B + W Circular PolarizerFeatures
Single Coating: Each glass surface is vacuum coated with one layer of Anti-Reflection coating. This single layer helps to prevent internal ghosting and reflections. It also improves light transmission from approximately 92% (uncoated glass) to over 98%
Multi coated for flare prevention
Gives the same deep contrast & glare reducing properties to black & white photography
Combines with Red filters for incredibly dramatic black & white landcsapes
Circular Polarizer Filter
Highly efficient standard Circular Polarizer SC Single Coated Glass Filter for all cameras with beam splitters in the light paths of their TTL exposure meter and with autofocus lenses. Circular polarization has the same pictorial effect as linear polarization, but allows for proper exposure metering and/or autofocus distance settings.
B + W Polarizers increase color saturation and reduce reflections. The neutral gray color and plane parallel polarizer material guarantee optimal image results. High-quality optical glass ensures excellent pictorial quality. The filter factor varies according to how the filter is positioned in relation to the sun. Filter factor is between 2.3 and 2.8.
Linear and circular polarizers both consist of a linear polarizer foil but differ in their construction in the following way. Modern SLR cameras have a beam-splitting prism that sends part of the incoming light to the meter and part to the viewfinder. The effect is that the light entering the meter is partially polarized by the beam-splitter.
A linear polarized placed on the lens of such a system will act as a second polarizer and block light to the meter by a degree dependent on the angle between the prism and the polarizer on the lens. The result is incorrect exposure/aperture values from the meter. The circular polarizer circumvents this problem through the addition of a 1/4-wave retarder, or delay, foil. This ensures that the linearly polarized light is changed into a rotation that appears unpolarized to the meter, resulting in proper exposure/aperture readings.