Coma

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Coma: A photographic lens aberration, which causes blurring at the edge of a picture. Off-axis highlights tend to grow radial tails (rather like comets, hence the name) and are due to differential magnification at the center and edge of the image.

Coma A lens defect which results in points of light appearing in the image not as points but as discs with comet-like tails.

Coma A lens aberration restricted to off axis image points; the inability of a lens to render point sources of light near the edges of the frame as circular; ...

Coma - lens aberration producing asymmetrical distortion of points in the image. Combination printing - producing a composite image by printing more than one negative on a single sheet of paper.

Coma This refers to the blurring of objects at the edge of the field of view, most common in short focal ratio Newtonian telescopes (at f/10 and longer, Newtonians are very well corrected for coma).

April 9 - Israeli Prime Minister Ariel Sharon is removed from office after four months in a coma. April 9 - Hungarian parliamentary election, 2006 April 10 - Romano Prodi narrowly defeats Silvio Berlusconi in the Italian parliamentary elections.

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 ...

03%, but we found a little "coma" in the extreme corners of the image. We're perhaps being a little harsh in the extent to which we're calling attention to the distortions and aberrations of the F505's lens, ...

Coma - the image of a point source of light cannot be brought into focus, but has instead a comet shape, Curvilinear distortion - distortion consisting of curved lines, Field curvature - the image is incorrectly curved, ...

This effect is achieved by choosing a relatively long exposure time and zooming just after the shutter is released. The picture below shows a sort of coma effect because the zooming was finished well before the shutter was closed.

Unless it’s blatantly obvious, I don’t comment much about vignetting, chromatic aberrations, coma, and other things that consume some reviewers. The final criterion is does the lens provide the results I desire?

See also: Image, Light, Aberration, Lens, Camera