Astigmatism
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astigmatism
a relective defect of a lens that prevents focusing of a sharply defined image and from bringing horizontal and vertical lines to a sharp focus at the same time on a flat surface.
-Astigmatism - lens aberration making a single point light source impossible to focus as a true point.
Astigmatism Edit
Astigmatism (pointlessness) is when a point sending light through a lens cannot be projected as one point behind the lens. It appears as a line on the focal plane.
Astigmatism
A lens aberration or defect that is caused by the inability of a single lens to focus oblique rays uniformly. Astigmatism causes an object point to appear as a linear or oval-shaped image.
Astigmatism
Cataracts
Damages in the neural pathways or in brain regions dedicated to vision ...
c) Astigmatism. Rays of light from a single point of an object which is not on the axis of a lens fail to meet in a single focus thus causing the image of a point to be drawn out into two sharp lines, ...
While astigmatism remains present in the Wright camera, it conveniently combines with the mirror's Petzval curvature to result in a flat best image surface.
APPENDIX I GLOSSARY ABERRATION -A defect in the formation of an optical image; for example, astigmatism, chromatic aberration, curvature of field, and so forth. ABSOLUTE TEMPERATURE-The temperature measured from absolute zero.
Astigmatism - lines in some directions are focused less sharply than lines in other directions, ...
There are 3 aberrations which directly lower the sharpness of an image, Spherical Aberration, Astigmatism and Coma. Some lenses use aspheric elements to better correct spherical aberration at wide apertures.
Find out more.Astigmatism One of Seidel's five aberrations. Astigmatism is an aberration that causes points to blur, degrading sharpness. It can be reduced but not eliminated by stopping down the lens.
Hint: Since these simple lenses introduce some astigmatism and distortion that is directly proportional to their power, it's best to stop the lens aperture down by 2-3 stops (say from f/2.8 to f/8) when shooting with close-up lenses, ...
5's award-winning Optics Engine corrects lens problems, such as distortion, softness, vignetting, color fringing and astigmatism, in images made with supported cameras and lenses (a list is available on the DxO website).
Anastigmat
A compound lens which has been corrected for the lens aberration "astigmatism".
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And I have horrible vision (+6 in my right eye, with astigmatism). After the sun's up tomorrow I want to play around with using these glasses over the lens.
Aspherical: A surface which is curved and is not spherical. Some lenses are made with such surfaces to correct aberration.
Astigmatism: Lens aberration causing vertical and horizontal lines to focus in different focal planes.
 See also: Image, Photograph, Lens, Aberration, Light
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