penetration, they may be considered special-purpose
filters. Although contrast filters can be used for cutting
haze, these filters affect the gray tone rendering of
colored objects. The contrast and correction filters that
absorb the shorter wavelengths are the most effective.
The recommended contrast and correction filter colors,
in the order of greatest to least effective for haze
penetration, are as follows:
penetration of all. Special, visually opaque infrared
filters completely absorb the scattered ultraviolet
radiation and the visible light that produce haze. This
absorption by an infrared filter allows the scene to be
photographed entirely with unscattered infrared
radiation. An infrared sensitive black-and-white film
is not effective for haze penetration. Infrared
black-and-white film is sensitive to ultraviolet radiation,
violet, and blue light as well as infrared radiation and
red light. The gray tone rendering of a colored subject
in a black-and-white print produced from an infrared
negative is greatly distorted or contrasty.
objects in a black-and-white print, filters that primarily
absorb ultraviolet (UV) radiation are required. These
identified by numbers as follows:
damage. It is much cheaper to replace a filter than it is
to repair or replace a lens.
you look at the blue sky through a polarizing filter while
rotating it. As you rotate the filter, the sky appears to get
darker, then lighter.
glass and water
be seen-the direction in which light rays vibrate.
Unpolarized light rays vibrate in all directions at right
angles to the ray itself. A light ray is polarized when
vibrations are in one direction only.
screen is a polarizer in sheet form.
over the camera lens and the other is designed to be used
over a light source. Since they do not affect color,
polarizing filters and screens may be used for both
black-and-white and color photography. A polarizing
device used over the camera lens may have small posts
(known as indicator handles) projecting from the rim for
aligning the axis of the polarizing grid.
Basic Photography Course