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 (10x13 cm) or larger. The most common large formats are 4x5 and 8x10 inches (20x25 cm). Less common formats include quarter-plate, 5x7 inches, 11x14 inches, 16x20 inches, 20x24 inches, various panoramic or "banquet" formats (such as 4x10 and 8x20 inches), as well as metric formats, including 9x12 cm, 10x13 cm, and 13x18 cm. Above 8x10 inches, the formats are often referred to as Ultra Large Format (ULF) and may be 11x14, 16x20, 20x24 inches, or as large as film, plates or cameras are available.
The Polaroid 20x24 camera is one of the largest format instant 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.
Control
Most, but not all, large-format cameras are view cameras, with fronts and backs called "Standards", that allow the photographer to better control rendering of perspective and increase apparent depth of field. Architectural and close-up photographers in particular benefit greatly from this ability. These 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, and those of the other Group f/64 photographers, 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 on large-format view cameras.
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 prepackaged film magazines and large format roll films have also been used in the past.
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.
Uses
The 4x5 inch sheet film format was very convenient for press photography since it allowed for direct contact printing on the printing plate, hence it was widely used in press cameras. 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 photography is not limited to film; large digital camera backs are available to fit large-format cameras. These are either medium-format digital backs adapted to fit large-format cameras (sometimes resulting in cropped images), step and repeat Multishot systems, or scanning backs (which scan the image area in the manner of a flat-bed scanner). Scanning backs can take seconds or even minutes to capture an image. When using a Sinar Macroscan unit and 54H data files, over 1 GB of data can be captured.
Large format, both film-based and digital, is still used for many applications, for example: landscape photography, advertising photos, fine-art photography, scientific applications and generally for images that will be enlarged to a high magnification while requiring a high level of detail.
Recordation of historic resources for the National Park Service (NPS) documentation programs: the Historic American Buildings Survey, the Historic American Engineering Record, and the Historic American Landscape Survey (HABS, HAER and HALS) requires large format film-based photography. 4"x5", 5"x7", and 8"x10" large format film formats are the only acceptable formats for inclusion in the HABS/HAER/HALS collections at the Library of Congress. 4x5 and 5x7 are generally used in the field (5x7 is preferred for very significant buildings) and 8x10 is generally utilized for photo-duplication of historic photographs, documents and blueprints. Through HABS/HAER/HALS, buildings and sites of historic significance are recorded with large format cameras and black and white film and using techniques that document the key features of the historic resource with special care not to distort the angles and views. This rectified photography can be accomplished with large format cameras by keeping the film, lens and subject perfectly parallel. Smaller format cameras need to be tilted to view high or low subjects, but the same subjects can be captured by shifting the lens element of a large format camera up or down to keep the film, lens and subject planes parallel.
HABS/HAER/HALS also requires the increased resolution of large format film. A sheet of 5x7 film has almost twice the resolution of 4x5 film, and 4x5 is almost 16 times larger than a 35mm film image (24mmx36mm). This added negative size not only allows for more detail, but the large format polyester film is also far more durable than acetate 35mm stock. HABS/HAER/HALS requires that all submissions to the Library of Congress include the original film (archivally washed) and it must also include contact prints on fiber-based paper – these contact are the same size as the film being submitted, 4x5, 5x7, 8x10 and the large size allows people to readily see the prints, while 35mm contacts would be too small and would require magnification.
In the printing industry, very large fixed cameras were also used to make large films for the preparation of lithographic plates before computer to film and computer to plate techniques were introduced. These are generally referred to as a 'process camera' and consist of vertically-mounted models for smaller work and horizontal units mounted on rails for very large works such as maps and plans.
Photographers who have used large format
See also
- View camera
- Press camera
- Medium format
- Reisekamera (tailboard view camera)
- Sinar
- APUG
References
- ^ "20 x 24 Studio". Retrieved 2007-03-24. [dead link]
National Park Service Website, HABS/HAER/HALS Standards & Guidelines , link to article
HABSPHOTO "HABS/HAER/HALS/CEQA NEW 2010 GUIDELINES FOR PREPARING HABS/HAER/HALS DOCUMENTATION" ,link to article
Secretary of the Interior's Standards and Guidelines for Architectural and Engineering Documentation HABS/HAER/HALS Illustration Standards , link to PDF document
