What is the exposure triangle?

In photography, the exposure triangle explains the relationship between shutter speed, ISO and aperture. Whether you’re shooting old school film or with a mirrorless, these three factors are at the center of every exposure. Understanding the exposure triangle, also called the photographic triangle, will help you determine how a picture will look before you take it. And while saving film in today’s digitally dominated world is probably not your first priority, knowing how aperture, shutter speed, and ISO work together to compose your image will make you a smarter, more efficient photographer. With getting to know these variables, you’ll also come to realize that, at least artistically, there is no one ‘correct’ exposure for a scene.

The Three Elements of the Exposure Triangle | Innovative Gear for Content Creators (

Quite often, you can tell with the naked-eye when an image is overexposed, underexposed, or just right. Underexposed  is simply the opposite of overexposed, where the image appears too dark. Check out our blog post highlighting the contrast between overexposure and underexposure.

What is overexposure?

Overexposure is when an image appears brighter than it should, or brighter than neutral exposure. When too much light hits the camera’s sensor, it results in an extremely bright image that is now overexposed. Overexposure limits detail in the photo and reduces any opportunity for shadowing or distinguishable highlights in the image.

In order to reduce that possibility of an overexposed picture or overexposed film, the photographer controls the amount of light that gets into the camera. There are two settings that control exposure — aperture and shutter speed. These two settings allow the photographer to collect light and bring that light into the camera.

ISO is another setting that can be adjusted to help regulate brightness, but because it doesn’t function to let light in, it doesn’t regulate exposure.

How to fix overexposed photos:

  • Adjust aperture, shutter speed, and ISO settings
  • Use bracketing as you’re taking your shots
  • Use exposure sliders in Lightroom or other post program
the exposure triangle

What is aperture?

Aperture is the opening of the lens through which light passes. When you hit the shutter release button to take the picture, the camera aperture opens to the predetermined width, letting a specific amount of light through. A large aperture lets more light in, and vice versa. Aperture is calibrated in f/stops, written in numbers like 1.4, 2, 2.8, 4, 5.6, 8, 11 and 16. The larger the number, the narrower the aperture.

size of Aperture
Aperture is the opening

Aperture adjusts how wide or narrow your lens opening is. The wider the aperture, the more light is let in, and the narrower, the less. Let’s review how aperture works in the process of exposing images.

What is Overexposure in Photography & How to Fix It (

Aperture is an integral part of photography that is implemented with shutter speed and ISO in mind. These three camera settings are part of what’s known as the exposure triangle, where each has a direct effect on the other. This is true for photography and videography.

the exposure triangle

These three pieces are what’s known as the Exposure Triangle.

What is ISO?

ISO is the setting that controls brightness. So it’s not what allows light to enter, but it works in unison with the two other settings. Let’s review how ISO works in the process of exposing images.

What is Overexposure in Photography & How to Fix It (

What is Shutter speed ?

Shutter speed is how fast or slow your camera’s shutter opens and closes will determine how much light gets let in when you snap a photo.

Shutter speed is how long the camera shutter is open, exposing the image to light, typically measured in milliseconds to minutes. If the shutter is left open for a long time, a lot of light is being let in, which could overexpose the image. When there are moving subjects in your photo, a slow shutter speed could cause motion-blur. If the speed is quick, it’s likely the picture will come out too dark. These speeds are measured in fractions of a second. ½ means “one half of a second,” while 1/250 means “one two[1]hundred-fiftieth of a second.” The smaller the number (the higher the denominator), the faster the shutter speed. Conversely, the higher the number, like whole numbers from 1 to 30 seconds, are considered slow shutter speeds. Lastly, fast shutter speed creates a shallow depth of field.

shutter speed
What is Overexposure in Photography & How to Fix It (

Let’s take a quick look at each of the three values in the exposure triangle:

the three values in the exposure triangle:

What does shutter speed control?

Exposure — depending the lighting conditions, a slow shutter will brighten the image and a fast shutter speed will darken it.
Motion — the slower the shutter speed, the more motion blur you’ll create. The faster the shutter, the motion will appear sharp and jittery.

boy running along city street lights street

boy running along city street lights street lights buildings camera stockphoto Nikon D300 170mm f/13 1/640 sec 320 ISO –ar 3:2 –s 750

boy running along city street lights street

boy running along city street lights street lights buildings camera stockphoto, Nikon D300, 18 mm, f/1.4, 3.5 sec , ISO 200 –ar 3:2 –s 750

What is Bulb Mode on your camera?

Bulb mode is simply a shutter speed option that you can select in manual mode on your camera. It allows your shutter speed to be any length you choose: one second, one minute, 17 minutes, or anything else. The key with bulb mode is that your camera’s shutter stays open for as long as you hold down the shutter release button. The limit on your Bulb exposure depends on the camera – sometimes 30 minutes, sometimes as long as you like (or until your battery dies)


Beautiful Fireworks, Summer in Japan, Colors, Ephemeral, Traditional, Shoot up into the night sky, Photographed with Canon 5D Mark IV, Wide –ar 16:9 –v 5.2 –s 750


Beautiful Fireworks, Colors, Ephemeral, Traditional, Shoot up into the night sky, closeup zoom, stockphoto, Photography with Camera Nikon D300, 95mm, f8, 1/640 sec, ISO 320 –ar 2:3 –s 750

Camera aperture and depth of field

Of course, light exposure isn’t the only result of adjusting aperture. When you change your f/stop, you’re also affecting the depth of field

The depth of field is an area of acceptable sharpness from foreground to background. Put simply, depth of field is how blurry or sharp the area is in front of or behind your subject.

This video will go over this simple relationship and some strategies on how to keep the elements in mind when you’re shooting in the field and need to make adjustments.

A large aperture (a low f/stop) blurs the background with less depth of field. This is what’s known as shallow depth of field. If you have a small aperture (a high f/stop), the greater the depth of field, and the sharper the background. This is what’s known as deep depth of field.

Here’s a breakdown of how filmmakers can use the various types of camera focus, including depth of field, in visual storytelling.

Conversely, a large f/stop will create a sharper image, which is ideal if you’re shooting landscapes with a deep depth of field. The image below would have to have been shot in a larger f/stop number like f/16 or f/22.