The field lens, heat absorber, and lamp with built-in reflector can be seen, and their functions discussed.
The picture at the center shows the projector turned upside down with the open access port to view the optical elements. The photograph at the right shows, in some detail, the bulb (right center), the mirror (bottom near center) directing the light beam toward the lens (upper left, not seen), the heat filter (left center) and the field lens (just above the heat filter). Note that the bulb has a built-in reflector that directs the light beam onto the mirror, and the field lens focuses the beam so that after passing through the slide (just above the field lens, under the cover) the entire beam passes through the slide projector zoom lens to give the brightest picture.