The invention enables users to adapt 35 mm SLR still cameras to function as 35 mm motion picture viewfinders and adapt 35 mm SLR still cameras to create photographs which correspond to what they see through its viewing system. By substituting an accurately marked focusing screen for the original and placing an identically marked insert within the camera we can accomplish both of these goals. The insert interrupts the image forming light path close enough to the film plane to precisely transfer its markings to the image exposed there. As the images are all formed in the same size as in 35 mm motion picture photography the optical characteristics they present are identical to those of 35 mm motion picture photography.