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Thread: Help with polar filters, are they ok?

  1. #1
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    Help with polar filters, are they ok?

    I ask to you friends.

    I have to replace a polarized cr39 backside AR filters for a prada frame, the originals are not avaible.

    My lab return the frame today, they mounted Zeiss Polar filter.

    They seems ok... but the 180 line (Z engraving for polarized axis) it is a little off... I think 2° tolerance... Also both filters have 2° off but NOT in the same way they are rotate both to the nasal side.

    also in front of an LCD Monitor for test, they have a cross effect, it seems they are cut ok, not too big

    In is in tolerance for you? Or I return back to the lab? I link photos

    This is the engraving https://www.dropbox.com/s/bhw9ars1bh4iblp/en.jpeg?dl=0 AND https://www.dropbox.com/s/lml5ugsg7cot1ld/en2.jpeg?dl=0


    This is Zeiss cross effect in front of lcd https://www.dropbox.com/s/ejteh5wx9s...eiss.jpeg?dl=0
    This is the ORIGINAL old filter in front of lcd https://www.dropbox.com/s/e1ndtmc9ss...inal.jpeg?dl=0

  2. #2
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    Ansi defines the tolerance + or - 3 degrees. Take the new lenses out of the frame and do your stress test, I bet there is still have a cross effect (maybe not as bold but still there). Virtually all of polar lens blanks come from the manufacturer with the polar wafer in the lens blank showing stress. I'm not a huge fan of comparisons between factory plano polar lens stress vs surfaced and edged plano polar stress. What is the thickness of the original polarized lenses?

  3. #3
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    Thank you.

    The original filter is 1mm CT, new filters are 2mm CT base 6.
    I put out of the frame the new flter and the cross effect is almost the same, they are cut correctly in size.

  4. #4
    Master OptiBoarder OptiBoard Silver Supporter lensmanmd's Avatar
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    Please realize that lcd screens are not polarized the same. Some are @45, some @135, some @90.
    The best tool is a Plano polarized marked at 90, or a tool from Younger, kBCo, or any polarized lens mfr.

    Other issues with RX lenses. Frame bezels. Most “sunglasses” are not designed for RX. Look at the bezels. Many are “T”, and varying widths. Some are step backs. Some are combinations of both.

    It takes experience and a good eye to identify these bezels, and to edge accordingly. There is no way that an automated edging line is capable of this, unless the lab is considerate enough to pre-program these variables in their LMS, or, send them to a “specialty” line.

    How many “in-house” techs have the ability to recognize these on the fly? My bet? Not too many. And even if they could, how many have multiple, or specialty edgers in house?

    So, yes. Many polar products will show stress at the corners, no matter how exact the sizing. This is due to both to frame design and not recognizing the various bezels.
    I bend light. That is what I do.

  5. #5
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    Thanks Lensmd,

    this is the original filter bevel.jpeg (dropbox.com) sorry for the quality of the photo,

    and.. yes It is a particular bevel, it is like a groove I can put a bit of my nailns in it.

    What type of bevel is it?

    The new polar filters are also plano but with standard V floating bevel in the middle.

  6. #6
    Master OptiBoarder OptiBoard Silver Supporter lensmanmd's Avatar
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    I’m sorry dima, but I cannot tell by the photo.
    I bend light. That is what I do.

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