film sizes are 4 inch by 5 inch (4"×5") and 8 inch by 10 inch (8"×10"). There are other formats, including 5×7 inch and 11×14 inch. Monorail cameras are among the simplest cameras possible according to their operating principles, consisting of the front standard (holding the lens) and rear standard (holding the ground glass viewing and focussing screen, then replaced by the film) sliding on a single rail, with a light-tight bellows stretched between. They are built to a high standard of precision and smoothness of operation, and sell in low volume, which makes prices higher than most smaller cameras. In addition to high-quality general images, monorails can be used for high-precision technical applications. For a general subject it does not matter if the geometry of the image is imperceptibly different from the subject; the measurable, though very small, optical aberrations of even good quality lenses do not cause problems. When photographing subjects which must be very accurately represented, for example in making a mask for integrated circuit manufacture, apochromatic lenses of very high geometric accuracy and minimal color aberration (traded off against a small maximum aperture) and high price, are used. Unlike with most other cameras, lenses used with view cameras (including monorails) are rarely manufactured by the body manufacturer. The body will be bought with lens panels and a film back; the owner will then choose lenses (in shutters) made by specialist manufacturers. A digital back from yet another manufacturer may be used. Several companies produce monorail camera bodies, including Arca-Swiss, Ebony, Horseman, Linhof, Cambo, Sinar, and Toyo. Older monorail cameras are available second-hand; unlike most other cameras they are relatively immune to obsolescence, so long as parts and accessories are available. Many parts which would be difficult to replace are unlikely to fail on these large, rugged, and basically simple devices. References External links Photo Notes definition of monorail camera Cameras by type