Main Page | See live article | Alphabetical index

Pentaprism

A pentaprism is a five-sided prism. Typically, a pentaprism has four optical faces, and one face that is left unworked. This prism has the virtue of transmitting an image through a right angle without inverting it as an ordinary right-angle prism would. The pentaprism is used in the viewfinder of a single-lens reflex camera.