What Is The Histogram?

What is the histogram, how does it work? Jason Parnell-Brookes shows you what the histogram does, and how to interpret it for better photos

A histogram is a chart that represents a quantity of something over a given range, and in terms of photography we’re talking about quantity of light over a given tonal range (from black to white).

The photographer’s histogram is split into four distinct sections. Starting from left-to-right, we see Blacks, Shadows, Highlights and Whites, respectively from darkest to lightest. If you want to view the histogram on a photo you’ve taken, head to Playback display options on your Nikon and tick the Overview box, then click OK. Then simply open an image you’ve taken. Next, click up or down on the multi-selector until the histogram appears.

There’s a common misconception that one should photograph to render a certain shape of histogram. Rather, it works the other way around – by informing the photographer of light and dark presence in a photo.

The two main areas we look at are: is it heavily stacked to one side; and does the data lay against the edge of the graph? If it’s the former, and the subject isn’t necessarily completely dark, or completely light, this may be an exposure issue that we have to rectify. However, the latter tells us whether there’s any clipping (distortion) occurring in the blacks or whites – under- or overexposure respectively, resulting in lost information.