Digital Cameras: Understanding Histogram Feature
Pretty much all digital cameras you buy nowadays have a histogram feature. And, pretty much every consumer who buys one of these cameras has no idea what a histogram is, unless he's a professional. A histogram is a graphical representation of all the tones in an image. When we talk about tones in an image, we're referring to the effect that light has on color. Bright lights can make colors appear washed out and not enough light can make them look too dark. Thus, a red object's color can be interpreted differently depending on how much light is hitting it.
The Histogram Feature
What the histogram does is it shows the distribution of the tones captured. The horizontal axis of the graph represents the variation between tones, while the vertical access represents the number of pixels from the image that correspond to that tone. The left of the graph represents dark tones and the right of the graph is white, bright tones.
With a histogram, a user can bring his photos into editing software and use the graph to help color correct his image. It can also be used to compare how much of a photo has been lost to over and under exposure.