The function of a microscope is to magnify (increase the size of) an image of your specimen. Magnification is produced by both the ocular and objective lenses. The total magnification is determined by the following equation:

Magnification of ocular lens X Magnification of objective lens = Total magnification.

For example, using the 100X (oil immersion) objective lens with a 10X ocular lens produces a total magnification of 1000X ( the maximum possible useful magnification of a light microscope).

Resolving Power
As the microscope increases the size of an image of your specimen, it must also maintain the clarity of the detail within that image. This is called the resolving power of the microscope and it depends upon the quality of your objective lenses. The wavelength of visible light limits the resolving power of light microscopes. Magnification above 1000X is not accompanied by sufficient resolving power to distinguish two very close objects as separate objects, as seen in the demonstration below.

Good Resolution.
2 Small Circles are visible.

Poor Resolution.
The 2 circles are visible as one object.

Continue on to Lab Exercises.