Commonly used microscopes are optical microscopes that use single lens with different magnifying powers, which will depend on the lens being used for a particular microscope.  Optical microscopes use visible light to create a magnified image.

Double convex lenses, which are generally used in such microscopes, can magnify an object up to fifteen times its original size. In a compound microscope, two lenses are mounted at the opposite ends of a closed tube. Magnification is thus increased several times over and can even reach to two thousand times the original size.

As you may recall from your biology lab class, objects that are viewed under microscopes are mounted on slides, or transparent strips of glass. We can take photographs through a microscope. For this, a camera takes the place of our eye at the microscope. Three-dimensional images can also be seen through a microscope. For this purpose, two low-powered microscopes are arranged in a certain manner. 

Certain objects cannot be viewed under normal illumination. Under such circumstances a dark-field microscope is used. The type of illumination provided by this microscope enables viewing of the desired images. Richard Adolf Zsigmondy (1865-1929) was an Austrian-born German chemist and Nobel laureate. To him goes the credit of developing an ultra-microscope with a dark field illumination.