 Resource Lesson Double Lens Systems
 When two or more lenses are used in an optical system, the formula used to calculate the magnification of the final image produced by the system is: Msystem = (Mlens #1)(Mlens #2)(Mlens #3) ....   When an optical system uses two lens, work each lens separately. Remember that the image of lens #1 will serve as the object for lens #2. If the image of lens #1 falls "in front of" lens #2, you can calculate the object distance for lens #2 by subtracting the value of di for lens #1 from the total distance separating the two lenses. In this example, two converging lens produce a final image which is real and upright. A scaled diagram would be necessary to determine how the height of the final image, I2, compares to the height of the original object, O.   A similar process will produce the image for a double lens system involving a converging and a diverging lens. In this second example, a converging lens followed by a diverging lens produce a final image which is virtual and inverted. A scaled diagram would be necessary to determine how the height of the final image, I2, compares to the height of the original object, O.