Photography Exposure Value (EV) Calculator
Calculate the Exposure Value (EV) from aperture, shutter speed and ISO. Get EV at your settings, the ISO 100-normalized EV100, the closest standard lighting condition (Sunny 16 family), and a table of equivalent same-exposure aperture/shutter pairs.
Input
Just the f-number — enter 2.8 for f/2.8
A fraction of a second (1/125) or decimal seconds (0.008)
Output
| Property | Value |
|---|---|
| No data yet | |
Equivalent Exposures (same EV100)
| Aperture | Shutter | Depth of Field |
|---|---|---|
| No data yet | ||
Guides
What does this calculator do?
Enter your aperture (f-number), shutter speed, and ISO, and this tool calculates the Exposure Value (EV) — the standard photography number describing how much light a combination of camera settings lets in. It reports the raw EV at the ISO you entered, the EV100 (the same exposure normalized to the ISO 100 baseline, so it's comparable across different ISO settings), the closest lighting condition from the classic "Sunny 16" reference scale, and a table of equivalent exposures — other aperture/shutter pairs producing the exact same brightness, so you can trade depth of field for motion blur without changing the exposure.
The math follows the standard APEX exposure relation:
- EV = log₂(N² / t) — N is the f-number, t is the shutter speed in seconds. A pure function of aperture and shutter; it doesn't depend on ISO.
- EV100 = EV − log₂(ISO / 100) — normalizes that raw EV to ISO 100, the reference speed every standard EV chart (including Sunny 16) uses. A higher ISO needs less light for correct exposure, so the same scene shot at a higher ISO produces a numerically larger raw EV — subtracting the ISO term recovers the ISO-independent scene brightness.
Sanity check: f/16 at 1/125s, ISO 100 — the textbook "Sunny 16" settings for a bright sunny day — works out to EV ≈ 15, the value photographers have used for decades to meter bright daylight without a light meter.
How to use it
- Enter your aperture as just the f-number (e.g.
2.8for f/2.8). - Enter your shutter speed as a fraction of a second (
1/125) or decimal seconds (0.008,2,30). - Enter your ISO (e.g.
100,400,1600). - Read the Exposure Value headline and details table for the EV at your ISO, the normalized EV100, and the closest matching lighting condition.
- Check the equivalent exposures table for other f-stop/shutter combinations at the same brightness — useful for deciding whether to freeze motion with a faster shutter and wider aperture, or maximize depth of field with a smaller aperture and slower shutter.
Why does EV100 stay the same when I change ISO?
EV100 describes the scene, not your camera settings — the light on the subject, independent of sensor sensitivity. Raise the ISO and speed up the shutter (or stop down the aperture) to hold the same correct exposure, and the raw EV goes up — but EV100 doesn't change, because the light itself hasn't changed, only how the camera meters it. The equivalent-exposures table shows exactly this: every row shares the same EV100, split differently between aperture and shutter.
What does "Depth of Field" mean in the table?
The trade-off behind each row: wide apertures (small f-numbers, like f/1.4) blur the background more but need a faster shutter; small apertures (large f-numbers, like f/16 or f/22) keep more in focus but need a slower shutter or a tripod. Each row is a different point on that trade-off, not a different exposure.
Does this run on my device?
Yes — entirely in your browser, or via the API if calling it programmatically. No image or camera data is uploaded anywhere.