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Lenses with fixed focal length and constant construction length for autofocus applications

A technology of lens and focal length, applied in the field of lens/objective lens

Active Publication Date: 2021-06-22
莱卡照相机股份公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, if high imaging performance should be achieved, complex and expensive lens structures with a large number of different lenses are required

Method used

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  • Lenses with fixed focal length and constant construction length for autofocus applications
  • Lenses with fixed focal length and constant construction length for autofocus applications
  • Lenses with fixed focal length and constant construction length for autofocus applications

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0054] The path of movement of the corresponding lens group during the focusing process is shown in the lens section of the drawing. Horizontal lines indicate the positions of lens groups G1, G2, G3, G4 and G5. The upper horizontal line among the horizontal lines indicates the position when focusing to infinity, the lower horizontal line indicates the position when focusing on the shortest object distance, and the middle horizontal line indicates the position when focusing to the middle. The vertical lines correspond to the fixed lens groups G1, G3 and G5, and the oblique lines correspond to the movable focusing groups G2 and G4.

[0055] for in figure 1 In the lens with a focal length of 21 mm shown in , the first lens group G1 has a negative power convex-concave lens G1L1 in which the concave (inner) radius of curvature is significantly smaller than the convex (outer) radius of curvature. This results in a geometrically measurably thin lens center relative to the material ...

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PUM

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Abstract

The invention relates to a fixed focal length lens comprising five lens groups, three of which (G1, G3, G5) are fixed in position and the other two (G2, G4) are movable along the light for focusing purposes. Axis movement, whereby the first front lens group (G1) viewed from the object side is stationary relative to the imaging plane (IM), the second lens group is movable relative to the imaging plane as the front focusing group (G2), The third lens group, which contains a variable aperture (AP) with a fixed opening, is fixed as the middle group (G3) relative to the imaging plane, and the fourth lens group is fixed as the rear focusing group (G4) relative to the imaging plane. Mobile and the fifth rear lens group (G5) are fixedly arranged in the lens barrel relative to the imaging plane. In order to make the lens focus on objects with different object distances, not only the front focus group (G2) but also the rear focus group (G4) Both move relative to each other and relative to the fixedly arranged lens groups ( G1 , G3 , G5 ), wherein the front lens group ( G1 ) and the rear lens group ( G5 ) have negative refractive power.

Description

technical field [0001] The invention relates to a fixed focal length interchangeable lens / objective according to the preamble of claim 1 . Background technique [0002] Such lenses for photographic recording purposes are known from analog photography and are likewise used in digital photography. Increasingly, digital cameras no longer have mirrors that can be swung into and out of the shooting light path (the mirrors shift the object field to be photographed into the viewfinder via prisms for focusing purposes and for selection of image parts ), but by means of a permanent capture with the camera sensor and the image is selected by means of the object area thus obtained and displayed on the display on the rear of the camera or by means of an electronic viewfinder. The focusing of the lens is carried out automatically by means of the electronic autofocus signal and the corresponding activation of the focusing elements in the lens. Usually, in order to produce good imaging p...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G02B27/00G02B13/04
CPCG02B27/0075G02B13/04G02B9/60G02B13/18G02B9/64G02B13/0045G02B13/006G02B15/24
Inventor D·斯图布尔S·卡曼斯
Owner 莱卡照相机股份公司