Image Inversion By Prism
To demonstrate that a right angle prism can invert an image.
Light source without condenser, iris diaphragm, centering pin, prism on rotating mount on tilting carriage, 10cm focal length convex lens.
In order in the picture are the following optical elements: light source, iris, post, right angle prism (long side up),and 10cm convex lens. With the prism out of the system, the lens is used to produce an image of the post, which is inverted on a distant screen. Inserting the prism inverts the image of the post, causing the image to be erect. This technique is sometimes used in optical instruments.