Polaroid (polarizer) Polaroid (polarizer) Polaroid is a type of synthetic plastic sheet which is used as a polarizer or polarizing filter. A trademark of the Polaroid Corporation, the term has since entered common use. The original material, patented in 1929 and further developed in 1932 by Edwin H. Land, consists of many microscopic crystals of iodoquinine sulphate (herapathite) embedded in a transparent nitrocellulose polymer film. The needle-like crystals are aligned during manufacture of the film by stretching or by applying electric or magnetic fields. With the crystals aligned, the sheet is dichroic: it tends to absorb light which is polarized parallel to
Field camera monorail cameras, modern field cameras tend to have most camera movements for the front standard, i.e. lens rise/fall/shift/tilt/swing, but are usually more limited in back movements, sometimes having only tilt/swing. They usually use sheet film, in sizes from 6x9cm (2.4×3.6") to 20×24 inches (e.g., the Polaroid 20×24 camera), but the most popular "standard" sizes are 4×5 and 8×10 inches. They are usually used by photographers who need the larger negative sizes and the portability. Field camera A field camera is a view camera that can be folded in a compact size. Modern designs are little different from the first folding