Production Lighting: How To Best Use Ambient Light
You can cut down the amount of work involved in lighting if you take advantage of ambient light. Ambient light is guaranteed to be natural, so building upon it as a base can yield very pleasant results.
Step 1: Light Quality
For this example, we will imagine that you are shooting in a living room during the day. There is a big window on one side of the room that is illuminating everything. In all likelihood, you could expose your scene without doing anything. The sensitivity on cameras today allows for relatively low light conditions. However, you need to plan for the quality of light changing throughout the day. Though in the morning you have a soft ambiance in the room, in the afternoon, the light will become much brighter and warmer. Perhaps in the evening, the sun will come around and shine directly through the window. Keep this in consideration while planning your scene.
Step 2: Diffusion
If you are lucky, your scene will be short enough that the light will not change much throughout the time you will be shooting. But if not, then you will need to make some modifications throughout the day. Always shoot the wide shots first. Wide shots are the most difficult because you see more than in any other shot. This way, you establish the scene with the nice soft morning light. Then, when the sun finally becomes a harsh direct source, you are shooting close-ups. Close-ups are much easier to manipulate since there is less space being seen by the camera.
Now you can set up a frame of diffusion next to the person to eliminate the direct light. If you were to have shot close-ups in the morning and wide in the evening, you would have had to diffuse the entire window. In the case that you do run into this mishap, sheer curtains are a quick and visually acceptable solution.
Step 3: Enhancement
You probably will not want to light your scene entirely with ambient light unless you get very lucky. Though your room is exposed, it is definitely not evenly lit. It is obviously much brighter by the window than on the other side of the room. You also may not be satisfied with the intensity of the light bouncing around on the fill side. So, you will need to bring your own light sources to enhance the existing light.
If your character will be walking back and forth from the window side to the dark side of the room, you will want to even out the spread. Some HMIs from out the window should do the trick. Though a discrepancy will still exist across the room, it will be less extreme. Do not be afraid to add highlights in the background or a rim light for the person's hair. Though you are going for the all-natural look, there is no reason to stop painting.
Ambient light can in some instances be all that you need. However, it is completely out of your control, so using it will require some intuition.Popular P&S Cameras for High Quality Photos: