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Angular aperture

About: Angular aperture is a research topic. Over the lifetime, 1771 publications have been published within this topic receiving 27257 citations.


Papers
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Proceedings ArticleDOI
TL;DR: In this paper, the dependency of the Zernike polynomials on the aperture size with respect to 3D space is investigated and the relation between these changes and the paraxial focal length is investigated.
Abstract: The paraxial focal length is still the most important parameter in the design of a lens. As presented at the SPIE Optics + Photonics 2016, the measured focal length is a function of the aperture. The paraxial focal length can be found when the aperture approaches zero. In this work, we investigate the dependency of the Zernike polynomials on the aperture size with respect to 3D space. By this, conventional wavefront measurement systems that apply Zernike polynomial fitting (e.g. Shack-Hartmann-Sensor) can be used to determine the paraxial focal length, too. Since the Zernike polynomials are orthogonal over a unit circle, the aperture used in the measurement has to be normalized. By shrinking the aperture and keeping up with the normalization, the Zernike coefficients change. The relation between these changes and the paraxial focal length are investigated. The dependency of the focal length on the aperture size is derived analytically and evaluated by simulation and measurement of a strong focusing lens. The measurements are performed using experimental ray tracing and a Shack-Hartmann-Sensor. Using experimental ray tracing for the measurements, the aperture can be chosen easily. Regarding the measurements with the Shack-Hartmann- Sensor, the aperture size is fixed. Thus, the Zernike polynomials have to be adapted to use different aperture sizes by the proposed method. By doing this, the paraxial focal length can be determined from the measurements in both cases.

11 citations

Patent
Toshinori Take1
22 Jun 2011
TL;DR: In this paper, a downsized imaging lens with a wide angle of view, capable of correcting various aberrations upon focusing on a close object from an infinitely distant object and having high optical performance over an entire picture is presented.
Abstract: The imaging lens includes, in order from an object side, a first lens group having positive refractive power; and a second lens group having the positive refractive power, the first lens group being fixed with respect to an image plane, the second lens group being moved toward the object side to adjust a focus on a close object, and a given conditional expression being satisfied, thereby disclosing a downsized imaging lens having a wide angle of view, capable of preferably correcting various aberrations upon focusing on a close object from an infinitely distant object and having high optical performance over an entire picture, an optical apparatus including the imaging lens and an imaging lens manufacturing method.

11 citations

Patent
07 Jul 1969
TL;DR: A camera has an adjustable lens aperture and a shutter member movable in a given path across the optical axis, the shutter member has an aperture for selectively passing light admitted by the lens aperture for exposing the film.
Abstract: A camera has an adjustable lens aperture and a shutter member movable in a given path across the optical axis. The shutter member has an aperture for selectively passing light admitted by the lens aperture for exposing the film. The shutter member, has an elongated opaque member extending across the shutter aperture and aligned with the lens aperture, the width of the opaque member being substantially equal to the minimum adjustment of the lens aperture. The opaque member has a plurality of cutouts for passing light to the film as the shutter aperture moves past the lens aperture.

10 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20234
20224
20217
20207
20195
201811