In previous issues, I have offered explanations for the basics behind shutter speed, aperture, and ISO, and have also done my best to provide examples of how each can be used effectively. These three settings constitute what is known as “the exposure triangle,” and are the major aspects of the use of a camera that one must understand to take correctly exposed photographs. Coupling an understanding of the exposure triangle with an eye for composition will give any person the tools they need to create awesome photography.

For quick a review, let’s break down the three settings one more time. Shutter speed, as its name suggests, refers to how fast the shutter of the camera opens and closes, and directly controls the amount of time light is allowed to reach the camera’s sensor. The aperture setting determines how large the opening in the lens is that actually allows the light to pass, thus controls both the amount of light entering, and the size of the depth of field (how much area is in focus). ISO is essentially just a compensation setting. It changes the sensitivity of the sensor to the light. With a higher ISO, the camera’s sensor will be more sensitive to light and therefore produce a brighter image. It’s important to understand that playing with one of these settings will require some change in at least one, if not both, of the others! This idea, that the three of these settings require balance, is the baseline for understanding the exposure triangle.

Let’s say that you’re at a show with some friends, and you brought along a camera to take a few pictures of the artist. You notice that when you take a photo, the artist is slightly blurry because they are moving a lot on the stage. So, knowing that freezing action requires a quick shutter speed, you make your shutter speed quicker. After changing it, the artist is perfectly frozen in time in your photos, but the area looks very dark. Here’s where knowledge of the entire exposure triangle comes in handy. You can now increase your ISO to compensate for the loss of light due to the faster shutter speed! Without knowledge of ISO along with shutter speed, one would be stuck with only two choices: taking a blurry picture or a dark one.

The importance of working with the balance of these three settings is not exclusive to just one niche. Another great example falls in the scope of landscape photography. You may want to get everything in a scene in focus and this will require a very small aperture (large f-stop; e.g. f14). In addition, you may have plans to print the photo you are shooting, so a low ISO is needed to avoid noise and the lower quality it causes. Because both of these choices cause a loss in the amount of light recorded by the sensor, you must then know to decrease your shutter speed, to allow plenty of time for light to enter the camera in compensation for what is lost by a small aperture and low ISO. In some cases, you may need a combination of changing all three to get the effect you want. When shooting photography and working with the exposure triangle manually, it’s important to remind yourself that every change you make can influence your exposure, and that there are always a few ways in which you can reverse that change!

The best way to practice and work with the exposure triangle is to use manual mode (M on the camera dial) which will give you complete control over all three of these settings (as well as others). Practice adjusting the shutter speed to compensate for changes in aperture or adjusting ISO after changing shutter speed or aperture. If you don’t have a camera, you can actually download an app for your phone that allows you to control these settings manual (not available on all phones). If you want to shoot photography, practice working with this concept! Pairing a good balance within the exposure triangle with a good composition guarantees a nice photograph.