The percent velocity error technique involves calculating the percentage difference between the velocity of an image spot at a specific field angle and the velocity at the optical axis of the lens. See percent position error.
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.