π· Exposure Calculator
Calculate equivalent exposures and find the perfect exposure settings.
Set original exposure, then change one setting to find the equivalent.
Equivalent Exposure with f/2.8
How to Use This Calculator
The Exposure tab helps you find a new shutter speed when you change aperture but want to keep the same brightness. The EV tab tells you the exposure value for any combination of settings, with a description of the scene it matches. Both tabs use the same three inputs: aperture (f-number), shutter speed, and ISO.
On the "Find Equivalent Exposure" tab, set your original aperture, shutter speed, and ISO. These are your current working settings.
Select the new aperture you want to use. The calculator shows the exact new shutter speed needed to maintain the same brightness.
On the "Exposure Value (EV)" tab, enter any combination of settings to see what EV they produce and what real-world lighting condition that corresponds to.
Use the nearest standard shutter speed shown in the result as your actual camera setting. The exact value is also displayed so you know how close the rounded value is.
Exposure Triangle Formula
EV stands for Exposure Value. N is the f-number and t is the shutter speed in seconds. At ISO 100, EV 15 is a sunny day outdoors; EV 5 is a dimly lit room. Each one-stop change in aperture, shutter speed, or ISO shifts EV by exactly 1. Equivalent exposures share the same EV but create different creative effects: a fast shutter freezes motion while a wide aperture blurs the background.
Real-World Examples
When You Need This
Imagine you're photographing a dancer at a concert with f/8 at 1/60s, ISO 800. The images look sharp on the back of the camera but are blurry when you zoom in. You need at least 1/500s to freeze the movement. This calculator tells you exactly what to change: open up 3 stops to f/2.8 and your shutter automatically stays equivalent, or bump ISO to 6400 and keep f/8 while going to 1/500s.
The EV lookup is also useful when you walk into an unfamiliar location and want a starting exposure before you even raise the camera. Know roughly what EV the scene is (a church interior is around EV 6, a floodlit stadium is around EV 12), and you can dial in a reasonable starting point on manual mode. You'll still meter and adjust, but having a sensible first guess avoids blown highlights on your first shot.
Frequently Asked Questions
What is the exposure triangle?
The exposure triangle consists of aperture (f-stop), shutter speed, and ISO. Changing any one setting by 1 stop doubles or halves the light. Equivalent exposures have the same total light (EV).
What is EV (Exposure Value)?
EV is a dimensionless number representing a specific luminance level. EV = logβ(NΒ²/t) where N is f-number and t is shutter speed in seconds. At ISO 100, EV 0 = f/1 at 1 sec.
What is a "stop" of exposure?
One stop = doubling or halving the amount of light. Opening aperture by 1 stop, doubling shutter time, or doubling ISO each add 1 stop of exposure.
How do I expose for bright sun (Sunny 16 rule)?
In bright sunlight at ISO 100: set aperture to f/16 and shutter speed to 1/ISO (i.e., 1/100s). This is the Sunny 16 rule β reliable for daylight exposure.
What does changing ISO do?
Increasing ISO amplifies the sensor signal (or film sensitivity), brightening the image without changing aperture or shutter. Higher ISO introduces noise. ISO 200 = twice the sensitivity of ISO 100.