axial ray मीनिंग इन हिंदी

However, this causes off-axis light to be focused closer to the lens than axial rays ( spherical aberration ); especially severe in wide angle or wide aperture lenses.
The most important is the chromatic difference of aberration of the axis point, which is still present to disturb the image, after par-axial rays of different colors are united by an appropriate combination of glasses.
It increases rapidly with the aperture, and is more important with medium apertures than the secondary spectrum of par-axial rays; consequently, spherical aberration must be eliminated for two colors, and if this be impossible, then it must be eliminated for those particular wavelengths which are most effectual for the instrument in question ( a graphical representation of this error is given in M . von Rohr, " Theorie und Geschichte des photographischen Objectivs " ).