Daniel Eggert, objc.io issue #21:
Let’s say you’re outside and looking around you. The sun, 150 million kilometers away, is emitting photons. These travel from the sun to our cozy planet in about eight minutes. Some of these photons hit the things around you and get reflected and hit the retina inside your eyes, and this triggers your brain to create an image, a visual representation of your surroundings.
What an amazing article about the basics of digital photography. The author explains basic terms in an easy to understand manner and points out, how all those pieces work together to generate the the images we see on the back of our cameras (or on the front of our phones, nowadays.) I highly recommend checking this out if you want to gain a basic understanding of what's going on inside these tiny boxes we use every day.