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For the purposes of ray tracing, this is equivalent to a series of identical thin lenses of focal length f = R/2, each separated from the next by length d. This construction is known as a lens equivalent duct or lens equivalent waveguide .
The signs are reversed for the back surface of the lens: R 2 is positive if the surface is concave, and negative if it is convex. This is an arbitrary sign convention; some authors choose different signs for the radii, which changes the equation for the focal length. For a thin lens, d is much smaller than one of the radii of curvature (either ...
Thin lens equation f ... List of equations in nuclear and particle physics; List of equations in quantum mechanics ... ISBN 978-0-521-57507-2. A. Halpern (1988). 3000 ...
Distances in the thin lens equation. For a lens of negligible thickness, and focal length f, the distances from the lens to an object, S 1, and from the lens to its image, S 2, are related by the thin lens formula: + =.
This comes from the principle of reversibility which states light rays will travel along the originating path if the light's direction is reversed. [2] Depending on how an optical system is designed, there can be multiple planes that are conjugate to a specific plane (e.g. intermediate and final image planes for an object plane).
Thin lenses produce focal points on either side that can be modeled using the lensmaker's equation. [5] In general, two types of lenses exist: convex lenses, which cause parallel light rays to converge, and concave lenses, which cause parallel light rays to diverge. The detailed prediction of how images are produced by these lenses can be made ...
In weak lensing by large-scale structure, the thin-lens approximation may break down, and low-density extended structures may not be well approximated by multiple thin-lens planes. In this case, the deflection can be derived by instead assuming that the gravitational potential is slowly varying everywhere (for this reason, this approximation is ...
In most cases, two thin lenses are combined, one of which has just so strong a positive aberration (under-correction, vide supra) as the other a negative; the first must be a positive lens and the second a negative lens; the powers, however: may differ, so that the desired effect of the lens is maintained. It is generally an advantage to secure ...