Last week we briefly discussed the types of filters used for digital camera lenses. The most commonly used filter is the polarizing filter and it's extremely important for landscape photographers. In simplest terms, they reduce the amount of reflected light passing through the sensor, while also increasing color saturation. Ever wonder why your pictures of blue skies aren't nearly as rich and beautiful? It's because you're not taking advantage of this nifty piece of equipment.
The intensity of the effect can be changed by rotating the filter –no more than 180 degrees is needed. The effect can also be changed depending on the direction the camera is pointed. It will be strongest when the camera is pointed in the direction perpendicular to the direction of the sun's incoming light. A polarizer used in conjunction with wide-angle lenses can create an unrealistic sky that visibly darkens, so use caution.
There are both linear and circularpolarizing filters. What's the difference? A circular can be used when the camera's metering and autofocus are being used. A linear cannot and because most photographers will want to use metering and autofocus, it's recommended to use a circular polarizing filter.