The ocular and objective lenses work together to create a magnified image. The magnification of these objective lenses typically ranges from 4⨯ to 100⨯, with the magnification for each lens designated on the metal casing of the lens. At the other end of the body tube are a set of objective lenses on a rotating nosepiece. The ocular lenses typically magnify images 10 times (10⨯). Some brightfield microscopes are monocular (having a single eyepiece), though most newer brightfield microscopes are binocular (having two eyepieces), like the one shown in Figure 2.12 in either case, each eyepiece contains a lens called an ocular lens. The brightfield microscope, perhaps the most commonly used type of microscope, is a compound microscope with two or more lenses that produce a dark image on a bright background. These various types of light microscopes can be used to complement each other in diagnostics and research. Examples of light microscopes include brightfield microscopes, darkfield microscopes, phase-contrast microscopes, differential interference contrast microscopes, fluorescence microscopes, confocal scanning laser microscopes, and two-photon microscopes. Many types of microscopes fall under the category of light microscopes, which use light to visualize images. In this section, we will survey the broad range of modern microscopic technology and common applications for each type of microscope. By comparison, the relatively rudimentary microscopes of van Leeuwenhoek and his contemporaries were far less powerful than even the most basic microscopes in use today. These advances led to major improvements in magnification, resolution, and contrast. The 20th century saw the development of microscopes that leveraged nonvisible light, such as fluorescence microscopy, which uses an ultraviolet light source, and electron microscopy, which uses short-wavelength electron beams. In 1830, Joseph Jackson Lister created an essentially modern light microscope. But microscopy continued to advance in the centuries that followed. The early pioneers of microscopy opened a window into the invisible world of microorganisms. Describe the distinguishing features and typical uses for various types of light microscopes, electron microscopes, and scanning probe microscopes.Calculate total magnification for a compound microscope.Identify and describe the parts of a brightfield microscope.By the end of this section, you will be able to:
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