Camera magazine

A camera magazine is a light-tight chamber or pair of chambers designed to hold film and move motion picture before and after it has been exposed in the camera. In most movie cameras, the magazine is a removable piece of equipment. Many still photo cameras also have removable camera magazines. A film cartridge serves the same function, but is usually not reusable.

In 16 mm filmmaking, most magazines are designed to accommodate up to 400 feet of film stock, which usually is the longest standard roll size available from film manufacturers (longer rolls can be made upon special request sometimes, but require special magazines). In 35 mm filmmaking, there tend to be three common magazine types - 1000 foot magazines, which accommodate the longest standard roll size of 35 mm film; 400 foot magazines, which are often used when the camera is handheld in order to minimize the amount of weight upon the camera operator; and 400 foot Steadicam magazines, which are specially designed with a pair of moving spindles that gradually change position as the film rolls through the camera in order to maintain a steady center of gravity, which is advantageous for Steadicam operation. While this last magazine is not strictly necessary for Steadicam, usage of other magazine types may require frequent rebalancing of the rig in between takes due to weight shifting as the film progressively moves from one side of the magazine to the other. Use of 1000 foot magazines on Steadicam tends to be rare due to the larger amount of shifting weight and the greater total weight of the camera.

All magazines are composed of a "feed" or "pay-out" side, in which the film is held before exposure (when it is "fed" into the camera) and a "take-up" side where the film is held after exposure. Furthermore, in between these two sides there are always two separate slots or throats where the film exits and then re-enters the magazine. These must also be designed to be light-tight enough to allow the film to exit the magazine without letting any light into the magazine itself, where it might fog the rest of the film inside. Various types of magazines handle the film in between the two sides differently. Aaton and Arri 16 mm cameras, as well as most 35 mm Arri models, require a fixed length "loop" which must be a certain number of perforations long and which moves the film with sprockets inside the magazine. Some more recent 35 mm cameras from Arri and all Moviecam and Panavision cameras, however, do not have any required loop size, and the film is not controlled with any sprockets in the magazine at all. Instead, the film is pulled through the camera solely through the power of camera sprockets until the end, at which point springs or belts in the camera magazine pull the film back to the take-up side.

...
Wikipedia