The Exposure Triangle Explained: How Shutter Speed, Aperture & ISO Work Together

Written by: Total Exposure
Posted on: January 12, 2026

On paper, photography consists of a simple formula; turn on your camera, point it and capture the world through your eye. But what most don’t understand are the easily overlooked settings and controls that take up the body of the camera. Most stray away from the big numbers and unique switches, but it might be simpler than you think.

Close-up view of a camera lens aperture with several overlapping blades forming an octagonal opening. Light reflections and colored dots are visible on the lens surface.

Shutter Speed

Let’s begin with shutter speed; which is exactly that, the speed in which the shutter closes and allows light to enter. While that is true, shutter speed can also be a tool for preventing noise, or a digital grain in a photo. When reducing ISO in a photo to avoid noise, shutter speed can be used to balance the exposure of the photo by either lowering it to brighten or raise it to darken the capture. While this is important, it’s also good to note this can lower the stability of the shot, so be sure to keep a steady hand or a tripod for this.

A person holds a plate with a shot glass and an orange wedge, while another person takes a close-up photo of it with a camera. The background is dimly lit with blurred bottles and shelves.

ISO

We previously mentioned ISO, or International Organization for Standardization, so what does it mean? It simply measures the sensitivity of light coming into the shutter. For instance, a higher ISO brings in more light, while a lower ISO brings in less light, making the exposure darker. Back to the topic of noise, how does ISO affect it? A lower ISO creates less noise, while a higher ISO does the opposite.

Wet cobblestone street at night with blurred car headlights in the background and a parked car’s wheel visible on the right side of the image. Buildings and neon lights are seen in the distance.

Aperture

Lastly, there is aperture. Aperture is your best friend when it comes to focusing on an object. It can make or break the way a subject is imposed. The lower the aperture, the more light is allowed in, drawing the focal point tighter and creating more background blur. It is measured by F-Stops, which is variable depending on the lens. Aperture is most defined in subjects that are up-close, and isn’t as prominent with a subject that is further away.

High-rise buildings line a city street at night, with light trails from moving vehicles creating streaks of red and white. Streetlights illuminate the area, and the sky is dark and cloudy.

Combining Them

Now, how do these three components come together? Well, each of them can’t just work on their own, they rely on another to create a balance. Lowering your ISO can require you to lower your shutter speed, but then if you want to lower your aperture, you might need to raise your shutter speed a little. They all seemingly work together to make sure the photo comes out exactly how you want it.