# US 7,466,496 B2 · Zoom lens and image pickup apparatus having the same

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- Number: US 7,466,496 B2
- Document ID: US7466496B2
- Status: Granted
- Kind: B2
- Application number: 11/755,384
- Filed: 2007-05-30
- Published: 2007-12-06
- Granted: 2008-12-16
- Earliest claimed: 2006-05-31
- Assignees: Canon Kabushiki Kaisha
- Inventors: Koji Hoshi
- Web page: https://patentgrep.com/patent/US7466496B2

## CPC

- G02B 15/144113: {arranged +-++}
- G02B 27/646: {compensating for small deviations, e.g. due to vibration or shake (movement of one or more optical elements for control of motion blur in cameras, projectors or printers G03B2205/0007; image stabilisation in cameras peculiar to the presence or use of an electronic image sensor H04N23/68)}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

A zoom lens includes: a first lens unit of positive refractive power; a second lens unit of negative refractive power; a third lens unit of positive refractive power; and a fourth lens unit of positive refractive power, being disposed in that order from an object side to an image side, in which the second and fourth lens units are moved in a direction parallel with an optical axis of the zoom lens during zooming, the first lens unit consists of one negative lens and three or fewer positive lenses, being disposed in that order from the object side to the image side, and the following condition is satisfied: 25.1<Z×BD1/BD2<4.1×Z, where BD1 and BD2 are lengths of the first and second lens units along the optical axis, and Z is a zoom ratio.

## Claims

### Claim 1

A zoom lens comprising:
a first lens unit of positive refractive power;
a second lens unit of negative refractive power;
a third lens unit of positive refractive power; and
a fourth lens unit of positive refractive power, being disposed in that order from an object side to an image side, wherein
the second and fourth lens units are moved in a direction parallel with an optical axis of the zoom lens during zooming,
the first lens unit consists of one negative lens and three or fewer positive lenses, being disposed in that order from the object side to the image side, and
the following condition is satisfied:
25.1<Z×BD1/BD2<4.1×Z,
where BD1 and BD2 are lengths of the first and second lens units along the optical axis, and Z is a zoom ratio.

### Claim 2 (depends on 1)

The zoom lens according to claim 1, wherein
the third lens unit comprises a third-a lens sub-unit of negative refractive power and a third-b lens sub-unit of positive refractive power, being disposed in that order from the object side to the image side, and
the third-b lens sub-unit is moved in a direction orthogonal to the optical axis so as to shift an image.

### Claim 3 (depends on 2)

The zoom lens according to claim 2, wherein the third-b lens sub-unit comprises a positive lens including an aspherical surface, a negative lens, and a positive lens, being disposed in that order from the object side to the image side.

### Claim 4 (depends on 1)

The zoom lens according to claim 1, wherein
the first lens unit consists of a negative lens G11, a positive lens G12, a positive lens G13, and a positive lens G14, being disposed in that order from the object side to the image side,
at least one of the following conditions are satisfied:
75<νdG12,
65<νdG13,
1.601<NdG14<1.811,
where νdG12 and νdG13 are Abbe numbers of materials of the positive lenses G12 and G13, and NdG14 is a refractive index of a material of the positive lens G14.

### Claim 5 (depends on 1)

The zoom lens according to claim 1, wherein
the second lens unit has a negative lens, and at least one positive lens G2p on the image side of the negative lens, and
the following condition is satisfied:
νdG2p<23.5,
where νdG2p is an Abbe number of a material of the positive lens G2p.

### Claim 6 (depends on 5)

The zoom lens according to claim 5, wherein the positive lens G2p is affixed to a negative lens.

### Claim 7 (depends on 1)

The zoom lens according to claim 1, wherein the first lens unit consists of the negative lens and three positive lenses.

### Claim 8 (depends on 1)

The zoom lens according to claim 1, wherein the zoom lens consists of four lens units.

### Claim 9 (depends on 1)

The zoom lens according to claim 1, wherein the zoom lens is adapted to form an image of an object on a solid-state image pickup element.

### Claim 10

An image pickup apparatus comprising:
a solid-state image pickup element; and
a zoom lens arranged to form an image of an object on the solid-state image pickup element, wherein
the zoom lens includes:
a first lens unit of positive refractive power;
a second lens unit of negative refractive power;
a third lens unit of positive refractive power; and
a fourth lens unit of positive refractive power, being disposed in that order from an object side to an image side,
the second and fourth lens units are moved in a direction parallel with an optical axis of the zoom lens during zooming,
the first lens unit consists of one negative lens and three or fewer positive lenses, being disposed in that order from the object side to the image side, and
the following condition is satisfied:
25.1<Z×BD1/BD2<4.1×Z,
where BD1 and BD2 are lengths of the first and second lens units along the optical axis, and Z is a zoom ratio.