Increasing the focal length in a telephoto lens by a factor of nine, while keeping the aperture size constant, will change the f-number by what factor?
a. 1/3
c. 9
b. 1/9
d. 3
Question 2
Decreasing the aperture diameter of a camera lens by a factor of three will change the f-number by what factor?
a. 3
c. 1/9
b. 9
d. 1/3