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A negative meniscus lens has a steeper concave surface (with a shorter radius than the convex surface) and is thinner at the centre than at the periphery. Conversely, a positive meniscus lens has a steeper convex surface (with a shorter radius than the concave surface) and is thicker at the centre than at the periphery.
A meniscus corrector is a negative meniscus lens that is used to correct spherical aberration in image-forming optical systems such as catadioptric telescopes. It works by having the equal but opposite spherical aberration of the objective it is designed to correct (usually a spherical mirror ).
Alvan G. Clark, the son of the founder of the eponymous American optical company, designed a photographic lens using a symmetric arrangement of two Gauss lenses and patented it in 1888; [4] Paul Rudolph introduced the Zeiss Planar as an improved Double-Gauss using cemented doublets in the place of the inner negative meniscus elements, [2]: 121 ...
The meniscus lens on the bottom is a positive element. The negative (diverging) meniscus lens has a thicker edge than the center, and represents the case where the concave surface (shown in red) has a smaller radius than the convex surface (shown in green). The meniscus lens on the top is a negative element.
Using a phoropter to determine a prescription for eyeglasses. An eyeglass prescription is an order written by an eyewear prescriber, such as an optometrist, that specifies the value of all parameters the prescriber has deemed necessary to construct and/or dispense corrective lenses appropriate for a patient.
Various lens shapes, and the location of the principal planes. ʟ̩. Converging or positive lenses. 1 - Symmetrical double convex lens. 2 - Asymmetrical double-convex lens 3 - Plano- convex lens. 4 - Positive meniscus lens. Diverging or negative lenses. 5 - Symmetrical biconcave lens. 6 - Asymmetrical biconcave lens. 7 - Plano-concave lens.
Diagram of a Mangin mirror. In optics, a Mangin mirror is a negative meniscus lens with the reflective surface on the rear side of the glass forming a curved mirror that reflects light without spherical aberration if certain conditions are met.
The telephoto lens configuration combines positive and negative lens groups with the negative at the rear, serving to magnify the image, which reduces the back focal distance of the lens (the distance between the back of the lens and the image plane) to a figure shorter than the focal length. This is for practical, not optical reasons, because ...