By far the most important accessory you can
buy for your professional camera lens is a
high quality filter. B+W filters are valued by
professional photographers for their exquisite
optical quality and fine multicoatings. B+W
is a must have for every pro quality lens.
Circular Polarizer filters are specially designed to be used with auto-exposure and auto-focus SLR and video cameras to increase color saturation and reduce reflections. The neutral gray color and plane parallel polarizer material guarantee optimal image results. The filter factor varies according to how the filter is positioned in relation to the sun.
It does not influence the metering systems of these cameras. Filter factor is 2.3 to 2.8.