Digital photography offers certain benefits for thinking photographers that are only realized with a basic understanding of a metering feature called the "histogram."
Using the histogram in your camera's image viewing LCD will guarantee you a much higher percentage of well exposed images. It is well worth working to understand the histogram, and is not overly complicated. I will try to cover this feature with enough detail to give you a working knowledge of how to use the histogram to make better pictures. If you are deeply interested in the histogram, there is much research material available on the Internet. This article is only covering a small amount of the information that is actually available, but will present enough knowledge to improve your technique immediately.
Light Range
A digital camera sensor can only record a certain range of light values. Remember how with film the light range was limited to only a few f/stops of range? With transparency film the limitation was about 3 or 4 "stops" of light, while with negative film it could go on out to 5 or 6 stops. Today's digital sensors seem to be able to record about 5 or so usable stops of light. Most will agree that the digital camera can record a little more than transparency film, and a little less than negative film. This will change, since some digital cameras are now offering extended range sensors.
Unfortunately, many of the higher contrast subjects we shoot can contain over 12-stops of light values. This is quite a bit more than it is possible to capture with film or a digital sensor today. It is important to understand how your digital camera records light, so that you can better control how the image is captured.
Look at Figure 1 below. The gray rectangular area is a representation of an in-camera histogram. Examine it carefully! Think about it for a minute before reading on.
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