Classic three-point lighting (key, fill and back light) is sometimes dismissed as "yearbook lighting." True, it can look hokey in story videos, but whenever you have a narrator, a spokesperson, an interviewee or anyone who stays in one place and talks, three-point lighting is bullet proof.
Why? The small-source key light models the face, adding dimensionality and character. The large-source fill light moderates shadows and reduces overall contrast. The small back light dusts hair and shoulders with enough light to separate the subject from the background. In addition, the slightly theatrical feeling of this lighting style makes the subject more interesting by literally putting them in the spotlight.
So let’s look at strategies for placing and controlling the classic three-point instruments: key, fill and back.
Because the key light delivers the basic illumination of your scene, you should place it as if it were the only light on the subject. That means anywhere from 10-45 degrees off full-front, horizontally (Figure 1) and maybe 15 degrees above horizontal. Tip: For fat or wrinkled necks, raise the key light a bit higher to darken the neck shadow.
How far back should it go? Start with a distance that doesn’t make a subject-held white test card flare out and then adjust to taste when you have the other light in place.
A spotlight works well as a key light for several reasons. First, as noted, a directional light molds subject features. Second, the focusable lamp allows some modification of both intensity and directionality. Finally, the attached barn doors let you control light spill.
If the light is a bit too harsh, you can soften it a skosh by clothes-pinning a sheet of spun glass or milky plastic to the barn doors. You can also make the light fall off toward the bottom of the screen by placing a graduated screen in the filter ring behind the barn doors. But don’t overdo it: if you soften a spotlight beam until it works like a softlight, you might as well use a soft light instead.
The fill light cuts contrast by lighting the off-key side of the face and filling in eye, nose and neck shadows. To do this, the fill needs to be about level with the subject’s face (Figure 2). A fill light can work anywhere from 5-60 degrees to the side opposite the key. In general, I like to place the fill light closer to the front than the key light.
Here again, watch the monitor. The goal is to show detail in the darker side of the face and soften shadows, but without wiping out the modeling achieved by the key light. Ideally, the fill side of the face should seem to be naturally shadowed from ambient light, rather than lit with a second light. To adjust the fill, move it toward or away from the subject and check your monitor frequently.
The instrument you choose for a fill light (assuming you have a choice) depends on your lighting style. If the key is a spotlight without diffusion, then a second spot, suitably softened by spun glass or gel, works well as a fill. For a softer overall design, I prefer an umbrella or a softbox as large, diffuse light sources. The umbrella tends to look slightly less natural than the softbox, but it all depends on the feeling you want.
The back light (i.e. "rim light" or "kicker") is usually another small spotlight, placed high and behind the subject. I like to place it on the same side of the key so that the harder, more directional light is all coming from one side. A typical position is perhaps 150- degrees away from the front (Figure 1) and 85- degrees high (Figure 2).
In placing the back light, the goal is to (a) keep its support out of the frame, (b) balance its intensity with that of the other two lights and (c) keep the light from reflecting on the camcorder’s lens, thereby creating a lens flare. To conceal the support, you can mount it on a light- or C-stand with a lateral arm. With an alligator grip mount, you can often clip it to the top of a nearby door, or even to the metal grid supporting a drop ceiling. If all else fails, simply move it as far to the side as practical and then zoom in until you exclude it.
To balance intensity, you can focus the lamp, or use metal screens (don’t use diffusion or you’ll defeat the purpose of the light) or try a dimmer. You can easily make a dimmer one by mounting a 15-amp capacity wall dimmer in a J box, with a male-plug pigtail coming in and a female pigtail going out. (I prefer a large plastic J box screwed down to a 12×12-inch plywood base.) Dimming the back light to reduce the output will lower its color temperature, but a slight golden sheen often looks very suave.
To keep the light off the camera lens and avoid lens flare, you can often adjust the top barn door on the back light. If that doesn’t work or if your back light doesn’t have barn doors, try shading the lens itself with a flag on a stand next to the camcorder.
If all else fails, you can move the back light off to one side and lower it, if need be. The result is called "back-cross lighting," and it can do much of a back light’s job quite effectively.
Alternatives and Cheats
You may want to modify this classic three-point setup, either for a different look or because you’re short of lights, location power or both. For example, you can get a soft, window light feeling by using soft boxes for the key as well as the fill.
A soft key light has its advantages. It looks less theatrical than a spotlight and it’s kind to wrinkles and less-than-perfect skin because its shadowless illumination doesn’t emphasize blemishes. In this setup, try placing the key a bit higher, for at least a slight neck shadow, and move it in to compensate for its lower light output.
You may also want to move it around until it hits the subject’s profile for a "sitting beside an off-screen window" look. Be careful to pull the soft fill light back until there’s an obvious difference between the two sides of the subject’s face.
Soft key and fill also does a fine job of illuminating the background with spill light, especially if your subject is fairly close to a wall. Because of their diffuse quality of the light, they won’t throw a shadow on the background.
To reduce the number of lights required, you have two options. For a more natural look, omit the back light. You’ll reduce both the number of lights and the power consumption by one-third. This option works much better with the soft key and soft fill approach.
Eliminating the back light from a hard-key design can make the setup look incomplete. As a possible alternative, omit the fill light instead, substituting a large, white card to reflect light from the key light back onto the subject. However, the framing must be fairly tight for this approach, because the card has to be quite near the subject.
Finally, before we shut down for today, remember that the subject does not always have to be stationary. You can get a very nice effect by having the subject walk into the three-light setup (guided by a mark on the floor).
Sidebar: The Fourth Musketeer
Just as the famous Three Musketeers were really four, a three-point lighting setup often needs a fourth component: a background light.
If you’re working close to a wall, spill from the key and fill lights may automatically light the background for you. If the background’s too dark, however, your subject may look artificially isolated by the foreground lighting. In that case, you need to bring up the background.
The simplest approach is to place a large white reflector out of frame, where the key light will bounce off it and onto the wall. For more control, try a large source like a softbox, well behind the subject and out of frame. If the result looks too hot, try aiming the light up at 45- degrees, bouncing some of the light off of the ceiling.
A variation is to place the light close to the wall and rake across it. This only works if the wall near the light is framed off, because it will otherwise look unrealistically bright.
You can also try the same trick from high above the center of the wall, aiming down. In effect, this "rim lights" anything on the wall (e.g. fixtures or pictures). In fact, you can sometimes make the back light do double duty by opening its wall-side barn door to allow light to spill onto the background.
However you place your lights, check your reference monitor carefully for hot spots and reflections that will attract the viewer’s eyes away from the subject. A too-bright wall is worse than one that’s too dark.