The distance between the center of the lens and the viewfinder causes parallax. The closer the lens is focused to the subject, the more evident the parallax. The top of the image will be cut off if the range finder or viewfinder is not corrected for parallax. Color transparencies are positive films. Selenium A chemical that is used to tone prints for longevity.
Selenium leaves the prints with a silver look.
Toned prints are less subject to light damage and oxidization. Shift lens See Perspective-control lens. The silver crystals that make up an image on a negative or print. When exposed to light, they create an image. SLR See Single lens reflex.