Light is one of the single most important elements in filmmaking.
As a cinematographer, much of your job centers around shaping light. Not only do you have to know where to get it, but you also have to know where to put it. In the video below, Simon Cade of DSLRguide uses a real set to...ahem...illuminate 4 basic lighting considerations that professionals take into account every day when making these decisions:
The four key concepts we can take away from Cade's video are:
Use what's available
Available light is what most beginner/no budget filmmakers are used to. It's the lamp on your nightstand. It's the bulb in your living room. It's the sun. It's the moon. It's the streetlight on a busy city street. This kind of light can be really useful if you don't have access to a pro light kit, especially when used with light modifiers like scrims, umbrellas, or even a big ol' white sheet. However, available light has its limitations and downfalls, including various light temperatures, power/brightness, location, and, you know, the fact that you and your set are orbiting around it making it difficult to shoot with it for long periods of time. (We're looking at you, Sun.) Cade's other tips show how one might get around these limitations.
Make sure your lighting choices are motivated
If you do have access to professional lighting equipment, you can start to make more motivated lighting choices. You can choose your keys and fills to help make your scene look more cinematic, to enhance your storytelling, and to correct any issues you might have with the way your scene is being lit. But the important thing to remember is that these decisions shouldn't be arbitrary, they should be motivated. They should serve a purpose. They should make the images and/or the story better—preferably "and."
Learn how to hide your lights
This is actually a skill you really have to practice to get any good at, because anyone can hide a light so it doesn't show up on camera, but the real artistry comes from knowing how to do it and still get the results you were looking for. This actually takes a ton of creativity and inventiveness, but, again, with some practice you'll get a keen sense of the most unobtrusive and effective light placement.
It's easy to get complacent and rely on tried and true methods for lighting a scene, but wherever you see an opportunity to experiment with lighting, take it. Play around with colors, placement, shadows, different types of bulbs, and modifiers. Use combinations you've never tried before. Try being more bold if you're subtle or more subtle if you're bold. Film and cinematography is an ever growing language that is eagerly waiting for new words to be added to it. As Cade says in the video, "It never hurts to ask yourself, 'Should we try something unpredictable?'"