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Camera Moire (Aliasing) Issues, Tests, Explanation

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  • Camera Moire (Aliasing) Issues, Tests, Explanation

    Interesting theory about lens fringing (chromatic aberration) and moire relations.

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  • #2
    Yup, that was very interesting indeed.
    I strongly suspect that his assertion that lenses that show stronger fringing will also show stronger moire is going to prove true in the majority of instances.
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    • #3
      I see the point, but I think it's semantics too.

      The moire effect occurs as a result of interactions between the image as projected on to the sensor, and the spacing of the photosites on the sensor. Chromatic Aberration (fringing) is a separate issue, but the both occur most noticeably where fine detail happens, especially with changes of contrast.

      I would think of them as mutlipliers. When both happens the image is worse and in the same areas. So a lens with more CA will bring more attention to moire as well.

      But the CA doesnt cause moire or vice versa, so they arent really related to each other, more like two different problems that have similar causes.

      THe argument that the CA spreads the image so that more moire occurs is actually backwards. Color differences aside, the more you spread or smear an image the LESS likely you are to have moire. This is how an optical low pass filter works, and why it is a good tool to combat moire, not increase it.

      SO they are truly separate effects that may occur on the same parts of the image and cause trouble, but arent really related. The idea that a lens with less CA will shop less moire is wrong. Its just that the CA wont help to bring your eye to that spot.