What Is a Lens Coating When Talking About Photography?

When talking photography and optical lenses a ‘lens coating’ is a coating that is applied to the surface of a lens element which is designed to reduce light reflection and increase light transmission within the lens. Lens coatings are used by lens manufacturers to produce optics that can render an image with the least unwanted optical degradation. The application of lens coatings can be extremely complex and costly, therefore complex multi-layer coatings are normally only found on expensive lenses. One example is the Zeiss T* coating, a multi-coat anti-reflective technology which greatly reduces the amount of inter element reflection within a lens, which can lead to a significant decrease in light transmission, and therefore lens performance.