Large format

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Large format describes large photographic films, large cameras, view cameras (including pinhole cameras) and processes that use a film or digital sensor, generally 4 x 5 inches or larger. The most common large formats are 4×5 and 8×10 inches. Less common formats include quarter-plate, 5×7 inches, 11×14 inches, 16x20 inches, 20x24 inches, various panoramic or "banquet" formats (such as 4x10 and 8x20 inches), as well as some metric formats, such as 9x12 cm.

The Polaroid 20×24 inch instant camera is one of the largest format cameras currently in common usage, and can be hired from Polaroid agents in various countries.^[1] Many well-known photographers have used the 235 pound (106 kg), wheeled-chassis Polaroid.

1 Control
2 Operation
3 Uses
4 Photographers who have used large format
5 References
6 See also

[edit] Control

Most large-format cameras have adjustable fronts and backs that allow the photographer to better control rendering of perspective and depth of field. Architectural and close-up photographers in particular benefit greatly from this ability.

Aside from the focusing action common to all formats, the special movements of many large format technical and view cameras allow the front and/or back of the camera to be tilted out of parallel with each other, and to be shifted up, down, or sideways. Based on the Scheimpflug principle, these "movements" make it possible to solve otherwise impossible depth-of-field problems, and to change perspective rendering, and create special effects that would be impossible with a conventional fixed-plane camera.

Ansel Adams' photographs demonstrate how the use of front (lens plane) and back (film plane) adjustments can secure great apparent depth of field when using the "movements" available from adjustable large format cameras.

[edit] Operation

A number of actions need to be taken to use a typical large format camera, resulting in a slower, often more contemplative, photographic style. For example, film loading using sheet film holders requires a dark space to load and unload the film, typically a changing bag or darkroom (although users of the most common formats, 4×5, may now use ready-loaded pre-packaged films, which are more convenient than regular film holders).

A tripod is typically used for view camera work, but some models are designed for hand-held use. These "technical cameras" have separate viewfinders and rangefinders for faster handling.

In general large format camera use, the scene is composed on the camera's ground glass, and then a film holder is fitted to the camera back prior to exposure. A separate Polaroid back using instant film is used by some photographers, allowing previewing of the composition, correctness of exposure and depth of field before committing the image to film to be developed later. Failure to "Polaroid" an exposure risks discovery later, at the time of film development, that there was an error in camera setup.

[edit] Uses

The 4×5 inch sheet film format was very convenient for press photography since it allowed for direct contact printing on the printing plate. This was done well into 1940s and 1950s, even with the advent of more convenient and compact medium format or 35 mm roll-film cameras which started to appear in the 1930s. The 35mm and medium format SLR which appeared in the mid-1950s were soon adopted by press photographers.

Large format's versatility is not limited to film; large digital capture backs are available to fit onto large format cameras.

Large format, whether film-based or with a digital back, will always be used for some applications. For example, landscape photography, advertising photos of high value consumer items, much fine-art photography, images that will be enlarged to a high magnification, or demanding scientific applications will benefit from the very high quality of the prints or transparencies produced.