Microscopes allow scientists to look at and study objects undetectable by the human eye. The two methods of looking at microbes are light microscopy and electron microscopy. Light microscopes use visible light to expose microbes. Because electron microscopy requires a vacuum to detect samples, it is at somewhat of a disadvantage; light microscopes are portable and affordable, and allow researchers to observe living organisms. But light microscopes also have their own disadvantages.
At a cap of roughly 2,000 times, light microscopes can't magnify as closely as electron microscopes can. Light's relatively long wavelength decreases the light microscope's ability to magnify by requiring small spherical lenses to focus and spread out the light.
Light microscopes have lower resolution. Because the refracted light waves are spread out, the resulting image is blurred. Even instruments that provide additional lenses for increasing magnification do very little to improve image resolution.
Observing Internal Structures
The internal structures of living things are difficult to observe without the use of dyes. Living specimens must be killed and fixed during the dyeing process, thereby eliminating what is normally an advantage of light microscopy.