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Thread: chromatic aberration calculator?

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    chromatic aberration calculator?

    I was wondering if there was a way to calculate the expected amount of aberration that can be expected given a certain material, prism amount and eye size. Usually the best ABBE value is called for but a certain point, wouldn't the thickness cause more aberration than the same specifications in a material that has a worse ABBE value but will make the thickness come out about half as thick?

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    What's up? drk's Avatar
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    I think the answer is that there is rough correspondence between chromatic aberration and index (thinness). You can make a thinner prism with more chromatic aberration, or a thicker prism with less chromatic aberration.

    In reality, you're asking the same question as we do when trying to get a high minus pair of glasses optimized.

    So...find the material with the highest index and the best abbe and use it. (I think it's Hoya's 1.71?)

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    Master OptiBoarder optical24/7's Avatar
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    LCA’s are the most troublesome form of aberrations. One of Daryll’s excellent papers he left us is on Chromatic Aberrations. Scroll down to the section on Lateral Chromatic Aberrations. Abbe values are alway the most important element in visual degradation due to LCA’s. There is a formula and chart to demonstrate. (All opticians that deal with prismatic patients need to be aware of this…)

    http://216.144.236.77/cecourse.php?u...ic_aberration/

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    Quote Originally Posted by drk View Post
    I think the answer is that there is rough correspondence between chromatic aberration and index (thinness). You can make a thinner prism with more chromatic aberration, or a thicker prism with less chromatic aberration.

    In reality, you're asking the same question as we do when trying to get a high minus pair of glasses optimized.

    So...find the material with the highest index and the best abbe and use it. (I think it's Hoya's 1.71?)
    At some point though, wouldn't a thicker material (higher ABBE) be disadvantageous since the light has to spend more time in the material and thus gets more disperse before exiting the lens?

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    What's up? drk's Avatar
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    The amount of deviation of light (all colors) is a function of how much index difference there is at the slanted interfaces (how much "braking" and "accelerating" for the light) and the angle of the interfaces (or, alternatively, the apical angle which controls the angle of the interfaces) (which corresponds to how much "slip one wheel has while the other wheel keeps turning").

    It's not how long the light stays in the medium itself. If what you're thinking were true, then a thin plate glass would have zero chromatic aberration but a thick plate glass wall would have chromatic aberration. No refraction or light bending occurs in any medium.

    Another way to think about it would be...does light travelling from Planet Fester through a non-negligible index (hot gas emanating from Planet Fester) end up "red shifted" (if Planet Fester and Earth are completely still relative to one another)? No.

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    Quote Originally Posted by optical24/7 View Post
    LCA’s are the most troublesome form of aberrations. One of Daryll’s excellent papers he left us is on Chromatic Aberrations. Scroll down to the section on Lateral Chromatic Aberrations. Abbe values are alway the most important element in visual degradation due to LCA’s. There is a formula and chart to demonstrate. (All opticians that deal with prismatic patients need to be aware of this…)

    http://216.144.236.77/cecourse.php?u...ic_aberration/
    Wowzers this is some good info

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    One eye sees, the other feels OptiBoard Silver Supporter
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    Quote Originally Posted by Prentice Pro 9000 View Post
    I was wondering if there was a way to calculate the expected amount of aberration that can be expected given a certain material, prism amount and eye size. Usually the best ABBE value is called for but a certain point, wouldn't the thickness cause more aberration than the same specifications in a material that has a worse ABBE value but will make the thickness come out about half as thick?
    The formula for TCA (transverse or lateral chromatic aberration) is cF/V. Where c is the distance from the OC in centimeters, F is lens power, and V is the Abbe number. According to Torgersen, acuity is not affected until TCA reaches 0.16 prism diopters and then it drops by one line on the Snellen chart.

    Spectacle Optics v2.0 Beta NEW VERSION!

    Hope this helps,

    Robert Martellaro
    Last edited by Robert Martellaro; 11-30-2023 at 12:24 PM.
    Science is a way of trying not to fool yourself. - Richard P. Feynman

    Experience is the hardest teacher. She gives the test before the lesson.



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    Compulsive Truthteller OptiBoard Gold Supporter Uncle Fester's Avatar
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    Quote Originally Posted by drk View Post

    Another way to think about it would be...does light traveling from Planet Fester through a non-negligible index (hot gas emanating from Planet Fester) end up "red shifted" (if Planet Fester and Earth are completely still relative to one another)? No.
    No. Truth be told I am actually a star. A Red Giant (at my age) to be precise and am already red shifted while emanating hot gas at ever increasing rates.

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