What Is the Definition for a Polarizing Filter?

Use a polarizing filter to reduce or enhance reflected images.

Polarizing filters block or reduce light reflected at certain angles from smooth, non-metallic surfaces such as glass or water.

Haze Reduction

Polarizing filters can reduce glare and enhance or darken the color of the sky by reducing reflections from particles in the atmosphere on hazy days.

Enhanced Visibility

When rotated for the best results, polarizing filters can reduce reflections from water surfaces to enable shots of fish or other wildlife beneath the surface, or from glass windows to give clearer photos of scenes on the opposite side.

Angle of Use

Barbara and John Upton, authors of the classic reference book "Photography," recommend using polarizing filters "at an angle of about 35 degrees to the reflecting surface" or, to darken skies, at a right angle to the sun. The "National Geographic Photographer's Field Guide" recommends using the filter at an angle of 45 degrees to the reflecting surface.

Caution

Because polarizing filters block light, photos taken with a polarizing filter require about 1-1/3 to 1-2/3 more exposure time.

Tip

Rob Sheppard, author of "The Magic of Digital Nature Photography," recommends using a polarizing filter to enrich color and reduce glare from natural objects such as leaves or flowers.

References

• "Photography;" Barbara London Upton and John Upton; 1989
• "National Geographic Photographer's Field Guide;" Albert Moldvay; 1988
• "The Magic of Digital Nature Photography;" Rob Sheppard; 2007

Resources

• See a photographer's tutorial on the use of polarizing filters in nature photography
• Learn about polarization at the University of Colorado's Physics 2000 online exhibit