Microscopes come in many different types, each of which has distinct functions and applications. However in a routine histology department, virtually all of the work is done using a light microscope, with transmitted light, meaning that the light passes through the section to the objective lens. This arrangement is sometimes called bright field microscopy, because the background appears bright. Rarely it may be necessary to use incident light, where the section or tissue is illuminated from the same side as the objective and in this case the background appears dark (dark field microscopy). A number of other functions can be done by most light microscopes, but they are rarely used for routine histology. Occasionally, it may be necessary to examine cells at a very high magnification, in which case, it is necessary to use an electron microscope because there is a limit to the magnification that can be obtained using a light microscope.