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A telecentric lens is a special optical lens (often an objective lens or a camera lens) that has its entrance or exit pupil, or both, at infinity. The size of images produced by a telecentric lens is insensitive to either the distance between an object being imaged and the lens, or the distance between the image plane and the lens, or both, and ...
Comparison of a conventional lens (1), object-space telecentric lens (2), image-space telecentric lens (3) and bi-telecentric lens (4), assuming the images are in sufficient focus by CMG Lee. Width 100%
An entocentric lens is a compound lens which has its entrance or exit pupil inside the lens. [1] This is the most common type of photographic lens. The aperture diaphragm is located between the objective and the image-side focus (optics). It corresponds to the "normal" human visual impression. Distant objects appear smaller than closer objects.
Secondly, it only applies to an object-space telecentric lens. Third, it loses the point of how a telecentric lens actually works. What makes a lens telecentric is not that all the rays are "about parallel" to the optical axis. The properties of a telecentric lens come specifically from the fact that the chief ray is parallel to the axis.
Depending on the lens design, the entrance pupil location on the optical axis may be behind, within or in front of the lens system; and even at infinite distance from the lens in the case of telecentric systems. The entrance pupil of the human eye, which is not quite the same as the physical pupil, is typically about 4 mm in diameter.
A hypercentric or pericentric lens is a lens system where the entrance pupil is located in front of the lens, in the space where an object could be located. In a certain region, objects that are further away from the lens produce larger images than objects that are closer to the lens.
Telecentric lens. Compound lens with an unusual property concerning its geometry of image-forming rays. In machine vision systems telecentric lenses are usually employed in order to achieve dimensional and geometric invariance of images within a range of different distances from the lens and across the whole field of view. Telephoto lens. Lens ...
Similarly, the allowed range of angles on the output side of the lens can be filtered by putting an aperture at the front focal plane of the lens (or a lens group within the overall lens), and a sufficiently small aperture will make the lens image-space telecentric. This is important for DSLR cameras having CCD sensors. The pixels in these ...