At 19:55 10/31/99 , Dirk wrote:
>
>it doesn't appear to be anything of the sort. tiffen says that the filter
>does not effect sharpness. since i don't have it yet, i can't make a
>definitive comment, but the pictures on the web site did not look anything
>like a diffusion filter.
B&H in New York has a large section on filters from all the major
manufacturers:
http://www.bhphotovideo.com/photo/filters/navigation.html
I prefer to use B+W or Heliopan as both are made using high quality Schott
optical glass. Schott is part of the Zeiss Foundation and the glass is
among the finest in the world. B+W is part of Schneider Optics (some might
recognize the name Schneider-Kreuznach) and the name Heliopan keeps gnawing
at me that it has a connection to Zeiss beyond Schott glass. Tiffen, IMHO,
runs second to B+W and Heliopan although I have a few of them also.
Adding a filter *does* affect image quality no matter what its purpose is
(dispersion, transmission loss and possibly flare); it's a matter of how
much and whether it will be noticed in the end product.
There is also a difference in the "soft focus," "fog," "mist" and other
"diffusion" type filters. It is a matter of *how* the light is dispersed
by the filter and there are numerous methods used. Some use minute
etchings, some use miniscule bumps, and yet others microscopic concentric
rings. Each will disperse the light slightly differently. Consequently
the effects will be slightly different, including how much "halo" is
created. See the descriptions by B+W, Heliopan of how images are softened
(found under their Special Effects filters heading). The Tiffen section on
this doesn't appear to reveal much about how it's donw.
I try to find pristine used filters rather than buying them new and go
through the filter bin whenever I'm in a large camera store. Sometimes
it's successful, sometimes not. Eventually if it's impossible to find a
used B+W or Heliopan, I will buy a new filter.
I do have Olympus 49mm and 55mm circular polarizers and they appear to be
pretty good quality also. Just out of curiosity, does anyone know who
makes these for Olympus (or any of the others sold with the Oly name)?
-- John
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