135底片

The film is clipped or taped to a spool and exits via a velvet-covered slot. The end of the film is cut on one side to form a leader, which is to be inserted into a corresponding slot in the camera take-up spool.

The standard image format is 24 × 36 mm. The perforation pitch is KS-1870. The film advances 8 perforations, approximately 38.00 mm (specified as 1.4960 inches), for each frame. This allows for 2-mm gaps between frames. Each camera model has a different location for the sprocket which advances the film. Therefore each camera model's frame will vary in position relative to the perforations.

Other image formats are also used, like the half-frame format of 18 × 24 mm that earned some popularity during an era of unusually high film costs in the 1960s and the 24 × 24 mm of the Robot cameras.

Odd formats include the 24 × 32 mm and 24 × 34 mm on the early Nikon rangefinders, and 24 × 23 mm for use with some stereo cameras. In 1967, the Soviet KMZ factory introduced a 24 × 58 mm panoramic format with its Horizont camera (descendants of which are called, in the Roman alphabet, Horizon). In 1998, Hasselblad introduced a 24 × 65 mm panoramic format with the XPan camera. There is also a 14 × 21 mm format used by Tessina subminiature camera.

The film is available in lengths for varying numbers of exposures. The standard full-length roll has always been 36 exposures (assuming a standard 24 × 36 frame size). Through about 1980, 20 exposure rolls were the only shorter length with widespread availability. Since then, 20 exposure rolls have been largely discontinued in favour of 24 and 12 exposure rolls. With most cameras it's in fact possible to get 3 more exposures than the nominal capacity on the film if the camera is loaded in a darkroom and some cameras allow this with daylight loading^[1]. 27 exposure disposable cameras are loaded in the dark with standard 24 exposure cassette.

Other, mostly shorter lengths have been manufactured. There have been some 6, 8, 10, and 15 exposure rolls given away as samples, sometimes in disposable cameras, or used by insurance adjusters to document damage claims. Photographers who load their own cassettes can use any length of film — with thinner film base up to 45 exposures will fit.

Ilford at one time made HP5 black and white film on a thin polyester base, which allowed 72 exposures in a single cassette. They produced special reels and tanks to allow this to be processed.

Ordinarily, the film must be rewound before the camera can be opened. Some motorized cameras unwind the film fully upon loading and then expose the images in reverse order, returning the film to the cassette; this protects exposed film except the one or two last images, should the camera back be accidentally opened. In disposables the film is also fully unwound at start and exposing the images returns the film to the cassette.

Since the 1980s, film cassettes have been marked with a DX encoding pattern for automatically setting the camera to use the correct sensitivity value for the film. Different films are sensitive to light at different degrees; this film speed is standardised by ISO. As of today, common film speeds for consumers are ISO 100/21° through ISO 800/30°, although films with more or less sensitivity are available for professional use.

ISO 400 Fuji 135 colour film.

The 35 mm film standard for motion picture film was established in Thomas Edison's lab by William Kennedy Laurie Dickson. Mr. Dickson took 70 mm film stock supplied by George Eastman's Eastman Kodak Company. The 70 mm film was cut lengthwise into two equal width (35 mm) strips, spliced together end to end, and then perforated along both edges. The original picture size was 18 x 24 mm, which in modern times is considered to be a "half-frame" format for still photography. There were four perforations on each side of a motion picture frame.

There were a number of 35 mm still cameras using perforated movie film prior to the Leica. The first patent for one was issued to Leo, Audobard and Baradat in England in 1908. The first full scale production camera was the Homeos, a stereo camera, produced by Jules Richard in 1913. It took stereo pairs, 18x24 mm, with two Tessar lenses, and was sold until 1920.

The first big-selling 35 mm still camera was the American Tourist Multiple, which also appeared in 1913, at a cost of $175 (at today's prices, the same cost as a modern $3000 Leica.) The first camera to take full frame 24x36 mm exposures seems to be the Simplex, introduced in the U.S. in 1914. It took either 800 half frame or 400 full frame shots on 50 ft (15.2 m) rolls.

The Minigraph, by Levy-Roth of Berlin, another half frame small camera was sold in Germany in 1915. The patent for the Debrie Sept camera, a combination 35 mm still and movie camera was issued in 1918, but was not marketed until 1922.

Finally, the Furet camera (made and sold in France in 1923) took full frame 24x36 mm negatives and was the first cheap small 35 mm camera to look vaguely like today's models.

Although Oskar Barnack designed his prototype camera around 1913, the first experimental production run of ur-Leicas (Serial No. 100 to 130) did not take place until 1923. Full scale production of the Leica did not begin until 1925. By that time there were at least a dozen other 35 mm cameras available. The success of the Leica was attributed by contemporary photographic writers, not only to the quality of its lens, its small size and the precision of its construction, but also to its relatively high price which established it as a "prestige" item amongst both photographers and people of fashion.

The Leica camera designed by Oskar Barnack used 35 mm film and proved that a format as small as 24 mm × 36 mm was suitable for professional photography.

In the earliest days, the photographer had to load the film into reusable cassettes and, at least for some cameras, cut the film leader. In 1934, Kodak introduced a 135 daylight-loading single-use cassette. This cassette was engineered so that it could be used in both Leica and Contax cameras along with the camera for which it was invented, namely the Kodak Retina camera. The Retina camera and this daylight loading cassette were the invention of Dr. August Nagel of the Kodak AG Dr. Nagel Werk in Stuttgart. Kodak bought Dr. August Nagel's company in December, 1931, and began marketing the Kodak Retina in the summer of 1934. The first Kodak Retina camera was a Typ 117. The 35 mm Kodak Retina camera line remained in production until 1969. Kodak launched 135-format Kodachrome color film in 1935. AGFA followed with the introduction of Agfacolor-Neu in 1936.

The designations 235 and 435 refer to 35 mm film in daylight-loading spools, that could be loaded into Leica or Contax style reusable cassettes without need of a darkroom. The 335 was a daylight loading spool for the 24 × 23 mm stereo format.

First shown in March 1959, the Nikon F SLR system camera greatly improved on the quality and utility of 35 mm format cameras. The DX film-speed encoding system was introduced in the 1980s.

In 1996, a new format called Advanced Photo System (APS) was introduced by a consortium of photography companies in an attempt to supersede 135 film. Due in part to its small negative size, APS was not taken seriously as a professional format, despite the production of APS SLRs. In the point-and-shoot markets at which the format was primarily aimed, it enjoyed moderate initial success, but still never rivalled the market penetration of 135. Within five years of its launch, cheap digital compacts started becoming widely available, and APS sales plummeted.

Such digital compacts have also inevitably eroded the market for 35 mm compact cameras. However, digital SLRs at a price (and quality) comparable with consumer-level 35 mm SLRs are a more recent phenomenon. Coincidentally, most of these use APS-C sized sensors, approximately 17×23 mm in size. A handful of digital SLRs use "full frame" sensors, being 24×36 mm like 135 film.