The Tiffen Ultra Pol 4.5" round mounted and non-rotating linear polarising filter helps to significantly reduce reflections and glare by filtering polarised light due to reflection from a non-metallic surface.,n,nThis results in a noticeable increase in saturation of skies and foliage, as well as sharper images when shooting in hazy conditions. A linear polariser differs from a circular polariser in that it does not support the use of a camera's autofocus or automatic exposure functions; it is best suited for use with manual devices, such as rangefinder cameras, which do not depend on internal mechanisms to determine focus or metering settings.,n,nThere is a total filter factor of approximately 4, requiring a 2-stop increase for normal exposure. This filter is constructed from Water White glass and manufactured using ColorCore technology, a process that involves laminating the filter substrate between 2 pieces of optical glass and polishing it flat to a tolerance of 1/10,000th of an inch. This filter measures 4.5" / 114.3 mm in diameter and is mounted in a metal ring. The non-rotating design of this filter is particularly suited to the use of lens hoods, adapters or other rings for rotational control of the polarising substrate.,n,nCompared to a standard polariser, the Ultra Pol design strives to increase the polarising effect for enhanced reflection reduction and greater colour saturation.,n,nOrganises and filters directionally polarised light perpendicular to reflected light, allowing absorption of much of the light.,n,nReduces haze in distant landscapes and provides more saturated and vivid colours.,n,nStrongest effect when used at 90° to the sun.,n,nWater White optical glass for excellent clarity.,n,nNon-rotating design is particularly suited to the use of lens hoods or adapter rings for better control of the filter's polarising effect