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US 9,377,606 B2Granted
Zoom lens and image pickup device including the same
AssigneeCanon Kabushiki Kaisha
InventorMakoto Nakahara
Life of this patent
Estimating the term…
Abstract
A zoom lens includes, in order from an object side to an image side: first and second lens units having negative and positive refractive powers, respectively; a middle lens group; and a final lens unit having a positive refractive power, wherein the middle lens group comprises a focus lens unit that has a negative refractive power and moves toward the image side during focusing from infinity to a short distance, the intervals between adjacent lens units vary during at least one of zooming and focusing, and wherein the focal length fimg of the final lens unit, the focal length ff of the focus lens unit, and the focal length fw of the entire system at the wide angle end are appropriately configured.
Claims16
A zoom lens, comprising, in order from an object side to an image side:
- a first lens unit having a negative refractive power;
- a second lens unit having a positive refractive power;
- a middle lens group including at least one lens unit;
- and
- a final lens unit having a positive refractive power,
- wherein the middle lens group comprises a focus lens unit that has a negative refractive power and moves toward the image side during focusing from infinity to a short distance, intervals between adjacent lens units vary during at least one of zooming and focusing, and
- wherein conditional expressions:
- 3.5<fimg/fw<10.0,
- −5.0<ff/fw<−1.0, and
- 2.0<BFw/fw<4.5
- are satisfied where a focal length of the final lens unit is fimg, a focal length of the focus lens unit is ff, a focal length of an entire system at a wide angle end is fw, and a back focus at the wide angle end is BFw.
8 more elements
An image pickup device comprising:
- a zoom lens;
- and
- an image pickup element that takes an optical image formed by the zoom lens,
- wherein the zoom lens comprises, in order from an object side to an image side:
- a first lens unit having a negative refractive power;
- a second lens unit having a positive refractive power;
- a middle lens group including at least one lens unit;
- and
- a final lens unit having a positive refractive power,
- wherein the middle lens group comprises a focus lens unit that has a negative refractive power and moves toward the image side during focusing from infinity to a short distance, intervals between adjacent lens units vary during at least one of zooming and focusing, and
- wherein conditional expressions
- 3.5<fimg/fw<10.0,
- −5.0<ff/fw<−1.0, and
- 2.0<BFw/fw<4.5
- are satisfied where a focal length of the final lens unit is fimg, a focal length of the focus lens unit is ff, and a focal length of an entire system at a wide angle end is fw, and a back focus at the wide angle end is BFw.
12 more elements
A zoom lens, comprising, in order from an object side to an image side:
- a first lens unit having a negative refractive power;
- a second lens unit having a positive refractive power;
- a third lens unit having a negative refractive power and moving toward the image side during focusing from infinity to a short distance;
- and
- a fourth lens unit having a positive refractive power,
- wherein intervals between adjacent lens units vary during at least one of zooming and focusing, and
- wherein conditional expressions
- 3.5<fimg/fw<10.0 and
- −5.0<ff/fw<−1.0
- are satisfied where a focal length of the fourth lens unit is fimg, a focal length of the third lens unit is ff, and a focal length of an entire system at a wide angle end is fw.
7 more elements
A zoom lens, comprising, in order from an object side to an image side:
- a first lens unit having a negative refractive power;
- a second lens unit having a positive refractive power;
- a third lens unit having a negative refractive power and moving toward the image side during focusing from infinity to a short distance;
- a fourth lens unit having a negative refractive power;
- and
- a fifth lens unit having a positive refractive power,
- wherein intervals between adjacent lens units vary during at least one of zooming and focusing, and
- wherein conditional expressions
- 3.5<fimg/fw<10.0 and
- −5.0<ff/fw<−1.0
- are satisfied where a focal length of the fifth lens unit is fimg, a focal length of the third lens unit is ff, and a focal length of an entire system at a wide angle end is fw.
8 more elements
A zoom lens, comprising, in order from an object side to an image side:
- a first lens unit having a negative refractive power;
- a second lens unit having a positive refractive power;
- a middle lens group including at least one lens unit;
- and
- a final lens unit having a positive refractive power,
- wherein the middle lens group comprises a focus lens unit that has a negative refractive power and moves toward the image side during focusing from infinity to a short distance, intervals between adjacent lens units vary during at least one of zooming and focusing,
- wherein the first lens unit comprises a first lens having a negative refractive power and a plastic aspheric lens having a negative refractive power in order from an object side to an image side, and
- wherein conditional expressions
- 3.5<fimg/fw<10.0,
- −5.0<ff/fw<−1.0 and
- −9.0<fasph/fw<−5.5
- are satisfied where a focal length of the final lens unit is fimg, a focal length of the focus lens unit is ff, a focal length of an entire system at a wide angle end is fw, and a focal length of the plastic aspheric lens is fasph.
9 more elements
A zoom lens, comprising, in order from an object side to an image side:
- a first lens unit having a negative refractive power;
- a second lens unit having a positive refractive power;
- a middle lens group including at least one lens unit;
- and
- a final lens unit having a positive refractive power,
- wherein the middle lens group comprises a focus lens unit that has a negative refractive power and moves toward the image side during focusing from infinity to a short distance, intervals between adjacent lens units vary during at least one of zooming and focusing,
- wherein the first lens unit comprises a first lens having a negative refractive power and a plastic aspheric lens having a negative refractive power in order from an object side to an image side, and
- wherein conditional expressions
- 3.5<fimg/fw<10.0,
- −5.0<ff/fw<−1.0 and
- 0.0001<dasph/TL<0.01
- are satisfied where a focal length of the final lens unit is fimg, a focal length of the focus lens unit is ff, a focal length of an entire system at a wide angle end is fw, a distance between the first lens having a negative refractive power and the plastic aspheric lens having a negative refractive power along the optical axis is dasph, and a distance from a lens surface of the first lens at an object side to an image plane along the optical axis is TL.
9 more elements
Dependencies are inferred from the claim text.