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Close-up lens, imaging apparatus, and method for focusing close-up lens

A camera lens, close-up technology, applied in the field of close-up lens, can solve the problem of large lens group movement, uncomfortable automatic focus and other problems

Inactive Publication Date: 2013-04-10
NIKON CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] However, even a close-up lens with a floating system still has a large amount of lens group movement and is therefore not suitable for autofocus

Method used

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  • Close-up lens, imaging apparatus, and method for focusing close-up lens
  • Close-up lens, imaging apparatus, and method for focusing close-up lens
  • Close-up lens, imaging apparatus, and method for focusing close-up lens

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0079] figure 1 is a cross-sectional view showing the lens structure of the close-up lens according to Embodiment 1 when focusing to infinity.

[0080] Such as figure 1 As shown, the close-up lens according to Embodiment 1 is composed of the following items in order from the object: a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop S, A third lens group G3 having positive refractive power, and a fourth lens group G4 having negative refractive power. When focusing from infinity to a close distance where a magnification of the same size as the real thing can be obtained, the first lens group G1, the fourth lens group G4, and the aperture stop S are fixed relative to the image plane I, and the second lens group G2 moves along the optical axis toward the image plane I, and the third lens group G3 moves along the optical axis to the object.

[0081] The first lens group G1 is composed of the followin...

Embodiment 2

[0147] image 3 is a cross-sectional view showing the lens structure when the close-up lens according to Embodiment 2 is focused to infinity.

[0148] Such as image 3 As shown, the close-up lens according to Embodiment 2 is composed of the following items in order from the object: a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop S, A third lens group G3 having positive refractive power, and a fourth lens group G4 having negative refractive power. When focusing from infinity to a close distance where a magnification of the same size as the real thing can be obtained, the first lens group G1, the fourth lens group G4, and the aperture stop S are fixed relative to the image plane I, and the second lens group G2 moves along the optical axis toward the image plane I, and the third lens group G3 moves along the optical axis to the object.

[0149] The first lens group G1 is composed of the following...

Embodiment 3

[0208] Figure 5 is a cross-sectional view showing the lens structure when the close-up lens according to Embodiment 3 is focused to infinity.

[0209] Such as Figure 5 As shown, the close-up lens according to Embodiment 3 is composed of the following items in order from the object: a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop S, A third lens group G3 having positive refractive power, and a fourth lens group G4 having negative refractive power. When focusing from infinity to a short distance where the magnification of the same size as the real thing can be obtained, the first lens group G1, the fourth lens group G4 and the aperture stop S are fixed relative to the image plane I, and the second lens group G2 moves along the optical axis toward the image plane I, and the third lens group G3 moves along the optical axis to the object.

[0210] The first lens group G1 is composed of the follow...

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PUM

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Abstract

Providing a close-up lens with superb optical performance capable of focusing from infinity to a close distance allowing a life-size magnification by an internal focusing system with small moving amounts of focusing lens groups, an imaging apparatus, and a method for focusing a close-up lens. The close-up lens includes four lens groups, and is able to focus an object with an imaging magnificationfrom beta=0 through at least beta=-0.5, wherein upon focusing, a first lens group and a fourth lens group are fixed with respect to an image plane, and a second lens group and a third lens group are moved along an optical axis.

Description

[0001] The contents of the following prior applications are incorporated herein by reference: [0002] Japanese Patent Application No. 2007-065400; and [0003] Japanese Patent Application No. 2008-034053. technical field [0004] The present invention relates to a close-up lens, in particular to a close-up lens with an internal focusing system having a constant total lens length, an imaging device and a method for focusing the close-up lens. Background technique [0005] A photographic lens for close-up photography has been proposed in, for example, Japanese Patent Application Laid-Open No. 2005-004041. Unlike ordinary photographic lenses, close-up lenses must focus on objects located from infinity to close distances, and can obtain the same magnification as the real thing or a magnification close to it, so the movement of the lens group during focusing The volume will inevitably increase. Therefore, it is not suitable for automatic focusing. When you try to focus from ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G02B13/00G02B13/18G02B15/16G03B19/12H04N5/225
Inventor 和田充晃
Owner NIKON CORP