Mirror arrangement for use in a single lens reflex camera

摘要

A mirror arrangement for use in a single lens reflex camera which divides a light transmitted through an objective lens of the camera into a first portion led to a viewfinder and a second portion led to a light receptor which detects a focusing condition of the objective lens or the like, is disclosed. The mirror arrangement comprises a total reflection mirror surface and a plurality of light transmitting slits arranged thereon in parallel to each other. A width of each slit is limited less than 80 mu . Pitches between two adjacent slits in the width direction are over than two times of an average width of all slits, and have at least two different values.