Question

Suppose your 48-mm focal length camera lens is 54 mm away from the image sensor in the camera. How far away, in meters, is an object that is in focus? What is the object height, in meters, if its image is 1.75 cm high? h_o =

Answer 1

for camera lens:

1/f = 1/u + 1/v

u = v*f/(v - f)

u = 48*54/(48 - 54)

u = -432 mm = -0.432 m

B.

magnification is given by:

M = -v/u = hi/ho

ho = -hi*u/v

ho = -1.75*(-432)/54 = 14 cm = 0.14 m