What is a spherical lens? What is an aspheric lens? What is the difference between the two? Why are aspheric lenses recommended? Let's talk about the difference between the two.
The spherical lenses have a spherical surface, and the radius of curvature of the entire lens is the same. On the contrary, the surface of an aspherical lens is more complicated, and the curvature gradually changes from the center to the edge. These design differences can reduce the number of elements in the assembly and result in thinner and lighter lenses.
The surface of the spherical lens looks like a part of a spherical or cylindrical surface.
The curve is the same across the entire surface. If you draw a straight line to follow the curve, it will form a circle. Because the design is simple, the spherical lens design is usually cheaper.
The surface of an aspheric lens must not be part of a sphere or cylinder. The curve of some parts of the lens surface changes to better focus the light. This change in the surface corrects various aberrations.
Imagine a transparent sphere with a circle in front of us. The surface of a sphere is a surface called a sphere. The spherical lens only means that one surface of the sphere is selected as the lens.
Literally, it is easy to understand, this means that the lens is not spherical.
In appearance, spherical lenses are "big belly", but aspheric lenses are relatively flat, so from an aesthetic point of view, aspheric lenses will look better. There are many aspheric lenses advantages. For example, aspherical lenses are precisely designed and optimized for the combination of lens powers, so they are thinner and more resistant to collisions than spherical lenses. Therefore, people with higher power usually wear aspheric lenses.
When you look at the world through the lens, the difference will be more obvious. When looking around the spherical lens, distortion occurs. Due to the aspherical lens design, the aspheric lens can minimize the difference between the edges of the lens. Seeing objects is more natural, less deformed, and more real.
For friends with mild myopia, the spherical and aspheric lenses are almost the same, there will be no aberration problems, and the lens thickness is similar. Considering the price factor, you can choose spherical lenses.
In addition, for a small number of people who are particularly sensitive to colors, such as wearing aspherical lenses will feel the rainbow phenomenon, you can try to replace the spherical lens.