Rangefinder

Measure the distance between the camera and the object to be photographed has always been the source of many inventions outside or on the device itself to this measure to be as accurate as possible but also as convenient as possible for the photographer. The sliding box allowed to move the frosted so that the image appears focused there. Since the invention of film, it’s no way to verify this focusing. The bellows mounted on racks provided with a distance scale have already made a difference to the optical rangefinders image coincidence which were placed in the accessory / accessory shoe and which were finally incorporated to cameras.