A 35-mm camera equipped with a 40-mm focal length lens is used to photograph a tree 17 m tall.If a 32-mm high image of the tree on the CCD sensor is required,how far should the camera lens be from the tree?
A)21 m
B)22 m
C)23 m
D)24 m
E)26 m

Question

Quizplus · Accepted Answer

The correct answer is A because the image height is directly proportional to the object height and inversely proportional to the object distance. So, the object distance is 17 m * (32 mm / 40 mm) = 13.6 m. The camera lens should be 17 m - 13.6 m = 3.4 m from the tree.

A 35-Mm Camera Equipped with a 40-Mm Focal Length Lens