uneven polarized sunglasses

Discussion in 'Glasses' started by porf67, Aug 2, 2006.

  1. porf67

    porf67 Guest

    Hi folks,

    I recently purchased a new pair of perscription sunglasses with
    polarized lenses. (They weren't cheap ones, ether...) The
    polarization on the lenses seem very uneven to me. If I look at a
    clear blue sky, I can see that the lenses looks splotchy, as if the
    direction of the polarization was not uniform throughout them. I see
    this as well if I examine them with a polarized camera filter.

    I've had polarized glasses before, and I've not noticed this, although
    it's not something I explicitly looked for. This pair seems
    particularly distracting - I've actually had these redone by the lab,
    with similar results both times.

    Before I take these back again, I'd like to know if I'm expecting too
    much. More specifically:
    - In general, how even should the polarization on perscription
    sunglasses be?
    - How much should a strongish perscription (~-5) affect the evenness of
    the polarization?
    - Would the fact that these are high IOR lenses affect how even a
    result I can expect?

    Thanks for any insight,
    -p
     
    porf67, Aug 2, 2006
    #1
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  2. porf67

    porf67 Guest

    Thanks for the response - it's very helpful. I'm aware of the effects
    you mention (stress patterns on glass, etc.) and this is entirely
    different. I guess they're going back again. Bleh.

    Thanks again.

    -p
     
    porf67, Aug 2, 2006
    #2
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  3. porf67

    David Combs Guest

    None.[/QUOTE]

    Not none with me!

    Looking at any kind of glare via reflection shows it --
    especially via tilting the head back and forth (left-right) --
    HUGE and OBVIOUS difference.

    Something in physics about non-porarized light, when
    reflected, or maybe glancing reflection, gets polarized
    at right angles to the plane of something -- was LONG ago,
    that course.

    And that effect is the *reason* for buying polarized
    glasses, for reduced glare reflected from highway when
    driving eg into setting sun.

    Ditto for piercing sky-reflection when looking at angle
    into eg a fishing-stream -- can see fish, bottom, etc
    much clearer.

    At least that's my experience -- although maybe not everyone's.

    Cheers!

    David
     
    David Combs, Aug 19, 2006
    #3
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