In these inflationary times the very thought of a 99-cent camera sounds preposterous - but let me assure you that it exists.

The one that I have is called a Diana. It looks like a 35-mm but it uses 120 roll film and 16 exposures are on a roll.

It has three distance settings, from four to six feet, six to 12 feet and 12 feet to infinity. There is a setting for shade, overcast sun and sunlight. The shutter has only one speed, of about 1/60 of a second.

It comes complete with lens shade, neck strap and instruction book packaged in an attractive orange box.

Where can you get a 99-cent camera? I don't know; you'll have to look around. Mine was given to me at the Amphoto booth (American Photographic Book Publishing Co.) at the American Booksellers Association convention in Los Angeles recently.

Perhaps I received one because Amphoto is publishing a series of my photographic books.

In any event, the gift was good for a laugh, but on second thought I wondered if maybe it was good for more than a laugh.

So I loaded up a roll of 120 Plus X film and asked my favorite model to pose right in the front yard.

The sky was overcast, so I set the adjustment accordingly, stepped back between four and six feet, set the scale for that distance and clicked.

Nothin' to it! No f/stops, no shutter speeds or careful focusing. I was a liberated photographer.

I shot all 16 exposures in different lighting conditions - even indoors by candlelight. And you know what I got?

Only the first exposure came out. After that the light had gotten so poor that all the rest were underexposed.

But that first shot was far better than I expected. It taught me what the camera can do - and the poor results from the rest of the roll taught me waht the camera won't do.

What a simple box camera with no f/stops or accurate focusing can do is take a good stand-up shot of one or two people from about six feet distance, or a group at 12 feet, or a general scene at infinity.

You should shoot on a bright day, or with at least hazy sun, at your back shining over your shoulder.

The degree of sharpness of your picture will depend on how accurately you judged the distance, so it's best to step it off. An average male foot is just that - about 12 inches in the size 10 to 11 shoe.

Position your subject in the center of the frame, because with cheap lenses the center area is the sharpest. If your model's face is in focus the rest of the picture won't matter.

Don't try to stop action. Ask your subject to hold still and make sure that the camera is held steadily. The only speed of 1/60th of a second is not fast enough for running, or even fast walking. You can try panning (moving the camera with the subject as you shoot) when shooting action.

You may get away with indoor pictures if you use fast 400 ASA film and push it. You can do this with Tri-X film, for example, and increase the ASA to 3200.

Don't waste your film on indoor shots, because the lens opening (about f/11) is too small and the shutter speed too fast for adequate exposure.

Q - I am interested in taking color photos of animals in the wilderness. What lens would you recommend?

A - The ideal lens for wildlife photography is the 500-mm catadioptic (mirror) lens. This lens will enable you to "reach out" and, because the mirror formula makes it half as long as a normal 500-mm lens, it can be hand-held.

The lens comes in one stop, f/8. You can't adjust it for depth or sharpness, but all you will need for wildlife is one sharp plane of focus - you're not going to shoot scenics.

A shoulder pod, which is like a gunstock, will help you hold the lens steady, and a motor drive would be a good addition for a quick re-firing when you've cornered your quarry.

There are some competing makes of this lens - Nikkor, Rokkor and Canon are prominent. You should stop around, but be sure to test shoot before you buy, because this lens has limited uses.