The zone system of light metering
The zone system was first used by Ansel Adams in 1941 to help set exposure correctly. I use the zone system to help set the proper exposure and tonality on wildflowers. The color tone will not always come out correct if you go by your meter reading alone. Most camera meters will try to set the camera to medium tone. Your exposure setting may also vary depending on what type of metering (spot, center weighted, matrix) you are using. This chart is similar to the one John Shaw explains in his book Nature Photography for setting tonality (page 25). The tonal range of most digital camera’s shooting in JPEG mode is similar to color slide film, which is about 5 to 6 exposure stops. Shooting in Raw mode will gain you a couple more exposure stops. Best when used with manual mode.
For a printable version of the zone chart, click on the chart or right click to save a copy of the image. I keep a laminated version in my camera bag to refer to when I’m taking pictures. An alternate method is to meter the open palm of your hand (zone VII – light) in the same light source as your picture and open up one stop from normal. I use this method when I’m not sure of the metering of a flower and it works very well.
An example of using the zone system would be a small white flower like this Prairie Star against a darker background. You would spot meter the flower and use the zone chart to adjust to the proper tonality of the white (+2 stops). Take a picture and adjust up or down, until you get it just right. After using it regularly over a period of time, you will find the zone system helpful in getting the tonality exactly as it appears and simple to do. For the most consistent results using the zone system, use your camera in manual mode and spot meter the critical parts of the image.
You can learn more about the Zone System of photography on the internet. Make a habit of using the correct white balance setting and avoid the blinkies (highlight warning) on your preview screen as much as possible. Along with this, learn to use your camera’s histogram function as a final check on proper exposure – Bruce Perrault