Zeiss Circular Polarizer
Graphs are in nanometers. Visible light is approximately 390 - 650 nm (the human eye can see very weakly into the 700-800nm range). Graphs used by permission.
A great source for filters at competitive prices is B&H Photo, which has an extensive selection of brands and types and sizes.
In the field
As of 2012, I prefer the Zeiss polarizers over B+W because the rings don’t bind as do the B+W ones; I’ve had endless trouble with high-friction rings on B+W polarizers (requiring so much force to turn that they unscrew themselves!). The B+W ones also can be uneven in force required to turn them. The Zeiss polarizers are free of this problem.
The Zeiss CZ circular polarizers were introduced in late 2011.
For photos that become revelations
Discover something new: the POL filters featuring the T* anti-reflective coating from Carl Zeiss provide you with entirely new photographic insights by avoiding reflections on non-metallic surfaces. Experience a new definition of color and contrast.
- Precision — Rotary mount to set the filter effect (light reduction: 1.5–2 EV).
- Quality — High-quality glass featuring Carl Zeiss T* anti-reflective coating.
- Flexibility — High-fit accuracy for fast filter change. Can be used with a lens shade.
- Compatibility — Ideal for ZEISS lenses. Can be used with non-ZEISS lenses.
- Effect — Minimizes light reflections on non-metallic surfaces and increases the color saturation of long-distance shots