Learning the Histogram
To kick this blog off in spectacular fashion, let’s find out what a histogram is. The Histogram is a graph that tells you the brightness (or luminosity, we’ll touch on this later) of the pixels that make up your image. From left to right it measures black pixels to white pixels with shadows, highlights and midtones being in the middle. The furthest left point is pure black, while the furthest right point is pure white. The grey and coloured peaks between these points represent how many of each different pixel there is at those specific brightness or luminosity levels throughout the image. Simple, right? At a quick glance you can tell if you’ve captured all the pixel information in the scene in front of you.
Let’s break down the Histogram a smidge more! Understanding the histogram will instantly improve your photography believe it or not.
The important thing to know about a Histogram is how the scale is measured. Notice I said it measures from black pixels to white pixels, not dark to bright. This is important because that’s how cameras see the world. They don’t look at bright sky and think it’s bright, they look at it and think ‘oh that sky is nearly white’. Obviously cameras can’t talk though, that would be ridiculous. The same can be said for a dark scene. To us we would say the scene is dark, but the camera will think ‘oh this scene is very black’. In order to judge how to expose your pictures correctly the camera will try place the black and white pixels on their correct place in the histogram. Often a camera will try and judge this by pushing dark pixels towards grey, and the white pixels towards grey.
Thanks for reading!
Ronan Harding Downes