ISO is the final piece of the exposure triangle. Understanding how ISO works will allow you to take shots where it normally wouldn’t be possible without working knowledge of how ISO actually works. ISO is basically the light sensitivity of the camera’s image sensor (or film). ISO is usually rated at 100, 200, 400, 800, 1600 and even 3200. In this article we’ll take a look at an easier way to think of ISO, how ISO can help with faster shutter speeds and ultimately how it affects your exposures.

Shutter speed, another main factor of the mysterious exposure triangle, however the good news is that it is usually the easiest of the big 3 for beginners to master (it was for me anyway). Shutter speed can allow you to get a razor sharp shot freezing the action or the nice motion blurred image implying movement and motion. Whichever type of shot you are shooting, it is important to know how shutter speed works and how it's going to affect your overall exposure.

Aperture, shutter speed and ISO, the big 3 that usually cause the most confusion early on. If you can get a grasp on how the big 3 work together to affect your exposures, taking pictures will be a much more pleasant experience and will have a lot less frustration. Once you understand it, it is like riding a bike. It may take some time and effort to learn, but once you learn it you won't forget it. The one that causes the most confusion out of the big 3 is usually aperture. Why? Well there’s that sequence of numbers that seem to work backwards and that little matter of depth of field. Understand the big 3 and the rest will come much, much easier.