The ratio between the speed of light through air to the speed of light through another medium; the ratio determines how much a ray of light will bend as it passes through a given medium.
SPHERICAL VS. ASPHERIC LENSES
HOW THEY’RE USED IN IMAGING APPLICATIONS
Optical Lenses are often categorized by their shape. Two common surface shapes are spherical and aspherical. Each offers unique characteristics that make it suitable for different use cases.