Section 2.7. Video Lighting: A Crash Course

2.7. Video Lighting: A Crash Course

Today's camera optics are good, but they're not human eyeballs. Every camera, from your camcorder to professional TV and film models, captures truer color , depth, and contrast if lighting conditions are good. The need for bright light grows more desperate if:

• You record onto videotape instead of film. Video picks up an even smaller range of light and shadow than film, so having enough light is especially important when using your camcorder. A movie whose acting, sound, and dialog are exceptional can be ruined by poor lighting.

• You plan to turn your finished production into a QuickTime movie. If the final product of your video project is to be a QuickTime movie (as described in Part 3), as opposed to something you'll view on TV, you need even more light.

  The compression software (codecs) that turn your video into QuickTime files do excellent work if the original footage was well lit. When you turn a finished dim iMovie production into a QuickTime movie, you'll notice severe drops in color fidelity and picture qualityand a severe increase in blotchiness.

  This desperate need for light explains why some camcorders have a small built-in light on the front. Unfortunately, such lights are effective only when shooting subjects just a few feet away. Better still are clip-on video lights designed precisely for use with camcorders. Not every camcorder has a shoe a flat connector on the top that secures, and provides power to, a video light. But if yours does, consider buying a light to fit it. The scenes you shoot indoors, or at close range outdoors, will benefit from much better picture quality.

If your camcorder doesn't have a light attachment, or if you want to get more serious yet, consider deliberately lighting the scene, just like TV and film cinematographers the world over.

Going to this extreme isn't always necessary, of course. If it's just you filming the New Year's Eve party, you're better off not asking the revelers to sit down and be quiet while you set up the lights. But when you're conducting interviews, shooting a dramatic film, making a video for broadcast, or making a QuickTime movie for distribution on a CD-ROM, lights will make your footage look much better.

The following discussion is dedicated to illuminating those more important filming situations. When you want the very best footage, lit the way the pros would light it, the following guidelines, theory, and equipment suggestions will serve you well indeed.

(If you're just shooting kids , relatives, or animals indoors, at least turn on every light in the room.)

2.7.1. Lighting Basics

Cinematographers spend entire careers studying the fantastically complex science of lighting. Here's what they worry about.

2.7.1.1 Exposure

Exposure refers to lightthe amount of illumination the camera picks up. When the scene is too dark, you lose a lot of detail in dark shadows. Worse, your camcorder's AGC (Automatic Gain Circuit, the video equivalent of the audio-leveling circuitry described in the previous section) tries to amplify the available light. The result, which you can see for yourself by filming in dim light, is video noise (colored speckles) and unrealistic colors (black becomes a noisy , milky dark gray).

If the scene is too bright, on the other hand, details can wash out, disappearing in white areas.

2.7.1.2 Contrast

The contrast ratio is the ratio of the brightest highlights in a scene to the darkest shadows. Professional film makers often set up huge arrays of extra lights to reduce the contrast ratio, thus evening out the illumination so that the camera can record more detail accurately. (When watching a movie being filmed, you sometimes see huge lights set up, even in daylight : they're there to fill in the shadow areas, so that the camera can "see," for example, the actors' eyes.)

Film cameras can photograph details in a scene that has a 10:1 contrast ratio (highlights are 10 times brighter than the dark shadow areas). Video, on the other hand, can't capture details outside a contrast ratio of about 3:1 or 4:1. That's another reason lighting is much more important when using a camcorder, as noted above.

2.7.1.3 Hard light vs. soft light

Hard light comes from a small light source falling directly on an object. It create shard edges between the highlight and shadow areas. For example, when someone's standing in direct sunlight, the shadows on his face are harsh and dark. This high contrast emphasizes wrinkles , skin blemishes, baggy eyes, and other facial features. In other words, hard light is unflattering light.

Soft light, on the other hand, is less direct, offering softer, smoother gradations of light from brightest to darkest areas. You get soft light from a large light source, usually reflected or diffused, like the outdoors light on an overcast day or the light reflected from the umbrellas used by photographers. The result: soft shadows or no shadows; everything is lit fairly evenly.

Soft light is much more flattering to human subjects, because it de-emphasizes wrinkles and other facial contours. Unfortunately, soft light can also make your subjects appear flat and lifeless. Harder light can reveal contours , shapes , and textures, making objects more interesting and three-dimensional.

The best video lighting, therefore, comes from direct light sources that are mechanically softened. That's why many video lights have milky translucent covers.

2.7.1.4 Key, fill, and backlight

In professional film and TV work, the most common lighting arrangement is called the three-point lighting setup. It requires that you set up at least three light sources, as shown in Figure 2-4:

• The key light is the primary source of illumination in a scene. This can be the light on the camera, the sun, the overhead light above a table, or the light from a window, for example.

• The fill light comes from a second light source. It's designed to fill in the shadows caused by the key light. By doing so, fill light reduces the contrast ratio, allowing the camcorder to pick up more details. If your camcorder has a built-in light, that's usually a fill light, too. It softens the shadows cast by the key light (such as the room lights).

• The backlight comes from behind the subject. It helps to separate the subject from the background. Backlight is especially helpful in distinguishing a dark subject (such as a person's hair) and a dark background, because it casts a glow around the rim of the subject's outline.

  Be careful, of course: When the light behind the subject is too bright, camcorders respond by dimming the entire picture, as described on page 26.

• In professional film and video, technicians sometimes set up a fourth light: the background light, which is pointed at the background to make it easier to see (especially in very dark scenes).

Figure 2-4. If there's only one source of light in a scenewhich may often be the case when you're making home moviesit's called the key light. The fill light usually goes right next to the camera. The backlight helps to differentiate the subject from its background. (It also enhances the effect of smoke, haze, rain, and other atmospherics.)

2.7.1.5 Color temperature

Believe it or not, even ordinary daylight or room light also has a color. In general, daylight has a bluish cast, fluorescent light is greenish, and household bulbs give off a yellowish light.

Filmmakers call these color casts the color temperature of the light. We don't usually notice the color casts of these common light sources because our eyes and minds have adjusted to it. DV camcorders usually do an excellent job of compensating to avoid noticeable color casts, thanks to the automatic white balance in the circuitry of every modern model.

If, even so, you notice that certain shots are coming out too blue, green, or yellow, you can help the camcorder along by switching on one of its programs (as several manufacturers call them)presets for Daylight, Indoor Light, Snow and Ski, and so on. Each is represented in your viewfinder by an icon (such as a sun or a light bulb). When you use these presets, the camcorder shifts its color perception accordingly .

And if even those adjustments don't fix a particular color-cast problem, your camcorder may offer a manual white-balance feature. White balancing means identifying to the camera some object that's supposed to look pure white (or colorless), so that it can adjust its circuitry accordingly. To use the manual white-balance feature, focus on something white that's illuminated by the key lightfor example, a clean T-shirt or piece of paper. Zoom in until the white area fills the screen, then press the White Balance button. The camcorder responds by compensating for the dominant color in the light.

2.7.1.6 The 45/45 Rule

This lighting guideline suggests that the key light be at a 45-degree angle to the camera-subject line and at a 45-degree angle above the ground (see Figure 2-5).

Figure 2-5. In professional moviesand very good amateur onesthe key light is usually positioned above and to one side of the subject. The fill light (Figure 2-5) is usually on the opposite side of the camera, so that it fills the shadows. The backlight is usually on the same side as the fill light.

2.7.2. General Guidelines for Lighting

The preceding discussion gives you the theory of lighting design. Here's the executive summarya distillation of that information down into just a few points to remember for the most professional-looking lighting.

• The subject should be brighter than the background. Don't shoot people with a bright window or doorway behind them, unless you want them to disappear into silhouette.

• If the background is bright, shine additional lights on the subject. If you can't do that, use your camcorder's Backlight button or its manual-exposure knob, if it has one, so that the subject is correctly exposed (even if that makes the background too bright).

• Stand so that the key lightthe sun, for exampleis behind you. Don't shoot a subject with the sun behind her (unless you want silhouettes).

• Avoid a key light that's directly above your subject. That arrangement causes ugly, heavy shadows under the eyes, nose, and chin. (The cinematographers for the Godfather movies set up lights this way on purpose, so that the mobsters' eyes would be hidden in shadows. That's not the effect you want when filming the mothers-in-law at a wedding ceremony. Usually.)

• If you decide to add lights to your setup, you don't need expensive movie lights. At the hardware store, buy some in expensive photoreflector lights (those cheap, silver, bowl-shaped fixtures) and equip them with photoflood or tungsten work-light bulbs.

• If you're aiming for professional quality, create soft fill lights by bouncing light off a big square of white foam- core board (which you can get at Kmart, Home Depot, and so on), or a big piece of cardboard covered by foil or newspaper. This arrangement creates a beautiful soft lightgreat for closeups.

  Bouncing lights off a white ceiling makes for a pleasantly soft key light, too.

• Tracing paper, tissue paper, and translucent plastic(such as shower-door material) make great diffusers for soft light, too. (Just don't put the paper in contact with the bulb; this kind of paper, especially tissue paper, ignites easily if it gets too hot.)

• Be alert to the presence of shiny surfaces like windows , glass, chrome, and highly polished wood in your shots. They can reflect your lights into the camera, making it look as though someone is shining a light directly into the lens.

• If the backlight spills into the lens, you get flares those oddly shaped patches of light that move across the frame as the camera pans. The sun behind the subject, or car headlights, often cause flares. If you can avoid this effect, do so.

Figure 2-6. When you're filming the school play, somebody's head or hat may confuse the autofocus . When you're filming scenery , a nearby branch may similarly fool it (top). The front bars of zoo cages are also notorious for ruining otherwise great shots of the animals inside them. The only solution is to use manual focus (bottom).