1 The focal length, F, of a camera's lens is related to the distance of
the object from the lens, J, and the distance to the image area in the
camera, W, by the formula below.
+
1
I
1
W
1
F
When this equation is solved for ) in terms of F and W. J equals
(1) F-W
(3)
FW
W - F
(2)
FW
F-W
1
F
1
W