Kenko
55mm Moose Warm Circular Polarizer Lens Filter

Collaboration between respected wildlife photographer and conservationist B. Moose Peterson of Wildlife Research Photography and THK Photo Products, Inc., has created a circular polarizing filter that uses 81A optical glass made by Hoya, the worlds largest optical glass manufacturer, instead of the clear optical glass of a normal circular polarizer. For many years, polarizers have been used to remove reflections from non-metallic surfaces such as water and glass as well as being used to darken blue skies to increase contrast in scenic photography. A side effect of both linear and circular polarizers is they cool down or make the over-all color balance of a scene slightly bluish. The addition of the 81A glass corrects the color temperature, bringing the scene back to the original 5500K for daylight films color balance. The 81A glass creates a much more pleasing and warm color balance to the entire scene while the circular polarizer increases color contrast and reduces the effect of atmospheric haze.