Exposure Value Calculator
Calculate exposure value from your aperture, shutter speed, and ISO, shown at base ISO 100 and adjusted for your chosen sensitivity.
Enter shutter time in seconds — 1/250 is 0.004, 1/60 is about 0.0167, and a two-second exposure is just 2. EV100 is the value at ISO 100; the ISO-adjusted EV shifts it for your chosen sensitivity.
How it works
Exposure value, or EV, is a single number that captures how much light a given aperture and shutter combination lets in. Each step of one EV either doubles or halves the light, so it's a clean way to compare very different settings.
The math is the base-two logarithm of the aperture squared divided by the shutter time in seconds. That gives EV at ISO 100, the standard reference point photographers quote for scene brightness.
Because raising ISO makes the sensor more sensitive, the tool adds the ISO adjustment on top. A shot at ISO 400 records the same brightness as an EV two stops lower at ISO 100, and the calculator shows both figures side by side.
Frequently asked questions
How do I enter my shutter speed?
Use seconds. A speed of 1/250 becomes 0.004, 1/60 is about 0.0167, and a full two-second exposure is simply 2. Fractions on your camera dial are just one divided by that number.
What's the difference between the two EV figures?
The first is EV at ISO 100, the standard way to describe how bright a scene is. The second folds in your ISO, so it reflects the exposure your actual settings produce.
Is a higher EV brighter or darker?
A higher EV means less light reaches the sensor, so it suits brighter scenes. Bright daylight sits around EV 15, while a dim indoor room might be EV 5 or lower.