Exposure value

Definition

Exposure value compresses aperture and shutter into one stop-scaled number. At ISO 100, EV = log₂(N² / t): f/16 and 1/125 s is about EV 15, classic Sunny 16. At another ISO the same formula gives EV at that speed, which is EV₁₀₀ + log₂(ISO/100): the same light reads two stops higher at ISO 400, where Sunny 16 is f/16 at 1/500 s. Use EV to compare scenes, ND stacks and flash fill — not as a substitute for a meter reading on a job that cannot miss.

Calculators that use this

• Exposure & light

  Exposure Value Calculator

  Convert aperture, shutter speed and ISO into EV at ISO 100 and EV at your working ISO. Use it to match meter readings or compare two camera settings.

• Exposure & light

  Exposure Shift Calculator

  Keep the same exposure while changing aperture or ISO: get the shutter that matches, plus how many stops the shutter had to move.

• Exposure & light

  Sunny 16 Calculator

  Apply the Sunny 16 rule: f/16 at 1/ISO in sun, then shift shutter for slight overcast, overcast, heavy overcast, or sand and snow.