The most commonly used film size is 35mm, which has images measuring 36mm x 24mm. Its worldwide success arises from the well-judged and highly successful compromise, between quality and equipment size and expense, that it represents. 35mm slides are just large enough to project onto a domestic screen without noticeable loss of quality, and colour negatives of the same format have the potential to produce good-quality prints large enough for most purposes. At the same time, 35mm equipment is compact and comparatively light. It is also modestly priced by comparison with larger-format equivalents, and has been developed to an astonishing degree of sophistication.

Films are stored in convenient cassettes, mostly containing sufficient film for 24 or 36 exposures, and loading is convenient and in some cases almost automatic. Many cassettes are also DX-coded so that an automatic camera can detect the film type and length.

Film of almost every conceivable type is available in the 35mm format. Colour negative, colour reversal (slide), black-and-white, chromogenic, infrared, duplicating film and others are all available in a range of speeds. Some are available for daylight and also for various types of artificial lighting.