Longitudinal chromatic aberration is most closely related to which lens property?

Longitudinal chromatic aberration is most closely related to which lens property?

• A. Abbe value
• B. Lens aperture
• C. Surface curvature
• D. Glass type

Answer: (A)

Longitudinal chromatic aberration comes from how much a lens material disperses light—the refractive index changes with wavelength, causing different colors to focus at different depths along the axis. The Abbe value is a measure of that dispersion: a higher Abbe number means the index varies less with wavelength, leading to smaller chromatic aberration, while a lower Abbe number means more dispersion and greater LCA. So this property directly explains how much LCA a given glass will produce. Aperture mainly affects light throughput and diffraction, not the wavelength-dependent focal shift. Surface curvature influences spherical and other aberrations rather than chromatic dispersion. Glass type matters because different materials have different dispersion, but the Abbe value is the quantitative descriptor used to compare and predict LCA between glasses.

Longitudinal chromatic aberration comes from how much a lens material disperses light—the refractive index changes with wavelength, causing different colors to focus at different depths along the axis. The Abbe value is a measure of that dispersion: a higher Abbe number means the index varies less with wavelength, leading to smaller chromatic aberration, while a lower Abbe number means more dispersion and greater LCA. So this property directly explains how much LCA a given glass will produce.

Aperture mainly affects light throughput and diffraction, not the wavelength-dependent focal shift. Surface curvature influences spherical and other aberrations rather than chromatic dispersion. Glass type matters because different materials have different dispersion, but the Abbe value is the quantitative descriptor used to compare and predict LCA between glasses.