Spherical aberration
A lens fault which causes loss of image definition at the image plane. Its affects are reduced by stopping down.
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Spherical Aberration
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Spherical aberration
Light passing through a convex lens will be brought to different focus depending upon whether the light passes through near the center of the lens or closer to the periphery.
Spherical aberration occurs due to the increased refraction of light rays that occurs when rays strike a lens, or a reflection of light rays that occurs when rays strike a mirror near its edge in comparison with those that strike nearer the center.
a) Spherical aberration. Basically, a beam of light passing through a lens parallel to the optical axis converges to form 3 focused images on the sensor.
Achromatic Lens An Achromatic lens is a system of lenses joined in order to minimize color and shape distortions (chromatic and spherical aberrations) that are inherent in a single lens system.
However, just so you know what these lens aberrations are, a brief definition is provided for each of them in the glossary; they are as follows: Astigmatism Chromatic aberration Coma Curvilinear distortion Spherical aberration Today's lenses can ...
Q: What are residual spherical aberrations ? This defect is actually a quite evil one. Residual spherical aberrations are focus shifts when stopping down e.g. if the lens has a max. aperture of f/2.
Open up more and spherical aberration will degrade the image, close down more and diffraction will degrade the image. In 99% of cases this will give you maximum sharpness of the in-focus image in the center of the frame.
This is called spherical aberration. In most lenses, spherical aberration is an undesirable trait as it causes the lens to be less sharp. On the other hand, in a soft focus lens, spherical aberration is desired as it softens the image.
This won't make up for poor focus, camera shake or the spherical aberration that often comes with shooting lenses wide open (these are all way too complex phenomena to correct this way), but it will give it a bit of a sharpness "kick".
Spherical Aberration One of Seidel's five aberrations. It is a variation in the focal length of a lens from the center to the edges, due to its shape. Spherical aberration appears as a halo, blur and loss of sharpness. Find out more.
Differing amounts of spherical aberration alter how lenses render out-of-focus points of light, and thus their bokeh. The word "bokeh" comes from the Japanese word "boke" (pronounced bo-keh) which literally means fuzziness or dizziness.
When corrective elements are incorporated into a lens design, most spherical aberrations can be minimized. Additionally, these spherical aberrations can often be adjusted with image-editing software. (See also Chromatic Aberration.) ...
Soft focus lens
A lens, uncorrected for spherical aberrations, used to produce a soft focus effect.
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The image might be sharp in the center, but at the edges there would likely be spherical aberrations (where objects that are supposed to be round are recorded more as an elongated ellipse) and chromatic aberration (where the colors are separated as ...
-Aplanat - lens which has been corrected for spherical aberration.
-Apochromat - lens corrected for chromatic aberration in all three primary colors.
Carl Zeiss has introduced the Lightweight Zoom LWZ.2, featuring radically shaped spherical glass, claimed high optical performance and reduced spherical aberrations for distortion-free shooting. Read more
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The end result is a softening of the image, like an old lens with really bad spherical aberrations. Used for allegedly romantic photos of lovers, or for portraits of older people who want to make their wrinkles less obvious.
You may also encounter Spherical Aberration, or wide-angle distortion of your images.
apochromatic lens
a process lens that has been corrected for both chromatic and spherical aberrations.
 See also: Aberration, Lens, Light, Focus, Camera
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