What Is ISO?
I want to talk to you about an essential principle in learning photography and filmmaking: the relationship between your ISO, your shutter, and your aperture. All three will brighten or darken your image, but all three also have a secondary effect. Let’s start with ISO: your image will become brighter as you increase your ISO amount. However, the secondary product is that the higher you raise your ISO, the more noise or grain on your image, which is not typically pleasing, so you want to keep it as low as possible.
And the broad range that you’ll find for ISOs is 100 to 25,600. If you’re shooting outside on a sunny day, keep your ISO around 100. But if it’s a cloudy day, you probably want to keep it around 400. Say you’re inside; you’re probably looking at between 800 and 1,600 ISO. Let’s say it’s nighttime, or you’re in a low light situation; you’re probably looking at a minimum of 3,200 ISO. Now, we can change the ISO by hitting a button on our camera. But, back in the film days, your ISO was your film stock. So, if you wanted to change your ISO, you had to take your film stock out and put in new film stock.
Stay tuned for part two, where I talk about the shutter.