This polarizing filter is used to increase colour saturation, darken blue skies so white clouds stand out, and eliminate reflections from nonmetalic surfaces like glass or water.
It will also reduce the softness in scenery caused by atmospheric haze.
This filter will not change the overall colour balance of a photograph.
Most modern SLR cameras use a polarizing half mirror (split beam metering) system and the circular PL is designed to be used with them.
Filter Factor 3~4 or 1 2/3 to 2 stops