Tiffen Polarizers are most useful for
increasing general outdoor color saturation and contrast.
Tiffen Polarizers can darken a blue sky, a key application, on color as well
as on black-and-white film, but there are several factors to remember when
doing this.To deepen a blue sky, it
must be blue to start with, not white or hazy.
Polarization is also angle-dependent.
A blue sky will not be equally affected in all directions.
The areas of deepest blue are determined by the following "rule of thumb."
When setting up an exterior shot, make a right angle between thumb and forefinger.
Point your forefinger at the sun.The
area of deepest blue will be the band outlined by your thumb as it rotates
around the pointing axis of your forefinger, directing the thumb from horizon
to horizon.Generally, as you aim your
camera either more into or away from the sun, the effect will gradually diminish.
There is no effect directly at or away from the sun.
Do not pan with a polarizer, without checking to see that the change in camera
angle doesn't create undesirable noticeable changes in color or saturation.
Also, with an extra-wide-angle view, the area of deepest blue may appear
as a distinctly darker band in the sky.
Both situations are best avoided.In
all cases, the effect of the polarizer will be visible when viewing through
Tiffen Polarizers need approximately
1-1/2 to 2 stops exposure compensation, usually without regard to rotational
orientation or subject matter.They
are also available in combination with certain standard conversion filters,
such as the 85BPOL.In this case, add
the polarizer's compensation to that of the second filter.
Certain camera optical systems employ
internal surfaces that themselves polarize light.
Using a standard (linear) polarizer will cause the light to be further absorbed
by the internal optics, depending on the relative orientation.
A Circular Polarizer is a linear one to which has been added,on the
side facing the camera, a quarter wave "retarder."
This "corkscrews" the plane of polarization, effectively depolarizing it,
eliminating the problem.The Circular
Polarizer otherwise functions in the same manner.
Combine the Tiffen ENHANCING filter
with a Tiffen Polarizer filter for more dramatic effects.