Trying to find well-produced fitness videos that are truly suitable for beginners can be a daunting challenge. Most tapes these days aim at intermediate exercisers, the ones who know a grapevine from a box step and a lateral raise from a biceps curl. These tapes may offer a few easier moves here and there, but the instruction clearly is geared to people who already know what to do. The few tapes that are marketed for beginners often are unspeakably repetitive, as if flabby muscles always mean a flabby brain. And too often, they provide no way to add extra challenge or difficulty to the routine, as if beginning exercisers are going to remain beginners forever. It's nice, then, to discover Yoga Zone: Flexibility and Tone, a beginners' tape that offers the depth of instruction and easy pace that true beginners need. The instructor here is Alan Finger, a genial-looking middle-aged man who wears a polo shirt, rolled-up cotton pants and a chin-length bob. His physique is not the standard chiseled form of exercise videos; he looks as if he might carry a few extra pounds around the middle. But he has a lovely voice (with a hint of a brogue) and a calm manner, two essentials for a yoga tape, where relaxation is key. And he has a true gift for instruction, combining the nuts-and-bolts details of positioning with what it feels like to stretch and balance. When he describes how the muscles of the feet ought to rotate through to the little toe, you'll know -- and be able to feel -- just what he's talking about. But each move contains so many of these instructions that it can be a little overwhelming to try to master all of them at once. If you have tried yoga before, you'll recognize some of them -- the down-on-all-fours stretch called the cat, the inverted V that forms the down dog, and the corpse, which requires little more than lying flat on one's back, completely relaxed. In another nod to beginners, Finger also provides true modifications and tips for those who may not be as flexible as they'd like. Finger shows how a folded blanket can be placed under the knees or for better support while performing seated postures. A folded towel also is used for several poses, although Finger doesn't announce that in advance. The 50-minute session ends with stretching and relaxation, set to gentle New Age music that might lull you to sleep.