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.
When using a camera with a split beam metering system (a metering
system that employs a polarized half mirror) which is most of today’s
auto focus camera bodies, traditional linear polarizers will cause
exposure errors do to their light absorption properties. Circular
polarizers yield the same optical effect while not causing exposure
problems with modern metering systems. 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 polarizes 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 film’s 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.
With Filter Without Filter
