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US 6,587,280 B2Granted
Zoom lens and optical device using the same
AssigneeCanon Kabushiki Kaisha
InventorAkihisa Horiuchi
Life of this patent
Estimating the term…
Abstract
A zoom lens comprises a first lens unit having positive refractive power, a second lens unit having negative refractive power, an aperture stop, a third lens unit having positive refractive power and kept fixed during zooming, a fourth lens unit having positive refractive power, and a fifth lens unit having negative refractive power, which are arranged in this order from an object side. In zooming from a wide-angle end to a telephoto end, the second lens unit is moved toward an image plane side such that a spacing between the first lens unit and the second lens unit is increased, and the aperture stop is also moved.
Claims44
A zoom lens comprising, in order from an object side to an image plane side:
- a first lens unit having positive refractive power;
- a second lens unit having negative refractive power;
- an aperture stop;
- a third lens unit having positive refractive power and not moving for zooming;
- a fourth lens unit having positive refractive power;
- and
- a fifth lens unit having negative refractive power,
- wherein, in zooming from a wide-angle end to a telephoto end, (i) said second lens unit is moved toward the image plane side such that a spacing between said first lens unit and said second lens unit is increased, and (ii) said aperture stop is also moved.
5 more elements
A zoom lens comprising, in order from an object side to an image plane side:
- a first lens unit having positive refractive power;
- a second lens unit having negative refractive power;
- an aperture stop;
- a third lens unit having positive refractive power and not moving for zooming;
- and
- a fourth lens unit having positive refractive power,
- wherein, in zooming from a wide-angle end to a telephoto end, (i) said second lens unit is moved toward the image plane side such that a spacing between said first lens unit and said second lens unit is increased, and (ii) said aperture stop is also moved, and
- wherein assuming that distances between said second lens unit and said aperture stop at a zoom position at which said aperture stop is positioned farthest from said third lens unit along an optical axis and the telephoto end are respectively L2s, L2t, and distances between said aperture stop and said third lens unit at said zoom position and the telephoto end are respectively Ls3, L3t, the following conditional formula is satisfied:
- 0.2<(L2s−L2t)/(Ls3−L3t)<0.9.
6 more elements
A zoom lens comprising, in order from an object side to an image plane side:
- a first lens unit having positive refractive power;
- a second lens unit having negative refractive power;
- an aperture stop;
- a third lens unit having positive refractive power and not moving for zooming;
- and
- a fourth lens unit having positive refractive power,
- wherein, in zooming from a wide-angle end to a telephoto end, (i) said second lens unit is moved toward the image plane side such that a spacing between said first lens unit and said second lens unit is increased, and (ii) said aperture stop is also moved, and
- wherein in the zooming from the wide-angle end to the telephoto end, said aperture stop is moved to follow a same locus as that of said first lens unit in a range from the wide-angle end to a medium position of a zooming range, and to follow a same locus as that of said second lens unit in a range from the medium position of the zooming range to the telephoto end.
5 more elements
A zoom lens comprising, in order from an object side to an image plane side:
- a first lens unit having positive refractive power;
- a second lens unit having negative refractive power;
- an aperture stop;
- a third lens unit having positive refractive power and not moving for zooming;
- and
- a fourth lens unit having positive refractive power,
- wherein, in zooming from a wide-angle end to a telephoto end, (i) said second lens unit is moved toward the image plane side such that a spacing between said first lens unit and said second lens unit is increased, and (ii) said aperture stop is also moved, and
- wherein assuming that focal lengths of the overall lens system at the wide-angle end and the telephoto end are respectively fw, ft, a focal length of said second lens unit is f2, and fA is defined as given below
- fA={square root over (fw·ft)}
- the following conditional formula is satisfied:
- 0.1<|f2/fA|<0.29.
8 more elements
A zoom lens comprising, in order from an object side to an image plane side:
- a first lens unit having positive refractive power;
- a second lens unit having negative refractive power;
- an aperture stop;
- a third lens unit having positive refractive power and not moving for zooming;
- and
- a fourth lens unit having positive refractive power,
- wherein, in zooming from a wide-angle end to a telephoto end, (i) said second lens unit is moved toward the image plane side such that a spacing between said first lens unit and said second lens unit is increased, and (ii) said aperture stop is also moved, and
- wherein assuming that a focal length of the overall lens system at the wide-angle end is fw and a spacing between principal points of said third lens unit and said fourth lens unit resulting in focusing on an infinite object at the telephoto end is e3T, the following conditional formula is satisfied:
- 1.79<e3T/fw<2.76.
6 more elements
A zoom lens comprising, in order from an object side to an image plane side:
- a first lens unit having positive refractive power;
- a second lens unit having negative refractive power;
- an aperture stop;
- a third lens unit having positive refractive power and not moving for zooming;
- and
- a fourth lens unit having positive refractive power,
- wherein, in zooming from a wide-angle end to a telephoto end, (i) said second lens unit is moved toward the image plane side such that a spacing between said first lens unit and said second lens unit is increased, and (ii) said aperture stop is also moved, and
- wherein assuming that a focal length of an i-th lens unit is fi, the following conditional formula is satisfied:
- 0.63<f3/f4<1.02.
6 more elements
A zoom lens comprising, in order from an object side to an image plane side:
- a first lens unit having positive refractive power;
- a second lens unit having negative refractive power;
- an aperture stop;
- a third lens unit having positive refractive power and not moving for zooming;
- and
- a fourth lens unit having positive refractive power,
- wherein, in zooming from a wide-angle end to a telephoto end, (i) said second lens unit is moved toward the image plane side such that a spacing between said first lens unit and said second lens unit is increased, and (ii) said aperture stop is also moved, and
- wherein assuming amounts by which said first lens unit and said second lens unit are moved in the zooming from the wide-angle end to the telephoto end are respectively M1, M2, the following conditional formula is satisfied:
- 0.5<M1/M2<1.2.
6 more elements
A zoom lens comprising, in order from an object side to an image plane side:
- a first lens unit having positive refractive power;
- a second lens unit having negative refractive power;
- an aperture stop;
- a third lens unit having positive refractive power and not moving for zooming;
- and
- a fourth lens unit having positive refractive power,
- wherein, in zooming from a wide-angle end to a telephoto end, (i) said second lens unit is moved toward the image plane side such that a spacing between said first lens unit and said second lens unit is increased, and (ii) said aperture stop is also moved, and
- wherein assuming that for an i-th lens surface in the second lens unit counted from the object side, R2i represents a radius of curvature when the lens surface is a spherical surface and a radius of paraxial curvature when the lens surface is an aspherical surface, the following conditional formula is satisfied:
- 0.52<|R22/R23|<0.92.
6 more elements
A zoom lens comprising, in order from an object side to an image plane side:
- a first lens unit having positive refractive power;
- a second lens unit having negative refractive power;
- an aperture stop;
- a third lens unit having positive refractive power and not moving for zooming;
- and
- a fourth lens unit having positive refractive power,
- wherein, in zooming from a wide-angle end to a telephoto end, (i) said second lens unit is moved toward the image plane side such that a spacing between said first lens unit and said second lens unit is increased, and (ii) said aperture stop is also moved, and
- wherein said third lens unit comprises a positive lens and a negative lens having a powerful concave surface faced toward the image plane side, which are arranged in order from the object side.
5 more elements
A zoom lens comprising, in order from an object side to an image plane side:
- a first lens unit having positive refractive power;
- a second lens unit having negative refractive power;
- an aperture stop;
- a third lens unit having positive refractive power and not moving for zooming;
- and
- a fourth lens unit having positive refractive power and including at least one negative lens,
- wherein, in zooming from a wide-angle end to a telephoto end, (i) said second lens unit is moved toward the image plane side such that a spacing between said first lens unit and said second lens unit is increased, and (ii) said aperture stop is also moved, and
- wherein said third lens unit comprises a plurality of lenses, and said third lens unit or a part of lenses of the plurality of said third lens unit is moved so as to have a motion component in a direction perpendicular to an optical axis.
5 more elements
A camera comprising:
- (a) a zoom lens comprising, in order from an object side to an image plane side, (i) a first lens unit having positive refractive power (ii) a second lens unit having negative refractive power, (iii) an aperture stop, (iv) a third lens unit having positive refractive power and not moving for zooming, and (v) a fourth lens unit having positive refractive power, wherein, in zooming from a wide-angle end to a telephoto end, (i) said second lens unit is moved toward the image plane side such that a spacing between said first lens unit and said second lens unit is increased, and (ii) said aperture stop is also moved;
- and
- (b) an image pickup device receiving light from said zoom lens,
- wherein assuming that a shortest exit pupil position of the overall lens system in the zooming from the wide-angle end to the telephoto end and in focusing from an infinite object to a proximity object is EP, a focal length of the overall lens system at the wide-angle end is fw, an effective size of an image pickup device is LD, and a half angle ωw of a view is expressed by ω w = tan - 1 LD 2 fw
- the following conditional formula is satisfied:
- 0<|(fw·tan ωw)/EP|<0.13
3 more elements
Dependencies are inferred from the claim text.