Exposure Triangle
See the exposure value of a shutter, aperture and ISO combination.
About Exposure Triangle
Exposure value combines aperture, shutter and ISO into one brightness number, comparing it against the familiar Sunny 16 baseline. Three separate controls always trade stops against each other, so an EV reference reveals when a combination is wildly off.
Formula
Exposure Triangle
EV = log2( aperture^2 x (100 / shutter seconds) x (ISO / 100) )
- Sunny 16
- Roughly EV 15, the classic bright-noon baseline
Worked example
With the default values below, Exposure Triangle returns Exposure Value of 12.9. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Shutter (1/X)minimum 1
- 250
- Aperture (f/)minimum 0.5
- 2.8
- ISOminimum 20
- 400
Results
- Exposure Value
- 12.9
- Stops vs Sunny 16
- -2.1
- Verdict
- Dark - open up, slow down or raise ISO
Step by step
- 1Values used
- 2Exposure Triangle
- 3Exposure Value= 12.9
- 4Stops vs Sunny 16= -2.1
- 5Verdict= Dark - open up, slow down or raise ISO
Assumptions and limits
- The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 1 decimal place, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Exposure Triangle calculated?
EV = log2( aperture^2 x (100 / shutter seconds) x (ISO / 100) ) Exposure value combines aperture, shutter and ISO into one brightness number, comparing it against the familiar Sunny 16 baseline.
Why does Exposure Triangle matter?
Three separate controls always trade stops against each other, so an EV reference reveals when a combination is wildly off.
What values do I need to enter?
This calculator takes 3 inputs: Shutter (1/X), Aperture (f/), ISO. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.