When your shooting it is very easy to focus all of your attention on your subject and how you want to frame it. After all you're subject is what makes your photo right? Only partly, people often ask me "What do you like to shoot?", and for a while this question really confused me, should I say attractions, shows, fireworks, buildings, or landscapes. The possibilities go on and on. Until I realized that the answer for me is light. I like to shoot nice light. Doesn't even necessarily matter what that light is bouncing off of.
Light creates texture.
Light and shadow together can create a sense of depth in your scene.
Allows you to control the viewer's eye, and controlling the viewer's eye is the essence of composition.
There's no photography without light, and the secret to controlling light is to understand exposure.
Even if you're well-versed in the history of photography you've probably seen a lot of movies. Think about the strong shadows in the great scene in "Snow White" as she is running through the woods or think of the rich colors and the dramatic lighting as Quasimodo lifts Esmeralda over his head crying sanctuary as the sun sets behind them in the classic "The Hunchback of Notre Dame". These are all moods and atmospheres that are created through lighting and exposure. Movies are a photographic process after all, and cinematographers have to know the same exposure theory that we as photographers do.
So what exactly is exposure? Have you ever experienced when you step outside from a dark room and it's too bright outside until your eyes adjust? If so you've probably experienced this, when you step into a dark room when entering from a bright outside you can't see anything until your eyes adjust. That's exposure.
The pupil in your eye, the black part, is an iris that can open and close to let in more or less light. now it takes a certain amount of light for you to be able to see. so when you're in a dark room your two pupils are open very wide to let in enough light for you to see. Now when you step outside into bright sunlight your pupils were still opened really wide, so wide that you couldn't see because your vision was over exposed. Now when that happens to you, you may not think of it as seeing white probably because you're more focused on the pain as the nerves in your eyes get overloaded but that is the same when you take a picture with your camera and all there is, is white.
Now to sum up when I mean one situation your eyes need a particular setting, when you take those same eyes into a very different lighting situation that setting is no longer correct and you cannot see. That may sound familiar to everyone not just because we all have eyes but because that is how your camera works. It needs different exposure settings depending on how bright or dark the light in your scene is. Like your eye inside your camera's lens there's an iris or aperture that can be opened or closed to let in more or less light. But your camera has an additional mechanism for controlling light in the form of a shutter, it's a little curtain that can be opened and closed quickly or slowly to let in more or less light.
That's all exposure is, controlling the amount of light that gets to the image sensor in your camera. Too much light and your images will be overexposed. It'll be too bright, highlight details will be lost to complete white, colors will be washed out. Too little light and your image will be underexposed. It'll be too dark, shadow details will be lost to complete black, tone and color will be dull and dingy.
Now you might be wondering why your camera has two mechanisms for controlling light when your eye can get away with just one. The answer to that is complicated and will be explored in detail throughout this series, right now know that the practical upshot of having two controls in your camera and the reason that you want to learn more about them is that they provide you with tremendous creative possibilities.
So we learn exposure theory not just to ensure that our images are neither too bright or dark, but to expand the creative talent that we have at our disposal when we're shooting. we're going to be learning a lot of numbers ,concepts, and terms in this series. But in the end your eye and your lens are both optical devices so a lot of what we're going to learn will feel familiar to you because you already have had a lot of experience with a pair of lenses and apertures that you use every single day.