The Tiffen 127mm Ultra Pol non-rotating linear polarising filter helps to significantly reduce reflections and glare by filtering polarised light due to reflection from a non-metallic surface. This results in a noticeable increase in saturation of skies and foliage, as well as clearer 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 cameras, such as viewfinder cameras, which do not rely on internal mechanisms to determine focus or metering settings.nnThere 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, grinding it flat to a tolerance of 1/10,000th of an inch, then mounting it on precision metal rings. The non-rotating design of this filter is best suited for use with lens hoods, adaptors or other rings for rotational control of the polarising substrate.nnnn- Compared to a standard polariser, the Ultra Pol design strives to increase the polarising effect for better reduction of reflections and greater colour saturation.nn- Arranges and filters directionally polarised light perpendicular to reflected light, enabling absorption of much of the light.nn- Reduces haze in distant landscapes and provides more saturated and vibrant colours.nn- Strongest effect when used at 90° to the sun.nn- Water White optical glass for excellent clarity.nn- Non-rotating design is best suited for use with lens hoods or adaptor rings to better control the filter's polarising effect.