Light rays which are reflected by any surface become polarised and polarising
filters are used to select which light rays enter the camara lens. PL (Linear
Polarising) and PL-CIR (Circular Polarising) filters have the same effect. They
allow user to remove unwanted reflections from non-metallic surfaces such as water,
glass etc. They also enable colors to become more saturated and appear clearer,
with better contrast. This effect is often used to increase the contrast and saturation
in blue skies and white clouds. HOYA's polarising filters do not affect the overall
color balance of a shot.