Changing the f-number of a camera by three stops by going from f/5.6 to f/16 will change the intensity of the light hitting the film by a factor of:
A)8.
B)4.
C)1/4.
D)1/8.

Question

Quizplus · Accepted Answer

The intensity of light hitting the film is inversely proportional to the square of the f-number.

So, going from f/5.6 to f/16, the change in f-number is (16/5.6)^2 = 8, which means the intensity of light hitting the film decreases by a factor of 8.

Therefore, the answer is D) 1/8.

Changing the F-Number of a Camera by Three Stops by Going