Photometric device for use in a single lens reflex camera

Claim 1

In a single lens reflex camera wherein light from a subject is imaged by a camera lens on a focusing means for viewing by an eyepiece through a pentaprism, the improvement comprising a photometric device located beside said eyepiece, said photometric device comprising: a first photometric lens mounted on one side of said eyepiece in a position such that said first photometric lens receives light through said pentaprism from substantially the entire area encompassed by the subject imaged by the camera lens of said single lens reflex camera on said focusing means for viewing by said eyepiece; and, a first light receiving element having a photosensitive surface, said first light receiving element mounted at the focal plane of said first photometric lens such that light received by said first photometric lens impinges on the entire photosensitive surface of said first light receiving element, said photosensitive surface being sized such that said impinging light is only a portion of the light received by said first photometric lens through said pentaprism from the area encompassed by the subject imaged by the photographic lens of the single lens reflex camera on said focusing means for viewing by said eyepiece, said first light receiving element producing an electrical output related to the intensity of the light impinging on said photosensitive surface of said first light receiving element.