Photography Remembered

The Exposure Triangle - Guide

2 min

A Guide to the Exposure Triangle

Now that we’ve covered ISO, shutter speed, and aperture individually, it’s time to bring them together. These three settings form the exposure triangle, the foundation of photography. Understanding how they work together is the key to taking full creative control of your photos.

What is the Exposure Triangle?

The exposure triangle describes the relationship between three camera settings:

  • ISO – Controls the brightness of the image through amplification. Higher ISO makes a photo brighter but adds noise.
  • Shutter Speed – Controls how long light hits the sensor. Fast speeds freeze motion, slow speeds blur it.
  • Aperture – Controls how wide the lens opens. Wide apertures let in more light and blur the background, narrow apertures let in less light and keep more of the scene sharp.

Each side of the triangle affects exposure (the brightness of your photo), but also influences details in the image.

The Balancing Act

Think of exposure like filling a glass of water. You can fill it faster or slower, but the goal is to get the right amount.

  • If you change one setting, you often need to adjust another to keep the exposure balanced.
  • For example, if you make the shutter speed faster (less light), you might need to open the aperture wider or raise the ISO to compensate.

This balance is what gives you creative control.

How Each Setting Affects Your Photo

  1. ISO

    • Lower ISO = cleaner image, less noise.
    • Higher ISO = brighter image in low light, but more noise.

  2. Shutter Speed

    • Fast = sharp, frozen action.
    • Slow = motion blur or light trails.

  3. Aperture

    • Wide (f/1.8, f/2.8) = shallow focus, blurred background.
    • Narrow (f/8, f/11) = deep focus, more of the scene sharp.

Example Scenarios

  • Sports Photography

    • Fast shutter speed (1/1000) to freeze action.
    • Wide aperture (f/2.8) to let in enough light.
    • ISO raised as needed to keep the photo bright.

  • Landscape Photography

    • Narrow aperture (f/11) for deep focus.
    • Slower shutter speed to capture enough light.
    • Low ISO to keep maximum detail and sharpness. Tripod recommended.

  • Portrait Photography

    • Wide aperture (f/2.8) for blurred background.
    • Moderate shutter speed (1/125) to avoid blur.
    • ISO adjusted depending on light.

  • Night Photography

    • Very slow shutter speed (5–30 seconds) with a tripod.
    • Narrow aperture or wide depending on the effect you want.
    • Low ISO to reduce noise in long exposures.
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Quick Exposure Triangle Reference

  • ISO – Brightness vs. noise.
  • Shutter Speed – Brightness vs. motion.
  • Aperture – Brightness vs. depth of field.
Camera knowledge