Tag: Binoculars

Anti-Reflection Coatings Part III: Oblique Incidence

December 24, 2024

Dealing with Non-normal Incidence In the previous post we developed the TMM for the special case of light incident in a direction perpendicular onto a multilayer coating. And as developed in the post before that, our treatment of the reflection and transmission coefficients required nothing more complicated than some commonsense assumptions about the behavior of … More Anti-Reflection Coatings Part III: Oblique Incidence

Technical References for Roof Prism Resolution Loss, Phase Coatings, and Related Topics

September 21, 2024

This page is meant to provide a list of references that are directly relevant (marked with a *) or in some cases marginally relevant to the topic of resolution loss in roof prisms and the so-called phase coatings used to mitigate the problem. If you know of any additional literature, please email me at hurbenm … More Technical References for Roof Prism Resolution Loss, Phase Coatings, and Related Topics

The Physics of Roof Prism and Phase Coatings, Simplified: Polarization Effects

June 7, 2024

Many binoculars utilize roof prisms to keep the light along a single optical axis, making for a more compact shape. But the novel geometry of the prism’s reflecting surfaces creates a subtle interference effect which reduces the binocular’s resolution. The only way to mitigate this problem is to use specialized coatings on the roof surfaces. … More The Physics of Roof Prism and Phase Coatings, Simplified: Polarization Effects

The Physics of Roof Prisms and Phase Coatings, Simplified: Part III

August 18, 2023

Diffraction patterns and resolution In the previous post we traced the passage of light through an Amici roof prism, which required decomposing vectors into components, accounting for phase shifts upon reflection, and then looking at how the waves will be recombined. We can now see that there will be an opportunity for interference effects to … More The Physics of Roof Prisms and Phase Coatings, Simplified: Part III

The Physics of Roof Prisms and Phase Coatings, Simplified: Part II

August 18, 2023

Phase shifts and interference The previous post introduced the topic of roof prism performance loss resulting from phase shifts that accompany total internal reflection (TIR). These shifts are endemic to TIR and to any device that employs it, including not only roof but Porro prisms. But in the latter case, the shifts have no deleterious … More The Physics of Roof Prisms and Phase Coatings, Simplified: Part II

The Physics of Roof Prisms and Phase Coatings, Simplified: Part I

August 18, 2023

Introduction Some time ago, I began a fruitless search for a detailed treatment of the performance losses endemic to roof prisms, and the so-called “phase coatings” that rectify the problem. Optics manufacturers tout the advantages of their proprietary coatings, but provide few specifics regarding the effect that their technology solves, or how their solution works. … More The Physics of Roof Prisms and Phase Coatings, Simplified: Part I

The Physics of Roof Prisms and Phase Coatings

July 22, 2023

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 reference that traced through this interesting problem in a non-trivial way. The article includes a derivation of … More The Physics of Roof Prisms and Phase Coatings