Exposure Calculator

Lock an exposure, then tweak aperture, time, ISO, flash or ND to see the others adjust
Aperture
f /
Exposure Time
s
Sensitivity
ISO
Flash
stops
ND Filter
stops
Lock
Exposure Value
EV100 =
ND Filter
ND
  • EV = log2(N² / t) where N = f-number and t = exposure time in seconds.
  • EV100 = EV - log2(S / 100) + NDstops - Flashstops — ND blocks light so it adds back stops, flash adds light so it subtracts stops.
  • ND stops and the ND filter number stay in sync (stops = log2(filter number)), e.g. ND8 = 3 stops, ND1000 ≈ 9.97 stops. Enter either field.
  • When locked, changing any field adjusts the exposure time to compensate, except changing time itself which adjusts aperture.
  • Keyboard shortcuts: A, T, S, F, D, L, ↑, ↓.
  • Background on exposure: Fred Parker · Exposure Value · Sunny f/16 rule · ND filters