In most 35 mm cameras the film back was either fixed to the camera body or changeable for a different type of back, taking a longer film length for example. In a few cameras the back was interchangeable and could be exchanged mid-roll. In the case of the Contaflex back the operating sequence was quite complicated.

With the advent of motor drives for 35 mm cameras bulk-film backs became more common, especially in industrial and scientific work.

The Agfa Karat cassette, introduced in 1936, was also used in a few non-Agfa cameras. It used standard 35 mm film, for 12 exposures, held in separate feed and take-up cassettes, the film was advanced by the sprocket holes but was held loose in the cassettes rather than being wound onto a spool. The idea was re-introduced as the Agfa Rapid cassette (1964) with the addition of a key on the side of the cassette indicating the film speed, this could be 'read' by the camera to set the metering system.

A very popular cassette that would fit most 35 mm cameras of the period. A film loader (similar to the model from Leitz) was available.

The T cassette was introduced with the Robot model II and was later replaced by the TR cassette. It was a feed cassette to be used with an N take-up cassette.