The Kenko Circular Polarising filter is used to increase colour saturation, darken skies so white clouds stand out, and eliminate reflections from non-metallic surfaces like glass or water. It will also reduce the softness in scenery caused by atmospheric haze. Circular polarisers are designed to be used with the metering systems of modern SLR and digital cameras and will not change the overall colour balance of a photograph. Filter Factor 3~4 (1 2/3 to 2 stops)