Aberrations of optical systems

Aberration of optical system — error or error image in the optical system caused by deviation of the beam from the direction in which he would have to go in a perfect optical system.

Aberrations can be divided into diffraction, chromatic (colored) and also monochromatic, that is inherent to monochromatic beams of rays. These include:

• spherical aberration
• coma
• astigmatism
• curvature of field (surface) image
• distortion

Spherical aberration of the lens due to the fact that its refractive surface to meet the individual rays in different angles of the light source becomes a ring.

Coma is manifested in the fact that every part of the optical system produces an image of a luminous point as a ring. The centers of the rings are not the same, resulting in their superposition, that is, the image of the point given by the system as a whole becomes unbalanced spots scattering.

Astigmatism occurs because the oblique rays of the beam have different points of convergence. In the pictures it looks like a blur point. At the same time luminous point located at the main optical axis, is transmitted as a point, but if the point is outside this axis, as dimming, crossed lines, etc. This phenomenon is most frequently observed at the edges of the image.

The image field curvature causes uneven sharpness across the image.

The distortion is manifested in the curvature and distortion of the geometry of the image. Distinguish between negative (barrel) and positive (pincushion).

Translated by «Yandex.Translator»