Chromatic aberration refers to the displacement (color shift) of an image created by a lens due to the wavelength of light. Even when using the same lens, the refractive index of the lens varies depending on the wavelength of light, causing differences in focal length based on color. As a result, when looking through the lens, the position where the image is focused shifts, causing blurring.

 

In a state where chromatic aberration is occurring: Blue, red, and green light are not focused together, but are dispersed separately.

 

To mitigate chromatic aberration, there are compound lenses such as achromatic lenses, which are made by bonding several types of lenses together. While using these lenses can minimize chromatic aberration as much as possible, it cannot be completely eliminated.