Although Aspheric lens has many advantages over ordinary spherical lens, its unique structure makes it more difficult to manufacture, so optical designers must balance performance advantages and higher cost.
The first advantage of an aspherical lens is to reduce spherical aberration. When the lens is unable to focus all incident light distortion at the same point, spherical aberration occurs. Even if it is processed to the theoretical limit, the standard spherical lens can never reach the precise focusing level provided by Aspheric lens. The essence of the irregular surface shape of an aspheric surface is to enable it to manipulate multiple wavelengths of light more accurately simultaneously, thereby obtaining clearer images.
Another optical advantage of an aspherical lens is its ability to correct the bent off axis aberration of the image field. Usually, optical designers must 'stop' their optical system to physically exclude the outermost area of the lens, which can cause image deformation near its edges. Due to the aspherical design, incident light can be better corrected to the focal point, thereby increasing the available aperture of the lens, which can provide greater luminous flux.
Finally, one of the biggest benefits of using an aspheric design is that it reduces the overall number of lenses required to obtain a given result. Because the Aspheric lens can better control the light passing through the system, in many cases, a single Aspheric lens can provide the same accuracy as multiple standard lenses used in series before. This reduces overall weight, size, and may even reduce the cost of the final design.