Photography and a simplified understanding of light
Available light photography can be very tricky. Available light used to mean no artificial lighting was used in photographing your subject. With the advent of of digital cameras 'available lightning' has taken on a whole new meaning. Artificial light - without a flash - is one way photographers are using light. Mixing natural light with artificial light is also part of the mix. How do we figure out how to use the variable lighting situations that are available?
Different types of light emit a different color which is not seen with our eyes. Film for example could not adapt to the different light. So daylight film had to be used in daylight or with flash whereby it simulated daylight. With digital cameras each frame can be shot with a different light source or even a multitude of light sources.
There are three ways that digital cameras compensate for lighting. The first, and easiest, is by leaving the color setting to automatic. This setting is correct most of the time. But it can be fooled. You get to see color casts that don't do it justice especially in the skin tones.
The second method is a little more finicky. It involves switching the color setting in relation to the existing light form. DSL's have setting for different light sources. You can choose florescent, tungsten, flash, daylight, or cloudy. Our eyes compensate for all these but the camera does not. The problem with this method is that if you are working in fleeting conditions , such as a wedding, you would have to stop and figure out what type of lighting is lighting the scene. Then go into the camera setting and make the proper adjustments.
The third method and the most complex is the custom setting adjustment. There are two ways of accomplishing this. But first what is a custom setting? It is a setting that lets you customize the white balance of the camera to the particular lighting in effect. With this setting you can use multiple types of light sources with excellent results.
The first way to accomplish this is by using a gray card. The way it's done is you take a picture of a 15% medium grey card - camera stores usually carry them - with the card place where the subject is. Then through the menu, find the custom white balance setting (check you camera's manual) it will ask you to choose the photo you want to use as your custom white balance, in this case it the gray card photo. Click set and your done. The other way of doing it is with what's called an 'Expo' disk, www.expodisk.com. It's a translucent disk that fits in front of the camera lens. You take a picture with the camera facing your light source. Then you go through choosing your custom white balance as in the previous method, but this time you choose this photo to create the custom white balance. Click set and your done.
The custom white balance method is the slowest but the most accurate. It is ideal when shooting still images. But a little time consuming when you are pressed for time and have to shoot in multiple locations with an array of light sources. Weddings are typical of this.
The best results are achieved when you know your camera inside out. Experiment and ask questions.