What is an achromatic aberration? A chromatic aberration is the inability of a lens to focus different wavelengths on a single focal point. This phenomenon happens because of the fact that the refractive index of a material depends on the wavelength. That is why materials are called dispersive, meaning their

Related Terms of Lenses Before discussing lens and their properties and application, one should be familiar with these terms. Refractive Index Refractive index is a ratio of the speed of light when it passes through the vacuum to its values when it passes through a specific medium. where c is