Zoom!

It's the last half of the ninth in a crucial Mets-Cubs game, with the Mets leading three to two. Don Kessinger is on second and Billy Williams is set at the plate. Suddenly, as Mets pitcher Gary Gentry releases a change-up, Kessinger is streaking for third. In the stands, other camera buffs are desperately juggling lenses and camera bodies in a vain effort to get a close-up of the play. You, however, have already rotated your zoom to bring in a crisp telephoto image of the action and, just as Kessinger dives into third, you snap the shutter. It's a close call. The umpire says Kessinger is out and the Cub fans howl. Among the loudest are those fellow photographers who neither saw the play nor got the shot. But you did; and when you see the photo a few days later, you find you have a perfectly composed, in-focus telephoto close-up of the play and, sure enough, the umpire called it right. But zoom lenses are for the pros, you say. They're too complicated. They cost a small fortune--and don't you need a tripod to use one? Not so. First, the manufacturing of a precision zoom is very complex, but operating the lens couldn't be simpler. All you do is attach (concluded on page 179) Zoom!(continued from page 101) the zoom to your single-lens reflex camera, sight through the view finder, rotate the zoom's knurled ring (on some models you slide the zoom's barrel as you would a trombone) to the desired degree of closeup and press the shutter button.

Admittedly, zooms aren't cheap. A Soligor 90-190mm model will set you back about $150. And from there, the prices zoom skyward. So, if you think of your purchase as one lens, it seems expensive. But if you compare its cost with what you'd have to pay for three lenses with varying focal lengths, you're definitely ahead of the game.

And the tripod? You'll need one only for some of the spectacular trick effects that we describe below. Of course, if you've got yourself an excellent railbird's-eye view of the race track, a telescoping monopod that you can slip into your camera bag will make the afternoon's shooting that much more comfortable.

Now that we've overcome some of the objections amateur photographers have to a zoom lens, let's take a look at how this handy instrument functions. First, the name zoom lens is a misnomer: It is really a series of lenses working in combination. In most models, there are 18 to 20 individual lenses arranged in groups of three or four, each one of which moves in relationship to the others. The effect is, as Buckminster Fuller would say, synergistic. That is, the parts work together in such a way that they produce a result that is more than the sum of each of the parts' individual properties. Technically, what you have in a zoom is a continuously variable-focal-length lens that remains at the same distance of focus during a change in focal length. This means that as you zoom closer in on, or farther away from, your subject, you always remain in focus.

This phenomenon is relatively unimportant when you're shooting a stationary object, but suppose that you're in a park on a balmy summer afternoon and there's a particularly lovely girl bicycling by. Shooting her with an ordinary lens would be easy, but you also want to snap a close-up of her face before she gets out of range. With a regular lens, you'd have lost that moment forever, but with a zoom, a mere flick of the wrist virtually guarantees a great close-up that's crystal-clear.

Knowledgeable camera buffs are keen on the zoom for reasons other than its instant-close-up advantages and ease of operation. Because it does the work of a dozen lenses, you can utilize its unique construction for some highly impressive photographic tricks.

Take the blurred-zoom technique, for example. All you need do is select your subject, set your camera on a tripod, adjust the shutter speed to a half second or so and carefully zoom the lens during exposure. What you've photographed is something the human eye cannot see: how an object looks as it's simultaneously seen from various distances.

An even more dramatic effect can be created by shooting against a black background while firing an electronic flash at each new focal-length setting of the lens. Here, the blur achieved by the previous technique disappears. What is seen is a sequence of sharp repetitive images, all on the same exposure. Only quantum physics, Marcel Duchamp's famous Nude Descending a Staircase and the more gifted LSD voyagers have ever entered that world of fractured time before. It's as if you were seeing time itself move in distinct steps, instead of in its normal, continuous flow.

A third trick effect is to simultaneously zoom and pan as you follow a moving figure. The subject--a goalward-bound fullback, for example--remains in sharp focus, while the background forms wildly diffused patterns, streaks and colors resembling the abstract expressionism of Jackson Pollock.

The fourth technique with a zoom involves the blurring achieved by combining an extended exposure with existing light while zooming. But in this instance, you leave your principal subject unlit until you've stopped zooming. Just as you hit the chosen telephoto position, you (or an assistant) fire off an electronic flash. (Fashion photographers often use this technique because it produces a psychedelic effect of the model emerging, sharp and unblurred, from a background of swirling mystery.)

As you perfect these techniques, you'll find yourself awakening to a new photographic experience--one in which you play the role of a fine artist standing at an easel, a zoom-equipped camera your paintbrush, ready to create new beauty.

Which zoom lens should you choose? Basically, it depends on whether you are chiefly interested in zooming in on distant objects (as in sports or nature photography) or mostly concerned with the artistic effects created by zooming and flashing, zooming and panning or similar techniques.Generally, lenses are differentiated by their focal lengths--a measurement that's baffling to laymen. The focal length is the distance between the film and the lens. But all you need to remember is that the greater the focal length, the less the apparent distance of the object. A 300mm-focal-length lens, for example, makes the third baseman appear six times closer than a 50mm-focal-length model does. A lens rated at 50-300mm, such as the $795 Auto-Nikkor zoom, brings a distant image much closer than, for instance, the $209.50, 43-86mm Auto-Nikkor zoom. For those interested in achieving artistic effects, the less expensive and lighter 43-86mm model is quite suitable. But if it's versatility you're seeking, we feel an 80-200mm zoom is the best choice.

Probably the most important rule in choosing a zoom lens is: Buy the one designed to go with the camera you are using. No manufacturer designs a lens to couple perfectly with another manufacturer's camera, and universally adaptable lenses, however good they may be, do not have the hand-in-glove fit of a zoom built especially for your camera by its designer.

Also, when choosing among zooms in a similar focal-length range, keep in mind that a lens with a smaller maximum opening, or f-stop (you'll find the f-stops on the ring near the rear of the lens), will usually be of lighter weight and produce sharper photos. Conversely, a lens with a larger aperture is heavier, but its ability to perform in less light helps compensate for this disadvantage.

An article on zooms wouldn't be complete without pointing out that some early models left much to be desired; colors were often untrue and the picture occasionally blurred, especially around the edges. To think of today's computer-designed zooms in terms of those earlier models would be like comparing a Cadillac with a gocart. It's true that in a side-by-side comparison of identical zoom and single-focal-length shots, the zoom photos will be slightly less sharp. But the average amateur would be unable to spot the difference.

While you're checking zooms out, you might also take a look at variable-focal-length lenses (V. F. L.). As the salesman lifts one from the case, he'll probably tell you that model operates "just like a zoom." It doesn't--the difference being that a V. F. L. must be refocused each time the lens is adjusted. But V. F. L.s do offer some technical advantages: They often have a larger aperture than most zooms and a wider angle of view. So if you already own a zoom, a V. F. L. would come in handy as a back-up lens to be used in available light--provided whatever you're shooting is not fast-action.

Finally, with a zoom lens, you can forget about that elusive moment missed when you attempted to change lenses. And you can forget about focusing hassles and money hassles (caused by buying three lenses of different focal lengths when one zoom would do the job better--and more cheaply). With this one purchase, you've made the whole world of photography more accessible, which, when you think about it, is a lot to get out of a single investment.