Lens Coating

Lens coatings are microscopically thin layers deposited on glass surfaces to reduce the light that reflects away at each air-to-glass boundary. Every uncoated surface inside a scope bounces back a few percent of the light, and a riflescope has many such surfaces, so coatings recover a meaningful share of that loss. The best treatments are described as fully multi-coated, meaning every air-to-glass surface carries multiple layers tuned to different wavelengths.

By suppressing those reflections, coatings raise light transmission and tame the internal flare that washes out contrast, especially through a large objective lens facing toward a bright sky. Paired with quality glass such as ED glass, good coatings are a large part of why one scope looks crisp and bright while another of the same size looks dim.