Regardless of whether you are a beginner or a professional photographer, one of the most important elements of photography involves something called the “exposure triangle”.
Understanding this concept can dramatically improve your photos and help you in your creativity. But don’t worry, it’s not that complicated, and this beginner's guide will help you understand the basics of what it is and how it impacts every photo.
1.) What is the exposure triangle?
Think of the exposure triangle as the blueprint of every photo taken. Whether that is with a smartphone or a DSLR camera, 3 elements combine to allow you to take a photo.
- Shutter speed - it determines how fast the shutter on your lens opens and closes.
- Aperture - measured in f/stops, this setting determines how open or close your aperture will be and in turn how much of your scene from the foreground to the background will be in focus
- ISO - this is the sensitivity of the sensor to light. The higher it is set, the more sensitive your sensor will be. So, you will be able to take photos in darker conditions. Read our guide to ISO here.
The reason that this is referred to as a “triangle” is that all these settings are connected. Which means changing one will impact the other two and allow you to be able to take a photo at the correct exposure level.
For example, by selecting a smaller aperture or in other words a higher f/number (i.e. greater depth of field), you will have to have a slower shutter speed. But if you are shooting without a tripod this can be problematic in resulting in blurred photos. So, the alternative is to select a higher ISO so you can have a faster shutter speed.
The “triangle” is simply an explanation of the connection between these settings.
2.) Why is the exposure triangle so important?
As mentioned above, every photo that you take will require you to set the three settings above. Even in automatic mode the same principle applies, the only difference is that the camera does this for you. So, understanding the exposure triangle will help you in two ways. Sometimes it will be out of necessity and sometimes because of creativity (i.e. because you want a particular look for the photo).
Sometimes photography is about compromises. You have to select one setting to allow you to be able to select another one so that you can capture the photo that you want to take. This is often to do with shutter speed. Your shutter speed determines how quickly the shutter on your lens opens and closes. We humans can only hold a camera steady enough at fast shutter speeds to avoid camera shake. If you can’t and the camera moves when the shutter is open, you will end up with a blurred photo.
For most people this will mean a minimum shutter speed of no slower than 1/60th sec. Some people might be able to go slower for handheld shots while some people might need to have a faster shutter speed. The only way for you to know is to test yourself and look at the results on your computer screen to see how slow you can go with your shutter speed. But no-one will be able to hold a camera steady enough for even 1 second to avoid a blurred shot. So sometimes you have no choice but to make adjustments to allow you to be able to shoot handheld.
For example, if you are taking a photo in low light conditions such as a covered market you may struggle to select a fast-enough shutter speed to be able to shoot handheld. This is where understanding the exposure triangle and the relationship between the settings can help.
To be able to have a faster shutter speed you need more light to be hitting the sensor. Based on the triangle above, you have two options. You can either increase your ISO (keep in mind that a higher ISO will mean more noise in your image), or you can select a shallower depth of field like f/2.8 (i.e. a wider aperture). This will allow more light to enter the camera and allow you to take the photo at a fast-enough shutter speed to avoid using a tripod.
Sometimes it won’t be necessity that determines your settings but instead the way you want a photo to look. For example, imagine you are photographing a landscape scene and want to capture some movement in the clouds. This means you will need a slow shutter speed to be able to capture the motion of the clouds. But as this is a landscape shot you also need to have a greater depth of field so that your foreground to your background is in focus.
As mentioned earlier these settings are connected and changing one impacts another. In this scenario, selecting a higher f/number such as f/16 (for your greater depth of field) will be making the size of the aperture on your lens smaller which mean less light. With less light coming in, it means a slower shutter speed as well. Otherwise your photo will look too dark or referred to as being underexposed.
So, by selecting your aperture you have also influenced your shutter speed at the same time to what you were looking for to be able to capture the motion of the clouds.
5.) How can you master it?
The good news is that with practice you will naturally become better at realising the impact that one has on another. Eventually it will become subconscious to you and you will be able to make decisions while you are taking photos based on the photography challenge that you will face. So, you will be able to decide what to compromise on to allow you to select the settings that you need.
The best way to improve your understanding of this concept is to also try to learn more about each of the elements of the exposure triangle. By learning more about depth of field, shutter speed and ISO you will be able to understand their relationships with another better.
6.) If you remember just one thing…
Hopefully, you now have a better understanding of the exposure triangle.
But just to recap, the exposure triangle is the relationship and impact that depth of field, shutter speed and ISO have on every photo and each other.
So, grab your camera and experiment with every different aspect of the exposure triangle to see how they impact each other. And most importantly... have fun!