- The failure of light
from a point on an object to converge to a point on the image after passing
through a lens.
- a. The failure of a lens or mirror to bring the light rays to the same
focus. When aberration is due to the form of the lens or mirror, it is
called spherical aberration. When due to the different refrangibility of
light of different colors, it is called chromatic aberration. When present
in magnifiers it often causes inaccurate decisions as to flawlessness or
color of gems.
b. Distortion produced by a lens. It is spherical if a flat image appears
closer to the viewer in the middle than toward the edges of the field of
view. It is chromatic if the visible spectrum is spread to give both a red
and a blue image. CF: achromatic;
See also: chromatic aberration
Dictionary of Mining, Mineral, and Related Terms