sagittal coma

sagittal coma

[¦saj·ə·təl ¦kō·mə]
(optics)
The radius of the circle formed in the focal plane by rays from an off-axis point passing near the edge of a lens that displays coma.
References in periodicals archive ?
4G has been extremely well received for its ability to minimize sagittal coma flare* for rendering of point light sources as sharp points with no distortion or fringes across the entire frame, even at maximum aperture.
In addition, adoption of an ED lens element and an aspherical lens element, which ensure superior image quality, and optical design that controls sagittal coma flare for excellent point image formation make the lens capable of maximizing the distinctive characteristics of high pixel-count digital SLR cameras with expression of the finest details.
Optical design that considers point image formation for very little sagittal coma flare
With shooting of distant night landscapes, the lens minimizes the sagittal coma flare that makes a point light source look like a bird with its wings spread to render point light sources as sharp points with no distortion or fringes across the entire frame, even at maximum aperture, for clear and crisp night landscape shots.