A 35-mm camera equipped with a 45-mm focal length lens is used to photograph a tree 15 m tall. If the aperture of the lens is set at f/2, what is the aperture diameter?
A) 23 mm
B) 27 mm
C) 32 mm
D) 18 mm
E) 14 mm

Question

Quizplus · Accepted Answer

The aperture diameter is given by the focal length divided by the f-number. In this case, the focal length is 45 mm and the f-number is f/2, so the aperture diameter is 45 mm / 2 = 22.5 mm.

A 35-Mm Camera Equipped with a 45-Mm Focal Length Lens