Microscopes allow scientists to observe and study objects that cannot be detected by the human eye. Two methods of observing microorganisms are light microscopy and electron microscopy. Optical microscopy uses visible light to expose microorganisms. This is somewhat disadvantageous because electron microscopes require a vacuum to examine samples. Portable and affordable, light microscopes allow researchers to observe living organisms. But optical microscopes also have their own drawbacks.
enlarge
The magnification of an optical microscope is about 2000 times, and it cannot magnify like an electron microscope. The relatively long wavelengths of light reduce the magnification power of an optical microscope because small spherical lenses are required to focus and spread the light.
Resolution
Optical microscopes have lower resolution. As the refracted light waves spread out, the resulting image is blurred. Even instruments that provide extra lenses to increase magnification do little to improve image resolution.
observe the internal structure
It is difficult to observe the internal structure of living things without using dyes. Living specimens must be killed and fixed during staining, eliminating the usual advantages of light microscopy.
