First off, I've gotta say I'm super excited for you to go through these fun lessons I've created to help you learn more about how your camera works, and how to use it to its full potential, as well as helping you become more confident as a photographer. 

Let's start with talking about the camera itself and how it actually works. It's easiest to understand how our modern digital cameras work if we start from the beginning - the camera obscura (Latin for "dark room"). It was discovered in 1021 AD by an Arab physicist named Ibn al-Haytham, who created the first camera obscura by having a large room with one small hole on one side. Light from an external scene passes through the hole and strikes the wall opposite the hole, where the scene is reproduced, yet upside down. 

Fast forward to 1885, when Kodak started manufacturing film. Film is basically a thin strip of an emulsion of silver halide crystals that react when exposed to light. This film was then used to capture that upside down image when it passed through the small hole of the camera body, which is now essentially this 'dark room'. 

Let's fast forward again all the way to the 2000s, when DSLR's started replacing film cameras at a rapid rate. They work very similarly to the common film camera, but just with a few more computerized twists. The DSLR ("digital single-lens reflex") camera uses a digital imaging sensor rather than photographic film. A DSLR also utilizes the mechanisms of a single-lens reflex camera, which uses the one lens (rather than having a separate viewfinder) to present an image that will not perceptibly differ from what is captured by the camera's sensor. When you press that shutter button, the mirror that is currently reflecting back up to what you see within your viewfinder is quickly flipped, allowing the image to be projected on to the photographic sensor located toward the back of the camera. That's why if you're looking through your viewfinder when you press the shutter, the image you see quickly disappears while that mirror moves, then returns again when the shutter closes.

So, now that we better understand how cameras work, these next few lessons might make a little more sense as far as what each setting changed is affecting inside the camera, and why you get the results that you do with each change.