EOS Re: Have you tried a Warming Polarizer?

[Henry Posner/B&H Photo-Video]

At 11:00 AM 12/18/2000, you wrote:
> >What do you mean with an "ncluded UV-filter"? AFAIK every filter
> >blocks UV-light, even normal window glass does so.

I asked a friend at THK (Hoya's importer). He said:

===//===
Henry,

It is true that all glass, except than which is specifically formulated not
to, has some UV absorption properties, even the glass in the windows of our
car has some.  Of course, you don't know what properties or how much
absorption and car window glass has a slight greenish tint to it.

It is true that polarizing film and clear optical glass used in Hoya Circular
Polarizers have some UV absorption properties as well, but it is not match to
anything that we would consider a "common" UV rating.  The UV-Cir-PL filters
have HOYA UV (0), which is a sharp cut L-39 glass (Sharp cut L-39 glass has
50% UV absorption as 390nm with shoulder at 90% transmission at 410nm, and 10%
transmittance at 370nm.)

The glass and PL film in a regular Cir-PL filter is not sharp cut so it's
transmission curve would be depicted at a much less steep (flatter) angle than
a sharp cut filter.

The UV-Cir-PL filter is great for people that do a lot of landscape or other
photography out doors because the filter cuts much more UV than a Cir-PL would
alone.

Thank you,
===//===

--
regards,
Henry Posner
Director of Sales and Training
B&H Photo-Video, and Pro-Audio Inc.
http://www.bhphotovideo.com

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