Image-pickup optical system

Abstract

An image-pickup optical system includes, from the object side to the image side, a first lens unit having positive optical power, an aperture stop, and a second lens unit. A diffractive optical element and a lens exhibiting extraordinary partial dispersion are appropriately disposed in the optical system. The image-pickup optical system is capable of reducing the generation of flare and ghosts at the diffractive optical element and effectively correcting chromatic aberration.

Description

technical field [0001] The present invention relates to image pickup optical systems, such as photographic or photographic systems. Background technique [0002] A known image pickup optical system having a long focal length includes a front lens assembly having positive refractive power and a rear lens assembly having negative refractive power from the object side to the image side. Such optics are known as telephoto optics, or simply telephoto lenses. [0003] In a typical telephoto lens, among various types of chromatic aberration, longitudinal chromatic aberration and lateral chromatic aberration in particular become worse as the focal length increases. In general, these types of chromatic aberrations are corrected by combining positive and negative lenses, where the positive lens is composed of a low-dispersion material such as fluorite, which has a special partial dispersion, and the negative lens is composed of a high-dispersion material. [0004] Special partial di...

AI Technical Summary

Problems solved by technology

However, when very intense light, such as sunlight from the sun outside the viewing angle, is incident on the diffractive optical element, flare and ghosting are produced

Images