FIGURE 15.1 SHOWS THE COURSE OF LIGHT RAYS IN A MODERN THREElens transmitted light microscope with infinity optics (the ICS principle, which means Infinity Color-corrected System). Let us follow the light rays that emanate from an object (1). From these rays the objective (2) projects an image to infinity. The intermediate lens (3) that also intervenes in the progress of the light rays creates amagnified intermediate image (4) from the rays that are now running parallel. This intermediate image is further magnified by the eyepiece (5). As the illustration shows, the visual angle 1 that results when this optical system is used is considerably greater than it is when the object is viewed by the naked eye at the same distance of 25 cm ( 10 in), visual angle 2.