Photography Basics: The Exposure Triangle - What Is It & Why Is It So Important?

If there is one thing that should be taught first to every new photographer worldwide, that lesson would be all about the exposure triangle. If you don’t know what that is, think of it as your 3 tools to manipulate light. Strip any camera down to its bare essentials, and you will always have 3 things that you control to create a great photograph, shutter speed, aperture, and ISO. Using these together, you can work through almost any lighting situation and create wildly different kinds of photography. When you feel ready to take your camera off Automatic Mode, these are the first things you will need to get comfortable with.

Shutter Speed

Example of long exposure, turning headlights into light beams

When looking at your camera, your shutter speed is represented by a fraction, such as 1/100 sec. This number is the speed at which your camera's shutter opens and closes, capturing a photo. By controlling your shutter speed, you can take a picture at 1/2000 sec which is so fast that it freezes a flying bird or you could take a long exposure of up to 60 seconds, making car headlights look like streaks across the photo. More importantly, your shutter speed is your first way to combat your light conditions. If it’s bright outside, you can make your shutter speed faster so that less light is allowed into the camera. If it’s dark, make your speed slower to let in more light, just be careful when shooting handheld, as any shaking starts to blur photos at approximately 1/100 sec depending on how still you can be. Whether it is for stylistic choices or lighting difficulties, your shutter speed is your number one tool that you will go to when shooting. 

Aperture

Subject isolation created by wide open aperture

On your camera, your aperture (or f-stop) is represented by a number such as f5.6. Put simply, the f stands for focal length, as it determines the depth of focus in a photograph. All lenses have aperture blades that change the size of the opening, which both changes the amount of light allowed and how large the field of focus is. If your aperture is wide open at a low number such as f1.8-2.8, that creates a very shallow depth of field and allows a lot of light into the camera. This low depth of field can help isolate your subject, by having the foreground and background out of focus. If you have a very high number such as f12-22, your aperture is closed up to a much smaller size, where little light comes through, but you have a large depth of field. Having a larger depth of field will ensure that the majority of your image is in focus. As you can see, your aperture is a tool to get different styles of photos by changing the depth of field and is also used to combat lighting issues. 

ISO

Using a low ISO can allow you to shoot in sunny situations

Last but not least, ISO is used to determine how sensitive your camera sensor is to light. Your ISO is represented by a number such as ISO 400. The lower your ISO is, the less sensitive your sensor is, making the image darker. A higher ISO will make your sensor more sensitive, making an image brighter. ISO is exclusively used to control the brightness of your image and doesn’t have any stylistic impacts (besides ISO noise, but we’ll get into that). If it's a bright day outside you’ll want to be around ISO 100-200, and if it is dark out you can increase it to around ISO 1000-2000 or more depending on your camera. However, the higher your ISO, the more noise you will see in the photo. ISO noise is a visual distortion that shows up as tiny speckles of colour or tone in the photo and cannot be removed with local adjustments in Lightroom. 

When used in tandem, these settings can get any photographer through tricky situations and also create really incredible images. For example, if it's incredibly bright out and you want a high depth of field for a portrait, a wide-open aperture will let a lot of light in. To counteract this, you can decrease your ISO, and increase your shutter speed. That way, despite being wide open you are only subjecting the sensor to a quick burst of light at low sensitivity. These settings all work in tandem, so when you change one, you must compensate by adjusting your other settings to maintain a well-exposed image. Photography has tons of “Rules” just like any other art form, and it's incredibly important that you properly understand these rules to build a foundation of skills. Only once you understand the rules, can you make the proper judgment calls on when to break the rules and establish your own unique style. When you think you are ready to start taking photography seriously, take the time to learn all that you can because that knowledge will help equip you for the chaos that ensues when you follow your passion.