This Circular Polarizer II Filter from Nikon is a 112mm multicoated filter that minimizes flare and glare, providing increased saturation and clearer images that are crisp and have more contrast.
The polarization effect is visible in the viewfinder or on the LCD screen as the front ring is rotated. When shooting on a bright day, the saturation of a blue sky may be controlled, which enhances the definition of cloud formations. In addition, when shooting into water, the reflections often associated with landscape or scenic photography may be minimized or eliminated. A circular polarizer is an essential tool for landscape photography. When shooting through a glass window, museum showcase, or car window, reflections and glare will be reduced allowing the subject behind the glass to be captured. This slim filter ring design allows this filter to be used on wide-angle lenses with a reduced potential for vignetting the image corners.
Note: Circular polarizers are specifically designed for use with auto-focus SLR cameras (They will also work on manual systems without problems)