Back Light separates subject from background, saints from sinners, and one pro from another. Angle: toward the lens from above and behind the subject, or above, behind, and slightly to the side of it, high enough to cut lens Flare. It is especially helpful for video images that may suffer loss-of-edge contrast. Sins: confusing this source withBackground Light, and, for Motivation purists, using it at all. Tip: Smoke, steam, and other Translucent subjects adore Back Light of almost any color.tiffaneduglossary
The removable part of a medium or large-format camera that holds the film or the digital recording surface. Backs are attached to the back of the camera, hence their name. They shield the sensor or film from light except when exposed in the camera.
Projection, usually of a transparency, onto the rear of a translucent screen.
The back button to return to the previous screen you were on, when using the COOLPIX S800c or S810c digital cameras.
The distance between the image sensor and the rear element of the lens, with lens mounted on the camera and focused at infinity. This distance must remain constant with zoom lenses to ensure constant subject focus during zooming.
Back focal distance, meaning the distance from the tip of the lens furthest rear surface to the film/image sensor surface where the image is focused.