Medium format has traditionally referred to a film format in photography and the related cameras and equipment that use film. Nowadays, the term applies to film and digital cameras that record images on media larger than the 24 mm × 36 mm used in 35 mm photography, but smaller than 4 in × 5 in.
Popular examples of medium format film cameras
A size comparison of medium-format film (left) and 35 mm film. Medium-format film lacks the sprocket holes of 35 mm film.
Pentax 6×7 format SLR camera with perspective control lens
50th anniversary Hasselblad 500 CM classic camera kit
135 film, more popularly referred to as 35 mm film or 35 mm, is a format of photographic film with a film gauge of 35 mm (1.4 in) loaded into a standardized type of magazine for use in 135 film cameras.
135 film. The film is 35 mm (1.4 in) wide. Each image is 24×36 mm in the most common "small film" format (sometimes called "double-frame" for its relationship to the "single-frame" 35 mm movie format or full frame after the introduction of 135 sized digital sensors. Confusingly, full frame was also used to describe the Full gate of the movie format half the size)
Leica I, 1927, the first successful camera worldwide for 35 cine film
Soviet camera Smena 6 with 35 mm films
Minox 35 ML, one of the smallest cameras built for the 135 film