Simple vs
Compound microscope optics
In simple
image magnification with a single double convex lens
(as in a magnifying glass), the angle of the light path between
the eye and the object is bent outward, such that an magnified
virtual image is created at an apparent distance
beyond the actual object. Note that the image is not inverted.
A compound
microscope uses an objective lens close to the
object being viewed to collect light, which focuses a real
image (image 1) of the object inside the microscope tube.
That image is then magnified by the eyepiece lens, which
creates an enlarged, inverted virtual image of the
object (image 2). The optics of the eyepiece lens
are essentially those of the simple microscope. The compound
magnification is multiplicative, so that the objective /
eyepiece combination creates much higher magnification. Eyepiece
lenses are typically 10X, and a set of alternative Objective
lenses may comprise 10X, 30X, and 100X, creating respectively
100X, 300X, and 1,000X magnification, the last of which is the
limit of magnification with light waves in the visual range.