Work out exposure value instantly with clear inputs, formula shown and shareable results.
Exposure value is the base-two logarithm of the aperture squared divided by the shutter time, and subtracting log2 of ISO over 100 refers it to the ISO 100 scale. EV is a single number for a whole exposure, which is why one EV equals one stop and any aperture and shutter pair on the same EV gives the same brightness.
Exposure value
EV = log2(aperture^2 / shutter time in seconds)
ISO reference
EV at ISO 100 = EV - log2(ISO / 100)
EV = log2(aperture^2 / shutter time in seconds). Exposure value is the base-two logarithm of the aperture squared divided by the shutter time, and subtracting log2 of ISO over 100 refers it to the ISO 100 scale.
EV is a single number for a whole exposure, which is why one EV equals one stop and any aperture and shutter pair on the same EV gives the same brightness.
Enter aperture, shutter speed, iso. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.