🎚️ Exposure Calculator
Enter your aperture, shutter speed, and ISO to see the exposure value — then change the aperture or ISO and get the exact shutter speed that keeps the same exposure. Master the triangle without the guesswork.
🎚️ Balance the Exposure Triangle
What is an Exposure Calculator?
It does the exposure-triangle maths for you. Feed it your current aperture, shutter, and ISO and it reports the exposure value; then tell it the setting you want to change and it hands back the shutter speed needed to keep the picture exactly as bright.
Use it to open up for a blurrier background without over-exposing, to freeze motion with a faster shutter and know what to give back, or to learn how stops of light trade between aperture, shutter, and ISO until the relationship becomes second nature.
❓ Frequently Asked Questions
What is the exposure triangle?
The exposure triangle is the relationship between the three settings that determine how bright your photo is: aperture (how wide the lens opens), shutter speed (how long the sensor is exposed), and ISO (how much the signal is amplified). Change one and you have to change another in the opposite direction to keep the same overall exposure.
What is an exposure value (EV)?
Exposure value is a single number that combines aperture and shutter speed into one figure: the base-2 logarithm of the f-number squared divided by the shutter time in seconds. Each whole step of EV is a doubling or halving of light. The tool also reports it referenced to ISO 100, the light level your settings suit: subtract one for every doubling of ISO above 100 (f/2.8 at 1/125 is EV 9.94, and at ISO 400 it suits an EV 7.94 scene).
If I open the aperture, how much do I change the shutter?
Light gathered falls with the square of the f-number, so this tool multiplies your shutter time by the ratio of the new aperture squared to the old aperture squared. Stopping down from f/2.8 to f/5.6 cuts the light per unit time to a quarter, so the shutter must be four times longer to hold the same exposure; opening up works the other way.
How does ISO trade off against shutter speed?
ISO amplification is linear: doubling the ISO doubles the sensitivity, so you can halve the shutter time (or stop down one stop) for the same brightness. Push ISO too high, though, and you introduce noise — so raise it only as far as you must to get a usable shutter speed in low light.