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I see the word "Coating" in different questions (related to lenses and filters). What is Coating, Multi-Coating, and Nano-Coating?


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Nanocoating in specific is covered here. –  mattdm May 14 '12 at 23:11
Also, tangentially (but importantly) related: What causes lens flare? –  mattdm May 14 '12 at 23:13
The 1/4-wavelength trap described in jrista's answer in mattdm's first link is a fairly complete (almost exhaustive, really) explanation of coating/multicoating (short of a complete explanation of superposition, which is really out of scope here). –  user2719 May 15 '12 at 1:36
@mattdm the links helped thanks –  akram May 15 '12 at 13:59

1 Answer 1

up vote 3 down vote accepted

Coatings are just special chemical compounds that are applied to the surface of glass filters and lens elements in order to change their optical properties usually in order to reduce reflections and other unwanted effects, as well as repealing water and grease, and providing resistance to scratches.

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what about multi-coating? what does multi mean here? –  akram May 14 '12 at 23:38
Multi is just more coatings, one over the other, with different material (different refractive index). Multiple layers allow for better cancellation of reflections more uniformly over the spectrum. –  Skaperen May 15 '12 at 5:22

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