Camera with automatic aperture setting and partially color deleted viewfinder selection

Abstract

In a shutter-priority automatic single lens reflex camera the operator views the scene through an eyepiece viewfinder whose optical path is through a variable iris diaphragm and a taking lens. When a depth of field preview button is pushed by the operator, the diaphragm closes down to the aperture (opening) determined to be correct for the selected speed under the ambient light conditions. A system is provided to aid the operator in envisioning a black-and-white picture of a color scene by presenting a partially color deleted view of the scene to the eyepiece viewfinder. The operator pushes a button which pulls a special color filter into the optical path of the viewfinder and simultaneously sends a control signal to the camera central processing unit (CPU). The CPU, upon receiving the control signal, determines the proper diaphragm opening for the scene, compensates for the filter (by stopping up) and permits operation of the diaphragm to close down to the compensated aperture. The operator sees the scene, partially color deleted and at the compensated taking aperture, and envisions the picture in black-and-white and in focus.

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