Your camera determines the focal distance required for your picture to be in focus using the lens equation, 1/F-1/S=1/D, where the focal distance to the object from the lens (D) is related to the focal length (F) and the distance from the lens to the film (S). If an object is placed 8 cm from a lens with a focal length of 4 cm, how far from the lens is the image (film) formed?