Window Light is one of the best ways to learn to see light and find good light. Window light has direction, which allows you to see light easy. Many times outdoors there is so much light, coming from all directions, it is hard to see the different lights (top light, side light, fill light, kicker light, directional light etc.)
First, let’s describe good window light. My favorite available light is open sky, “Beautiful, blue sky streaming through an opening like a window”. Open sky is a soft light. Sometimes the light coming through a window is hard, direct sunlight. This light can be beautiful too. But the two different lights have different qualities.
The first thing I look for in window light is the quality of the light. Let’s consider window light with open sky. For portraits, I walk to the place where I am going to place the subject and turn toward the camera position I plan on using. I should be able to see open sky. Sometimes, I can only see trees, green leaves, buildings, etc. These objects will change the quality and color of the light.
As you start using window light, one of the first things you will notice is the contrast ratio of the subject. (Contrast is the difference between the brightness of the shadow area vs the diffused highlight area.
There are several factors that control contrast;
- The size of the widow. A larger window will have a lower contrast range, while a narrow window will have a larger contrast range (the shadows will be darker in comparison to the highlights).
- The reflectivity of the walls in the room. If the walls are white or light in color, the contrast range will be lower (the shadows will be lighter in comparison to the hightlights). If the walls are darker the contrast range will be larger. The size of the room will also effect the ratio. Consider two rooms with windows in opposite walls. If one room is 10 feet wide, the light from the opposite window will affect the contrast of the subject much more than if the room is 30 feet wide, because of light fall off.
- Other windows or lights in the room. If you have lamps, other lights, or windows in the room, that light will strike the shadow side of the subject and lower the contrast ratio. (the other light may also be of a different color balance which will affect the image)
- The final factor that will affect the contrast range is the distance the subject is from the window (light source). As you move the subject away from the window, the light falls off and is less on the highlight side of the subject, however, the shadow side remains relativity the same because it is lit by the light bouncing around the room. Therefore, the contrast range lowers as the subject moves further from the window. (since the amount of light striking the highlight side of the subject is less, you will need to adjust the exposure on your camera).
(This is an excerpt from my newest book “Doug Box’s Available Light Book” due out late summer)