The Tiffen Ultra Pol 4 x 4" linear polarising filter helps to significantly reduce reflections and glare by filtering polarised light due to reflection on non-metallic surfaces.,n,nThis results in a noticeable increase in the saturation of skies and foliage, as well as sharper images when shooting in hazy conditions.,n,nA linear polariser differs from a circular polariser in that it does not support a camera's autofocus or auto-exposure functions; it is best suited for use with manual devices, such as large format cameras, which do not depend on internal mechanisms to determine focus or metering settings.,n,nThis filter is made from Water White glass and is produced using ColorCore technology, a process that involves laminating the filter substrate between 2 plates of optical glass and polishing it 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 4 x 4" / 101.6 x 101.6 mm.,n,n,n-Compared to a standard polariser, the Ultra Pol design strives to increase the polarising effect for enhanced reflection reduction and improved colour saturation.,n-Arranges and filters directionally polarised light perpendicularly to reflected light allowing absorption of much of the light.,n-Reduces haze in distant landscapes and offers more saturated, richer colours.,n-Strongest effect when used at 90° to the sun.,n-Water White optical glass for excellent clarity.