Title: Zoom lens and apparatus using the same
Abstract: A zoom lens according to the present invention includes, in order from the 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 negative refractive power, and a fourth lens unit having a positive refractive power. During a magnification change from the wide-angle end through the telephoto end, the first lens unit and the fourth lens unit shift from the image-surface side toward the object side, a space between the first lens unit and the second lens unit increases, and spaces between individual lens units change. During a focusing from an object at the infinite distance onto an object at a near distance, the second lens unit and the third lens unit individually shift independently.
Patent Number: 7,009,780 Issued on 03/07/2006 to Ishii
| Inventors:
|
Ishii; Atsujiro (Nishitokyo, JP)
|
| Assignee:
|
Olympus Corporation (Tokyo, JP)
|
| Appl. No.:
|
842528 |
| Filed:
|
May 11, 2004 |
Foreign Application Priority Data
| May 13, 2003[JP] | 2003-134803 |
| Current U.S. Class: |
359/688; 359/676; 359/740; 359/775; 359/683; 359/684; 359/685 |
| Current Intern'l Class: |
G02B 15/14 (20060101) |
| Field of Search: |
359/676,683-685,688,715,740,775
|
References Cited [Referenced By]
U.S. Patent Documents
| 5144488 | Sep., 1992 | Endo et al.
| |
| 5737128 | Apr., 1998 | Usui.
| |
| 5898525 | Apr., 1999 | Suzuki.
| |
| 6002528 | Dec., 1999 | Tomita.
| |
| 2002/0063970 | May., 2002 | Uzawa et al.
| |
| Foreign Patent Documents |
| 03-289612 | Dec., 1991 | JP.
| |
Primary Examiner: Lester; Evelyn A.
Attorney, Agent or Firm: Kenyon & Kenyon
Claims
What is claimed is:
1. A zoom lens 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 negative refractive power; and
a fourth lens unit having a positive refractive power,
wherein, during a magnification change from a wide-angle end through a telephoto
end, the first lens unit and the fourth lens unit shift from an image-surface side
toward an object side, a space between the first lens unit and the second lens
unit increases, and spaces between individual lens units change, and
wherein, during a focusing from an object at an infinite distance onto an object
at a near distance, at least the second lens unit and the third lens unit individually
shift independently.
2. A zoom lens according to claim 1, wherein an amount of shift of each of the
second lens unit and the third lens unit for a focusing from an object at the infinite
distance onto an object at any finite distance between the infinite distance and
a proximate distance has a predetermined value differing by zooming position.
3. A zoom lens according to claim 1, satisfying the following condition:
-2<
X2W/X3W<0.5
where X
2W is an amount of shift of the second lens unit for a focusing
from the infinite distance onto a proximate distance at the wide-angle end, and
X
3W is an amount of shift of the third lens unit for the focusing from
the infinite distance onto the proximate distance at the wide-angle end, upon a
shift toward the image-surface side being given a positive value.
4. A zoom lens according to claim 3, satisfying the following condition:
-1<
X2W/X3W<0.3.
5. A zoom lens according to claim 3, satisfying the following condition:
-0.8
<X2W/X3W<-0.01.
6. A zoom lens according to 2, wherein, during a focusing from an object at the
infinite distance onto an object at a finite distance, the second lens unit shifts
toward the image-surface side at the wide-angle end and shifts toward the object
side at the telephoto end, and the third lens unit shifts toward the object side
irrespective of zooming state.
7. A zoom lens according to claim 6, wherein an amount of shift of the second
lens unit for a focusing from an object at the infinite distance onto an object
at a particular finite distance continuously changes as a zooming state changes
from the wide-angle end through the telephoto end.
8. A zoom lens according to claim 6, wherein an amount of shift of the third
lens unit for a focusing from an object at the infinite distance onto an object
at a particular finite distance continuously changes as a zooming state changes
from the wide-angle end through the telephoto end.
9. A zoom lens according to claim 8, wherein, during the focusing from the object
at the infinite distance onto the object at the particular finite distance, the
third lens unit shifts towards the object side, with an amount of shift thereof
increasing as a zooming state changes from the wide-angle end through the telephoto end.
10. A zoom lens according to 2, satisfying the following condition:
0.001
<D12W/D12T<0.1
where D
12W is a space between the first lens unit and the second lens
unit at the wide-angle end under a condition where the infinite distance is in
focus, and D
12T is a space between the first lens unit and the second
lens unit at the telephoto end under the condition where the infinite distance
is in focus.
11. A zoom lens according to claim 10, satisfying the following condition:
0.005
<D12W/D12T<0.07.
12. A zoom lens according to claim 10, satisfying the following condition:
0.01
<D12W/D12T<0.05.
13. A zoom lens according to 2, satisfying the following condition:
3.0
<D23W/D23T<20.0
where D
23W is a space between the second lens unit and the third lens
unit at the wide-angle end under a condition where the infinite distance is in
focus, and D
23T is a space between the second lens unit and the third
lens unit at the telephoto end under the condition where the infinite distance
is in focus.
14. A zoom lens according to claim 13, satisfying the following condition:
4.0
<D23W/D23T<10.0
15. A zoom lens according to claim 13, satisfying the following condition:
5.0
<D23W/D23T<7.0
16. A zoom lens according to claim 13, satisfying the following condition:
0.7
<X2T/X3T<1.5
where X
2T is an amount of shift of the second lens unit for a focusing
from the infinite distance onto a proximate distance at the telephoto end, and
X
3T is an amount of shift of the third lens unit for the focusing from
the infinite distance onto the proximate distance at the telephoto end.
17. A zoom lens according to claim 16, satisfying the following condition:
0.7
<X2T/X3T<1.3.
18. A zoom lens according to claim 16, satisfying the following condition:
0.9<
X2T/X3T<1.1.
19. A zoom lens device comprising:
a zoom lens according to claim 1; and
a lens mount section arranged on the image-surface side of the zoom lens, the
lens mount section being connectable with a camera.
20. A zoom lens device comprising:
a zoom lens according to claim 2; and
a lens mount section arranged on the image-surface side of the zoom lens, the
lens mount section being connectable with a camera.
21. A zoom lens device comprising:
a zoom lens according to claim 3; and
a lens mount section arranged on the image-surface side of the zoom lens, the
lens mount section being connectable with a camera.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a zoom lens used in a silver-halide camera,
a digital camera, a video camera or the like.
2. Description of the Related Art
Conventionally, in a zoom lens used in a silver-halide camera, a
digital camera, a video camera or the like, it is known as a method for focusing
from an object at the infinite distance to an object at a near distance to shift
whole or a part of one unit out of lens units that change mutual spaces during
a zooming operation (For example, refer to Japanese Patent Application Preliminary
Publication (KOKAI) No. Hei 3-289612 or Japanese Patent Application Preliminary
Publication (KOKAI) No. Hei 3-228008).
There is a type including four units having positive-negative-negative-positive
power arrangement in order from the object side and performing focusing by shifting
the positive first lens unit toward the object side, as in the method shown in
KOKAI No. Hei 3-289612. Also, there is another type including three lens units
having positive-negative-positive power arrangement in order from the object side
and performing focusing by shifting forth the negative second lens unit toward
the object side as in the method shown in KOKAI No. Hei 3-228008.
SUMMARY OF THE INVENTION
A zoom lens according to the present invention includes, in order from the 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 negative refractive
power, and a fourth lens unit having a positive refractive power, wherein, during
a magnification change from the wide-angle end through the telephoto end, the first
lens unit and the fourth lens unit shift from the image-surface side toward the
object side, a space between the first lens unit and the second lens unit increases,
and spaces between individual lens units change, and wherein, during a focusing
from an object at the infinite distance onto an object at a near distance, the
second lens unit and the third lens unit individually shift independently.
Also, a zoom lens according to the present invention includes, in order from
the 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 negative
refractive power, and a fourth lens unit having a positive refractive power, wherein,
during a magnification change from the wide-angle end through the telephoto end,
the first lens unit and the fourth lens unit shift from the image-surface side
toward the object side, a space between the first lens unit and the second lens
unit increases, and spaces between the individual lens units change, wherein, during
a focusing from an object at the infinite distance onto an object at a near distance,
the second lens unit and the third lens unit individually shift independently,
and wherein, for a focusing from an object at the infinite distance onto an object
at any finite distance between the infinite distance and the proximate distance,
amount of shift of the second lens unit and the third lens unit have predetermined
values differing by zooming state.
Furthermore, a zoom lens according to the present invention includes,
in order from the 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 negative refractive power, and a fourth lens unit having a positive refractive
power, wherein, during a magnification change from the wide-angle end through the
telephoto end, the first lens unit and the fourth lens unit shift from the image-surface
side toward the object side, a space between the first lens unit and the second
lens unit increases, and spaces between individual lens units change, wherein,
during a focusing from an object at the infinite distance onto an object at a near
distance, the second lens unit and the third lens unit individually shift independently,
wherein, for a focusing from an object at the infinite distance onto an object
at any finite distance between the infinite distance and the proximate distance,
amount of shift of the second lens unit and the third lens unit have predetermined
values differing by zooming state, and wherein the following condition is satisfied:
-2
<X2w/X3W<0.5
where X
2W is an amount of shift of the second lens unit and X
3W
is an amount of shift of the third lens unit for a focusing from the infinite
distance to the proximate distance at the wide-angle end, upon a shift toward the
image-surface side being given a positive value.
According to the present invention, it is possible to provide a zoom lens
in which fluctuation of aberrations involved in focusing is stayed small and in
which the proximate distance is designed sufficiently close without size increase
of the lens system.
These features and advantages of the present invention will become apparent
from the following detailed description of the preferred embodiments when taken
in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A, 1B, and 1C are sectional views taken along the optical
axis that show the optical configuration of the zoom lens of the first embodiment
according to the present invention, showing the states at the wide-angle end, the
intermediate position, and the telephoto end, respectively.
FIGS. 2A, 2B and 2C are sectional views taken along the optical
axis that show the optical configuration of the zoom lens of the second embodiment
according to the present invention, showing the states at the wide-angle end, the
intermediate position, and the telephoto end, respectively.
FIGS. 3A, 3B and 3C are sectional views taken along the optical
axis that show the optical configuration of the zoom lens of the third embodiment
according to the present invention, showing the states at the wide-angle end, the
intermediate position, and the telephoto end, respectively.
FIGS. 4A, 4B and 4C are sectional views taken along the optical
axis that show the optical configuration of the zoom lens of the fourth embodiment
according to the present invention, showing the states at the wide-angle end, the
intermediate position, and the telephoto end, respectively.
FIGS. 5A-5D, 5E-5H, and 5I-5L are diagrams that
show spherical aberration, astigmatism, distortion, and chromatic aberration of
magnification of the first embodiment at the wide-angle end, the intermediate position,
and the telephoto end, respectively.
FIGS. 6A-6D, 6E-6H, and 6I-6L are diagrams that
show spherical aberration, astigmatism, distortion, and chromatic aberration of
magnification of the second embodiment at the wide-angle end, the intermediate
position, and the telephoto end, respectively.
FIGS. 7A-7D, 7E-7H, and 7I-7L are diagrams that
show spherical aberration, astigmatism, distortion, and chromatic aberration of
magnification of the third embodiment at the wide-angle end, the intermediate position,
and the telephoto end, respectively.
FIGS. 8A-8D, 8E-8H, and 8I-8L are diagrams that
show spherical aberration, astigmatism, distortion, and chromatic aberration of
magnification of the fourth embodiment at the wide-angle end, the intermediate
position, and the telephoto end, respectively.
FIG. 9 is a configuration diagram of a single-lens reflex camera in which the
zoom lens according to the present invention is used as a photographing lens.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preceding the explanation of the embodiments shown in the drawings, function
and effect of the present invention are described below.
Regarding a zoom lens according to the present invention, it is possible
to achieve small fluctuation of aberrations involved in focusing and to design
the proximate distance to be sufficiently close without size increase of the lens
system, by performing focusing by way of shifting each of the plurality of lens
units in the zoom lens independently for an optimum amount in each zoom state.
To be specific, in a zoom lens including a positive first lens unit, a negative
second lens unit, a negative third lens unit, and a positive fourth lens unit with
the first lens unit and the fourth lens unit shifting toward the object side and
a space between the first lens unit and the second lens unit increasing during
a magnification change from the wide-angle end through the telephoto end, configuration
is made so that the second lens unit and the third lens unit individually shift
independently during a focusing from an object at the infinite distance onto an
object at a near distance.
If the focusing be made by shifting forth the second lens unit as stated above
at the wide-angle end, it would be necessary, for the purpose of setting the proximate
distance to be sufficiently close, to secure a wide space between the first lens
unit and the second lens unit under the condition where the infinite distance is
in focus. As a result, a lens diameter of the first lens unit would be rendered
large. In addition, shift of the second lens unit would cause the problem of large
fluctuation of astigmatism, distortion or the like. According to the present invention,
the focusing is made by shifting forth mainly the third lens unit at the wide-angle
end, to dispense with an extra space between the first lens unit and the second
lens unit and to stay fluctuation of aberrations small. In addition, by shifting
back the second lens unit toward the image-surface side by an amount smaller than
the amount of shift of the third lens unit at the same time as the third lens unit
is shifted forth toward the object side, fluctuation of aberrations involved in
the shift of the third lens unit can cancel. Here, it is preferable to satisfy
the following condition:
-2<
X2w/X3W<0.5 (1)
where X
2W is an amount of shift of the second lens unit and X
3W
is an amount of shift of the third lens unit for the focusing at the wide-angle
end, with a shift toward the image-surface side being given a positive value.
Condition (1) specifies a ratio of the amount of shift of the second lens
unit to the amount of shift of the third lens unit for the focusing. If the upper
limit of Condition (1) is exceeded, the amount of shift of the second lens unit
toward the object side is large, to result in a large lens diameter of the first
lens unit and increase in fluctuation of aberrations during the focusing, as stated
above. If the lower limit of Condition (1) is not reached, the amount of shift
back toward the image-surface side of the second lens unit is large, to result
in increase in amount of shift of the third lens unit, for a shift of the imaging
position caused by the shift of the second lens unit is in the opposite direction
to the focusing.
Here, the case where X
2W/X
3W=0 is explained. Upon designing
focusing to be performed by shifting the second lens unit and the third lens unit
for respectively independent amount at any position other than the wide-angle end,
the configuration can be made so that the second lens unit is not shifted in a
focusing at the wide-angle end.
It is much preferable to satisfy the following condition (1′):
-1<
X2W/X3W<0.3 (1′)
Furthermore, if the following condition (1") is satisfied, good focusing
operation can be achieved over the full zooming range while precluding a large
lens diameter of the first lens unit.
-0.8
<X2W/X3W<-0.01 (1")
Also, for a magnification change, a space between the first lens unit and the
second lens unit should be sufficiently wide at the telephoto end. Thus, in order
to achieve compact design of the length of the entire zoom lens, it is desirable
that a space between the second lens unit and the third lens unit is small. In
this case, it is desirable that the focusing is performed by shifting forth both
of the second lens unit and the third lens unit. At the telephoto end, the space
between the first lens unit and the second lens unit is large and the field angle
is small. Thus, since fluctuation of aberrations involved in the shift of the second
lens unit is small, the above-mentioned problem at the wide-angle end is not raised,
and the proximate distance can be designed sufficiently small without degradation
of performance.
In order to configure a system in which spaces for zooming are efficiently used
and in which performance fluctuation caused by focusing is small, it is preferable
that the second lens unit shifts toward the image side at the wide angle end and
toward the object side at the telephoto end during a focusing from an object at
the infinite distance onto an object at a finite distance.
In such an inner focus method, amount of shift of focusing lens unit(s) for a
focusing onto a certain finite distance inevitably varies with zooming position,
irrespective of whether a single lens unit or a plurality of lens units are used
for focusing.
In a case where focusing is performed by a single lens unit, once the paraxial
power arrangement of the entire system is determined, amount of shift of the focusing
lens unit is uniquely determined by the object distance.
According to the present invention, in a case where focusing is performed
by shifting a plurality of lens units independently, distribution ratio of amount
of shift among the respective lens units may be arbitrarily selected. In this case,
for realizing a smooth moving mechanism, it is desirable that, for a focusing from
an object at the infinite distance onto an object at a certain finite distance,
amount of shift of the second lens unit continuously changes as a zooming state
changes from the wide-angle end through the telephoto end.
Also, it is desirable that, for a focusing from an object at the infinite distance
onto an object at a certain finite distance, amount of shift of the third lens
unit continuously changes as a zooming state changes from the wide-angle end through
the telephoto end. In addition, if the configuration is made so that the third
lens unit is shifted from the image side toward the object side during a focusing
from an object at the infinite distance onto an object at a certain finite distance
with its amount of shift increasing as a zooming state is changed from the wide-angle
end through the telephoto end, a smooth moving mechanism can be much easily realized.
In this configuration, effect of compensation for aberrations by shift of the second
lens unit does not abruptly changes dependent on a zooming state, and thus a zoom
lens in a good balance as a whole is achieved.
Also, upon expressing a shift of a focus lens by a function curve corresponding
to f(Z)+g(L), which curve has a cam shape, where f(Z) and g(L) are cam rotation
angle for zooming and cam rotation angle for focusing, respectively, upon taking
zooming position Z and object distance L as parameters, it is desirable that distribution
ratio of amount of shift for focusing between the respective lens units in each
zooming position is set so that each of the second lens unit and the third lens
unit can be expressed by an independent function curve corresponding to f(Z)+g(L).
Also, in a case where a focusing is performed by the second and third lens
units in a zoom lens having positive-negative-negative-positive arrangement of
refractive power with amount of shift of the second lens unit being small at the
wide-angle end and increasing as a zooming state changes toward the telephoto side
as set forth above, it is desirable that the cam curve of the second lens unit
has an extreme value.
Also, it is much preferable to satisfy the following condition (2):
0.001
<D12W/D12T<0.1 (2)
where D
12W is a space between the first lens unit and the second
lens unit at the wide-angle end under the condition where the infinite distance
is in focus, and D
12T is a space between the first lens unit and the
second lens unit at the telephoto end under the condition where the infinite distance
is in focus.
If the lower limit of Condition (2) is not reached, the space between the first
lens unit and the second lens unit at the wide-angle end is so small that frames
of the lens units are likely to interfere. On the other hand, if the upper limit
is exceeded, the space between the first lens unit and the second lens unit at
the wide-angle end is wide, to render the lens diameter of the first lens unit large.
It is much preferable to satisfy the following condition (2′):
0.005
<D12W/D12T<0.07 (2′)
It is still much preferable to satisfy the following condition (2"):
0.01
<D12W/D12T<0.05 (2")
Also, it is preferable to satisfy the following condition (3)
3.0
<D23w/D23T<20.0 (3)
where D
23W is a space between the second lens unit and the third
lens unit at the wide-angle end under the condition where the infinite distance
is in focus, and D
23T is a space between the second lens unit and the
third lens unit at the telephoto end under the condition where the infinite distance
is in focus.
Condition (3) specifies a ratio of the space between the second lens unit
and the third lens unit at the wide-angle end to the space between the second lens
unit and the third lens unit at the telephoto end. If the lower limit of Condition
(3) is not reached, variation of the space between the second lens unit and the
third lens unit in zooming is small, to less contribute to compensation, by change
of the space between the second lens unit and the third lens unit, for fluctuation
of aberrations. On the other hand, if the upper limit is exceeded, the space between
the second lens unit and the third lens unit at the wide-angle end is large, to
less contribute to compact design of the entire length at the wide-angle end.
It is much preferable to satisfy the following condition (3′):
4.0
<D23W/D23T<10.0 (3′)
It is still much preferable to satisfy the following condition (3"):
5.0
<D23w/D23T<7.0 (3")
Also, it is preferable to satisfy the following condition (4):
0.7
<X2T/X3T<1.5 (4)
where X
2T is an amount of shift of the second lens unit for a focusing
from the infinite distance onto the proximate distance at the telephoto end, and
X
3T is an amount of shift of the third lens unit for the focusing from
the infinite distance onto the proximate distance at the telephoto end.
Condition (4) specifies a ratio of the amount of shift of the second lens
unit to the amount of shift of the third lens unit for the focusing at the telephoto
end. If the lower limit of Condition (4) is not reached, the amount of shift of
the second lens unit in the focusing is small, and thus the second lens unit and
the third lens unit are likely to interfere, to make it difficult to shorten the
proximate distance. On the other hand, if the upper limited is exceeded, the amount
of shift of the third lens unit in the focusing becomes small, and thus contribution
of the third lens unit to the focusing is reduced.
It is much preferable to satisfy the following condition (4′):
0.8
<X2T/X3T<1.3 (4′)
It is still much preferable to satisfy the following condition (4");
0.9
<X2T/X3T<1.1 (4′)
In each of the examples above, the upper limit value alone or the lower limit
value alone may be specified. Also, a plurality of the conditional expressions
may be satisfied simultaneously.
In reference to the drawings and numerical data, the embodiments of the zoom
lens
according to the present invention are described below.
First Embodiment
FIGS. 1A,
1B, and
1C are sectional views taken along the optical
axis that show the optical configuration of the zoom lens of the first embodiment
according to the present invention, showing the states at the wide-angle end, the
intermediate position, and the telephoto end, respectively. FIGS. 5A-5D,
5E-
5H,
and
5I-
5L are diagrams that show spherical aberration, astigmatism,
distortion, and chromatic aberration of magnification of the first embodiment at
the wide-angle end, the intermediate position, and the telephoto end, respectively.
As shown in FIG. 1, the zoom lens of the first embodiment includes, in order
from
the object side X toward an image-pickup element surface P, a first lens unit G
11
having a positive refractive power, a second lens unit G
12 having a
negative refractive power, a third lens unit G
13 having a negative refractive
power, and a fourth lens unit G
14 having a positive refractive power.
During a magnification change from the wide-angle end (FIG. 1A) through the telephoto
end (FIG. 1C), the first lens unit G
11 and the fourth lens unit G
14
are shifted from the image-surface side toward the object side. In this event,
a space D
1 between the first lens unit G
11 and the second
lens unit G
12 increases, and spaces between individual lens units change.
During a focusing from an object at the infinite distance onto an object at a near
distance, the second lens unit G
12 and the third lens unit G
13
individually shift independently. In FIG. 1, the reference symbol S denotes
a stop, the reference symbol FL
1 denotes an infrared absorption filter,
the reference symbol FL
3 denotes a lowpass filter, and the reference
symbol FL
4 denotes a cover glass of a CCD or CMOS sensor. The reference
symbol P denotes an image pickup surface, which is disposed in the effective image-pickup
diagonal direction of the CCD or CMOS sensor.
The first lens unit G
11 is composed of, in order from the object side
X, a negative first lens L
11, a positive second lens L
12,
and a positive third lens L
13. The first lens L
11 and the
second lens L
12 form a cemented lens.
The second lens unit G
12 is composed of, in order from the object
side X, a negative fourth lens L
14, a negative fifth lens L
15 with
its image-side concave surface being aspherical, a negative sixth lens L
16,
and a positive seventh lens L
17.
The third lens unit G
13 is composed of, in order from the object side
X, a positive eighth lens L
18, and a negative ninth lens L
19 with
its object-side concave surface being aspherical.
The fourth lens unit G
14 is composed of, in order from the object
side X, a positive tenth lens L
110 with its image-side concave surface
being aspherical, a positive eleventh lens L
111, a negative twelfth
lens L
112, a positive thirteenth lens L
113, and a negative
fourteenth lens L
114. Of these lenses, the twelfth lens, the thirteenth
lens, and the fourteenth lens form a cemented lens.
The stop S is arranged between the third lens unit G
13 and the fourth
lens unit G
14. The infrared absorption filter FL
1, the lowpass
filter FL
2, and the cover glass FL
3 of the CCD or CMOS sensor
are arranged on the image side of the fourth lens unit G
14 in this order
toward the image pickup surface P.
The numerical data of the optical members constituting the zoom lens according
to the first embodiment are shown below.
In the numerical data of the first embodiment, r
1, r
2, .
. . denote radii of curvature of the respective lens surfaces, d
1, d
2,
. . . denote thicknesses of or airspaces between the respective lenses, n
d1,
n
d2, . . . are refractive indices of the respective lenses or airspaces
ford-line rays, V
d1, v
d2, . . . are Abbe's numbers of the
respective lenses, Fno. denotes F-number, and f denotes a focal length of the entire
system. Values of r, d, and f are in millimeters.
It is noted that an aspherical surface is expressed by the following equation:
z=(
y2/r)/[1+{1-(1
+K)(
y/r)
2}
1/2]+A4y4+A6y6+A8y8+A10
where z is taken along the direction of the optical axis, y is taken along
a direction intersecting the optical axis at right angles, a conical coefficient
is denoted by K, and aspherical coefficients are denoted by A4, A6,
A8, and A10.
These reference symbols are commonly used in the numerical data of the subsequent
embodiments also.
| |
focal length f = 14.69~53.88 mm, Fno. = 2.85~3.55 |
| |
2ω = 74.36°~23.36° |
| |
r1 = 92.1912 |
|
|
| |
d1 = 2.5 |
nd1 = 1.84666 |
νd1 = 23.78 |
| |
r2 = 50.9961 |
| |
d2 = 5.84 |
nd2 = 1.6516 |
νd2 = 58.55 |
| |
r3 = 193.066 |
| |
d3 = 0.13 |
nd3 = 1 |
| |
r4 = 47.0946 |
| |
d4 = 4.36 |
nd4 = 1.7725 |
νd4 = 49.6 |
| |
r5 = 104.1756 |
| |
d5 = D1 |
nd5 = 1 |
| |
r6 = 63.4707 |
| |
d6 = 1.89 |
nd6 = 1.7725 |
νd6 = 49.6 |
| |
r7 = 11.2012 |
| |
d7 = 6.64 |
nd7 = 1 |
| |
r8 = 311.5503 |
| |
d8 = 1.8 |
nd8 = 1.58313 |
νd8 = 59.38 |
| |
r9 = 17.622 |
| |
d9 = 3.22 |
nd9 = 1 |
| |
r10 = -49.2708 |
| |
d10 = 1.5 |
nd10 = 1.57281 |
νd10 = 65.72 |
| |
r11 = -135.9067 |
| |
d11 = 0.17 |
nd11 = 1 |
| |
r12 = 39.3696 |
| |
d12 = 3.3 |
nd12 = 1.84666 |
νd12 = 23.78 |
| |
r13 = -59.013 |
| |
d13 = D2 |
nd13 = 1 |
| |
r14 = 92.5004 |
| |
d14 = 3.94 |
nd14 = 1.53609 |
νd14 = 60.92 |
| |
r15 = -18.2971 |
| |
d15 = 0.2 |
nd15 = 1 |
| |
r16 = -17.4747 |
| |
d16 = 1.8 |
nd16 = 1.8061 |
νd16 = 40.92 |
| |
r17 = 116.0971 |
| |
d17 = D3 |
nd17 = 1 |
| |
r18 = ∞ (aperture stop) |
| |
d18 = 1.5 |
nd18 = 1 |
| |
r19 = 19.9443 |
| |
d19 = 4.98 |
nd19 = 1.51633 |
νd19 = 64.14 |
| |
r20 = -154.1774 |
| |
d20 = 1.1 |
nd20 = 1 |
| |
r21 = 44.2951 |
| |
d21 = 8.4 |
nd21 = 1.497 |
νd21 = 81.54 |
| |
r22 = -24.6953 |
| |
d22 = 0.19 |
nd22 = 1 |
| |
r23 = -99.5386 |
| |
d23 = 1.3 |
nd23 = 1.7725 |
νd23 = 49.6 |
| |
r24 = 13.692 |
| |
d24 = 8.82 |
nd24 = 1.48749 |
νd24 = 70.23 |
| |
r25 = -12.0725 |
| |
d25 = 1.3 |
nd25 = 1.62684 |
νd25 = 40.98 |
| |
r26 = -23.8764 |
| |
d26 = D4 |
nd26 = 1 |
| |
r27 = ∞ |
| |
d27 = 0.8 |
nd27 = 1.51633 |
νd27 = 64.14 |
| |
r28 = ∞ |
| |
d28 = 0.8 |
nd28 = 1 |
| |
r29 = ∞ |
| |
d29 = 2.8 |
nd29 = 1.54771 |
νd29 = 62.84 |
| |
r30 = ∞ |
| |
d30 = 0.5 |
nd30 = 1 |
| |
r31 = ∞ |
| |
d31 = 0.87 |
nd31 = 1.5231 |
νd31 = 54.49 |
| |
r32 = ∞ |
| |
d32 = 1.07 |
nd32 = 1 |
| |
IMG = ∞ (image pickup surface) |
| |
|
aspherical coefficients
| K = 0 |
|
|
| A2 = 0 |
A4 = -5.1635 × 10-5 |
A6 = -1.7186 × 10-7 |
| A8 = -2.5602 × 10-9 |
A10 = 3.2674 × 10-11 |
A12 = -2.1983 × 10-13 |
| K = 0 |
|
|
| A2 = 0 |
A4 = 1.3943 × 10-5 |
A6 = 4.9740 × 10-8 |
| A8 = 1.0865 × 10-9 |
A10 = 6.4354 × 10-12 |
| K = 0 |
|
|
| A2 = 0 |
A4 = 4.9366 × 10-5 |
A6 = 3.3833 × 10-8 |
| A8 = 4.6617 × 10-10 |
A10 = -6.8786 × 10-12 |
A12 = 3.4557 × 10-14 |
|
(variable space in focusing)
| |
|
| |
f = 14.67 |
f = 28.1 |
f = 53.88 |
| |
|
| |
| IO = ∞ (object distance (mm)) |
| |
zooming space D1 |
1 |
16.21 |
30.51 |
| |
D2 |
11.1 |
4.41 |
1.15 |
| |
D3 |
12.62 |
6.11 |
1 |
| |
D4 |
29.15 |
38.87 |
50.72 |
| IO = 220 (object distance (mm)) |
| |
zooming space D1 |
3.13 |
15.54 |
26.13 |
| |
D2 |
5.92 |
1.41 |
0.99 |
| |
D3 |
15.67 |
9.78 |
5.54 |
| |
D4 |
29.15 |
38.87 |
50.72 |
| |
|
Second Embodiment
FIGS. 2A, 2B, and 2C are sectional views taken along the optical
axis that show the optical configuration of the zoom lens of the second embodiment
according to the present invention, showing the states at the wide-angle end, the
intermediate position, and the telephoto end, respectively. FIGS. 6A-6D, 6E-6H,
and 6I-6L are diagrams that show spherical aberration, astigmatism,
distortion, and chromatic aberration of magnification of the second embodiment
at the wide-angle end, the intermediate position, and the telephoto end, respectively.
As shown in FIG. 2, the zoom lens of the second embodiment includes, in order
from the object side X toward an image-pickup element surface P, a first lens unit
G21 having a positive refractive power, a second lens unit G22
having a negative refractive power, a third lens unit G23 having
a negative refractive power, and a fourth lens unit G24 having a positive
refractive power. During a magnification change from the wide-angle end (FIG. 2A)
through the telephoto end (FIG. 2C), the first lens unit G21 and the
fourth lens unit G24 are shifted from the image-surface side toward
the object side. In this event, a space D1 between the first lens unit
G21 and the second lens unit G22 increases, and spaces D2,
D3, and D4 between individual lens units change. During a
focusing from an object at the infinite distance onto an object at a near distance,
the second lens unit G22 and the third lens unit G23 individually
shift independently. In FIG. 2, the reference symbol S denotes a stop. The reference
symbol P denotes an image pickup surface, which is disposed in the effective image-pickup
diagonal direction of a CCD or CMOS sensor.
The first lens unit G21 is composed of, in order from the object side
X, a negative first lens L21, a positive second lens L22,
and a positive third lens L23. The first lens L21 and the
second lens L22 form a cemented lens.
The second lens unit G22 is composed of, in order from the object
side X, a negative fourth lens L24, a negative fifth lens L25 with
its image-side concave surface being aspherical, a negative sixth lens L26,
and a positive seventh lens L27.
The third lens unit G23 is composed of, in order from the object side
X, a negative eighth lens L28, a positive ninth lens L29 with
its image-side convex surface being aspherical, and a negative tenth lens L210.
The eighth lens L28 and the ninth lens L29 form a cemented lens.
The fourth lens unit G24 is composed of, in order from the object
side X, a positive eleventh lens L211 with its image-side concave surface
being aspherical, a negative twelfth lens L212, a negative thirteenth
lens L213, a negative fourteenth lens L214, and a positive
fifteenth lens L215. Each lens of the fourth lens unit G24 is
constructed as a singlet lens. The stop S is arranged between the third lens unit
G23 and the fourth lens unit G24. The image pickup surface
P is arranged on the image side of the fourth lens unit G24.
This embodiment specifies a zoom lens having focal length of 14.71{tilde over
( )}53.88 mm, F-number of 2.85{tilde over ( )}3.75, and 2ω=74.58°{tilde
over ( )}23.49°.
| |
focal length f = 14.71~53.88 mm, Fno. = 2.85~3.57 |
| |
2ω = 74.58°~23.49° |
| |
r1 = 84.456 |
|
|
| |
d1 = 2.27 |
nd1 = 1.84666 |
νd1 = 23.78 |
| |
r2 = 51.995 |
| |
d2 = 6.73 |
nd2 = 1.6968 |
νd2 = 55.53 |
| |
r3 = 229.3 |
| |
d3 = 0.13 |
nd3 = 1 |
| |
r4 = 45.1147 |
| |
d4 = 4.16 |
nd4 = 1.69213 |
νd4 = 55.37 |
| |
r5 = 82.4423 |
| |
d5 = D1 |
nd5 = 1 |
| |
r6 = 70.9504 |
| |
d6 = 1.18 |
nd6 = 1.804 |
νd6 = 46.57 |
| |
r7 = 13.2517 |
| |
d7 = 5.02 |
nd7 = 1 |
| |
r8 = 48.8445 |
| |
d8 = 0.99 |
nd8 = 1.65313 |
νd8 = 58.37 |
| |
r9 = 18.6211 |
| |
d9 = 4.42 |
nd9 = 1 |
| |
r10 = -50.977 |
| |
d10 = 1 |
nd10 = 1.61017 |
νd10 = 61.49 |
| |
r11 = 67.7526 |
| |
d11 = 2.44 |
nd11 = 1 |
| |
r12 = 41.3578 |
| |
d12 = 4.2 |
nd12 = 1.84666 |
νd12 = 23.78 |
| |
r13 = -49.5698 |
| |
d13 = D2 |
nd13 = 1 |
| |
r14 = 429.3566 |
| |
d14 = 1 |
nd14 = 1.79802 |
νd14 = 38.51 |
| |
r15 = 18.4994 |
| |
d15 = 4.77 |
nd15 = 1.51633 |
νd15 = 64.14 |
| |
r16 = -31.5464 |
| |
d16 = 0.31 |
nd16 = 1 |
| |
r17 = -24.6047 |
| |
d17 = 1 |
nd17 = 1.7994 |
νd17 = 45.15 |
| |
r18 = -52.1062 |
| |
d18 = D3 |
nd18 = 1 |
| |
r19 = (S: stop) |
| |
d19 = D4 |
nd19 = 1 |
| |
r20 = 30.2789 |
| |
d20 = 3.11 |
nd20 = 1.56602 |
νd20 = 56 |
| |
r21 = -139.0487 |
| |
d21 = 2.25 |
nd21 = 1 |
| |
r22 = 19.4216 |
| |
d22 = 6.25 |
nd22 = 1.497 |
νd22 = 81.54 |
| |
r23 = -32.3709 |
| |
d23 = 0 |
nd23 = 1 |
| |
r24 = 94.8037 |
| |
d24 = 1 |
nd24 = 1.80123 |
νd24 = 44.49 |
| |
r25 = 19.8715 |
| |
d25 = 1.46 |
nd25 = 1 |
| |
r26 = 119.9151 |
| |
d26 = 0.94 |
nd26 = 1.80547 |
νd26 = 43.54 |
| |
r27 = 13.8717 |
| |
d27 = 0.02 |
nd27 = 1 |
| |
r28 = 13.9681 |
| |
d28 = 6.34 |
nd28 = 1.48749 |
νd28 = 70.23 |
| |
r29 = -24.2991 |
| |
d29 = D5 |
nd29 = 1 |
| |
IMG = ∞ |
| |
|
aspherical coefficients
| K = 0 |
|
|
| A2 = 0 |
A4 = -1.2201 × 10-5 |
A6 = -8.3210 × 10-8 |
| A8 = 2.9877E × 10-10 |
A10 = -3.5791 × 10-12 |
| K = 0 |
|
|
| A2 = 0 |
A4 = -1.9830 × 10-5 |
A6 = -7.8377 × 10-8 |
| A8 = 1.0328 × 10-9 |
A10 = -1.0396 × 10-11 |
| K = 0 |
|
|
| A2 = 0 |
A4 = 3.8514 × 10-5 |
A6 = 6.4175 × 10-8 |
| A8 = -2.1234 × 10-10 |
A10 = 3.8743E × 10-12 |
|
(variable space in focusing)
| |
|
| |
f = 14.71 |
f = 29 |
f = 53.88 |
| |
|
| |
| IO = ∞ (object distance (mm)) |
| |
zooming space D1 |
1 |
16.37 |
30.52 |
| |
D2 |
9.29 |
4.37 |
1.32 |
| |
D3 |
13.58 |
6.18 |
1.08 |
| |
D4 |
7.82 |
3.25 |
1 |
| |
D5 |
34.68 |
43.69 |
52.01 |
| IO = 220 (object distance (mm)) |
| |
zooming space D1 |
1.1 |
13.81 |
23.28 |
| |
D2 |
4.77 |
1.21 |
0.99 |
| |
D3 |
18 |
11.89 |
8.65 |
| |
D4 |
7.82 |
3.25 |
1 |
| |
D5 |
34.68 |
43.69 |
52.01 |
| |
|
Third Embodiment
FIGS. 3A, 3B, and 3C are sectional views taken along the optical
axis that show the optical configuration of the zoom lens of the third embodiment
according to the present invention, showing the states at the wide-angle end, the
intermediate position, and the telephoto end, respectively. FIGS. 7A-7D, 7E-7H,
and 7I-7L are diagrams that show spherical aberration, astigmatism,
distortion, and chromatic aberration of magnification of the third embodiment at
the wide-angle end, the intermediate position, and the telephoto end, respectively.
As shown in FIG. 3, the zoom lens of the third embodiment includes, in order
from
the object side X toward an image-pickup element surface P, a first lens unit G31
having a positive refractive power, a second lens unit G32 having a
negative refractive power, a third lens unit G33 having a negative refractive
power, and a fourth lens unit G34 having a positive refractive power.
During a magnification change from the wide-angle end (FIG. 3A) through the telephoto
end (FIG. 3C), the first lens unit G31 and the fourth lens unit G34
are shifted from the im
