Magnetic recording on film of scene parameters and photofinishing

Abstract

A camera embodying the invention includes a magnetic recording head adjacent the film and a processor which senses the lens focal length, the aperture size and shutter speed, and the film ISO number or film speed. The processor causes the scene brightness value sensed at the time of exposure of each film frame to be recorded by the magnetic head in a magnetic track adjacent or in registration with the current film frame. The processor senses the aperture size and shutter exposure time acutally employed by the camera in exposing the current film frame to compute an actual exposure value. It then determines whether this actual exposure value deviates significantly from the ideal exposure value and if so by how much. The deviation thus computed, if any, is also recorded in the same magnetic track in the film or one next to it. The photofinishing apparatus searches a particular one of the magnetic tracks adjacent each film frame prior to its print exposure to determine the deviation between the ideal exposure value (computed from the recorded scene brightness value and film speed) and the actual exposure value (computed from the recorded aperture size and shutter speed actually employed by the camera in exposing the film frame). The photofinishing apparatus transmits this deviation to a print exposure controller, which changes the amount of light (exposure value) used to expose print paper to the current film frame so as to compensate for the deviation.