NOW THAT autumn's reds, greens and yellows are nearing their full splendor, there's no better way to spend the weekend than capturing them all on film.

Chances are, you can make pretty pictures simply by pulling your car off the side of the road. But you'll do better on foot or bike, with greater freedom to wander and explore the scene in depth.

Toting your camera bag on a long hike can be wearying -- and downright hazardous if you're climbing steep slopes. Instead, stash your camera gear in a fisherman's vest; they've got plenty of pockets for lenses, filters and film. To keep your camera from bouncing about with every stride, try a so-called "fanny pack" that holds the camera around your waist, or a belt that will hold it against your chest until you're ready to use it.

If your chosen scene is one you can easily return to, t will pay to observe it at various times of day. Sunlight is more reddish in early morning and late afternoon, but bluish at midday; you'll want to know how the color temperature of the light will harmonize with the palette of colors nature has provided. Low-angled light will add a greater sense of texture and depth to most scenes, compared with the relatively "flat" light and short shadows of midday.

If you restrict your shooting to early and late hours, you'll be working with relatively low light levels -- even more so if you're under forest cover, which can block four or five stops of light from reaching your subject. Fast film will enable you to shoot hand-held, but this is one situation where slow film -- providing high contrast, good color saturation and sharp resolution appropriate to the subject -- and a tripod might be a better choice.

You can boost saturation even more by using a polarizing filter over your camera lens; its effect will be obvious as you rotate the filter and look through the viewfinder.

Though the wide variety of hues in fall landscapes is dazzling, the photographic results can often be disappointing -- often because the photo lacks a center of interest. Careful thinking will bring a sense of order to visual chaos.

Include complementary subjects -- fallen branches, a meandering stream or high tufts of grass, for example -- in the near foreground of your viewfinder to impart a sense of depth and pull the viewer's eye into the rest of your picture.

The number of colors, and the patterns and amounts of each, can have a profound influence on your picture's success. A hillside speckled with equal amounts of red, green and yellow leaves may allow the eye to move randomly about the image area. On the other hand, one lone red leaf, lying in a pile of yellow ones, will rivet the attention. Be alert, too, for patterns formed by tree trunks, overhead branches and shafts of sunlight filtering through the forest cover. You'll find many of them if you look, particularly if you aim your camera upward at the treetops, instead of horizontally from a standing position.

Use your exposure meter carefully if you're shooting in the deep woods. It can be "fooled" by small intense patches of sunlight (resulting in underexposure) and broad areas of deep shadows (causing overexposure). Move in close to a middle- toned area, take your meter reading, then back off and use that reading for your exposure. If you're shooting from a tripod, meter off an 18-percent gray card (available at photo dealers) or a middle-gray toned jacket, held in the same light as your subject.

If black and white is your forte, there's no reason not to use it on the trail. Keep in mind, however, that b&w films tend to see the colors red and green as nearly identical shades of gray. Yellow, orange and red filters will provide increasing amounts of tonal separation by lightening red and yellow laves, while darkening blue sky and green foliage. Make sure you put the filter on your lens before metering, or underexposure will result.

If you'd like a little pre-hike inspiraton, I can recommend several good books. For color enthusiasts, the classical, purist vision of Eliot Porter and the abstract imagery of Ernst Haas' "The Creation" will give you much food for thought. In black and white, the nature works of Ansel Adams, Paul Caponigro and the Westons -- Edward, Paul and Brett -- should prove instructive.

Go to it, and don't delay! One good windstorm, after all, and you'll have to wait until next year.