WATCH PEOPLE strolling through one of the city's art museums, and you'll see that cameras stay slung over shoulders until it's time for the group photo by the outside steps.

There's a widely held -- but largely mistaken -- belief that art museums and photography don't mix. But in truth, as long as you're not shooting with the intention of selling your images, your camera is usually as welcome as you are.

Among a dozen or so area museums surveyed for this column, hand-held cameras won thumbs-up across the board. Tripods, which may be tripped over or impede pedestrian flow, are less favored (though many museums do allow them at "off-peak" hours with advance permission). Electronic flash or flashcubes are okay, but flashbulbs -- which may break when discharged or dropped -- are not.

One important caveat: The above applies solely to artworks owned by the museum. At shows on loan from artists or other institutions, photos are often restricted or banned. If that's the case, however, you'll usually be informed by a sign on the wall or a note in the exhibition brochure. So if you've been confining your museum shooting to a few "grab shots" made while the security guard was looking the other way, your stealth is probably unnecessary.

Museums vary widely in the quality and type of their lighting, from natural light to tungsten or even fluorescent, so it helps to plan your film choice accordingly.

Museums lacking natural light generally illuminate their art with tungsten spot lamps. Tungsten- balanced film, such as Ektachrome Type B or 3M's 640 T, is made to order for such situations. (Remember to put an 85B "warming filter" over your lens if you shoot part of the roll in daylight, or your pictures of the gang on the museum steps will be distressingly blue.)

When shooting under mixed lighting (window light augmented by tungsten spotlights, for example), you might try color negative film in the ISO 200-400 range. Those emulsions are fast enough to permit hand-held shooting in all but the gloomiest surroundings, and any reddish cast produced by the tungsten can be minimized in printing. Ultra-high-speed stuff (ISO 1000) may show more grain and less sharpness than appropriate for the subject matter, and should be used only when nothing else will do.

Even with high-speed film, you'll still need good low-light shooting techniques to ensure sharp hand- held pictures when your tripod is off- limits. Stand with your weight evenly distributed and your feet about shoulder width apart. Press your elbows into your rib cage to steady your arms, and finally, don't jab the shutter release -- push it gently, to quell camera motion during exposure.

Take advantage of surrounding objects to steady your aim, if you can do so without creating an obstruction. If a bare wall faces the artwork you're shooting, lean against it, feet at shoulder width, to brace your torso. A doorway, too, can provide additional support. Make absolutely sure, however, that you're not getting in anyone else's way when you do.

Whenever possible, photograph artwork dead-center, to keep its edges parallel to the boundaries of your viewfinder. If reflections of spotlights, room surroundings, or yourself prove distracting from the ideal vantage point, you'll need another game plan. A polarizing filter will reduce room reflections; wearing dark clothes will minimize yours. If all else fails, move in lower, closer or slightly to one side and photograph only a portion of the entire work. Not only will you eliminate glare, but the search for compositional detail will enhance your appreciation of the whole.

Sculptures present a different challenge: how to effectively represent a three-dimensional object in a two-dimensional medium -- film. Before you shoot, walk slowly around the object and observe carefully the interplay of light and form. Don't confine yourself to "eye- level" views; bend those knees!

Once you've found your vantage point, you may find a polarizer useful in reducing "hot spots" and reflections. You won't remove them all, though, so observe carefully as you rotate the filter.

Museums generally light sculpture very carefully for best effect; try to keep your strobe in your camera bag. If you must use it, bounce it off the ceiling, if possible, to provide soft overall illumination. Failing that, hold it off-camera, high and to the side, so that shadows fall below and to the side of the sculpture. Otherwise, the shadows created by the interplay of on-camera flash and sculpture will transform the loveliness you see in your viewfinder into a photographic jumble.