What is that little graph on the back of your camera and in your editing program and do you even need to know?
If you’re like me, I didn’t really know what the histogram was for, and didn’t really care what the histogram was. It sounded complicated and I am not a fan of complicated! I look at the back of my camera, it looks good, done. And most of the time that is exactly all you need, “but”, the Histogram holds information about your exposure you may not see on that little LCD screen that could really make or break a photo. It is true, our cameras are remarkable at recovering from our poor exposures, but if we just knew what that little graph was telling us we might just save ourselves some grief, but first, lets “un-complicate” it .
The histogram is simply a visual, graphical representation of the light as it is recorded on our sensor. Your camera doesn’t know if you just took a picture of Aunt Annie or Aunt Annie’s Alligator. All it knows is it recorded light of different values (lightness and darkness) and different colours. The graph you see is showing you what it recorded and from it you can tell if you will have enough information in your file for a reasonably good or even great exposure. Most of the time we can see the image we took on the back of our camera and tell it’s pretty good, (or not). Some of us have another feature we can turn on and see blinking black areas if we over exposed it. Most of the time this is enough. If you have Lightroom, you can click the little triangle at the top corners of the histogram and see if you have lost shadow detail or lost highlight detail. It really does come in handy now and again.
So lets look at 3 images in Lightroom (it can be any software that shows us a histogram) and see what we can learn by quick observation.