Question

Derive an expression for the

longitudinal chromatic aberration.​

Answer 1

Answer:

prismaAs the refractive index of a transmittive medium is dependent on the wavelenght of light, dispersion occurs, when white light transmits such a medium. Refraction is stronger for light of short wavelengths, for example blue, and less intensive for light of long wavelngths, for example red.

Different kinds of glasses cause refraction or dispersion of various intensities. In photographical lenses the the same effect occurs. So it is neccessary to correct these abberations, otherwise you get to see these effects in the images.

There are two main types of chromatic aberrations:

the LATERAL (or transverse) and the LONGITUDINAL chromatic aberration.

longitudinal chromatic aberration

There is LONGITUDINAL CHROMATIC ABERRATION, if a lens cannot focus different colors in the same focal plane. It is caused by straight incident light. The foci of the different colors lie at different points in the longitudinal direction along the optical axis.

longitudinal chromatic aberration effectsThe longitidinal chromatic aberration leads to colored areas in the images, that arise, because not all three colors can be displayed in focus.