The Histogram Explained

Photography Tips

Getting a handle on using your camera’s various settings and tools can sometimes make you want to pull your hair out—and the histogram is one of the trickiest to understand. Looking more like something to measure earthquakes than camera data, the histogram often has beginning photographers scratching their heads. But professional photographer Joshua Cripps breaks it down—what a histogram is and how to use it—in this easy-to-understand explanation:

How to Read a Histogram

Histograms are a type of chart, and like most charts, the horizontal and vertical directions represent different things:

1. The horizontal axis, from left to right, represents the photo’s brightness values from pure black to pure white, with middle gray in the center.
2. The vertical axis represents how many pixels have that corresponding brightness value.

Here’s an example. There are three distinctive levels of brightness in this black-and-white photo, and those are clearly represented by the big spikes in the histogram:

“Since we know understand that a histogram is your camera’s way of representing all the brightness values in your image, you can use it to tell if your photo is underexposed, overexposed, or if you’ve clipped any shadows or highlights.”

“Possibly the greatest gift digital photography has given photographers is the histogram, because it makes guessing at exposures a thing of the past.”

Even if you wouldn’t go so far as saying the histogram is a photographer’s greatest gift, hopefully this simple tutorial will get you on the right track to using histograms to get the right exposure every time.