Photography is the process of visually capturing light. Therefore, light is the key element to every photograph. Having an understanding of light is essential to becoming a photographer. Relying on your camera's automatic settings will at some point become a hindrance because these settings can be misleading. The camera does not always make the correct choice. Instead, you, the photographer, have to be able to recognize the light and know how it will affect your final product.
There are different types of light and different directions of light. The direction of the light determines your choice of aperture, shutter speed, and ISO. The type of light determines your white balance. What is white balance? White balance is just what its name suggests; it is the proper balance of the color of the light. Light itself is never one shade of color, but comes in a full spectrum, its color determined by what type of light it is.
But okay, before we get too far ahead of ourselves, let's take this one step at a time.
DIRECTION OF LIGHT
Light comes primarily from one of three directions - the front, the back, or the side. No one direction of light is incorrect. They each have a place in photography. However, sometimes one can be a detriment to the result you are trying to achieve. This is because each type of light creates shadows. Shadows are, by definition, the absence of light, and they can often "make or break" a photograph.
This first photograph is an example of front lighting. Two natural sources of front lighting are sunrises and sunsets. Flash photography is also front lighting. Front lighting does just what its name suggests; it places the greatest light source from the forward direction of the object. The shadows in a front lit image therefore will fall to the back of the image.
This second image is an example of side lighting. Side lighting gives a scene more texture. It prevents photographs from appearing "flat" by creating longer shadows (like those you'd see in late afternoon). Sand, wood, and architectural photographs often benefit from side lighting.
The third type of directional light is backlighting. Backlight has two effects in a photograph. It creates silhouettes, as in my example above, or strong highlights, as in my example below. Backlighting is one of my favorite types of lighting. I like the stronger shadows and the greater contrast in colors. I use it also to hide distracting backgrounds.
As you can see, part of the importance of knowing the direction of the available light comes from where it places the shadows. Shadows are the areas in your photograph where the most detail is lost. You can understand then, how incorrectly placed shadows ruin an image. In reverse, correctly placed shadows greatly enhance an image.
Knowing the direction of the light also affects your choice of metering. Metering is how your camera decides to deal with the available light. In stronger light, I use spot metering the most. Spot metering enables me to choose where to place the shadows and how strong I desire them to be. However, it must be used wisely because you never want to make an object that should be highlighted into an area of shadow. When your whites appear gray, you can know you've over-metered. The other two forms of metering, average and center-weighted metering, have the affect of evening out the light. Either of these will create more balance between light and dark areas.
It is worth mentioning at this point, another direction of light - diffused lighting. Diffused lighting is most ideal for many types of subjects. The most common example of diffused lighting is a cloudy day. Think also of a lamp. The purpose of a lampshade is to soften and spread out the light within the room. Diffused lighting causes shadows to almost entirely disappear. For this reason, floral images and portraits benefit from diffused lighting.
TYPE OF LIGHT
Learning the direction of the light becomes easier with time, and choosing the proper settings with experience. Knowing the types of light is much easier, but it enters into the equation another important decision, white balance. Most digital cameras depict white balance as small symbols: a full sun, a cloud, an incandescent light bulb, and different types of fluorescent bulbs. These symbols visually depict different types of light and therefore, different colors of light.
Remember I said earlier that all light has a particular color. For an example of this, take a picture of the same object using each of these symbols. Notice how the overall image shifts from blues to reds. Now take a picture of a scene in each type of light using the proper symbol for that type of light and notice the difference. The final object of white balance is to keep your white areas white. A white bird or flower should look just that.
The best gauge for white balance is your own eyesight. Ask yourself if the photograph you've taken looks like the scene you saw. If it doesn't, then adjust your settings and retake it.
Here's another thought about white balance. There are times when the white object does not appear white. For this idea, think of paint. Walk into any home improvement store and ask an associate for a can of white paint. They will look at you strangely and then lead you to a rack with various colors of white paint. Applying this idea to photography, look at my waterfall photograph below. This waterfall was in heavy shade and had a bluish cast. I controlled the white balance, keeping the white of the water more blue, through my use of the shade (or cloud) symbol and average metering.
Learning to recognize the type of light and its direction is the first step a photographer makes toward choosing the correct camera settings for each situation. Without a working knowledge of how the given light changes a photograph, a photographer will continually struggle with his results. Knowledge of the light is also essential toward any decisions made to change or enhance the light.
As in most things in photography, light and white balance work hand-in-hand, each one affecting the other. By developing an awareness of light in different situations, a photographer will be able to make quicker decisions and in the end better control the final result of his photographs.