Tips to Understanding ISO for Beginners

ISO is basically a measure of your camera sensor's sensitivity to light. Most cameras have a base ISO of 100 or 200. And when you're shooting at this ISO, that's when you're gonna get the best image quality. But you'll have more options than just shooting at base ISO. Cameras will allow you to choose ISO 200, 400, 800, 1,600 and beyond. And the higher you go, the more sensitivity to light your sensor has. And these higher ISOs can be useful when you're working in low light conditions. The trade off of using these higher ISOs is that you're gonna get something called digital noise. Basically when you're using these higher ISOs, you're pushing the sensor's ability to gather light, but you're doing it through artificial electronic means. And the result is, you get this pattern of grain that's introduced into the image and this grain will degrade image quality. So the higher the ISO you use, the more light you can get, but the less quality you're gonna have. Every time you double your ISO numbers, say, go from maybe 100 to 200, you double your sensor's ability to gather light. And most cameras will give you the option of shooting ISOs as high as 4,000 or 6,400, or even higher. A lot of digital cameras these days do a pretty good job at correcting the digital noise even with these high ISOs, but all things being equal, you're gonna have better image quality the lower the ISO that you use. You also have the option of setting your ISO to the auto setting. And I find this useful if I'm working in specific conditions where the light might be changing fast. So usually the only time I use auto is when I'm photographing wildlife and I'm working in conditions where the light is changing. That way I can just keep shooting and not think about the fact that the light is changing and have to change my ISO every time the light changes.