Spherical Lenses vs. Aspherical Lenses — Key Differences

1. Different Surface ShapesSpherical LensesThe surface is part of a standard sphere with a constant radius of curvature everywhere, making them simple to manufacture.

Aspherical LensesThe surface is not a perfect sphere; its curvature varies continuously from the center to the edge. It is a high-order curved surface that allows precise design optimization.

2. Aberration Performance (The Most Critical Difference)Spherical LensesSuffer from significant spherical aberration: marginal rays focus earlier than paraxial rays, resulting in blurred spots.Chromatic aberration, coma, and other aberrations are also relatively difficult to correct.

Aspherical LensesCan directly compensate for spherical aberration, enabling both central and marginal rays to focus at the same point, delivering sharper and more uniform imaging.

3. Optical PerformanceSpherical: Low resolution, poor edge image quality, prone to halos, and unnatural bokeh.Aspherical: Higher resolution, clearer edges, lower distortion, and more uniform light spots.

4. Number of Elements and System SizeSpherical: Require multi-element combinations to correct aberrations, resulting in large and heavy lenses.Aspherical: A single element can replace multiple spherical lenses, greatly reducing the number of components, size, and weight.

5. Manufacturing and CostSpherical: Simple molds, easy mass production, and low cost.Aspherical: Extremely high requirements for design and manufacturing precision, complex molds, and higher cost.

Summary in One Sentence

Spherical lenses are inexpensive but suffer from large aberrations and produce bulky lens assemblies; aspherical lenses offer superior imaging quality and more compact size, yet are more difficult to fabricate and more costly.