The Exposure Triangle is a term that you might have heard about but never quite taken the time to understand. It’s not a specific camera setting or technique which means that it often gets overlooked. That doesn’t make it any less important.
Understanding what the Exposure Triangle is and how it works is an essential part of becoming a better photographer. It’s one thing to know what the individual camera settings do but actually understanding how they work together is critical.
The Exposure Triangle is part of the fundamentals of photography and in this article, you’ll learn exactly what it is and how you can take advantage of understanding it.
What is the Exposure Triangle?
You might already be familiar with the fundamental camera settings, shutter speed, aperture and ISO. These settings are important to understand if you want to become a better photographer but in addition to understanding what each of them do, you should know how they work together.
That’s where the Exposure Triangle comes in; it’s a collective term that consist of those exact settings. It’s a term that describes how each of these settings have a direct impact on each other.
So, before we look closer at how it works, let’s take a quick look at the camera settings it consists of:
#1 The shutter speed
The first component of the Exposure Triangle in photography is the shutter speed. This camera setting refers to the duration that the camera’s shutter is open, allowing light to reach the sensor, and create a photograph. You measure this period in seconds or fractions of seconds.
A large denominator such as 1/1000 is a quick shutter speed. The camera’s sensor is exposed to light for only a fraction of a second, meaning that less light is let through. This is commonly used when photographing in broad daylight or when photographing quickly moving elements.
A slower shutter speed, such as 1/10, means that the sensor is exposed to light for a longer duration. This is common when photographing in dimmed light. However, the camera registers all movements while the shutter is open. If it’s open for a long time, it also picks up vibrations from the camera. In those cases, it’s wise to use a tripod.
Read More: Introduction to Shutter Speed in Photography
#2 The aperture
The second camera setting in the Exposure Triangle is the aperture. The easiest way to understand aperture is to think of it as a hole that lets light through your lens. The bigger the hole (a smaller number such as f/2.8), the quicker light passes through. A smaller hole (a higher number such as f/22) requires more time.
It’s also important to understand how the aperture affects the Depth of Field. This, however, doesn’t affect the exposure so we’re not looking at that in this article. For a better understanding, I recommend reading our Introduction to Aperture in Photography.
#3 The ISO
The third, and final, camera setting in the Exposure Triangle is the ISO.
ISO expresses the camera’s sensitivity to light; The higher the ISO value, the more sensitive it is to light. Vice versa, a lower value makes the camera less sensitive to light. However, the more sensitive the sensor is to light, the more grain and noise are introduced in the image.
Read More: An Introduction to ISO in Digital Photography
How the Exposure Triangle works – connecting the settings
So how exactly does the Exposure Triangle work? How are these camera settings impacting each other?
Let’s get visual for a second as I explain this in the simplest way I know.
Imagine that you, for some reason, want to fill a room with water. There’s a window on the wall where water enters. In order to let water in through the window, you need to open it. The more you open the window, the more water comes in. This resembles the aperture.
The longer you keep the window open, the more water enters the room, and vice versa. This resembles the shutter speed. Now let’s connect the shutter speed and aperture to see how they rely on each other. If there’s just a small opening in the window, it will take a longer time to fill the entire room with water. If you open the window to the widest, it will go a lot faster.
In photography terms, that means that the wider aperture you have (such as f/2.8), the quicker shutter speed you need to get a correctly exposed image.
So what about the ISO? Let’s stick to the same scenario and pretend that there’s a lot of dirt in the water you’re letting in. You get rid of this dirt by installing a strainer inside the window. A strainer with tiny holes removes all the dirt from the water, this resembles a low ISO such as 100. However, since the holes are so small, water enters at a slower rate. This means you need to either leave the windows open for longer (i.e. slower shutter speed) or open the window wider (large aperture).
A strainer with big holes lets water come through quicker but it reduces the water quality. In photography, that means a higher ISO results in more grain and noise, and overall lower image quality.
I know it can be a little confusing to understand how the camera settings are connected but I hope this explanation made it a little less confusing.
The Exposure Triangle is a term that describes how the three camera settings shutter speed, aperture and ISO all have an impact on the exposure of an image. Changing one setting has a direct impact on the others.
Using a high ISO makes it possible to use a quicker shutter speed or smaller aperture but at the expense of the image quality. Reducing the ISO means you need to use a wider aperture or slower shutter speed.
There are a few more factors to consider when adjusting the Exposure Triangle but neither of these have an impact on the exposure of the image. For example, a slower shutter speed means you probably need to use a tripod in order to get a sharp image. The choice of aperture affects the Depth of Field and focus of the image.
But, for now, grab your camera and set it to manual mode and play around with these three camera settings. Try to notice how adjusting one or the other affects the exposure and quality of the image.