>From what I recall, the Pentax SMC coatings fitlered UV considerably but old single coated or uncoated lenses passed much more UV spectrum and benefitted from using UV filters more than SMC lenses for high UV conditions.
-- J.C. O'Connell (mailto:[email protected]) Home Page - www.jchriso.com Join the Audio CD PLAYER DISCUSSION list - http://tech.groups.yahoo.com/group/cdplayers/ -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Anthony Farr Sent: Wednesday, September 09, 2009 7:38 AM To: Pentax-Discuss Mail List Subject: Re: Front Element Protection (was: Dropped K200D) AFAIK, "normal" glass is opaque to UV rays. You need flourite lenses to photograph in the UV spectrum, while much of what is known as UV photography is actually flourescence photography. I don't know what the transmission characteristics of ED glass is. Which means that UV filters won't contribute to elimination of UV light from your shots, because none is getting through your lens anyway. OTOH, they usually remove a little of the barely visible near UV, so will trim some excessive blueness from overcast or open shadow light when you're using film and can't adjust white balance per shot. Skylight filters just cut a little into visible blue wavelengths while UV filters only cut invisible blue wavelengths, but not enough to matter when you can tweak the WB instead. Which raises another matter. FIlm was oversensitized to UV so vulnerable to shifts in that direction. Digital sensors, especially CCDs, are oversensitized to IR but are usually protected by "hot filters" (more or less effectively from one camera model to another). They are relatively insensitive to UV light. Which leaves protection as the only real motive for using a UV filter. I live on the coast, and feel better about cleaning dried salt off a filter than off a lens. regards, Anthony "Of what use is lens and light to those who lack in mind and sight" (Anon) 2009/9/9 eckinator <[email protected]>: > Is there such a thing as a final verdict on UV vs Skylight vs > 'Protection' (whatever those are - do they block overprotective rays?) > Filters? I need to buy one for my 16-50 seeing the time I spend in > sandboxes with my camera these days... a blower wont do the trick for > me all the time. > Thanks > Ecke > > 2009/9/9 Larry Levy <[email protected]>: >> I come from the capital K Klutz school of carefulness. Starting with >> the 10D, I've been putting Giottos Aegis screens on the LCDs. It's a >> lot cheaper to replace if (when) something goes wrong. >> >> I'm also one of those who typically puts a UV filter in front of the >> lens. When I dropped my camera bag in an airport, the only damage was >> some cross-threading in the lens (which Eric fixed for me) and the >> replacement of the filter (which had given itself up to save the >> lens). >> >> Larry in Dallas >> >> -- >> 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. >> > > -- > 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. > -- 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. -- 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.
