Q. I'm thinking about buying a new camera for myself for Christmas. I want to go up a step from my Instamatic. Can you tell me the difference between program and non-program on some of these cameras?

A. Programable cameras are the high-tech, state-of-the-art way of taking pictures.

These cameras can select the speed of the shutter and the size of the aperture for you. In other words, they'll shoot a given subject at the fastest possible speed and at the narrowest aperture.

Non-programable automatic cameras will select either the fastest speed at a given aperture or the smallest aperture at a given speed.

Most programable cameras have a "manual" mode that allows you to set both the aperture and the speed. Usually in the manual mode, you still have a through-the-lens metering capability to help yu.

Most programs are set up for "neutral reflectance" conditions. This means that the camera reads middle-range greys. This can cause problems in very bright areas such as beaches, low-angle sky shots or shots on sun-reflecting water. In such cases, the program tends to get confused by the bright light being reflected.

Make sure that your camera has a compensation dial, which will allow you to get better specific exposures on these super-bright subjects. By using this compensation, you can get better exposure on foreground subjects that might otherwise be underexposed. Your camera's instruction book will help with the specifics.

There's a wide range of programable cameras. Some of the multi-program modes are smart enough to know if you're using a wide-angle, normal or telephoto lens, and meter accordingly.

There's even a program mode on one camera that, in effect, meters five different areas of your picture and assigns values and weight toach. It then compares the situation you're photographing with 100,000 other situations stored in the camera's memory. When it finds the right match, it locks in and the chances are 100,000 to one you'll have a successful picture.

Once again, I urge you to visit your camera store and see the difference. Try before you buy.

Carl Kramer, former director of photography for The Washington Post, will try to answer your photography questions in his column, but cannot reply individually. Send your questions to: Carl Kramer, c/o Weekend, The Washington Post, 1150 15th Street NW, Washington, D.C. 20071.

KODAK'S BIG SHOW -- The 50th anniversary exhibit of the Prizewinning Photographs of the Kodak International Newspaper Snapshot Awards goes on display at the National Geographic Society's Explorer's Hall on Tuesday.

Regarded as the world's largest annual photo contest, the exhibit will run through January 4. On display are the prize winners of contests held by 257 newspapers in the U.S., Mexico and Canada, representing more than a quarter of a million entries in both black-and-white and color photography.