Objective lenses tube length

Fig. 4.—Diagram illustrating optics of a compound microscope in use. Pi, Upper focal plane of objective P2, Lower focal plane of eyepiece A, Optical tube length = distance between Fi and P2 Oi, object Os, real image in Pj, transposed by the eollective lens, to Oj, real image in eyepiece diaphragm O4, virtual image formed at the projection distance C, 250 mm. from EP, eyepoint CD, condenser diaphragm L, mechanical tube length (160 mm.) i, 2, 3, three pencils of parallel light coming from different points of a distant illuminant, for instance, a white cloud, which illuminate three different points of the object. (Courtesy of Bausch and Lomb Optical Co.)...

Figure 1 Schematic diagram of an optical microscope with an infinity-corrected microscope objective of focal length /o and a back aperture diameter D. The tube lens of focal length / focuses the light on an electronic detector such as a CCD.

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