Q) I know you've answered this in the past, I but can't seem to find my issue. I want to get a polarizer for my camera. Which type should I get?
Lou K., Santa Fe, New Mexico
A) There are two choices for polarizing filters: linear and circular. Both achieve the same effect, and you'd be hard pressed to look at an image and tell whether it was shot with a linear or circular polarizer. The circular version is very similar to the linear, but it adds one more optical step to the process.
Let me take a step back and talk about how these filters work. If you consider light as "vibrating," when it hits certain types of surfaces, the light vibrates in a single direction. This single-direction vibrating light is polarized. The polarizing filter can then be used to reduce the polarized light.
Many cameras' autofocusing and metering systems are negatively affected by polarized light, unfortunately. A circular polarizer makes the light entering the lens (and the meter and autofocus system) appear to be unpolarized. The autofocusing and metering systems can then operate correctly.
May 7, 2007 HelpLineDPMag Published in HelpLine
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