The exposure index EI for a 35 millimeter camera is a measurement of the amount of light that hits the film.

Question

 It is determined by the equation EI= log base 2 (f^2/t), where f is the "f-stop" setting on the camera, and t is the exposure time in seconds. Suppose the f-stop setting is 16 and the desired exposure time is 2 seconds. What will the resulting exposure index be?

EI =

Answer 1

Ei = log₂ (16² / 2) substituting values

Ei = log₂ = 128

Ei = log₂ 2⁷

Ei = 7 definition of log