Standard exchangeable fixed-focus lens

Abstract

The invention relates to a standard exchangeable fixed-focus lens, which comprises: a first lens group and a second lens group that are sequentially disposed from an object side to an image side, wherein the first lens group comprises a first lens having negative focal power, a second lens having negative focal power and a third lens having positive focal power; the second lens group comprises a fourth lens having positive focal power, a fifth lens having positive focal power, a sixth lens having negative focal power, a glued lens, namely, a seventh lens having negative focal power, an eighthlens having positive focal power, a ninth lens having positive focal power, and a diaphragm arranged between the sixth lens and the seventh lens; and when a photographic object changes from infinity to a close range, the first lens group is fixed, the second lens group moves from the image side to the object side so as to perform focusing, namely, the rear group performs floating focusing. The standard exchangeable fixed-focus lens can satisfy the video and film photographic requirements without obvious vignetting, having minimal distorsion, having weak breathing effect and the like by means of a full-frame and super35-frame 8k resolution video camera.

Description

technical field [0001] The invention relates to a technology in the field of optical devices, in particular to a standard interchangeable fixed-focus lens. Background technique [0002] Cine lenses are specially tailored for video shooting of movies, TV dramas, etc. It not only needs to match the size of the full-frame sensor, but also needs to be comprehensively considered in terms of resolution, optical aberration, breathing effect, etc. in combination with the actual conditions of shooting videos. Weight and cost aspects also need to be balanced. Cine lens not only has the top optical quality, but also its mechanical structure design fully takes into account the professional needs of film production, so it is very professional. However, due to the high difficulty of designing and manufacturing movie lenses, no company in China has launched a real movie shooting lens so far. During the focusing process of the lens, the internal lens group will undergo a series of displac...

AI Technical Summary

Problems solved by technology

The main defects of current movie lenses include: 1) The resolution is not high: the resolution of movie cameras can reach 6K or 8K, but almost all camera lenses on the market have low resolution and cannot match high-resolution cameras; 2) There are obvious vignetting: Due to the limitations of the laws of optical reflection and refraction and the limitation of the lens coating level, all lenses will have vignetting more or less; and the control of camera lenses on vignetting is not as strict as that of movie lenses, so vignetting It is more obvious and cannot meet the needs of video and movie shooting; 3) Large distortion: the picture distortion of dynamic images is often more obvious than that of static photos, and pincushion or barrel distortion will appear immediately when dynamic elements appear in the picture, while It will be more serious when the camera's subjective perspective moves; if there is too obvious distortion in the audience's field of vision in the theater, it may cause motion vertigo; so the image field of the movie lens must be as flat as possible; The control of distortion is not enough, so it cannot meet the high requirements of movie lenses for distortion; 4) The breathing effect is obvious: the breathing effect will occur during the focusing process of the lens. For the camera lens, the breathing effect is not only the almost imperceptible composition change The picture is not affected by the breathing effect; for film production, it is very common to follow the focus within the picture or shift the focus between different subjects, so the requirements for suppressing the breathing effect are very high, and general camera lenses cannot meet the requirements

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