Is It the Coating?

Started 4 months ago | Discussions thread
Futax Senior Member • Posts: 1,256
Re: Is It the Coating?

Mark Scott Abeln wrote:

Coatings act to cut the amount of light that’s reflected off of a lens element instead of it being transmitted through it. Bare glass might reflect 3 to 4% of the light at each surface.

An uncoated lens will deliver a lower contrast image was well as a dimmer image, so yes, a better coated lens may very well be easier to focus.

I do wonder how this higher transmission works, because my understanding is that anti-reflection coatings work by creating a second reflection (from the surface of the coating) which (at some wavelengths) are in anti-phase - and thus cancel the reflection from the glass surface itself.

This wouldn't affect transmission through the glass, since the reflection is cancelled, rather than removed.  So are other mechanisms at work?  Any insight?

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