Understanding the Exposure Triangle
The exposure triangle is the foundation of photography. It describes the relationship between three camera settings that control how much light reaches the sensor: aperture, shutter speed, and ISO. Mastering these three variables allows you to take creative control of your images, achieving the exact look you envision rather than relying on automatic modes.
Every time you change one setting, the other two must compensate to maintain the same overall brightness. This calculator automates that math, letting you explore equivalent exposures instantly. Enter your current settings, choose which variable you want to change, and the calculator solves for the remaining value.
How the Exposure Triangle Formula Works
The exposure value (EV) combines aperture and shutter speed into a single number: EV = log2(N²/t) + log2(ISO/100), where N is the f-number and t is the shutter speed in seconds. Two different combinations of settings produce the same brightness when they share the same EV. This calculator keeps the EV constant while solving for the unknown variable.
Aperture and Depth of Field
Aperture controls both exposure and depth of field. Wider apertures like f/1.8 let in more light and create a shallow depth of field with creamy bokeh. Narrower apertures like f/11 let in less light but keep more of the scene in sharp focus. Standard full-stop aperture values are f/1.0, f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, and f/22.
Shutter Speed and Motion
Shutter speed controls how motion is rendered. Fast shutter speeds like 1/1000s freeze action, while slow shutter speeds like 1/30s or longer introduce motion blur. Standard full-stop shutter speeds double or halve: 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8, 1/4, 1/2, 1 second.
Frequently Asked Questions
What is the exposure triangle?
The exposure triangle consists of three camera settings that control how much light reaches the sensor: aperture (f-stop), shutter speed, and ISO sensitivity. Changing one setting requires adjusting at least one of the others to maintain the same overall exposure.
What is an exposure value (EV)?
Exposure value is a number representing a combination of aperture and shutter speed at a given ISO. Each whole EV step doubles or halves the amount of light reaching the sensor.
How do I calculate equivalent exposures?
If you change one setting by a certain number of stops, compensate by changing another setting by the same number of stops in the opposite direction. For example, opening the aperture by 1 stop requires doubling the shutter speed.
What is a stop in photography?
A stop is a doubling or halving of light. One stop more light means twice as much; one stop less means half.
How does ISO affect image quality?
Higher ISO values amplify the signal, brightening the image but also amplifying noise. Lower ISO values produce the cleanest images with the least grain.