Conversion lens, interchangeable lens, and image capturing apparatus

A technology for converting lenses and lenses, applied in installation, instruments, optics, etc., can solve problems such as difficult to convert lenses

Active Publication Date: 2021-05-14
CANON KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Therefore, it is difficult to configure the conversion lens in a small size, suppress stray light, and correct curvature of field and lateral chromatic aberration

Method used

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  • Conversion lens, interchangeable lens, and image capturing apparatus
  • Conversion lens, interchangeable lens, and image capturing apparatus
  • Conversion lens, interchangeable lens, and image capturing apparatus

Examples

Experimental program
Comparison scheme
Effect test

no. 1 example

[0119] image 3 is a sectional view of the conversion lens RCL according to the first embodiment. Figure 4 is an aberration diagram of the conversion lens RCL according to the first embodiment when focusing on an object at infinity when disposed on the image side of the main lens ML.

[0120] In conversion lens RCL according to the first embodiment, first lens element L1 is a positive single lens disposed closest to the object side in conversion lens RCL. The second lens element L2 is a cemented lens in which two lenses of a negative lens and a positive lens are sequentially cemented from the object side to the image side. Lens element LT is a positive single lens disposed closest to the image side in conversion lens RCL, and lens element LS is a cemented lens in which three lenses of a negative lens, a positive lens, and a negative lens are sequentially cemented from the object side.

no. 2 example

[0122] Figure 5 is a sectional view of the conversion lens RCL according to the second embodiment. Image 6 is an aberration diagram of the conversion lens RCL according to the second embodiment when focusing on an object at infinity when disposed on the image side of the main lens ML.

[0123] In conversion lens RCL according to the second embodiment, first lens element L1 is a positive single lens disposed closest to the object side in conversion lens RCL. The second lens element L2 is a cemented lens in which two lenses of a negative lens and a positive lens are sequentially cemented from the object side to the image side. Lens element LT is a positive single lens disposed closest to the image side in conversion lens RCL, and lens element LS is a cemented lens in which three lenses of a negative lens, a positive lens, and a negative lens are sequentially cemented from the object side.

no. 3 example

[0125] Figure 7 is a sectional view of the conversion lens RCL according to the third embodiment. Figure 8 is an aberration diagram of the conversion lens RCL according to the third embodiment when focusing on an object at infinity when disposed on the image side of the main lens ML.

[0126] In conversion lens RCL according to the third embodiment, first lens element L1 is a positive single lens disposed closest to the object side in conversion lens RCL. The second lens element L2 is a cemented lens in which three lenses of a negative lens, a positive lens, and a negative lens are sequentially cemented from the object side to the image side. Lens element LT is a positive single lens disposed closest to the image side in conversion lens RCL, and lens element LS is a cemented lens in which two lenses of a positive lens and a negative lens are sequentially cemented from the object side.

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PUM

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Abstract

The invention discloses a conversion lens, an interchangeable lens, and an image capturing apparatus. The conversion lens (RCL) has a negative refractive power and is disposed on the image side of a main lens (ML) so that the focal length of the entire system is longer than the focal length of the individual main lens. The conversion lens includes an image-most-side lens element (LT) disposed closest to the image side in the conversion lens, wherein the image-most-side lens element has a lens surface that is convex toward the image side, a lens disposed closest to the image side in the conversion lens has a positive refractive power, and mN<mP and 0.0 <=LR2 / AR2<1.0 is satisfied.

Description

technical field [0001] The present invention relates to conversion lenses, interchangeable lenses and image capture devices. Background technique [0002] Rear conversion lenses are known which can extend the focal length of the entire lens system by being placed between the image capture device and the interchangeable lens including the main lens. [0003] In the case of the rear conversion lens, there is an advantage that the entire lens system can be made compact compared to the case where it is disposed on the object side of the main lens. However, the residual aberration of the main lens is amplified in proportion to the magnification, so that image quality may deteriorate. Therefore, even when the rear conversion lens is disposed on the image side of the main lens, various aberrations of the rear conversion lens itself need to be properly corrected in order to properly maintain various aberrations of the entire lens system. [0004] International Publication No. WO 2...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G02B13/00G02B15/10
CPCG02B13/005G02B13/006G02B15/10G02B27/0018G02B13/16G02B9/12G02B7/14
Inventor 斋藤慎一郎江部裕基
Owner CANON KK
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