Imaging system
First Claim
1. An imaging system comprising a zoom lens comprising a plurality of lens groups and an aperture stop located in an optical path for limiting at least an axial light beam diameter, and an electronic image pickup device located on an image side of the zoom lens, wherein:
- said zoom lens comprises at least a first lens group having negative refracting power, and a second lens group having positive refracting power and located just after the first lens;
a spacing between the first lens group having negative refracting power and the second lens group having positive refracting power becomes narrower at a telephoto end than at a wide-angle end of said zoom lens;
said aperture stop has a fixed shape;
said aperture stop is located between an image-side surface in the first lens group having negative refracting power and an object-side surface in the second lens group having positive refracting power;
said aperture stop is such that a position where a perpendicular going from said aperture stop down to the optical axis intersects the optical axis is found within a lens medium in the lens groups;
when said focal length is varied, said aperture stop moves together with the positive lens group;
said aperture stop and said lens group of positive refracting power are positioned more on the object side at the telephoto end than at the wide-angle end;
a filter for implementing light quantity control by varying transmittance is located on the optical axis; and
said filter for implementing light quantity control is located on an image plane side with respect to said lens group of positive refracting power.
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Accused Products
Abstract
The invention relates to an imaging system in which, while high image quality is maintained with the influence of diffraction minimized, the quantity of light is controlled, and which enables the length of the zoom lens to be cut down. The imaging system comprises a zoom lens comprising a plurality of lens groups G1 and G2 wherein the spacing between individual lens groups is varied to vary a focal length and an aperture stop located in an optical path for limiting at least an axial light beam diameter, and an electronic image pickup device I located on the image side of the zoom lens. The aperture stop has a fixed shape, and a filter S2 for performing light quantity control by varying transmittance is located on an optical axis of a space located at a position different from that of a space in which the aperture stop is located.
44 Citations
21 Claims
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1. An imaging system comprising a zoom lens comprising a plurality of lens groups and an aperture stop located in an optical path for limiting at least an axial light beam diameter, and an electronic image pickup device located on an image side of the zoom lens, wherein:
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said zoom lens comprises at least a first lens group having negative refracting power, and a second lens group having positive refracting power and located just after the first lens; a spacing between the first lens group having negative refracting power and the second lens group having positive refracting power becomes narrower at a telephoto end than at a wide-angle end of said zoom lens; said aperture stop has a fixed shape; said aperture stop is located between an image-side surface in the first lens group having negative refracting power and an object-side surface in the second lens group having positive refracting power; said aperture stop is such that a position where a perpendicular going from said aperture stop down to the optical axis intersects the optical axis is found within a lens medium in the lens groups; when said focal length is varied, said aperture stop moves together with the positive lens group; said aperture stop and said lens group of positive refracting power are positioned more on the object side at the telephoto end than at the wide-angle end; a filter for implementing light quantity control by varying transmittance is located on the optical axis; and said filter for implementing light quantity control is located on an image plane side with respect to said lens group of positive refracting power. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An imaging system comprising a zoom lens comprising a plurality of lens groups and an aperture stop located in an optical path for limiting at least an axial light beam diameter, and an electronic image pickup device located on an image side of the zoom lens, wherein:
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said zoom lens comprises at least a first lens group having negative refracting power, and a second lens group having positive refracting power and located just after the first lens; a spacing between the first lens group having negative refracting power and the second lens group having positive refracting power becomes narrower at the telephoto end than at a wide-angle end of said zoom lens; said aperture has a fixed shape; said aperture stop is located between an image-side surface in the first lens group having negative refracting power and an object-side surface in the second lens group having positive refracting power; said aperture stop is such that a position where a perpendicular going from said aperture stop down to the optical axis intersects the optical axis is found within a lens medium in the lens group; when said focal length is varied, said aperture stop moves together with the positive lens group; said aperture stop and said lens group of positive refracting power are positioned more on the object side at the telephoto end than at the wide-angle end; a shutter is located in the optical axis; and said shutter is located on an image plane side with respect to said lens group of positive refracting power. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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Specification