Balance the Intensities of Lights in Close-Up Photography
The studio can be a close-up photographer’s best friend. It’s a totally controlled environment, meaning there’s wind only if you choose to create it, light comes from whatever direction you wish it to, and the subject matter is as interesting as you yourself can provide.
When working with multiple light sources, you need to balance the intensity of your lights in order to control the level of contrast you want in your images.
Two factors determine the brightness of a light source: The light’s power setting and how close it is to the subject.
If one light is set to be much brighter than another and they are at an equal distance from the subject, the brighter light has a greater effect on your exposure.
If two lights are set to the same brightness and are at an equal distance from your subject, then they have an equal effect on your exposure.
If two lights are set to an equal power setting, the closest light to the subject appears brighter in your exposure.
To control the shadows and contrast in an image you must expose for your key light and adjust your fill light accordingly. The brighter your fill light is in relation to the key light, the brighter your shadows will be.
If you want to maintain some mystery by having dark shadow areas, try to ensure your fill light is at least three stops dimmer than your key light. You can tweak the settings of battery-operated flash units and strobe lights to control their intensity. If you’re using lights that don’t have a range of power settings, simply move them away from your subject to make them dimmer.
Increasing the intensity of your fill light in relation to that of your key light brightens your shadow areas and provides less drama in a scene. Notice in the figure how the subject is represented in three separate ways simply by changing the intensity of the fill light.
The first image provides a dramatic look with three stops of contrast between the key and fill lights. (The fill light is underexposed by three stops when your camera exposes for the key light source.) In the middle image, raising the level of the fill light by one stop reduced the contrast, and in the last image, the intensity level of the fill light was raised another stop.
All: 100mm, 1/15, f/16, 50