Polarizing Filters reduce reflections and glare, they are a neutral color and can
be used for color or black and white imaging.
As the light coming from the sun is not polarized parts of the light become
partially polarized due to the scattering of particles in the atmosphere. This
scattering reduces the transparency of the air and creates haze in the distance
and the blue in the sky on a sunny day.
Polarization also controls in the reflections of light on the original color of the
surface.
The Heliopan Polarizer improves the color of the sky, (in distant pictures,
mountain scenes, etc.) it reduces the bluish cast in landscapes and increases
the blue color of the sky. The effect is strongest at a 90° angle to the sun.
In addition polarizers enhance the color saturation of the scene by suppressing
the reflections on the surface, undesired reflections are largely eliminated.
While increasing color saturation with software can also improve the color
saturation the faded parts of the leaves in the illustration above will increase
as well. This procedure will not replace the need for a polarizer. For digicams
we recommend using a circular polarizer, linear polarizers may result in incorrect
exposure or focus under some lighting conditions. They are available
with or without SH-PMC coating and in slim or standard rims. The rims are
calibrated to help in finding the proper settings when a TTL preview is not
available.