Exposure Value (EV) Calculator

What is exposure value?

EV collapses aperture and shutter speed into one number: EV = log₂(N² ÷ t). Every combination with the same EV lets in the same light. EV₁₀₀ normalizes to ISO 100 so it can describe scene brightness: a sunny day meters around EV 15, a living room around EV 5–6, and moonlight around EV −2.

The Sunny 16 rule

In full sun, set f/16 and a shutter speed of 1/ISO (e.g. f/16, 1/100, ISO 100 — that's EV 15). From there: f/11 for hazy sun, f/8 for bright cloud, f/5.6 for overcast, f/4 for open shade — each step matching one EV less light.

Frequently asked questions

Why does ISO change EV₁₀₀ but not EV?

EV proper describes only the aperture–shutter combination. Adjusting for ISO turns it into a measure of the light the scene needs, which is what meters and scene tables use.

Is higher EV brighter or darker?

A higher EV means the scene is brighter (or that your settings admit less light). Each +1 EV is one stop: half the light through the lens.