Dispersion is the optical property of a material, such as glass, to bend light rays of different wavelengths by varying amounts. This phenomenon occurs because each wavelength (or colour) of light travels at a slightly different speed through the material, causing them to spread apart.
In photography and optics, dispersion is particularly important in lens design, as it can lead to chromatic aberration-where colours at the edges of objects appear fringed or blurred. Understanding and controlling dispersion allows lens manufacturers and photographers to produce sharper images with accurate colour reproduction, improving overall image quality.