Each brand of film exhibits a different characteristic curve. Film clips are metal or plastic clips used to prevent the curling of a length of drying film. Film holder is a light tight container to hold sheet film. Film pack is a container holding several sheets of film, so devised that when fitted to the camera the photographer can pull a tab to remove an exposed sheet and replace it with another. Film packs are typical with Polaroid film.
Film plane is the plane at the back of the camera across which the film lies.
Film speed see Speed . Filter factor is a number by which an unfiltered exposure reading must be multiplied to give the same effective exposure through the filter. This compensates for the absorption of light by the filter. This process is unnecessary with TTL metering systems as long as the filter is attached during the metering process. Filters are colored glass, gelatin or plastic disks, which modify the light passing through them, mainly in terms of color content.