Archived posting to the Leica Users Group, 1999/01/27

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Subject: Re: [Leica] Polarizing Filter
From: "Robert G. Stevens" <robsteve@istar.ca>
Date: Wed, 27 Jan 1999 18:13:33 -0400

Peter:

The clerk is wrong.  The circular polarizers were introduced to deal with
half silvered mirrors like in the R4 and autofocus cameras.  A part of the
light passes through the mirror to the metering system, and in the case of
autofucus, to the autofocus sensors as well.  The half silvered mirror
partially polarizes the light.  If you use a linear polarizer, the metering
will change as you turn the polarizer.  It is like when you take two
polarizers and put them together and turn them wathcing it eventually go
black.

Regards,

Robert


At 04:51 PM 1/27/99 -0500, you wrote:
>Armed with the good information that I received from this list about
>filters, I went to NYC today to buy circular B + W multi-coated polarized
>filters. The sales clerk at B&H, who was quite helpful, told me that I
>didn't need a circular filter for my R4. I had just read in the Bove manual
>that was the one to use for the R4. I got confused and ended up buying
>neither. The sales clerk said that the circular filters are only needed for
>auto focus cameras.
>
>Who is correct, Bove or the sales clerk?
>
>Thanks for any assistance in clarifying this issue.
>
>Peter in NJ
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