Zoom lenses (or varied focal length lenses) are by far the most common type of lenses known to the average consumer. Prosumer camcorders and professional video cameras often come with it right from the box. This is the case because with zoom lenses you can go telephoto or wide-angle at the push of a button. It’s a no-brainer; if you can zoom in or zoom out, the lens is called a zoom lens.
The advantage of zoom lenses over prime lenses is that you don’t have to change lenses to get to a tighter or a wider composition; it saves time. Plus, if the cameraperson is not switching lenses, they don’t have to worry about carrying them or constant cleaning. This choice of lens is ideal for documentary and newsgathering since, in both situations, the operator doesn’t have the luxury of pre-planning, rehearsals, and second takes. With zoom lenses, the operator can record, for instance, a podium with several people on it, or go for tight close-ups and show each one’s faces.
The disadvantage of zoom lenses is the loss in image quality, which is minimal but still present. Narrative filmmakers should always use prime lenses, unless they are going for a specific camera effect or trick, such as the dolly counter zoom.
Prime lenses (or fixed focal length lenses) can’t zoom in or zoom out. Therefore, when using a prime, every time the filmmaker wants to get tighter on his composition, he can either (1) physically move the camera closer to his subject or (2) change the camera lens for one with a longer focal length and narrower field of view – the telephoto lens. Accordingly, if the filmmaker decides for a wider composition, he can either (1) move the camera away from the subject or (2) change the camera lens for one with a shorter focal length and wider field of view – the wide-angle lens.
As a trade-off for the inconvenience of switching lenses, the image quality is far superior with prime lenses, offering more pristine, clearer recordings. Professional narrative filmmakers always prefer prime lenses. These are the different flavors of primes:
Telephoto lenses are longer than the average. In comparison to normal lenses or the human eye, telephoto can get really tight on the subject. It correlates to a zoom in with zoom lenses. The image is optically enlarged to show fine details from a subject that is far away.
Telephoto lenses compress space, making people and objects that are far apart appear really near one another. If a filmmaker is shooting a scene on the freeway where actors have to run among speeding vehicles, telephoto lenses can be a safe method to keep actors distant from danger while still selling the illusion that the talent is just a few feet away from moving cars.
One drawback of telephoto lenses is that shakiness and movements are more pronounced and therefore noticeable. Mathematically speaking, even though the camera itself may be moving only a fraction of an inch, the framing may be moving several feet. With ultra telephoto lenses, pans and tilts may be a pain since the moves could be too fast or shaky. Use a tripod!
Shallow depth of field is another inherent characteristic of telephoto lenses. Ergo, telephoto lenses are ideal to rack focus.
By comparison, wide-angle lenses are the opposite of telephoto. Wide-angle lenses have a broader field of view, and therefore they can show sweeping panoramas of mountains, oceans, and forests. Since camera jiggle is minimized with wide-angle, this choice of lens is ideal for handheld work.
Wide-angle lenses also exaggerate depth, making people and objects appear further apart from one another. Extreme wide-angle lenses should not be used too close to actors unless for a specific purpose since wide-angle bends the image, which is totally unflattering.
Normal lens are halfway between telephoto and wide-angle lenses. Normal lenses mimics what the human eye sees, without neither getting too close to the subject nor distorting it, nor compressing the distance among the several grounds you may have.