Zone-type range-detecting devices for cameras

Abstract

A zone-type range-detecting device for a camera, detects in which one of a plurality of zones an object to be photographed is located, these zones being spaced from the camera different distances along an axis which can be the optical axis of the picture-taking lens of the camera, or another axis. In one embodiment, a light-sensing device located on that axis senses the luminosity of all objects located on that axis regardless of the zone in which the object is located, and a plurality of individual light-sensing devices is also provided, each of which senses the luminosity of an object within only a respective one of those zones. A plurality of differential amplifiers calculates the differences between the outputs from the common light-sensing device and each one of the plurality of individual light-sensing devices, and the minimum output among the outputs from the plurality of differential amplifiers is detected, thereby to locate the zone in which the object to be photographed is located. In another embodiment, there is no common light-sensing device, but rather a plurality of pairs of light-sensing devices, each directed toward an individual one of those zones. In this case, the light-sensing devices are preferably arranged in pairs on diametrically opposite sides of the picture-taking lens of the camera, with the various light-sensing devices thus forming a circular series about the picture-taking lens.