Do you remember the histogram from Maths class? The thing that looked like a bar graph? I do, and I remember thinking it was confusing. So that chart on the back of my camera that looked like a mountain range? I just ignored it. It looked way to confusing. Plus, photography is a creative pursuit, how important can a graph be?

Histogram

Turns out, pretty important. And when you take some time to learn it, the histogram is not complicated. It’s actually a really useful tool to improve your photos. So what is a histogram? Your histogram is simple a graphical illustration of the light and dark tones in your image. From left to right, the histogram shows the darkest part of the image, to the lightest part.

Histogram Labels

On the left is pure black, then we have the blacks, which are the darkest parts of the image. After that is the shadows, then the midtones. The whites are the light parts of the image and the highlights are the brightest parts. Finally, at the right, we have pure white. The “mountain ranges” you see, are the pixels in the image. So if you have an image with lots of light areas, your histogram will show a peak somewhere on the right of the histogram, like this image below. The big peak on the right shows all the snow in the image.

Histogram

Conversely, this image is very dark. Most of the pixels are pushed up on the left of the image as they are pure black. There are only a few pixels along the bottom of the histogram which show the lighter areas around her face. Often, a histogram like this one would mean the image is underexposed, but it can sometimes be used with intention. In this image I deliberately made most of the image dark because this is the image is had in my mind.

Your histogram doesn’t just show you what your image looks like in camera. It can also change when you edit an image. Take a look at this image below. It’s overexposed. The peak on the right side of the histogram shows the overexposed sky.

Overexposed histogram

However, after I edited the image, the histogram changed dramatically. I was able to recover the detail in the sky because the image was shot in RAW. The histogram has shifted to the left and the image is no longer overexposed.

To do this, I reduced the highlights and exposure in Lightroom and I then used a brush so that the foreground would not be too dark. I also increased the contrast and vibrancy slightly.

So How Can a Histogram improve your images?

Once you know how to read your histogram, you can use this information to check your images and make changes if you need to. The histogram is a better indicator of the light in your image than the little image on the back of your camera. It’s especially useful in bright sunlight, when it’s hard to see the image. In the image below, I was shooting in bright sunlight at the beach. I didn’t want to overexpose the sky, but on the back on my camera, the family looked too dark. Looking at my histogram, I could see that the shadows were not too dark and I didn’t need to increase exposure.

During editing, I recovered the highlights and lightened the shadows. If I had ignored the histogram and just looked at the image on the back of my camera, I would have increased my exposure and I wouldn’t have been able to recover the detail in the sky.

So are you ready to give your histogram a try? It may seem confusing at first but I think you’ll find it really helpful, especially when shooting in bright sunlight.