B + W 72mm Extra Wide Kaesemann Circular Polarizer MRC Filter

Circular polarizing filters are made 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. The high-end" polarizing foils of the Ksemann-type filters are neutral in color, they have a higher efficiency than conventional polarizing foils and they are cemented between high-grade plano-parallel optical glasses. The resulting sandwich is then precision-polished again to achieve highly accurate plano-parallel surfaces. Subsequently they are edge-sealed to protect the foil against humidity. Discriminating photographers regard the B+W Ksemann-Type Polarizing Filter to be the very best of all polarizing filters. They are well suited for applications that require the highest possible imaging quality, especially with high-speed telephoto lenses and apochromatic lenses.

Multi-Resistant Coating (MRC)
MRC by B+W is not only an extraordinarily effective multiple layer coating, it is also harder than glass, so that it protects filters from scratches (for instance when cleaning the filters) and it is also water and dirt repellent, thus facilitating filter maintenance.

Mount
This filter uses B + W Extra Wide mount made of brass. The diameter of the front portion of an EW "oversized" filter mount is much larger than the male thread that is screwed into the lens. As a result, the corresponding filter glass is also larger. When mounted to a wide angle lens with an angle of view of 110 degrees or even 120 degrees, vignetting is not an issue. Available in 72mm thru 112mm, EW filters should be used without a lens hood as vignetting may occur.