Zoom lens and image pickup apparatus
AssigneeCanon Kabushiki Kaisha
InventorTakahiro Hatada
Life of this patent
Estimating the term…
Abstract
A zoom lens includes, in order from an object side to an image side, a first lens unit having positive refractive power, a second lens unit having negative refractive power, and a rear group having positive refractive power as a whole and including three or more lens units. During zooming, all lenses move and a distance between adjacent lens units changes. A lens unit closest to an image plane in the rear group moves toward the object side during zooming from a wide-angle end to a telephoto end. The first lens unit consists of, in order from the object side to the image side, one negative lens and two positive lenses. Predetermined inequalities are satisfied.
Claims20
A zoom lens comprising, in order from an object side to an image side:
- a first lens unit having positive refractive power;
- a second lens unit having negative refractive power;
- and
- a rear group having positive refractive power as a whole and including three or more lens units,
- wherein during zooming, all lens units move and a distance between adjacent lens units changes,
- wherein a lens unit closest to an image plane in the rear group moves toward the object side during zooming from a wide-angle end to a telephoto end,
- wherein the first lens unit consists of, in order from the object side to the image side, one negative lens and two positive lenses, and
- wherein the following inequalities are satisfied:
- 14.71
- ≤
- R
-
- 1
-
- r
- /
- fw
- ≤
- 25.
- 0.2
- ≤
- mL
-
- 1
- /
- f
-
- 1
- ≤
- 0.7
- 20
- ≤
- vd
-
- 1
-
- n
- ≤
- 30
- where R1r is a radius of curvature of a lens surface closest to the image plane in the first lens unit, fw is a focal length of the zoom lens at the wide-angle end, mL1 is a moving amount of the first lens unit during zooming from the wide-angle end to the telephoto end, the moving amount from the image side to object side the being defined to be positive, f1 is a focal length of the first lens unit, and vd1n is an Abbe number of the negative lens in the first lens unit based on d-line.
An image pickup apparatus comprising:
- a zoom lens;
- and
- an image sensor configured to capture an object through the zoom lens,
- wherein the zoom lens includes, in order from an object side to an image side:
- a first lens unit having positive refractive power;
- a second lens unit having negative refractive power;
- and
- a rear group having positive refractive power as a whole and including three or more lens units,
- wherein during zooming, all lens units move and a distance between adjacent lens units changes,
- wherein a lens unit closest to an image plane in the rear group moves toward the object side during zooming from a wide-angle end to a telephoto end,
- wherein the first lens unit consists of, in order from the object side to the image side, one negative lens and two positive lenses, and
- wherein the following inequalities are satisfied:
- 14.71
- ≤
- R
-
- 1
-
- r
- /
- fw
- ≤
- 25.
- 0.2
- ≤
- mL
-
- 1
- /
- f
-
- 1
- ≤
- 0.7
- 20
- ≤
- vd
-
- 1
-
- n
- ≤
- 30
- where R1r is a radius of curvature of a lens surface closest to the image plane in the first lens unit, fw is a focal length of the zoom lens at the wide-angle end, mL1 is a moving amount of the first lens unit during zooming from the wide-angle end to the telephoto end, the moving amount from the image side to object side the being defined to be positive, f1 is a focal length of the first lens unit, and vd1n is an Abbe number of the negative lens in the first lens unit based on d-line.
Dependencies are inferred from the claim text.