The power or intensity of the main light is not the determining factor for the distance the main light is placed from the subject. It is the visual effect the light has on the subject that determines this distance. When the main light is too high and close to the subject, there may be too much light falling on the forehead and not enough light falling on the lower part of the face. This effect can be improved by moving the main light farther away from the subject and placing it correctly.

Highlights on the forehead, the upper cheeks, the chin, and along the bridge of the nose are created by the main light. These highlights give life, brilliance, and form to a portrait, and the quality of these highlights are controlled by the main light distance.

To determine the main light distance, start with the light about 4 feet from the subject and about 2 feet above the subject's eye level. The light should be about a 45-degree angle to the lens axis. Observe the forehead highlight and move the light closer to the subject; as the light gets closer to the forehead, highlights spread out to a large, flat area and begin to wash out.

Now, start moving the main light away from the subject. As you slowly move it back, you will find there is a point where the forehead highlight becomes relatively small and bright. When the light is moved back much further from this point, the highlight spreads and disappears. Between the point where the highlight is brightest and where it starts to disappear lies the range where the highlight still has character. This point is where you get the most pleasing effect. Once you have found the distance where the main light gives your desired effect, the distance should remain the same regardless of the direction you need to move the light. This main light distance should always be considered as the starting point of portrait lighting.

Main Light Height

To determine the correct height for the main light, move the light directly in front of the subject while maintaining the distance determined for the forehead highlight. Raise or lower the light until the shadow cast by the nose is just long enough to touch the top edge of the upper lip. This is the height the main light should normally be no matter at what position you place it in an arc around the subject.

When your subject is wearing a hat with a visor, the visor shadow should fall naturally across the face. Many photographers think the shadow cast by the visor should not shade the eyes. The shadow from the visor should shade the eyes, however, in a portrait, this shadow should not be so dark that shadow detail is lost and the eyes are hard to see. To prevent this shadow from being too dark, raise the main light to the desired height, and instead of aiming it down at an angle, aim it straight.

This way the light is cast under the visor and prevents the shadow from becoming too dark

Main Light Direction

By the time you have determined the main light distance and the height for a given subject, you should have a pretty fair idea of the direction you want the main light to come from. To establish the direction from which this light should come, move the main light in an arc, to the right or left, around the subject. Remember, while moving the main light, its established distance and height should be maintained.

The shadow cast by the subject's nose is your key to main light direction. The light should be moved around until the shadow cast by the nose merges with the cheek shadow and leaves a small, triangular highlight on the cheek. When this is done, the main light is in position. Remember, the main light must always be the dominant, directional, shadow pattern forming light.

Fill-in Light

Once the main light has been established, the fill or fill-in light is added. This fill light is a secondary light and must not overpower the main light. Its purpose is to fill in and soften the shadow areas, making them lighter, and to provide shadow detail.

The fill light is normally placed slightly above the subject's eye level, on the opposite side of the camera from the main light and near the camera lens axis. The fill-in light should be less intense than the main light and of softer quality. This light is often diffused even when the main light is not.

By placing the fill light slightly above the subject's eye level, you can cast a shadow under the chin. This shadow separates the head from the neck. The chin shadow should be soft and unpronounced.

The intensity of the fill-in light can be controlled by either adjusting the power setting of an electronic studio light set or adjusting the light-to-subject distance. The fill light can be moved in an arc to the side of the subject and away from the camera. The fill light must not produce conflicting shadows (shadows that point toward the main light).