One of the three pillars of photography that can dramatically affect the look of your images is the camera ISO. ISO stands for the International Standards Organization. In digital photography ISO measures the image sensor. It is a crucial setting to use properly if you want to take the best possible images. The lower the number the less sensitive your camera is to light and the finer the grain. Higher numbers mean your sensor becomes more sensitive to light which allows you to use your camera in darker situations. The problem with choosing higher ISO settings is that you begin to get higher grain in your images the higher you go. Every camera has a different range of ISO values that you can use. When you double your ISO speed, you are doubling the brightness of the photo.