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
MiNT camera Polaroid SX-70 does not provide full manual control over exposure. SLR670m comes with the 'Time Machine', which enables manual control over shutter speed. MiNT re-designed the camera motherboard to provide a port of communication for the Time Machine. Shutter speeds on Time Machine range from 1s to 1/2000s plus bulb, time and auto exposure. The Time Machine only works with the SLR670m produced by MiNT, the standard Polaroid SX-70 will not respond to the Time Machine. ISO 160 when Time Machine is removed, or under Auto mode. In 2015, MiNT released a twin lens reflex instant camera called InstantFlex TL70.