Tiffen 67mm Circular Polarizing

Polarizers provide colour and contrast enhancement. Reflected light often shows up as whitish glare that washes out colour in an image. A Polarizer corrects this problem producing deep, dramatically blue skies. It also removes glare from non-metallic surfaces, such as windows and water. Colour saturation in general, especially outdoors, can be improved significantly.

There are two different polarizing filters, a circular and a linear filter. Linear filters are less expensive and more effective than circular filters. However, you need a circular polarizing filter if you have a camera with through the lens metering or autofocus. Otherwise you must disable one or both functions.