Overview
- [Publication number] P2023092730
- [Publication date] 2023-07-04
- [Title of Invention] Optical system and imaging device
- [Application date] 2021-12-22
- [Applicant]
[Identification number] 000133227
[Name] Tamron Co., Ltd. - Kind Code: A1 A zoom lens and an imaging device are provided which are compact and lightweight and have high imaging performance over the entire zoom range.
- 2. Description of the Related Art
Imaging devices using various solid-state imaging devices such as video cameras, digital still cameras, single-lens reflex cameras, and single-lens non-reflex cameras have been widely used. As an imaging optical system used in these imaging apparatuses, there is a demand for a high-resolution, compact zoom lens that can cover a wide imaging angle of view. Further, in such a zoom lens, realization of high-speed and high-precision autofocus is also required. - [0003]
In recent years, image capturing apparatuses having not only still image capturing functions but also moving image capturing functions have become widespread. Even in the case of adopting autofocus by the phase difference method when capturing still images, the contrast method is used when capturing moving images. For example, a part of the lens group (focus lens group) is oscillated (wobbling) at high speed in the optical axis direction to create an out-of-focus state and a focused state, and the output signal of the image pickup device is used to detect a part of the image area. By repeating a series of operations such as detecting signal components in the frequency band, finding the optimum position for the focus lens group at which the focus is achieved, and moving the focus group to that optimum position, it is possible to continuously focus on the subject even during video recording. Autofocus is possible. - [0004]
However, the size of an image corresponding to a subject may change during wobbling. This is mainly due to the change in the focal length of the entire lens system due to the movement of the focus lens group in the optical axis direction. If the angle of view fluctuates greatly due to wobbling, a sense of discomfort may occur in the captured image or the like. In order to alleviate this discomfort, it is conceivable to use the lens group behind the diaphragm as the focus lens group. As the size of non-reflex cameras continues to shrink, there is a demand for smaller zoom lenses themselves. Further, in order to continuously drive the focus lens group, it is desired to further reduce the size and weight of the focus lens group. - [0005]
Conventionally, in an image sensor that receives an optical image and converts it into an electrical image signal, there is a limitation in order to efficiently capture incident light with an on-chip microlens or the like. It has been desired to secure the telecentricity of the incident light flux to the imaging sensor by enlarging the exit pupil on the side by a certain amount or more. However, in recent years, imaging sensors have improved aperture ratios and improved degrees of freedom in designing on-chip microlenses, and the restrictions on the exit pupil required on the lens side have become less. For this reason, conventionally, various inventions have been made to place a positive lens group behind the lens of a zoom lens to ensure telecentricity. Even if a light beam is obliquely incident on the image pickup sensor, peripheral dimming (shading) due to a pupil mismatch with the on-chip microlens has become less noticeable. In addition, due to advances and improvements in software and camera systems, distortion is large to some extent, and it has become possible to correct it by image processing even if it was conspicuous in the past. - SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a zoom lens and an image pickup apparatus which are compact and lightweight and have high imaging performance over the entire zoom range .
Example 1
- Focal length: 17.520-48.483
- F-value: 4.120
- Half angle of view: 110.747-47.366
- Image height: 21.633
- Overall length: 134.456
- Back focus: 18.462-50.815
Example 3 (configuration diagram only)
VC is anti-vibration group
via asobinet
