Lots of information about polarizing filters at Digital Photography For What It's Worth. Topics include:
* Unwanted Light—Scatter and Glare
* The Really Short Answer
* Other Uses for Polarizers
* When Not to Bother with a Polarizer
* Polarization Primer
* Polarization By Absorption—How a Polarizer Works
* Calibrating and Adjusting Your Polarizer
* Polarizer Theory 101—Intermediate Settings
* Polarization By Scatter—Targeting Atmospheric Scatter
* Non-TTL Scatter Control
* Polarization By Reflection—Targeting Glare
* Polarizer Theory 102—Brewster's Angle
* Non-TTL Reflection Control
* Correcting Exposure For Your Polarizer
* Circular vs. Linear Polarizers
* How to Tell a CP from an LP—the Mirror Test
* Fun with Reversed Circular Polarizers—An Instructive Diversion
* Geez, Why Not Just Post-Process?
From this article, I learned that the polarizing filter I bought back in the late 1970s (and still use) is a linear polarizer. Below is a photo I took of the Auckland skyline employing the polarizer on my old G1 camera. (Click image for larger view.)
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