Lenses magnifications

When an eyepiece is used, the total magnification should be the objective lens magnification multiplied by eyepiece magnification. 

Figure 10. Hand-lens magnification of sample shown in Figure 9. Note chamber proximity to top surface of beam.

To increase the spatial resolution and detection sensitivity in surface analysis, two important characteristics of a microscope lens [magnification and numerical aperture (NA)] should be considered. 

Figure Bl.17.8. Iron oxide particles coated with 4 nm of Pt in an m-planar magnetron sputter coater (Hennann and Mtiller 1991). Micrographs were taken in a Hitachi S-900 in-lens field emission SEM at 30,000 primary magnification and an acceleration voltage of 30 kV. Image width is 2163 nm.

The final set of magnetic lenses beneath the specimen are jointly referred to as post-specimen lenses. Their primary task is to magnify the signal transferred by the objective lens. Modern instruments typically contain four post-specimen lenses diffraction, intermediate, projector 1, and projector 2 (in, order of appearance below the specimen). They provide a TEM with its tremendous magnification flexibility. 

To adjust the lens to the object was so long and tedious a task that it is not surprising that Leeuwenhoek used an individual lens for each object. The magnification varied and at best did not exceed... 

Focal length This is the distance from the lens to the center of the focus. The greater the focal length, the higher the magnification, but the narrower the field of vision. 

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