Portrait photographers use four different types of lights when setting up studio light for portrait or product photography. The strength of each of these lights differs based on the camera’s aperture. The power of the light is measured in F stops.
The Main or Key light is the strongest of all studio lighting. For outdoor photos, the sun would be considered this light. It will create the most vital highlights and shadows in the photograph. When adjusting the power for this light, the F stop will equal the camera’s aperture taking the photo. For example, if the camera’s aperture was F11, the key light should be metered and adjusted to F11.
The Fill light is used to soften the key light’s effects; this prevents the total impact from being too dramatic. When establishing the power of this light, calculate two F stops below the key light. For example, if the key light is F11, the fill light will be F5.6. This concept is considered a 5:1 ratio.
The Hair light is used to create a ridge of light to separate the subject from the background. When the subject’s hair is dark, and the background is dark, this light because essential in making the subject stand out. An evening or dawn sunlight can be used to create a dramatic effect in an outdoor setting. When establishing the power of this light, calculate one F stop below the key light. For example, if the key light is F11, the fill light should be F8.
The Background light is a light that is not directed at the subject. Like the hair light, its purpose is to differentiate the subject from the background. The background light’s strength is equal to that of the key light. For example, if the key light is F11, the background light should be F11 as well.
The lights were set at the following powers for the example photograph:
Key light: F11
Fill light: F5.6
Hair light: F8
Backlight: F11
