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  1. #1

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    Question on Circular Polarizers

    I've recently ended up with two circular polarizers, both made by Kenko. One is a vernier, marked C-PL(W). The other reads Kenko Pro1D Wide band C-PL(W). This latter one is the reason for my question. Under reflected light, it has the look of fine crepe paper under the glass, but when I look through it, does not appear to distort. The other is smooth. Is this normal, or indicative of a problem with the polarizing film?

    Thanks,
    Tim

  2. #2
    glaiben's Avatar
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    I thnk it's B+W that describes that crepe paper-like appearance in a circular polarizer to be an optical illusion and that no distortion is actually present. Maybe it's a function of the quarter wave polarization. I thought it was odd looking too, especially when comparing a circ to a linear polarizer. I had both - needed one - got rid of the circ.

  3. #3
    Ed Sukach's Avatar
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    glaiben,

    Are you using the linear polarizer in an "autofocus" system?
    Carpe erratum!!

    Ed Sukach, FFP.

  4. #4

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    Autofocus systems are not necessarily 'allergic' for linear polarizers.
    So try before you buy.

  5. #5
    Nicholas Lindan's Avatar
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    Quote Originally Posted by Q.G. View Post
    Autofocus systems are not necessarily 'allergic' for linear polarizers.
    So try before you buy.
    And some that are, only have problems with one orientation of the polarizer.
    DARKROOM AUTOMATION
    f-Stop Timers - Enlarging Meters
    http://www.darkroomautomation.com/da-main.htm

  6. #6
    glaiben's Avatar
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    Quote Originally Posted by Ed Sukach View Post
    glaiben,

    Are you using the linear polarizer in an "autofocus" system?
    No - Hasselblad manual focus.

  7. #7

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    So no problems now and in the future.

    I would be interested if you find any diferences between them when shooting, if one is better.
    I use B&W circular, like it.

    Peter

  8. #8
    Ed Sukach's Avatar
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    Quote Originally Posted by Q.G. View Post
    Autofocus systems are not necessarily 'allergic' for linear polarizers.
    So try before you buy.
    Trying before buying might not be easy, or possible.

    In reading this, my "carved-in-stone" belief that ALL autofocusing systems REQUIRE the use of a circular polarizer was shaken. So - I went to my latest acquisition, and my only autofocusing camera, a Canon EOS Elan IIe.
    In scouring the Instruction book .. not one word about polarizing filters. Nada.

    Then to the B&W web site and their .pdf Filter Catalog, page 15:

    "B&W Circular Polarizing Filter - Highly efficient standard circular polarizing filter for all cameras with beam splitters in the light paths of their TTL exposure meters and with autofocus lenses. Circular polarizers have the same pictorial effect as linear polarization, but allow for proper exposure metering and distance settings."

    The question then is whether or not the camera in question has a "beam splitter". If so, proper operation would be suspect, at least, with the use of a "linear polarizer"; while a circular polarizer would be appropriate in either case.

    It might be wise to opt for the "circular", given the possibility of its use in a future system, with "beam splitter".
    Carpe erratum!!

    Ed Sukach, FFP.

  9. #9
    PhotoJim's Avatar
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    Autofocus isn't the only issue. Autoexposure can be an issue too. The beam splitter is the key, as mentioned above.
    Jim MacKenzie - Regina, Saskatchewan, Canada

    A bunch of Nikons; Feds, Zorkis and a Kiev; Pentax 67-II (inherited from my deceased father-in-law); Bronica SQ-A; and a nice Shen Hao 4x5 field camera with 3 decent lenses that needs to be taken outside more. Oh, and as of mid-2012, one of those bodies we don't talk about here.

    Favourite film: do I need to pick only one?

  10. #10

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    By auto exposure, I suppose you really mean any through the lens exposure metering , auto or manual.
    My wife's new camera has the beam splitter and I put a linear polarizer on it and focused and metered in all orientations, distances and light levels.
    I could not find a discrepency at all.
    Than I chickened and bought her a circular filter.
    But it makes me wonder if this isn't left over from earlier technology and now urban myth.
    "There are a great many things I am in doubt about at the moment, and I should consider myself favoured if you would kindly enlighten me. Signed, Doubtful, off to Canada." (BJP 1914).

    Regards
    Bill

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