In Terms of Media: Photography

With millions of cameras owned by even more millions of individuals, photography is probably the most popular hobby in the United States. It is also a basic building block of modern communications. Without it, television and movies would not exist. Even newspapers and magazines would not be the sane. As for the milestones in our own lives-vacations, holidays, celebrations - how much photography contributes to our sense of personal history and sharing with one another!

Whether a camera is the simplest instamatic or the most complex adjustable model, three ingredients are necessary for picture-taking: light, a black box (the camera) and light-sensitive particles embedded in film. The light strikes the film through an opening, the lens, which has a shutter that opens and closes to let the light in. When the film is processed in special chemicals, an image becomes visible. It is called a negative because it is a reverse image of the "real" scene photographed. A complementary chemical process is necessary to get a positive image, that is, light must shine through the negative onto light sensitive chemicals embedded in special photographic paper. After chemical bath, a permanent "picture" is ready.

Sometimes the resulting image is not a negative, but rather a positive transparency known commonly as a slide. Any film name that incorporates the word "chrome' in it — Kodachrome, Ektachrome, Dynachrome, etc. — will result in color slides rather than negatives and prints.

The "trick" of photography, if there is one, is to determine how much light strikes the film. Too much and the picture is washed out; too little and it is too dark. Light is variable, even outdoors. But film has a fixed sensitivity. (Film is available in different speeds or sensitivities, but within any one roll of film, there can be no change.) How do you insure that the right amount of light comes through the lens to create a "good" picture?

The lens of a camera works like the pupil of the human eye. If the light is low, the eye o- pens wide; if the light is bright, it opens only a bit. Selecting the aperture, the "opening" of the lens, is one way to control how much light comes into the camera. A second control is the speed at which the shutter opens and shuts. A lot more light gets in if the shutter is open one second than if it is open for 1/250 of a second!

The difference between an inexpensive camera and a more expensive model is basically the amount and quality of adjusting is possible. Cheaper cameras have a fixed setting and a fixed speed and are designed to permit the amateur to get acceptable pictures outdoors on a sunny day or indoors with extra light from a flash.

Better cameras are more flexible, providing many features that assist in creating memorable photographs. Generally, the more expensive the camera, the 'wider" the lens can be opened, allowing pictures to be taken in lower light situations. Critical focusing makes the objects or person "stand-out" by slightly blurring the background and/or the foreground. And interchangeable lenses lets the photographer choose special lenses—telephoto, wide-angle, close-up, fish-eye, etc.— f or special effects.

Today, better cameras have built-in electronic light meters or sensors that "read" the amount of light available in the situation and "choose" the proper aperture and speed automatically. Such advances make the science of photography easy even for the beginner. But the art of photography, the creating of images that capture and touch the human spirit, is the gift of talented individuals who go beyond science to communicate their vision of the world to others.