Understanding the Exposure Triangle

Understanding the Exposure Triangle

If you want to take great photos, you need to understand exposure, and the Exposure Triangle is the foundation of photography. If you’re new to photography, you can get away with taking respectable pictures right out of the box using automatic settings.

However, if you want to produce quality images, you need to have a solid grasp of this basic concept before moving on to the next level. Look at it this way; exposure is to the photographer, what measuring is to a carpenter. It’s an essential skill. Understanding what exposure is and how it works is an important first step in becoming a good photographer.

What Is the Exposure Triangle?

diagram of the exposure triangle.

Exposure in photography is all about light, and the process of controlling how much light hits the digital sensor in your camera to produce an image. You could say exposure is an umbrella term for controlling the lightness or darkness of a photo.

Three main ingredients or elements work together in exposure: Aperture, Shutter Speed, and ISO. The Exposure Triangle is described as the foundation for photography. Once you understand how it works, you’ll be able to take better photos using the various settings on your camera.

Understanding it may sound a bit complex and complicated at first. Still, we promise you will get a clearer grasp of lighting and the three components with enough practice, and hopefully, after reading this article!

It’s important to remember that aperture, shutter speed, and ISO work closely together to produce the most balanced exposure. As you start changing one element, you’ll have to change the other to maintain the exposure. We will get into this in detail later in the article, but first, let’s take a look at a few videos for an easy-to-understand presentation on exposure.


You may associate ISO with the ISO in film photography, but we’ll mainly be referring to ISO used in digital photography. ISO stands for International Standards Organization, and it is a measurement that dates back to film photography days. ISO standardizes sensitivity ratings for sensors.

The best way to remember ISO is that it controls your camera’s sensitivity to light. The higher the ISO number, the higher the sensitivity to light. The lower the ISO number, the lower the sensitivity to light. You can easily change your camera’s ISO on the dial or in the menu function.

ISO illustration.

Typically the ISO range is between ISO 100 to 1600. With newer cameras, you can go as low as 50 and as high as 204800 (like on the Sony a7 III). This gives photographers extensive control over exposure settings, but it also comes with some setbacks.

Beginner photographers should know that the higher the ISO value, the more noise your photos will produce. Each time you dial up the ISO value, it increases the sensitivity by double. If you like detail and sharpness in your photos, then you’ll want to keep the ISO at a lower number (e.g., ISO 100) for maximum clarity.

Once you are comfortable adjusting the different ISO settings, you’ll be ready to experiment with photographing in different light conditions! ISO is a swift and easy way to change your exposure settings without compromising too much on image quality.


Now that you know ISO, let’s talk about aperture. While ISO is about the camera’s sensitivity to light, the aperture is how much light enters the camera sensor. It’s really as simple as that! Notice the lens on your camera. Can you see the ring or metal blades? They open and close every time you take a photo. Controlling the aperture or f-stop is how you change the size of the opening on your camera lens.

camera lens.
Close up of camera lens with aperture blades and bokeh in the background.

The narrower the opening, the less light comes through to the sensor. The wider the opening, the more light comes through. You control all of this by adjusting the f-stop values. Common f-stop values are f/1.4, f/1.8, f/2, f/2.8, f/3.6, f/4, f/5.6, f/8, f/11, f/16, and f/22.

Interestingly, the lower the number of the f-stop, the wider the opening is in your lens. The higher the f-stop number, the narrower the aperture becomes (less light coming through). In addition, the wider the aperture, the shallower your depth of field will be. That’s how you create beautiful bokeh photography with a blurry background.

The depth of field is closely related to aperture values. Depth of field is the amount of your photo that appears in acceptably sharp focus. The higher your f-stop, the deeper your depth of field will be. The lower your f-stop, the shallower your depth of field will be. When you set your aperture to f/1.4, for example, there is much light passing through to the sensor, but you are also creating a narrow depth of field.

exposure triangle: effects of aperture on depth of field - illustration diagram.

Another good way to remember the aperture is that every time you adjust the aperture by one stop, you are actually doubling or halving down the amount of light that enters the sensor. For instance, going from f 2 to f 2.8 is one stop. This means you doubled the amount of light coming through your sensor. On the other hand, going down from f 5.6 to f 4 is still one stop, but you will have half the amount of light entering the camera.

Shutter Speed

Lastly, in the exposure triangle, we have the shutter speed. You can probably guess how the shutter speed works just by hearing the shutter click every time you snap a photo. The shutter speed is basically the length of time your shutter is open when you press the shutter release button.

The shutter speed is measured by fractions of a second. For example, if you use a shutter speed of 1/250, that means your camera sensor is exposed to light for two hundred fiftieths of a second. The lower the denominator, the longer the shutter speed is open, allowing more light into your sensor.

light trail.
Light trail showing the use of slow shutter speed and long exposure.

Shutter speed can be a fun and creative way to experiment with your photography. You can create unique motion blur photos using a slower shutter speed or capture a fast-moving subject in action using a breakneck shutter speed. It all depends on your vision and environment while taking photos.

You can set your shutter speed manually in your camera’s menu setting or set it to Shutter Speed Priority mode so your camera can automatically set the aperture and/or ISO for you. Unless you have a purpose for choosing a certain shutter speed, we recommend letting the camera choose the shutter speed for you automatically. This allows you to focus more on aperture values, so you don’t have to worry about shutter speeds.

Keep in mind that slow shutter speeds will allow more light into the sensor, which affects the exposure directly. In contrast, a fast shutter speed like 1/1000 will limit the amount of light entering the sensor dramatically – typically resulting in a darker, underexposed image.

Let’s say it’s bright and sunny outside, however, and you’re out shooting. You’ll want to use a faster shutter speed to compensate for the brightness outside. If it’s nighttime and you’re inside, you’ll automatically want to reduce the shutter speed, increase the ISO and open your aperture. You want to allow as much light as possible without compromising camera shake or an extremely noisy image. That’s why image stabilizers are great to have on hand, as well as a handy tripod, so camera shake is eliminated.

Putting It All Together

Let’s put the three components you learned in this article together! ISO, aperture, and shutter speed. A good tip is to keep each component constant. Let’s say you choose to keep the shutter speed constant (you won’t change this component). The next component you’ll have to focus on is the aperture value and ISO. If you are using a wide aperture, you may want to lower your ISO, so your photo doesn’t overexpose. You’ll want to slowly fine-tune the values until you get the exposure you want.

It’s easier said than done, but with a bit of experimentation and practice, you’ll be putting all three components together in no time!

  • Try not to go lower than 1/50 for the shutter speed, especially if you are hand-holding your camera. Going any lower is tough in achieving sharp-looking photos.
  • If you have to use a fast shutter speed, make sure you use a lens that allows for wide apertures (f 1.4, 1.8, f.2). This will give you more lighting control. Bump up your ISO as well.
  • If you can, use the lowest ISO possible. This is key to getting the highest quality photos without the image noise.
exposure triangle settings.
Closeup of a person with a camera in hand controlling the camera settings with nature in the background.

As you can see, the relationship between ISO, aperture, and shutter is incredibly important. If you’re adjusting one part of the exposure triangle, you probably will have to adjust the other. This is not the only way to memorize and learn about photography exposure, but we think it’s a great way to see the relationship between all three and how they relate to each other.

To gain a comprehensive understanding of exposure and its role in photography, we are posting several videos about photography exposure throughout this article, created by Mark Wallace for Adorama TV. These videos are beneficial for beginners and professional photographers to grasp a clear concept of exposure and the fundamentals of aperture, shutter speed, and ISO.

In this first video by Mark Wallace for Adorama TV, he introduces the basic concepts behind the Exposure Triangle. He provides a high-level overview of aperture, shutter speed, and ISO and how they work together.

Understanding Exposure Trinagle

Exposure Triangle: F-Stops Explained

In Part 2 of Mark’s video, he explains stops (or f-stops), which measure exposure relating to the doubling or halving of the amount of light.

Aperture and Depth of Field

In the third video, Mark Wallace explains how aperture and lens choice affects depth-of-field (DOF).

Shutter Speed

In the fourth video, Mark Wallace explains the differences between a slow versus fast shutter speed and how it controls motion in photography. He also gives us useful tips on how to shoot hand-held successfully.

Exposure Triangle in Practice

In the last video, Mark puts it into practice on the streets of South Africa.

To recap, always relate exposure to how much light is entering your camera sensor. We can control how much light enters through these three components – ISO, Aperture, and Shutter Speed.

  • Aperture – how large the lens opening is
  • Shutter Speed – how long the shutter remains open
  • ISO – how sensitive the sensor is

Memorizing these three components will ensure you are on your way to mastering exposure, which plays a huge chunk in photography!


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  1. hey am from africa that is fantastic am not read all with the shortege of connection but am gonna be show as much as i can thank you

  2. I have been taking photos for a two year period and the information I have read through your site have given me a higher knowledge which will greatly improve my photos. This is a great source of information for me so far. Thanks

  3. Great lesson, I am sure I will be reviewing so Im sure not to have missed anything. Seems really clear just want to be sure for myself.. Thank you

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