The Distal

The distal tip of the VE houses the video capture component and, like a video camera, can be fitted with various lenses including close-up lenses (near focus), distant view lenses (far focus), wide angle lenses, right angle lenses, and split screen stereo, or binocular lenses for 3D and measurement applications (Figure 4.12; see also Figure 4.4). The distal tip is typically maneuverable from controls found at the proximal end. The lens selection characteristic allows the researcher to match the lens, and therefore the image and data collected, to the research objectives and to adapt to imaging challenges within any given subject or object of study. For example, Figure 4.13 shows two views of the same thoracic area, one using a near-focus forward view lens and the other using a far-focus forward view lens. The far-focus lens gives a better view of the entire internal thoracic cavity. The distal tip of the endoscope houses the terminal end of the fiber-optic bundles used to deliver light. If the far-focus lens is used to examine a large open space, such as in preexcavation tomb analysis, additional illumination may be required.

Figure 4.12 Various interchangeable lens used in videoendoscopy. From left: Forward view near focus, right angle view near focus, and stereo lens used for measurements and 3D renderings.

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