Thursday, February 22, 2007

Compound microscopes are what most people visualize when they think about microscopes. The compound microscope essentially consists of two or more double convex lenses fixed in the two extremities of a hollow cylinder. The lower lens is called the objective, and the upper lens - the eyepiece. Typically the range of magnification on a compound microscope is between 40x and 1000x, although some are capable of higher or lower magnifications. The cylinder is mounted upright on a screw device, which permits it to be raised or lowered until a clear image is formed. Because only one objective is used at a time, the viewer sees a two-dimensional image of the specimen (usually reversed and upside-down).