
108 OPTICS FOR ENGINEERS
Entrance
window
Aperture stop
Exit
pupil
Field stop
Figure 4.26 Microscope apertures. The entrance window is near the object, and the entrance
pupil is at infinity. The exit pupil is at the back focus of the eyepiece and the exit window is at
infinity, as is the image.
the eld stop is at the front focal plane of the eyepiece. Thus, the exit window is in the same
plane as the image.
If we wish to build a microscope, we may use objectives and an eyepiece from manufac-
turers that will not want to provide the details of their proprietary designs. Thus we may not
know the locations of principal planes or any of the components that make ...