Exposure: The Meat and Potatoes

So you’ve got a new camera! Or… you got a used one. Or… you pulled the old one out of the closet. Or… A friend gave you theirs because they can’t figure the damn thing out, which is not filling you with a lot of confidence but you’re willing to give it the old college try.

There are three parts to knowing how to really use a camera for something more than alcohol-fueled “selfies” at the bar with your BFF. These are the differences between photography and “taking pictures.” For the latter, any camera left on automatic, or just a mobile phone, will do. You’re reading this because you’re interested in photography as a creative pursuit, and in mastering your camera as a tool for this pursuit.

The first part is knowing what makes a good photograph. This is the intangible part, mostly a matter of taste. The rest is easier to learn than it is to teach. Deciding that you like someone else’s photograph, is easy enough. The next step is a lot harder. This involves looking at the same photograph with a technical eye, figuring out what about it makes it good and how the original photographer achieved whatever made this photo work for you.

To understand the next requires some basic understanding of how photography works, how different choices affects the final appearance of the photograph. With that knowledge, combined with a familiarity with the features of controls on your own camera, you can then figure how to duplicate the effect or even improve upon it, if you’re feeling especially ballsy.

The first part of this knowledge is understanding the basic mechanics of photography, how a gadget we call a camera turns light into an image. It’s not excessively complicated. It might seem like it involves a lot of incomprehensible numbers, but once you get a handle on what they stand for, they begin to make a little sense. Ultimately, what you really need to know is that, when number A is bigger than number B, it means this, and when it is smaller, it means the opposite.

The second part is knowing how those mechanics affect the final image and the third is how your camera controls those mechanics. I’ll touch on the second two in this article, but for now I will focus on the theory, on the why before the what and the how.

Exposure: Let There Be Adequate Light

Exposure is the heart of photography, which is basically the process of exposing a certain thing to outside light so that this thing can turn that light into an image. In ye olden days, the village elders first called that certain thing “witchcraft” but then settled on “film.” Now it’s a sensor chip inside one of your new-fangly digital thingamabobs. Either way, you need the right amount of light. Too little and the image is too dark; too much and it’s all washed out.

Photographers refer to the three elements that control exposure as the “exposure triangle.” They are, in order of their relative ease of comprehension, ISO, shutter speed, and aperture. By understanding how they interact, how changing one affects the others, you will know how to control the exposure of a photograph.

Stops in the Name of Light

Before we dive into these settings, however, we need to understand how photographers think about light. We compare one amount of light to another using a concept called the “stop.” A stop isn’t really a specific amount of light, but rather the relationship between two different amounts.

If there is twice as much light here than there is there, then we say that there is a one stop difference. If it was four times as much, then we have two stops difference. Every stop is twice as much light (or half as much going the other way) as the next one.

The key thing to remember is that light doubles or is cut in half with every stop. All three of our concepts, ISO, shutter speed, and aperture, work in stops.