The Abbe value of a lens is MOST associated with which aberration?

The Abbe value of a lens is MOST associated with which aberration?

• A. Curvature of Field
• B. Coma spherical aberration
• C. Longitudinal chromatic aberration
• D. Longitudinal spherical aberration

Answer: (C)

The Abbe value measures how strongly a lens material disperses light, meaning how its refractive index changes with wavelength. That dispersion causes longitudinal (axial) chromatic aberration—the shift of the focal point along the optical axis for different colors. So the Abbe number is most closely tied to longitudinal chromatic aberration. Other aberrations described—curvature of field, coma, and spherical aberrations (including longitudinal spherical aberration)—are geometric or off-axis effects that depend more on lens shape and arrangement than on material dispersion, and they aren’t what the Abbe value quantifies.

The Abbe value measures how strongly a lens material disperses light, meaning how its refractive index changes with wavelength. That dispersion causes longitudinal (axial) chromatic aberration—the shift of the focal point along the optical axis for different colors. So the Abbe number is most closely tied to longitudinal chromatic aberration. Other aberrations described—curvature of field, coma, and spherical aberrations (including longitudinal spherical aberration)—are geometric or off-axis effects that depend more on lens shape and arrangement than on material dispersion, and they aren’t what the Abbe value quantifies.