Re: Pol's (was: submission to IR Digest)

["Willem-Jan Markerink" <w.j.markerink@xxxxx>]

On  1 Sep 96 at 15:34, JoePaduano@xxxxxxx wrote:

> Willem-- just a quick note again on the Cokin varicolor filters. The reason
> you need to use a separate gray linear polarizer with those filters is that
> they are actually colored linear polarizers.  

Mmm....I think they are more nifty/complex than just 'colored'
pol's....otherwise you could get the same effect with two grey pol's
and a color filter. A pity B+W doesn't make them, I have a good
contact there for technical questions. Neither Cokin nor Hoya has a
good technical helpdesk that I know of. I even doubt one can expect 
an answer in the newsgroup sci.optics....this is one weird filter....8-))

Btw, IMO the fact that the colored pol is a linear can't be the
reason to require a second *linear* grey pol....if the analogy is
double crossed pol's (which I believe is almost identical in
interaction), then a circular second in line should make no
difference. The retarder/quarter wave plate of a circular is on the
back, the double crossed effect also occurs with a linear up front
and a circular second in line. And if you have two circulars
available, you just flip the first one piggy-back to get the same
effect once again.


> also a question--did you ever
> receive my bio info?I E-mailed it twice because the system was down on your
> end the first time I tried.

Yep, the second one got through fine! 

--
Bye,

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The difference 
between men and boys
is the price of their toys

<w.j.markerink@xxxxx>
[note: 'a-one' & 'en-el'!]

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Topic No. 8