Polarizers

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  • 09-13-2004, 12:44 AM
    PerPlunk
    Polarizers
    Just a quick and simple question. What's the difference between circular and linear polarizers on the effect of the resulting image? From what I gather the only real difference is that modern cameras meter through circular polarizers better then they do through linear polarizers, but that the actual effect on the image is the same(given proper exposure, of course). Is this correct? Thanks.
  • 09-13-2004, 05:38 AM
    Michael Fanelli
    Quote:
    Originally Posted by PerPlunk
    Just a quick and simple question. What's the difference between circular and linear polarizers on the effect of the resulting image? From what I gather the only real difference is that modern cameras meter through circular polarizers better then they do through linear polarizers, but that the actual effect on the image is the same(given proper exposure, of course). Is this correct? Thanks.
    A linear polarizer polarizes light in an "up-down right-left" manner. This interferes with the beam splitter that assumes the light is unpolarized. A circular polarizer adds a 1/4 wave retarder plate to the back of a linear polarizer. This "twists" the light so the polarization is now more of a spiral (not really circular). The beam splitter is not adversly affected by this type of polarization.

    Yes, you get the same effect with either one.
  • 09-13-2004, 01:10 PM
    another view
    You've got it right. AF cameras need circular polarizers. Actually since good polarizers are expensive, I'd only buy a circular - you probably need it at some point even if not today.

    The effect is the same on the image.
  • 09-13-2004, 01:34 PM
    paulnj
    WOW Mike.... I now know how a circular polorizer is made and technicly works :)

    THANK YOU , as I only knew which one is needed, and how they basicly work .