Wide-angle telephoto imaging optical system

Abstract

A wide-angle telephoto imaging optical system is composed of a front lens group with negative focal power and a rear lens group with positive focal power which are sequentially arranged from an objectside to an image side. The front lens group is composed of a negative first lens, a negative second lens and a positive third lens. The rear lens group is composed of a positive fourth lens, a negative fifth lens, a positive sixth lens and a negative seventh lens. A diaphragm is located between the front lens group and the rear lens group. The imaging system meeting the conditional expression ofthe invention can obtain a larger focal length while meeting a larger field angle.

Description

technical field [0001] The invention relates to an imaging optical system, in particular to a wide-angle imaging optical system with a relatively large focal length. Background technique [0002] Existing optical imaging systems have deficiencies in field of view and focal length. For example, the wide-angle single-focus lens disclosed in CN102621667A has a field of view of 71° and an effective focal length of only 5.8 mm. The field of view is not large enough and the focal length is relatively short; In CN206411328U, although the field of view is increased to 95°, the focal length is only 3.61mm. When applied to monitoring, although a larger viewing angle image can be taken, it cannot be focused on a slightly distant object and cannot obtain a clear image. Therefore, in In many cases, the application is limited. Although a zoom lens can be used, its cost will increase significantly, and the field of view angle will be greatly reduced when the zoom lens becomes a telephoto ...

AI Technical Summary

Problems solved by technology

[0002] Existing optical imaging systems have deficiencies in field of view and focal length. For example, the wide-angle single-focus lens disclosed in CN102621667A has a field of view of 71° and an effective focal length of only 5.8 mm. The field of view is not large enough and the focal length is relatively short; In CN206411328U, although the field of view is increased to 95°, the focal length is only 3.61mm. When applied to monitoring, although a larger viewing angle image can be taken, it cannot be focused on a slightly distant object and cannot obtain a clear image. Therefore, in In many cases, the application is limited

Although a zoom lens can be used, its cost will increase significantly, and the field of view will be greatly reduced when the zoom lens is changed to a telephoto lens

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