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Thread: Light transmission?

  1. #1
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    Light transmission?

    Ok optipros...i need some clarification/explanation please.

    if a lens claim to have 30% light transmission what does that mean exactly? some of their other lens colors are 10%, 9%, and 14%.

    what are some reasons you would prefer one over the other?

    Which is better a higher or lower percentage?

  2. #2
    ATO Member OptiBoard Bronze Supporter HarryChiling's Avatar
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    That means 30% of the light that reaches the lens is transmitted through it. Sunglasses generally have a lower transmission which is a good thing, clear lenses should have a higher transmission, Higher index lenses have lower transimissions that lower index lenses.

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    G-15...

    That's where the term G-15(and others) is derived from. It allows 15% of the visible light to penetrate the lens and reach the eye.

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    Manuf. Lens Surface Treatments OptiBoard Gold Supporter
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    Redhot Jumper Another term....................

    Quote Originally Posted by FVCCHRIS View Post
    That's where the term G-15(and others) is derived from. It allows 15% of the visible light to penetrate the lens and reach the eye.
    There is also another term that is used in Europe and most other countries which is absorbtion. This means , the lens absorbs a certain percentage, it is actually the reverse of the transmission.

    If a lens absorbs 50% of visible light it would also transmit 50%. For the sale of sunglasses it is believed in Europe that a consumer understands the term of a certain percentage better than the term transmission.

    Spectrometers can be set to give a reading in either way you prefer.

    I also belive that the word G-15 is an old trademark of B&L like the TrueColor by AOCO and stands for their greyish green lens. You can tint that color to 30 - 50 - 75 percent or whatever transmission or absorbtion wanted.
    Chris Ryser
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    DLO. NA.IC.I.T.PO

    http://optochemicals.com............................. http://arcoatings.com

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    Carl Zeiss Vision OptiBoard Gold Supporter Darryl Meister's Avatar
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    G-15 was indeed a gray-green tint from Bausch & Lomb, meant to replicate the relative luminous efficiency of the human eye.
    Darryl J. Meister, ABOM

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