Thanks so much Kent. I think the issue of circular versus linear is
addressed by Leica. Did you use the thin versions on your zoom lenses?
The entire question arose when I was thumbing through Eastland's book on the
R8. My wife and I are heading to Buenos Aires and Santiago, with lots of
stops in between, and I was thinking of which camera system to take...the M
versus the R. With the R I thought I should consider some polarizers since
we will be going to the Andes Lake District which separates Argentina from
Chile. I took a quick look at my 28-70 and noted that the rotation of the
front element might interfere with the ability to rotate the filter. To my
surprise, Eastland indeed mentions that, "The design of this objective
prohibits the satisfactory use of a circular polarizing filter. The depth of
the filter mount causes some vignetting at the shorter focal length range
and the retracting front element prevents rotation of the filter when the
lens is used at longer focal lengths". I had called several dealers BEFORE
reading Eastland to ask them if their observations were the same as mine,
and they both said, in effect, no sweat, get the standard E 60 Polarizer, I
was wrong! Of course, the next issue was Leica ( very costly ) versus
another brand, but I thought I needed more advice since the dealers differed
from Eastland's advice, and my observation. To decide the issue I asked
our friends on the thread, and the consensus seems to be that the thin
filter is the way to go. Unexpectedly, I received an education on linear
versus circular polarizers vis-a-vis the R system!! The response proves how
very lucky we all are to have members who are so well informed, and so
willing to share information freely and easily.
I almost hesitate to ask....Leica versus third party? My inclination is to
go with a third party...
Let me issue a very sincere thanks to all of you who have taken the time and
trouble to respond. Again, what a great group to be a member of! I only
wish more of us could have the opportunity to meet personally.
Elliot
----- Original Message -----
From: "Kent Christensen" <lkchris@xxxxxxxxxxxxx>
To: "leica_reflex_forum" <LeicaReflex@xxxxxxxxxxxxx>
Sent: Monday, January 17, 2005 12:48 PM
Subject: [LRFlex] Re: Polarizer
re: If I am not mistaken circular polarizers are required only in the case of autofocus systems, manual focus lenses can be used with the original style polarizers which you may own already. (Steven)
No, I think you're off one technology generation.
Circular polarizers are generally required with through-the-lens metering.
Linear can be used with other metering.
It's not focussing type, it's metering.
For this forum, then, it's circular from SL on.
Here's the word from Leica in the 1983 "Leica R-lenses" booklet:
"The previous exclusively used linearly polarising filters have been replaced by Leitz circularly polarising filters to simplify operation of the LEICAFLEX SL and LEICA R models (cameras with light metering through the lens), because the use of circularly polarising filters saves the cumbersome corrections necessary with linearly polarising filters. This is due to the type of light metering through the lens used in the Leica s.l.r. cameras. With the selective exposure measurement of the LEICAFLEX SL/SL2 and the LEICA R3 the light necessary for the measurement is branched off by means of a physical beam splitter (the semi-silvered hinged mirrors of these cameras). This also applies to the two exposure measuring methods (integrating and selective) of the LEICA R4. Because these beam splitters themselves act as polarizers, the measuring result when normal linearly polarizing filters are used is falsified: unless corrections are introduced, exposures will be wrong.
The situation is similar with the two measuring methods of the LEICA R3/R3-MOT (also integrating and selective). In these camera models, however, the proportion of the total light necessary for the exposure meter that reaches the measuring cells in the bottom of the camera through the semi-silvered hinged mirror (pyhsical beam splitter) depends on the measuring method. But the two measuring cells above the focusing screen are unaffected.
With the circularly polarizing filter, on the other hand, the measured exposure value can always be directly accepted. Only circularly polarising filters are therefore recommended for use on the LEICA R models."
Kent Christensen Albuquerque SL, R3, R8
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