Ghostless filters were made by Pentax in the 60's. They achieved their ghostless effect by being curved (outer surface is convex, while inner one is concave), as opposed to conventional flat filters, which cause a mirror effect when bright lights are in the field. E.g. a bright spot in upper left corner of a night shot doubles as a non+existent bright spot in lower right corner.
Asahi's hostless filters were a brilliant soluition to a little-known problem, but they got not enough attention and purchases for keep manufacturing them (since they were costly compared to manufacturing filters by cutting many filters out of a single flat glass plate) Such filters were made before smc, hence they are not smc coated. They have nothing to do with ghostless coating, which is a much newer coating technology for inner lens elements, developed by Pentax in the 90's. Dario ----- Original Message ----- From: "Steve Jolly" <[EMAIL PROTECTED]> To: "Pentax-Discuss Mail List" <[email protected]> Sent: Monday, June 19, 2006 11:18 AM Subject: Re: Asahi ghostless filter > Toine wrote: >> I can buy an Asahi ghostless filter. Are these filters SMC coated? > > They're not SMC, they're "ghostless", which is an even higher > performance coating. (Probably with more layers.) > >> While searching with google someone claimed these filters are curved >> to prevent flare... > > I have heard that stated on this list, too. > > S > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
