Light measuring apparatus for a single lens reflex camera

摘要

An object image is formed on a screen by an objective lens. The light beam from the object image formed on the screen is guided in a direction to an eye piece by a pentagonal roof prism. Only one light measuring means is provided facing an upper part of the exit face of the pentagonal roof prism. Therefore, the light beam from the screen passing through the upper part of the pentagonal roof prism impinges into the light measuring means. Also the light beam from the screen passing through both left and right end parts of the exit face of the pentagonal roof prism is directed onto the light-measuring means through a reflective plane. A shutter means is provided at least for one of the luminous flux from the upper part of the pentagonal roof prism and the luminous flux from the both left and right end parts. The light measurement distribution in an object scene may be varied by the shutter means.