Polarising filters are used to select what light rays enter your camera lens. They can remove unwanted reflections from non-metallic surfaces like water or glass and also saturate colours for better contrast. The effect can be seen through the viewfinder and varied by rotating the filter. The “high-end†polarizing foils of the Käsemann (KSM) -type filters are neutral in color, they have a higher efficiency than conventional polarizing foils and they are cemented between high-grade plano-parallel optical glass. The resulting sandwich is then precision-polished again to achieve highly accurate plano-parallel surfaces. Subsequently they are edge-sealed to protect the foil against humidity. They are well suited for applications that require the highest possible imaging quality, especially with high-speed telephoto lenses and apochromatic lenses. The new generation of Kasemann High Transmission (HTC) polarizing filters is fitted with a new polarizing foil which has higher translucency (transmission), yet still provides outstanding effectiveness. The filter factor is only 2 to 2.8, equivalent to approximately 1 to 1.5 f-stops. An application of Multi-Resistant Coating (MRC), which includes mutiple layers of anti-reflection coating on each glass surface, internal ghosting and reflections are prevented. Furthermore, this coating provides added protection to the filter substrate from scratches and helps the filter to stay clean longer than uncoated filters. This filter uses the F-Pro brass ring which helps to prevent hamming whilst providing additional strength.
