It isn't an acronym. PL was originally the abbreviation printed on linear polarizers from almost all manufacturers. When circular polarizers came into being (and were necessary to avoid exposure and focus problems with modern cameras that use semi-silvered mirrors or prisms to split the light entering the viewfinder in order to calculate exposure and focusing distance) they had to be differentiated in some way. You will see them called CPL, PL-CIR, and PL-C (perhaps others) by various manufacturers.
-- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
