Before we talk about photographic and video lighting let me briefly introduce another concept: f-stops. Around the lens, on a ring, or in the viewfinder of all non point and shoot cameras there is an array of numbers called f-stops that can be selected. F, in this case, stands for focal length. Here is a partial listing of the array and what it looks like:
f 2.8 4 5.6 8 11 16 22
These stops control the aperture or opening of the lens; how much light hits the film or sensors. F4 lets in half the light of f2.8. f5.6 lets in half the light of f4 and so on.
Now to the photographic and video lighting part: A basic, talking head, photographic and video lighting set-up consists of three lights:
The Key or main light
The Fill or supplemental light
and, The Highlighter.
For the sake of discussion let’s say all three lights are the same number of watts, the same brightness. From the camera position, facing the subject, the Key light is usually placed to the cameras left about 22 degrees. The fill light is usually placed to the right at about 22 degree. The fill light should be one half the brightness of the Key light. How do you accurately do that if they are both are the same brightness? It’s simple, put the fill light further away than the key light. But how much further away should it be? Now it gets really simple. Refer to the list of f-stops above. Now let’s think of the F as meaning feet instead of focal length. If your Key light is 4 feet away than placing your fill light at 5.6 feet makes the brightness of it half as bright on the subject as the Key light. This is a 2 to 1 lighting ratio. Want more dramatic effects? Move you Fill Light to eight feet away, or two foot-stops from f4, for a 3 to 1 lighting ratio.
The Highlighter is placed behind and to the right or left of the subject. It may be shined on the hair to give highlights there or on the shoulders to give separation from the background or on the background itself to add depth to the image. Use the Highlighter at less or equal to the distance of the Key light.
If you can remember the simple array of numbers above you can be successful at basic photographic and video lighting techniques without any guess work. Other photographic and video lighting questions include whether to use short or long lighting, butterfly or cameo lighting, high key or low key lighting, but first master the basics. Some people say creativity happens by luck or chance. Creativity comes from knowing the rules and manipulating them. I like what the photographer Ansel Adams said: Chance favors the prepared mind.
Good luck, and, shine on brightly.