# US 10,502,937 B2 · Variable magnification optical system and image pickup apparatus using the same

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- Number: US 10,502,937 B2
- Document ID: US10502937B2
- Status: Granted
- Kind: B2
- Application number: 15/479,714
- Filed: 2017-04-05
- Published: 2017-10-12
- Granted: 2019-12-10
- Earliest claimed: 2016-04-06
- Assignees: Olympus Corporation
- Applicants: Olympus Corporation
- Inventors: Kazuteru Kawamura; Koji Nakagawa; Masahiro Imamura
- Web page: https://patentgrep.com/patent/US10502937B2

## CPC

- G02B 15/144113: {arranged +-++}
- G02B 15/163: having a first movable lens or lens group and a second movable lens or lens group, both in front of a fixed lens or lens group (G02B15/177 takes precedence)
- G02B 15/173: arranged +-+
- G02B 27/0025: {for optical correction, e.g. distorsion, aberration}
- 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 variable magnification optical system includes: in order from an object side, a first lens unit having a positive refractive power; a second lens unit having a negative refractive power; a third lens unit having a positive refractive power; and an image-side lens unit. The image-side lens unit includes a lens belonging to a first region and a lens belonging to a second region. At a time of changing magnification, the second lens unit and the third lens unit move.

## Claims

### Claim 1

A variable magnification optical system comprising:
in order from an object side,
a first lens unit having a positive refractive power;
a second lens unit having a negative refractive power;
a third lens unit having a positive refractive power; and
an image-side lens unit, wherein:
the image-side lens unit includes a lens belonging to a first region and a lens belonging to a second region,
a refractive power based on all lenses belonging to the first region is a negative refractive power, and a refractive power based on all lenses belonging to the second region is a positive refractive power,
at a time of changing magnification,
a distance between the lens units changes,
the first lens unit and an aperture stop are fixed,
the second lens unit moves so that a distance between the first lens unit and the second lens unit is widened at a telephoto end than at a wide angle end, and
the third lens unit moves,
the third lens unit includes a positive lens and a negative lens, and
the following Conditional Expressions (1-1) and (4-2) are satisfied:
1.52≤|fG2/fw|≤10.0 (1-1), and
3.1≤fG1/fw≤50 (4-2)
where
fG1 is a focal length of the first lens unit,
fG2 is a focal length of the second lens unit, and
fw is a focal length of the variable magnification optical system at the wide angle end.

### Claim 2 (depends on 1)

An image pickup apparatus comprising:
an optical system; and
an image pickup element having an image pickup surface, and converting an image formed on the image pickup surface with the optical system into an electric signal, wherein
the optical system is the variable magnification optical system according to claim 1.

### Claim 3

A variable magnification optical system comprising:
in order from an object side,
a first lens unit having a positive refractive power;
a second lens unit having a negative refractive power;
a third lens unit having a positive refractive power; and
an image-side lens unit, wherein:
the image-side lens unit includes a lens belonging to a first region and a lens belonging to a second region,
a refractive power based on all lenses belonging to the first region is a negative refractive power, and a refractive power based on all lenses belonging to the second region is a positive refractive power,
at a time of changing magnification,
a distance between the lens units changes,
the first lens unit and an aperture stop are fixed,
the second lens unit moves so that a distance between the first lens unit and the second lens unit is widened at a telephoto end than at a wide angle end, and
the third lens unit moves,
the third lens unit includes a positive lens and a negative lens, and
the following Conditional Expressions (1-1), (7), and (32) are satisfied:
1.52≤|fG2/fw|≤10.0 (1-1),
1.7≤|fG1/fG2|≤9.1 (7), and
0.04≤ΣG1/LTLw≤0.35 (32)
where
fG1 is a focal length of the first lens unit,
fG2 is a focal length of the second lens unit,
fw is a focal length of the variable magnification optical system at the wide angle end,
ΣG1 is a thickness of the first lens unit, and
LTLw is an overall length of the variable magnification optical system at the wide angle end.

### Claim 4

A variable magnification optical system comprising:
in order from an object side,
a first lens unit having a positive refractive power;
a second lens unit having a negative refractive power;
a third lens unit having a positive refractive power; and
an image-side lens unit, wherein:
the image-side lens unit includes a lens belonging to a first region and a lens belonging to a second region,
a refractive power based on all lenses belonging to the first region is a negative refractive power, and a refractive power based on all lenses belonging to the second region is a positive refractive power,
at a time of changing magnification,
a distance between the lens units changes,
the second lens unit moves so that a distance between the first lens unit and the second lens unit is widened at a telephoto end than at a wide angle end,
the first lens unit is fixed,
the third lens unit moves, and
an aperture stop moves only in one direction or is fixed,
the first lens unit includes a negative lens and a positive lens,
the positive lens in the first lens unit is a positive meniscus lens having a convex surface facing the object side,
the third lens unit includes a positive lens and a negative lens, and
the following Conditional Expression (1-3) is satisfied:
1.60≤|fG2/fw|≤10.0 (1-3)
where
fG2 is a focal length of the second lens unit, and
fw is a focal length of the variable magnification optical system at the wide angle end.

### Claim 5

A variable magnification optical system comprising:
in order from an object side,
a first lens unit having a positive refractive power;
a second lens unit having a negative refractive power;
a third lens unit having a positive refractive power; and
an image-side lens unit, wherein:
the image-side lens unit includes a lens belonging to a first region and a lens belonging to a second region,
a refractive power based on all lenses belonging to the first region is a negative refractive power, and a refractive power based on all lenses belonging to the second region is a positive refractive power,
at a time of changing magnification,
a distance between the lens units changes,
the second lens unit moves so that a distance between the first lens unit and the second lens unit is widened at a telephoto end than at a wide angle end,
the first lens unit is fixed,
the third lens unit moves, and
an aperture stop moves only in one direction or is fixed,
the third lens unit includes a positive lens and a negative lens, and
the following Conditional Expression (4-1) is satisfied:
8.7≤fG1/fw≤50 (4-1)
where
fG1 is a focal length of the first lens unit, and
fw is a focal length of the variable magnification optical system at the wide angle end.

### Claim 6

A variable magnification optical system comprising:
in order from an object side,
a first lens unit having a positive refractive power;
a second lens unit having a negative refractive power;
a third lens unit having a positive refractive power; and
an image-side lens unit, wherein:
the image-side lens unit includes a lens belonging to a first region and a lens belonging to a second region,
a refractive power based on all lenses belonging to the first region is a negative refractive power, and a refractive power based on all lenses belonging to the second region is a positive refractive power,
at a time of changing magnification,
a distance between the lens units changes,
a distance between (i) the lenses belonging to the first region and (ii) the lenses belonging to the second region changes,
the second lens unit moves so that a distance between the first lens unit and the second lens unit is larger at a telephoto end than at a wide angle end,
the third lens unit moves, and
all the lenses belonging to the second region are fixed,
the first lens unit includes a negative lens and a positive lens,
the positive lens in the first lens unit is a positive meniscus lens having a convex surface facing the object side,
the following Conditional Expressions (1-1) and (2-1) are satisfied:
1.52≤|fG2/fw|≤10.0 (1-1), and
0≤ΔSS/LTLw≤0.065 (2-1)
where
fG2 is a focal length of the second lens unit,
fw is a focal length of the variable magnification optical system at the wide angle end,
ΔSS is a maximum amount of movement of an aperture stop at a time of changing magnification, and
LTLw is an overall length of the variable magnification optical system at the wide angle end.

### Claim 7 (depends on 6)

The variable magnification optical system according to claim 6, wherein the following Conditional Expression (3) is satisfied:
−0.067≤fG2×PG1G2a≤0.207 (3)
where
fG2 is a focal length of the second lens unit,
PG1G2a is represented by the following expression:
PG1G2a=1/RG1B−1/RG2F, where
RG1B is a radius of curvature of the lens surface positioned closest to the image side in the first lens unit, and
RG2F is a radius of curvature of the lens surface positioned closest to the object side in the second lens unit.

### Claim 8 (depends on 6)

The variable magnification optical system according to claim 6, wherein the following Conditional Expression (5) is satisfied:
−0.20≤(LTLt−LTLw)/LTLw≤0.46 (5)
where
LTLt is an overall length of the variable magnification optical system at the telephoto end, and
LTLw is an overall length of the variable magnification optical system at the wide angle end.

### Claim 9 (depends on 6)

The variable magnification optical system according to claim 6, wherein the following Conditional Expression (4-2) is satisfied:
3.1≤fG1/fw≤50 (4-2)
where
fG1 is a focal length of the first lens unit, and
fW is the focal length of the variable magnification optical system at the wide angle end.

### Claim 10 (depends on 6)

The variable magnification optical system according to claim 6, wherein the following Conditional Expression (6) is satisfied:
0.1≤fG1/ft≤3.0 (6)
where
fG1 is a focal length of the first lens unit, and
ft is a focal length of the variable magnification optical system at the telephoto end.

### Claim 11 (depends on 6)

The variable magnification optical system according to claim 6, wherein the following Conditional Expression (7) is satisfied:
1.7≤|fG1/fG2|≤9.1 (7)
where
fG1 is a focal length of the first lens unit, and
fG2 is a focal length of the second lens unit.

### Claim 12 (depends on 6)

The variable magnification optical system according to claim 6, wherein the following Conditional Expression (8) is satisfied:
1.0≤fG3/fw≤9.0 (8)
where
fG3 is a focal length of the third lens unit, and
fW is the focal length of the variable magnification optical system at the wide angle end.

### Claim 13 (depends on 6)

The variable magnification optical system according to claim 6, wherein the following Conditional Expression (9) is satisfied:
−14%<DTw<5% (9)
where
DTw is a distortion amount at the maximum angle of view at the wide angle end, and is indicated with the following Equation:
DTw=(IHw1−IHw2)/IHw2×100(%),
IHw1 is a real image height when light flux including the ray of the maximum angle of view is imaged on the image surface at the wide angle end,
IHw2 is a paraxial image height when light flux including the ray of the maximum angle of view is imaged on the image surface at the wide angle end, and
both image heights are image heights at the time of focusing to an infinite object point.

### Claim 14 (depends on 6)

The variable magnification optical system according to claim 6, wherein the third lens unit includes a predetermined positive lens that satisfies the following Conditional Expression (10):
63≤νdG3P1≤100.0 (10)
where
νdG3P1 is Abbe number of the predetermined positive lens.

### Claim 15 (depends on 6)

The variable magnification optical system according to claim 6, wherein:
the third lens unit includes a first positive lens and a cemented lens, and
the cemented lens consists of a negative lens and a biconvex positive lens, or
the cemented lens consists of a positive lens and a negative lens, and has a meniscus shape having a convex surface facing the object side.

### Claim 16 (depends on 6)

The variable magnification optical system according to claim 6, wherein at the time of changing magnification, all the lenses belonging to the first region move so that a distance between the third lens unit and all the lenses belonging to the first region changes.

### Claim 17 (depends on 6)

The variable magnification optical system according to claim 6, wherein at the time of changing magnification, all the lenses belonging to the first region move so that a distance between the third lens unit and all the lenses belonging to the first region is widened at the telephoto end than at the wide angle end.

### Claim 18 (depends on 6)

The variable magnification optical system according to claim 6, wherein at a time of changing magnification from the wide angle end to the telephoto end, all the lenses belonging to the first region move along a locus convex towards the object side.

### Claim 19 (depends on 6)

The variable magnification optical system according to claim 6, wherein all the lenses belonging to the first region are fixed at the time of changing magnification.

### Claim 20 (depends on 6)

The variable magnification optical system according to claim 6, wherein all the lenses belonging to the second region are fixed at the time of changing magnification.

### Claim 21 (depends on 6)

The variable magnification optical system according to claim 6, wherein all the lenses belonging to the first region are moved at a time of focusing.

### Claim 22 (depends on 6)

The variable magnification optical system according to claim 6, wherein only one negative lens belongs to the first region and moves at a time of focusing.

### Claim 23 (depends on 6)

The variable magnification optical system according to claim 6, wherein a predetermined negative lens that satisfies the following Conditional Expression (11) is disposed in the first region:
51.0≤νdGI1N1≤100.0 (11)
where
νdGI1N1 is Abbe number of a predetermined negative lens.

### Claim 24 (depends on 6)

The variable magnification optical system according to claim 6, wherein:
all the lenses belonging to the second region are divided into lenses belonging to a first sub-lens unit and lenses belonging to a second sub-lens unit,
the first sub-lens unit has a positive refractive power, and
the second sub-lens unit includes a negative lens and a positive lens.

### Claim 25 (depends on 6)

The variable magnification optical system according to claim 6, wherein the aperture stop is disposed closer to the image side than the second lens unit is, and closer to the object side than the surface closest to the image side in the third lens unit.

### Claim 26 (depends on 6)

The variable magnification optical system according to claim 6, wherein the aperture stop is fixed at a time of changing magnification.

### Claim 27 (depends on 6)

The variable magnification optical system according to claim 6, wherein the first lens unit is fixed at a time of changing magnification.

### Claim 28 (depends on 6)

The variable magnification optical system according to claim 6, wherein the following Conditional Expression (19) is satisfied:
2.0≤fG1/fG3≤10.0 (19)
where
fG1 is a focal length of the first lens unit, and
fG3 is a focal length of the third lens unit.

### Claim 29 (depends on 6)

The variable magnification optical system according to claim 6, wherein the following Conditional Expression (20) is satisfied:
0.5≤|fG3/fGI1≤2.0 (20)
where
fG3 is a focal length of the third lens unit, and
fGI1 is a focal length on the basis of all the lenses belonging to the first region.

### Claim 30 (depends on 6)

The variable magnification optical system according to claim 6, wherein the following Conditional Expression (21) is satisfied:
0.20≤fG2/fGI1≤2.0 (21)
where
fG2 is a focal length of the second lens unit, and
fGI1 is a focal length on the basis of all the lenses belonging to the first region.

### Claim 31 (depends on 6)

The variable magnification optical system according to claim 6, wherein the following Conditional Expression (22) is satisfied:
0.20≤|fG2/fG3|≤2.0 (22)
where
fG2 is a focal length of the second lens unit, and
fG3 is a focal length of the third lens unit.

### Claim 32 (depends on 6)

The variable magnification optical system according to claim 6, wherein the following Conditional Expression (23) is satisfied:
0.5≤|fGI1/fGI2|≤2.0 (23)
where
fGI1 is a focal length on the basis of all the lenses belonging to the first region, and
fGI2 is a focal length on the basis of all the lenses belonging to the second region.

### Claim 33 (depends on 6)

The variable magnification optical system according to claim 6, wherein the third lens unit move to be positioned closer to the object side at the telephoto end than at the wide angle end.

### Claim 34 (depends on 6)

The variable magnification optical system according to claim 6, wherein the first lens unit further includes one positive lens.

### Claim 35 (depends on 6)

The variable magnification optical system according to claim 6, wherein:
the negative lens in the first lens unit and the positive lens in the first lens unit is disposed in proximity to each other, and
the following Conditional Expression (24) is satisfied:
−0.1≤fG1×PG1NPa≤0.27 (24)
where
fG1 is a focal length of the first lens unit,
PG1NPa is represented by the following expression:
PG1NPa=1/RG1NB−1/RG1PF, where
RG1NB is a radius of curvature of an image-side lens surface of the negative lens in the first lens unit, and
RG1PF is a radius of curvature of an object-side lens surface of the positive lens in the first lens unit.

### Claim 36 (depends on 6)

The variable magnification optical system according to claim 6, wherein the following Conditional Expression (27) is satisfied:
0.03≤ΔG3M/LTLw≤0.3 (27)
where
ΔG3M is an amount of movement of the third lens unit moved from the wide angle end to the telephoto end, and
LTLw is an overall length of the variable magnification optical system at the wide angle end.

### Claim 37 (depends on 6)

The variable magnification optical system according to claim 6, wherein the third lens unit includes a positive lens and a negative lens.

### Claim 38 (depends on 6)

The variable magnification optical system according to claim 6, wherein the following Conditional Expression (28) is satisfied:
33.4°≤ΩHw/2≤70.0° (28)
where
ΩHw is the total angle of view in the horizontal direction at the wide angle end.

### Claim 39 (depends on 6)

The variable magnification optical system according to claim 6, wherein the following Conditional Expression (29) is satisfied:
5.0≤ft/fw≤120.0 (29)
where
ft is the focal length of the variable magnification optical system at the telephoto end, and
fW is the focal length of the variable magnification optical system at the wide angle end.

### Claim 40 (depends on 6)

The variable magnification optical system according to claim 6, wherein the following Conditional Expression (30) is satisfied:
0.60≤FNOw≤2.5 (30)
where
FNOw is an F-number at the wide angle end.

### Claim 41 (depends on 6)

The variable magnification optical system according to claim 6, wherein the following Conditional Expression (31) is satisfied:
0.70≤FNOt≤5.5 (31)
where
FNOt is an F-number at the telephoto end.

### Claim 42 (depends on 6)

The variable magnification optical system according to claim 6, wherein at a time of changing magnification, the aperture stop is moved only in one direction or is fixed.

### Claim 43 (depends on 6)

The variable magnification optical system according to claim 6, wherein a negative lens and a positive lens belong to the second region.

### Claim 44 (depends on 6)

The variable magnification optical system according to claim 6, wherein the following Conditional Expression (32) is satisfied:
0.04≤ΣG1/LTLw≤0.35 (32)
where
ΣG1 is a thickness of the first lens unit, and
LTLw is an overall length of the variable magnification optical system at the wide angle end.

### Claim 45 (depends on 6)

The variable magnification optical system according to claim 6, wherein the following Conditional Expression (33) is satisfied:
0.0≤ft/fw+143.9×tan(ΩHw/2)−121.88≤110 (33)
where
fW is the focal length of the variable magnification optical system at the wide angle end,
ft is a focal length of the variable magnification optical system at the telephoto end, and
ΩHw is a total angle of view in the horizontal direction at the wide angle end.

### Claim 46 (depends on 6)

The variable magnification optical system according to claim 6, wherein the following Conditional Expression (34) is satisfied:
0.0≤ft/fw+126.52×tan(ΩHw/2)−101.91≤120 (34)
where
fW is the focal length of the variable magnification optical system at the wide angle end,
ft is a focal length of the variable magnification optical system at the telephoto end, and
ΩHw is a total angle of view in the horizontal direction at the wide angle end.

### Claim 47 (depends on 6)

The variable magnification optical system according to claim 6, further comprising:
a predetermined resin negative lens that has an aspheric surface and satisfies the following Conditional Expression (36), and
the predetermined resin negative lens is disposed in the first region,
1.4≤ndGI1N1≤1.55 (36)
where
ndGI1N1 is a refractive index on d-line of the predetermined resin negative lens.

### Claim 48 (depends on 6)

The variable magnification optical system according to claim 6, further comprising:
a predetermined resin positive lens that has an aspheric surface and satisfies the following Conditional Expression (37), and
the predetermined resin positive lens is a positive lens positioned closest to the object side among the positive lenses in the first sub-lens unit:
1.4≤ndGI2SUB1P≤1.55 (37)
where
ndGI2SUB1P is a refractive index on d-line of the predetermined resin positive lens.

### Claim 49 (depends on 6)

The variable magnification optical system according to claim 6, wherein:
the second lens unit consists of, in order from the object side, a first negative lens, a second negative lens, and a cemented doublet lens,
the second negative lens consists of a resin negative lens,
the cemented doublet lens consists of a negative lens and a positive lens, and the following Conditional Expression (38) is satisfied:
0.7≤|fG22/RG2C|≤2 (38)
where
fG22 is a focal length of the second negative lens, and
RG2C is a radius of paraxial curvature of the cemented surface of the cemented doublet lens.

### Claim 50 (depends on 6)

The variable magnification optical system according to claim 6, wherein:
the second lens unit consists of, in order from the object side, the first negative lens, the second negative lens, and the cemented doublet lens,
the cemented doublet lens consists of the negative lens and the positive lens,
a lens belonging to the second region consists of one positive lens, and the following Conditional Expression (39) and is satisfied:
0.7≤RG2C/fGI2≤1.9 (39)
where
RG2C is a radius of paraxial curvature of the cemented surface of the cemented doublet lens, and
fGI2 is a focal length on the one positive lens belonging to the second region.

### Claim 51 (depends on 6)

An image pickup apparatus comprising:
an optical system; and
an image pickup element having an image pickup surface, and converting an image formed on the image pickup surface with the optical system into an electric signal, wherein
the optical system is the variable magnification optical system according to claim 6.

### Claim 52

A variable magnification optical system comprising:
in order from an object side,
a first lens unit having a positive refractive power;
a second lens unit having a negative refractive power;
a third lens unit having a positive refractive power; and
an image-side lens unit, wherein
the image-side lens unit includes a lens belonging to a first region and a lens belonging to a second region,
a refractive power based on all lenses belonging to the first region is a negative refractive power, and a refractive power based on all lenses belonging to the second region is a positive refractive power,
at a time of changing magnification,
a distance between the lens units changes,
the second lens unit moves so that a distance between the first lens unit and the second lens unit is larger at a telephoto end than at a wide angle end,
the third lens unit moves, and
all the lenses belonging to the second region are fixed, and
the following Conditional Expressions (1-2) and (3) are satisfied:
1.61≤|fG2/fw|≤10.0 (1-2), and
0.067≤fG2×PG1G2a≤0.207 (3)
where
fG2 is a focal length of the second lens unit,
fw is a focal length of the variable magnification optical system at the wide angle end,
PG1G2a is represented by the following expression:
PG1G2a=1/RG1B−1/RG2F, where
RG1B is a radius of curvature of a lens surface positioned closest to an image side in the first lens unit, and
RG2F is a radius of curvature of a lens surface positioned closest to the object side in the second lens unit.

### Claim 53

A variable magnification optical system comprising:
in order from an object side,
a first lens unit having a positive refractive power;
a second lens unit having a negative refractive power;
a third lens unit having a positive refractive power; and
an image-side lens unit, wherein:
the image-side lens unit includes a lens belonging to a first region and a lens belonging to a second region,
a refractive power based on all lenses belonging to the first region is a negative refractive power, and a refractive power based on all lenses belonging to the second region is a positive refractive power,
at a time of changing magnification,
a distance between the lens units changes,
the second lens unit moves so that a distance between the first lens unit and the second lens unit is larger at a telephoto end than at a wide angle end,
the first lens unit is fixed, and
the third lens unit moves,
the first lens unit includes a negative lens and a positive lens,
the positive lens in the first lens unit is a positive meniscus lens having a convex surface facing the object side,
the third lens unit includes a positive lens and a negative lens, and
the following Conditional Expressions (1-3) and (2-2) are satisfied:
1.60≤|fG2/fw|≤10.0 (1-3), and
0≤ΔSS/LTLw≤0.11 (2-2)
where
fG2 is a focal length of the second lens unit,
fw is a focal length of the variable magnification optical system at the wide angle end,
ΔSS is a maximum amount of movement of an aperture stop at a time of changing magnification, and
LTLw is an overall length of the variable magnification optical system at the wide angle end.

### Claim 54

A variable magnification optical system comprising:
in order from an object side,
a first lens unit having a positive refractive power;
a second lens unit having a negative refractive power;
a third lens unit having a positive refractive power; and
an image-side lens unit, wherein:
the image-side lens unit includes a lens belonging to a first region and a lens belonging to a second region,
a refractive power based on all lenses belonging to the first region is a negative refractive power, and a refractive power based on all lenses belonging to the second region is a positive refractive power,
at a time of changing magnification,
a distance between the lens units changes,
the second lens unit moves so that a distance between the first lens unit and the second lens unit is larger at a telephoto end than at a wide angle end,
the first lens unit is fixed, and
the third lens unit moves,
the third lens unit includes a positive lens and a negative lens, and
the following Conditional Expressions (2-2) and (4-1) are satisfied:
0≤ΔSS/LTLw≤0.11 (2-2), and
8.7≤fG1/fw≤50 (4-1)
where
ΔSS is a maximum amount of movement of an aperture stop at a time of changing magnification,
LTLw is an overall length of the variable magnification optical system at the wide angle end,
fG1 is a focal length of the first lens unit, and
fw is a focal length of the variable magnification optical system at the wide angle end.

### Claim 55

A variable magnification optical system comprising:
in order from an object side,
a first lens unit having a positive refractive power; and
a second lens unit having a negative refractive power, wherein:
an image-side first positive lens unit having a positive refractive power is included on an image side of the second lens unit,
an image-side second positive lens unit having a positive refractive power is included on the image side of the image-side first positive lens unit,
at a time of changing magnification,
the second lens unit moves so that a distance between the first lens unit and the second lens unit is widened at a telephoto end than at a wide angle end, and
an aperture stop moves, and
the following Conditional Expressions (28-1), (29-1), and (32) are satisfied:
35.3°≤ΩHw/2≤70.0° (28-1)
7.0≤ft/fw≤120.0 (29-1), and
0.04≤ΣG1/LTLw≤0.35 (32)
where
ΩHw is a total angle of view in a horizontal direction at the wide angle end,
ft is a focal length of the variable magnification optical system at the telephoto end,
fw is a focal length of the variable magnification optical system at the wide angle end,
ΣG1 is a thickness of the first lens unit, and
LTLw is an overall length of the variable magnification optical system at the wide angle end.

### Claim 56 (depends on 55)

An image pickup apparatus comprising:
an optical system; and
an image pickup element having an image pickup surface, and converting an image formed on the image pickup surface with the optical system into an electric signal, wherein
the optical system is the variable magnification optical system according to claim 55.

### Claim 57

A variable magnification optical system comprising:
in order from an object side,
a first lens unit having a positive refractive power; and
a second lens unit having a negative refractive power, wherein:
an image-side first positive lens unit having a positive refractive power is included on an image side of the second lens unit,
an image-side second positive lens unit having a positive refractive power is included on the image side of the image-side first positive lens unit,
at a time of changing magnification,
the second lens unit moves so that a distance between the first lens unit and the second lens unit is larger at a telephoto end than at a wide angle end, and
an aperture stop moves, and
the following Conditional Expressions (28-2), (29-2), and (30-1) are satisfied:
33.4°ΩHw/2≤70.0° (28-2)
5.0≤ft/fw≤65.0 (29-2), and
0.60≤FNOw≤1.84 (30-1)
where
ΩHw is a total angle of view in a horizontal direction at the wide angle end,
ft is a focal length of the variable magnification optical system at the telephoto end,
fw is a focal length of the variable magnification optical system at the wide angle end, and
FNOw is an F-number at the wide angle end.

### Claim 58

A variable magnification optical system comprising:
in order from an object side,
a first lens unit having a positive refractive power; and
a second lens unit having a negative refractive power, wherein:
an image-side first positive lens unit having a positive refractive power is included on an image side of the second lens unit,
an image-side second positive lens unit having a positive refractive power is included on the image side of the image-side first positive lens unit,
at a time of changing magnification,
the second lens unit moves so that a distance between the first lens unit and the second lens unit is larger at a telephoto end than at a wide angle end, and
the following Conditional Expressions (29-3), (30-2), and (31) are satisfied:
10.0≤ft/fw≤65.0 (29-3)
0.60≤FNOw≤1.62 (30-2), and
0.70≤FNOt≤5.5 (31)
where
ft is a focal length of the variable magnification optical system at the telephoto end,
fw is a focal length of the variable magnification optical system at the wide angle end,
FNOw is an F-number at the wide angle end, and
FNOt is an F-number at the telephoto end.

### Claim 59

A variable magnification optical system comprising:
in order from an object side,
a first lens unit having a positive refractive power; and
a second lens unit having a negative refractive power, wherein:
an image-side first positive lens unit having a positive refractive power is included on an image side of the second lens unit,
an image-side second positive lens unit having a positive refractive power is included on the image side of the image-side first positive lens unit,
at a time of changing magnification,
the second lens unit moves so that a distance between the first lens unit and the second lens unit is larger at a telephoto end than at a wide angle end, and
the first lens unit is fixed, and
the following Conditional Expressions (29-4), (33), (35), and (32-1) are satisfied:
10.2≤ft/fw≤120.0 (29-4),
0.0≤ft/fw+143.9×tan(ΩHw/2)−121.88≤110 (33),
2.5 mm≤Rimg≤22.0 mm (35), and
0.04≤ΣG1/LTLw≤0.33 (32-1)
where
ft is a focal length of the variable magnification optical system at the telephoto end,
fw is a focal length of the variable magnification optical system at the wide angle end,
ΩHw is a total angle of view in a horizontal direction at the wide angle end,
Rimg is a radius of an image circle at an image pickup element,
ΣG1 is a thickness of the first lens unit, and
LTLw is an overall length of the variable magnification optical system at the wide angle end.

### Claim 60

A variable magnification optical system comprising:
in order from an object side,
a first lens unit having a positive refractive power; and
a second lens unit having a negative refractive power, wherein:
an image-side first positive lens unit having a positive refractive power is included on an image side of the second lens unit,
an image-side second positive lens unit having a positive refractive power is included on the image side of the image-side first positive lens unit,
at a time of changing magnification,
the second lens unit moves so that a distance between the first lens unit and the second lens unit is larger at a telephoto end than at a wide angle end, and
the first lens unit is fixed, and
the following Conditional Expressions (29-5), (34), (35-1), and (32-1) are satisfied:
6.1≤ft/fw≤120.0 (29-5)
0.0≤ft/fw+126.52×tan(ΩHw/2)−101.91≤120 (34)
3.3 mm≤Rimg≤22.0 mm (35-1)
0.04≤ΣG1/LTLw≤0.33 (32-1)
where
ft is a focal length of the variable magnification optical system at the telephoto end, fw is a focal length of the variable magnification optical system at the wide angle end,
ΩHw is a total angle of view in a horizontal direction at the wide angle end,
Rimg is a radius of an image circle at an image pickup element,
ΣG1 is a thickness of the first lens unit, and
LTLw is an overall length of the variable magnification optical system at the wide angle end.