A two-lens system. Two converging lenses, A and B, with focal lengths and , are placed apart. An object is placed in front of the first lens.
Determine (a) the position, and (b) the magnification, of the final image formed by the combination of the two lenses.
a) Using the lens equation, we find the image for the first lens to be 30.0 cm behind that lens. This becomes the object for the second lens - it is a real object located 50.0 cm away. Using the lens equation again we find the final image is 50 cm behind the second lens.
b) The magnification is the product of the magnifications of the two lenses: . The image is half the size of the object and upright.