Advanced Photo System

Advanced Photo System (APS) is a film format for still photography. The film is 24 mm wide, and has three image formats:

H for "HDTV" (30.2 x 16.7 mm; aspect ratio 16:9; 4x7" print)
C for "classic" (25.1 x 16.7 mm; aspect ratio 3:2; 4x6" print)
P for "panoramic" (30.2 x 9.5 mm; aspect ratio 3:1; 4x12" print)

The "C" and "P" formats are formed by cropping. The full image is recorded on the film, and an image recorded in one aspect ratio can be reprinted in another. The "C" format has an equivalent aspect ratio to a 135 film image. Most APS cameras (with the exception of some disposable cameras) can record all three formats; the format selection is indicated on the film by a series of exposed squares alongside the image area or recorded on the magnetic coating (see below) depending on the camera. In the absence of an operator-specified format, the machine printing an APS roll will use these indicators to determine the output format of each print.

Film and cartridge

The film is on a polyethylene naphthalate (PEN) base, and is housed in a single-spool 39 mm long plastic cartridge. The basic diameter is 21 mm, while it measures 30mm at the slot where the film exits. The slot is protected by a lightlock door. It comes in lengths for 40, 25 and 15 exposures. The film surface is coated by a transparent magnetic coating, and the camera uses this information exchange (IX) system for recording information about each exposure. The camera handles winding and rewinding automatically, to the extent that partially exposed films can be removed and used later. Numbered symbols (called 'visual indicators') on the cartridge end indicate the status:

Full circle: Unexposed
Half circle: Partly exposed
Plus sign: Fully exposed but not processed
Square: Processed

Additionally, a tab on this end of the cartridge serves as an indicator that the cartridge has been processed; APS processing equipment will punch out this tab.

Information exchange

The major distinction of APS film from other formats was its ability to record information other than the image. This information exchange was most commonly used for print aspect ratio, but could also be used to record the date and time that the photograph was taken, store a caption, record exposure data such as shutter speed and aperture setting. This information could be read by the photo printing equipment to determine the print aspect ratio, print information on the back (or, rarely, the front) of the photograph or to improve print quality.

Two methods for storing information on the film were employed, "magnetic IX" and "optical IX." Optical IX was employed on less expensive cameras and disposable cameras, and employed a light source to expose a small section of the film, outside of the image negative area. This method was limited to determining the print aspect ratio of the finished print.

Magnetic IX was used in the more expensive cameras and allowed for a great deal more information exhange. Most cameras with magnetic IX automatically recorded the exposure date and time on the magnetic layer, with more advanced models allowing the user to specify a predetermined caption to be printed on the photo or record the exposure settings, as well as determine print aspect ratio. Magnetic IX caused some problems for photo processors, who found their magnetic reading heads had to be cleaned frequently, or that their equipment's ability to print this information was limited.

Processing

Unlike 135 film, processed (developed) APS film is stored in the original cartridge. For identification, every roll of APS film has a six-digit ID code on the label, which is also stored magnetically and is visible on either end of the processed negative. This ID is usually printed on the back of every individual print. This ID was designed to be an additional convenience both for the photoprocessor (who can easily match each strip of processed film with its cartridge, and each cartridge to a particular customer's order) and for the consumer, who can easily locate the correct cartridge if reprints are desired.

To facilitate automatic processing of film, a unique DX number is assigned to the different types of film.

Cameras

The format was introduced in 1996 by Kodak, Fujifilm, Minolta, Nikon, Canon and others. APS is mainly used for point and shoot amateur cameras, although some SLR systems were also created: Canon EOS IX, Minolta Vectis, Nikon Pronea with Nikon IX lenses. Of these the Canon EOS IX and the Nikon Pronea could use the existing 35mm SLR lenses, whereas Minolta opted to create a new lens line-up. Nikon developed the IX series of lens that were lighter and had a smaller field of view. Although the Nikon IX series of lenses were not compatble with the Nikon 35mm SLR, lenses for the Nikon 35mm SLR were compatible with the Nikon Pronea. Using existing lenses meant that the field of view was reduced by around 1.6x, but had the advantage of a larger lens selection. Creating a new lens system on the other hand gave the possibility of creating smaller and lighter lenses as that had a smaller image circle to cover. APS SLR cameras were too expensive for the high end amateur market when they first appeared, and professional photographers stuck with 35mm cameras, which offered greater image quality and resolution. Few APS film cameras are available new today.

Presently the terms APS-C and APS-H are most often used in reference to various makes of digital SLR that contain imaging sensors that are (very) roughly equivalent to their respective film dimensions given above. Concurrently to their APS SLR film cameras, some manufacturers released lenses intended for use on APS film cameras, in that they had a similar field of view to a given longer focal length lens on a 35mm camera. Some of these lenses have survived and are now marketed towards use on "APS" digital SLRs for the same reason. In reference to digital cameras, APS may also mean Active Pixel Sensor, a type of CMOS image sensor.

Adoption and marketshare

Despite the added features, APS never really caught on with professional photographers because the film area was just too small. The APS film surface area is only 56% of 135 film, and many professionals consider even 135 film to be small. The film area of APS is usually only suitable for 6x4 prints, enlargements to 10x8 start to show its lack of resolution. Color 'slide' or reversal film, popular with professional photographers, as well as black-and-white print film proved unpopular in APS format and was soon discontinued, while color print film was normally available only in a limited selection of film speeds and color format. These developments, combined with the fact that 35mm cameras could now be made almost as compact as APS-format cameras, prevented APS from attaining greater popularity.

APS cameras continued to be produced in compact fully-automatic form for the consumer 'point and shoot' market. However, less than five years after the 1996 launch of APS, the compact autofocus digital camera became available at increasingly reasonable prices, and APS camera sales plummeted.

As of 2006, APS cameras are rarely seen for sale in new production. APS film is more expensive to buy and labs capable of processing it are less likely to be encountered than for 35mm film. Available film types and formats have dropped off dramatically.

External links

photo.net - Reviews and comments on APS

Film_formats