Focusing aid for copying cameras

摘要

A device for assisting a person in focusing a camera on a surface is provided. A mirror at an angle of 45 DEG to the horizontal, and an incandescent filament, are mounted on a device that may rest on the surface to be photographed. The distance from the filament to a point on the mirror equals the distance from that point to the surface. By focusing the camera on the image of the filament that appears in the mirror, the camera will be correctly focused on the surface.