This polarizing filter is used to increase color saturation, darken blue skies
so white clouds stand out, and eliminate reflections from nonmetallic surfaces
like glass or water. It will also reduce the softness in scenery caused by atmospheric
haze. This filter will not change the overall color 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.