When we look at something and do not focus it well, the optical system is undergoing an “aberration” that is a difference between the real image and the one we perceive. The anomaly may influence the geometry or the focal level by changing the image at the peripheral level. Aberrations may concern sharpness, distortion of the image, difference in seeing colors and brightness.
When all this happens in the field of photography, the image becomes special and interesting, but when the aberrations are due to the lenses that we wear every day… it could become annoying.
On the physical level, to explain the aberration, we have to fix the idea that the image is formed by electromagnetic waves which, if faithfully reported, can alter an image size: form, color, sharpness.
This is because the light that touches an object and comes to our eye, through the phenomenon of refraction and subdivision of the image in the different wavelengths with respect to the colors, is perceived in an altered manner.
This means that light is what influences the aberration phenomenon, but it is not the only factor: also the structure of the lens itself plays an important role.
One of the types of aberration is defined spherical aberration due to the geometry of the lens. It is important to distinguish the spherical geometry From the spherical correction. Here we talk about geometry: that is when the ray lights come in different points of the spherical surface with different lengths do not collect the same focus point. To counter this phenomenon, aspherical geometries that compensate for the distortions were introduced. The aspherical geometry is more complex and expensive to realize.
To avoid this phenomenon, have been introduced aspheric geometry that help to offset the distortions. The aspheric geometry is more complex and expensive to realize but helps you to get best image.
*This content has been translated and written by staff non-medical so may be subject to different interpretations. The source are public and proposed in simple language
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