Using a convex lens of focal length +100 mm, for instance,
measure the distance e at which a sharp image is obtained for
both possible lens positions (repeat the measurement and calculate
the average value e–. Now take a measurement in the
same way but using the convex lens from the first measurement
and a concave lens (-200 mm for example). Make the
distance d as large as possible, and measure at least four
times the combined forcal length.
3.1. Slide projector
Place the slide – Emperor Maximilian – immediately behind the
condenser and project an image on the screen with the lens L2