Birding Despite Disability

Obsessions Don't Care About Limitations

The Physics of Roof Prisms and Phase Coatings

I’ve written a technical article on the topic of why the roof prisms used in binoculars require specialized coatings in order to improve their performance. I was prompted to pull this together because I couldn’t find a single source that traced through this interesting problem in a non-trivial way. The article includes a derivation of the phase shifts at the heart of the effect, the role of the roof prism geometry, a demonstration of how resolution is lost (based on changes to the diffraction pattern), and finally some details concerning how coatings can mitigate the problem.

Leave a Reply

%d bloggers like this: