Closeup photography can produce some strikingly beautiful works, but equipping your camera with a closeup or macro lens is no guarantee of photographic success.

Many newcomers to closeup shooting are frequently disappointed with the results. Even shots that are technically perfect - well composed, in sharp focus, properly exposed, etc. - can turn out little better than blah . There are several possible reasons, but the most common one is insufficient light, resulting in poor contrast and, with rare exception, dull, lifeless photos.

What can be done on a cloudy day or deep in the woods where direct sunlight rarely falls? Perhaps more than you'd think.

Whenever you're shooting under indirect, reflected light, ask yourself: "How's the contrast?" If the answer is "lousy," don't waste your film. Instead, reach into your camera bag and pull out that sheet of white cardboard you carry for just such occasions. Eight inches square will work just fine.

Mount the camera on a tripod, aim the face of the reflective cardboard toward your subject, take a meter reading, set the camera, and fire. Under average conditions, you'll find the cardboard reflects from one to two f/stops of additional light. If the cardboard is in direct sun, it should reflect even more light onto your subject, giving higher contrast and a more interesting shot.

Some nature photographers use a small mirror, insisting that it reflects the most light possible. I'm not sure that's scientifically true, but I do know that white cardboard produces a less harsh light.

Although the reflected-light routine sounds bothersome, you'll soon find it more fun than trouble. With a little practice, you'll be handling those deep-woods shots like a pro. Of course, having a helper along makes the job even simpler: one handles the camera, the other the light.

Another way to light up a shaded subject is to use flash. Though few units are recommended for distances of less than six feet, you can use yours to light up that flower head just inches from the lens. Here's how.

If you have an auto electronic flash, set it to manual. Next, fold a clean white handkerchief in half and secure it over the head of the unit with a rubber band or masking tape, to cut the amount of light the unit throws on the subject.

Using the type of film you most often shoot, and with the camera fitted with closeup or macro lens, run a test roll of film. Mount the camera with flash on a tripod, focus on a suitable subject in a shaded area, and - with the shutter speed set to normal electronic flash speed - fire off one frame for each aperture on the lens, from the widest opening (say f/3.5) to the narrowest (f/16 or f/22). Then remove the handkerchief, fold it once more, put it back on the flash and repeat the test.

Take notes on the setting for each frame, so you can compare the frames to select the best setting.

A simpler way of using electronic flash for closeups requires the aid of an assistant.

With the camera mounted on a tripod and focused on the subject, remove the flash (no handkerchief, but connected to the camera with a long synch cord available at most photo stores) and have your assistant hold it the required minimum distance from the subject. Set the camera according to the flash unit's recommendations and fire. A little experimentation will show the best flash-to-subject angle for the most impressive results.