Black and White Photography

Polarizing filters do not have much effect when you point them directly at the

surface of your subject. If you are trying to eliminate reflection from a store window,

for example, don’t point your camera directly at the window; stand to the

side and shoot obliquely. A 30–35-degree angle maximizes the polarizing effect.

There are two types of polarizing filters; both accomplish the same results. A

linear polarizer is compatible with many through-the-lens (TTL) meters, allowing

accurate automatic exposure. However, linear polarizers adversely affect the

metering systems and autofocus function of some cameras. For these models,

you will need a circular polarizer. Your camera’s instruction manual or your

camera store can tell you which type you need for your camera model.

Neutral-density filters. A neutral-density (ND) filter uniformly blocks some of

the light that reaches the film, without affecting the tones or contrast of the

final print. You may want to use an ND filter when there is too much light in a

scene for a desired effect or for your chosen film speed. Because ND filters cut

the light reaching the film, you must open the lens aperture or slow the shutter

speed when using them. This decreases depth of field and/or increases blurring

due to subject movement, both of which can be desirable effects for certain

types of pictures. ND filters are rated in third stops; an ND.1 filter cuts exposure

by 1/3 stop, an ND.3 cuts exposure by 1 stop, an ND.6 cuts it by 2 stops,

and so forth.

Special effects filters. Filters also are available for a wide variety of special

effects. One example previously discussed is the various filters that maximize

the eerie effect and contrast of infrared films.

A diffusion filter reduces the overall sharpness of the image, while lowering

contrast and decreasing the sense of detail. This ordinarily makes subjects

appear more dreamy and romantic, and with portrait subjects helps hide skin

blemishes and wrinkles.

A fog filter is a type of diffusion filter that simulates the effects of a foggy day,

producing a misty glow from highlight areas of the subject—as well as lowering

contrast and sharpness.

A graduated filter selectively reduces exposure in portions of an image. Half

of the filter is clear and the other half is either colored and/or neutral density,

with the two halves gradually blending together. There are many types of graduated

filters, and the abruptness of the blending varies with the type used.

Among their other effects, graduated filters darken skies that would otherwise

print too light without affecting the rest of the scene, making them useful for

landscape photography.

A multi-image filter has contoured prismatic surfaces that create repeating

images. The shape and amount of repetition depends on the type of multi-image

filter you use.