coma
Quick Summary
In optics, coma is an aberration where the image of a point appears comet-shaped. This occurs when light rays from an off-axis object point are focused by different zones of a lens. Instead of a single point, the image is blurred into a shape with a bright tip and a hazy tail, often resembling a comet. This aberration causes images in the outer parts of a field of view to appear smeared. While spherical aberration affects on-axis points, coma specifically impacts off-axis points.12
Ask Britannica AI about this topic
Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.
aberrationComa, so called because a point image is blurred into a comet shape, is produced when rays from an off-axis object point are imaged by different zones of the lens. In spherical aberration, the images of an on-axis object point that fall on a plane…
Read MoreComa, so called because a point image is blurred into a comet shape, is produced when rays from an off-axis object point are imaged by different zones of the lens. In spherical aberration, the images of an on-axis object point that fall on a plane…
Read More
technology of photographyAberrationsAnother aberration, called coma, makes image points near the edges of the film appear as irregular, unsharp shapes. Distortion is present when straight lines running parallel with the picture edges appear to bow outward (barrel distortion) or inward (pincushion distortion).
Read MoreAnother aberration, called coma, makes image points near the edges of the film appear as irregular, unsharp shapes. Distortion is present when straight lines running parallel with the picture edges appear to bow outward (barrel distortion) or inward (pincushion distortion).
Read More