The Tiffen 6.6 x 6.6" Ultra Pol Linear Polarizer Filter helps to greatly reduce reflections and glare by filtering out light that has become polarized due to reflection from a non-metallic surface. This results in a noticeable increase in the saturation of skies and foliage, as well as clearer imagery when photographing in hazy conditions. A linear polarizer differs from a circular polarizer in that it does not supports use of a camera's autofocus or auto exposure functions; it is best suited for use with manual cameras, such as view cameras, that are not dependent on internal mechanisms to determine focus or metering settings. This filter is constructed from Water White glass and is made using ColorCore technology, a process that involves laminating the filter substrate between 2 pieces of optical glass and grinding flat to a tolerance of 1/10,000th of an inch. It has a filter factor of 4, requiring two additional stops of exposure for normal results, and measures 6.6 x 6.6" / 167.6 x 167.6mm.