? The circulars tend to be more expensive, and it does not seem I would need this type since I am using older, manual focus cameras. I am thinking of purchasing the Hoya Purple Label linear... Thanks, Glen -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net

