# US 5,353,163 A · Wide-angle zoom lens

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- Number: US 5,353,163 A
- Document ID: US5353163A
- Status: Granted
- Kind: A
- Application number: 07/912,718
- Filed: 1992-07-13
- Granted: 1994-10-04
- Earliest claimed: 1991-07-17
- Assignees: Nikon Corporation
- Inventors: Atsushi Shibayama; Masahiro Nakatsuji
- Web page: https://patentgrep.com/patent/US5353163A

## CPC

- G02B 15/1421: {the first group being positive}
- G02B 15/142: {having two groups only}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

A wide-angle zoom lens has a first lens group having a positive refracting power and a second lens group having a negative refracting power, which are moved relative to each other along the optical axis so as to attain zooming. The first lens group is constituted in turn from the object side by a front group having a negative refracting power and a rear group having a positive refracting power. The front group has at least one negative lens. The rear group has at least two positive lenses. The zoom lens is constituted to satisfy the following conditions: 0.75<.vertline.f.sub.F /f.sub.W .vertline.<4, f.sub.F <0 0.1<K/f.sub.W <0.4 0.1<L/f.sub.W <0.7 wherein f.sub.F is the focal length of the front group in the first lens group, f.sub.W is the focal length of the zoom lens at the wide-angle end, K is the axial distance from a lens surface at the extreme image-side end of the first lens group to a rear-side principal point of the first lens group when a direction toward the image side is defined as a positive direction, and L is the axial distance from a lens surface at the extreme object-side end of the front group in the first lens group to a lens surface at the extreme object-side end of the rear group in the first lens group.

## Claims

### Claim 1

A wide-angle zoom lens consisting of:
a first lens group having a positive refracting power and a second lens group having a negative refracting power, which are moved relative to each other along an optical axis so as to attain zooming, a lens in the first lens group which is closest to the object side having a convex surface facing the object side,
said first lens group being constituted in turn from the object side by a front group having a negative refracting power and a rear group having a positive refracting power, and being constructed so that the spacing between the front group and the rear group is constant during zooming,
said front group having at least one negative lens, said rear group having at least two positive lenses, and
said zoom lens being constituted to satisfy the following conditions:
0.75<.vertline.f.sub.F /f.sub.W .vertline..ltoreq.4, f.sub.F <0
0.1<K/f.sub.W <0.4
0.1<L/f.sub.W <0.7
where f.sub.F is the focal length of said front group in said first lens group, f.sub.W is the focal length of said zoom lens at the wide-angle end, K is the axial distance from a lens surface at the extreme image-side end of said first lens group to a rear-side principal point of said first lens group when a direction toward the image side is defined as a positive direction, and L is the axial distance from a lens surface at the extreme object-side end of said front group in said first lens group to a lens surface at the extreme object-side end of said rear group in said first lens group.

### Claim 2 (depends on 1)

A wide-angle zoom lens according to claim 1, wherein said rear group in said first lens group includes a positive lens with a convex surface facing the object side, a lens with a concave surface facing the object side, and a positive lens, and
said first lens group is constituted to satisfy the following conditions:
0.6<f.sub.1 /f.sub.W <0.95
0.38<M/f.sub.W <0.86
where f.sub.1 is the focal length of said first lens group, f.sub.W is the focal length of said zoom lens at the wide-angle end, and M is the axial distance from a lens surface at the extreme object-side end to a lens surface at the extreme image-side end of said rear group in said first lens group.

### Claim 3 (depends on 1)

A wide-angle zoom lens according to claim 1, wherein said second lens group has at least one positive lens with a convex surface facing the image side, and at least one negative lens with a concave surface facing the object side, and
said second lens group is constituted to satisfy the following conditions:
0.7<.vertline.f.sub.2 /f.sub.W .vertline.<1.7, f.sub.2 <0
where f.sub.2 is the focal length of said second lens group, and f.sub.W is the focal length of said zoom lens at the wide-angle end.

### Claim 4 (depends on 1)

A wide-angle zoom lens according to claim 1, wherein said front group in said first lens group is constituted to satisfy the following condition so as to satisfactorily correct a chromatic aberration of magnification:
.nu..sub.d >50
where
.nu..sub.d : the Abbe's number of said negative lens in said front group in said first lens group.

### Claim 5 (depends on 1)

A wide-angle zoom lens according to claim 1, wherein said front group in said first lens group is constituted by a negative meniscus lens with a convex surface facing the object side, said rear group in said first lens group is constituted by a positive meniscus lens with a convex surface facing the object side, a combination lens which has a negative refracting power, is constituted by combining a double-concave negative lens and a double-convex positive lens, and has a meniscus shape with a concave surface facing the object side as a whole, and a double-convex positive lens, said second lens group is constituted by a positive meniscus lens with a convex surface facing the image side, and a negative meniscus lens with a concave surface facing the object side, and said first lens group is constituted to satisfy the following conditions:
0.91<.vertline.f.sub.F /f.sub.W .vertline.<4, f.sub.F <0
0.1<K/f.sub.W <0.4
0.1<L/f.sub.W <0.7
where
f.sub.F : the focal length of said front group in said first lens group
f.sub.W : the focal length of said zoom lens at the wide-angle end
K: the axial distance from a lens surface at the extreme image-side end of said first lens group to a rear-side principal point of said first lens group when a direction toward the image side is defined as a positive direction in said first lens group
L: the axial distance from a lens surface at the extreme object-side end of said front group to a lens surface at the extreme object-side end of said rear group in said first lens group.

### Claim 6 (depends on 5)

A wide-angle zoom lens according to claim 5, wherein said rear group in said first lens group is constituted to further satisfy the following conditions:
0.6<f.sub.1 /f.sub.W <0.95
0.38<M/f.sub.W <0.86
where
f.sub.l : the focal length of said first lens group
M: the axial distance from a lens surface at the extreme object-side end to a lens surface at the extreme image-side end of said rear group in said first lens group.

### Claim 7 (depends on 5)

A wide-angle zoom lens according to claim 5, wherein said second lens group is constituted to further satisfy the following conditions:
0.7<.vertline.f.sub.2 /f.sub.W .vertline.<1.7, f.sub.2 <0
where
f.sub.2 : the focal length of the second lens group.

### Claim 8 (depends on 5)

A wide-angle zoom lens according to claim 5, wherein said front group in said first lens group is constituted to satisfy the following condition so as to satisfactorily correct a chromatic aberration of magnification:
.nu..sub.d >50
where
.nu..sub.d : the Abbe's number of said negative lens in said front group in said first lens group.

### Claim 9 (depends on 5)

A wide-angle zoom lens according to claim 5, wherein said wide-angle zoom lens is constituted according to the following data:
______________________________________ 2.omega. = 80.9.degree. to 65.7.degree., F.sub.NO = 4.10 to 5.65 r d .nu. n ______________________________________ 1 22.650 1.40 57.0 1.62280 2 11.723 5.00 3 13.335 2.50 40.9 1.79631 4 46.542 2.00 5 -15.567 3.30 40.9 1.79631 6 12.959 4.00 69.9 1.51860 7 -15.241 0.10 8 26.064 2.00 69.9 1.51860 9 -18.856 (d9) 10 -28.030 2.30 45.4 1.79668 11 -21.549 6.60 12 -15.352 1.30 55.6 1.69680 13 -123.872 (Bf) (Variable Interval Upon Zooming) f 24.7000 28.0000 34.0000 d9 12.9868 9.3127 4.4598 Bf 4.3908 9.6408 19.1862 12th Surface (Aspherical Surface) Cone Constant: k = 1.00 Aspherical Surface Coefficients c2 = 0.0, c4 = -0.2810E-04, c6 = -0.2017E-07, c8 = -0.1980E-09, c10 = -0.1268E-11 (Numerical Values Corresponding to Conditions) .vertline.f.sub.F /f.sub.W .vertline. = 1.662, K/f.sub.W = 0.141, L/f.sub.W = 0.259 ______________________________________
where numerals at the left end in the table represent the order from the object side, r is the radius of curvature of a lens surface, d is the lens surface interval, .nu. is the Abbe's number, n is the refractive index of the d ray (.lambda.=587.6 nm), f is the focal length of the entire system, 2.omega. is the field angle, and F.sub.NO is the f-number;
an aspherical shape is expressed by:
X(h)=(h.sup.2 /r)/[1+(1-kh.sup.2 /r.sup.2).sup.1/2 ]+c2h.sup.2 +c4h.sup.4 +c6h.sup.6 +c8h.sup.8 +c10h.sup.10
where X(h) is the distance along the optical axis direction from a tangent plane of the vertex of each aspherical surface at a height h in the vertical direction from the optical axis, r is the reference paraxial radius of curvature, k is a cone constant, and cn is an nth-order aspherical surface coefficient; and
E-n at the right end in the cone constant k and the nth-order aspherical surface coefficient cn represents 10.sup.-n.

### Claim 10 (depends on 5)

A wide-angle zoom lens according to claim 5, wherein said zoom lens is constituted according to the following data:
______________________________________ 2 = 80.8.degree. to 48.5.degree., F.sub.NO = 4.01 to 7.87 r d .nu. n ______________________________________ 1 36.582 1.40 69.9 1.51860 2 14.913 10.00 3 12.918 3.00 47.1 1.67003 4 67.006 1.50 5 -21.100 3.30 44.7 1.80218 6 9.053 4.70 69.9 1.51860 7 -22.449 1.00 8 28.564 3.00 69.9 1.51860 9 -15.476 (d9) 10 -25.423 2.30 45.4 1.79668 11 -18.559 5.40 12 -12.104 1.30 49.4 1.77279 13 -91.224 (Bf) (Variable Interval Upon Zooming) f 24.7000 35.0000 48.5003 d9 14.7790 8.5239 4.3486 Bf 4.3098 16.5718 32.6435 11th Surface (Aspherical Surface) Cone Constant: k = 1.00 Aspherical Surface Coefficients c2 = 0.0, c4 = -0.1125E-05, c6 = -0.2433E-06, c8 = 0.1205E-08, c10 = -0.7595E-11 (Numerical Values Corresponding to Conditions) .vertline.f.sub.F /f.sub.W .vertline. = 2.010, K/f.sub.W = 0.194, L/f.sub.W = 0.462 ______________________________________
where numerals at the left end in the table represent the order from the object side, r is the radius of curvature of a lens surface, d is the lens surface interval, .nu. is the Abbe's number, n is the refractive index of the d ray (.lambda.=587.6 nm), f is the focal length of the entire system, 2.omega. is the field angle, and F.sub.NO is the f-number;
an aspherical shape is expressed by:ps
X(h)=(h.sup.2 /r)/[1+(1-kh.sup.2 /r.sup.2).sup.1/2 ]+c2h.sup.2 +c4h.sup.4 +c6h.sup.6 +c8h.sup.8 +c10h.sup.10
where X(h) is the distance along the optical axis direction from a tangent plane of the vertex of each aspherical surface at a height h in the vertical direction from the optical axis, r is the reference paraxial radius of curvature, k is a cone constant, and cn is an nth-order aspherical surface coefficient; and
E-n at the right end in the cone constant k and the nth-order aspherical surface coefficient cn represents 10.sup.-n.

### Claim 11 (depends on 5)

A wide-angle zoom lens according to claim 5, wherein said zoom lens is constituted according to the following data:
______________________________________ 2.omega. = 72.3.degree. to 44.5.degree., F.sub.NO = 4.50 to 5.62 r d .nu. n ______________________________________ 1 24.670 1.40 57.0 1.62280 2 13.333 7.50 3 15.860 2.50 45.0 1.74400 4 82.002 2.00 5 -17.913 3.30 44.7 1.80218 6 13.483 4.70 70.0 1.51860 7 -16.789 1.00 8 29.915 3.00 70.0 1.51860 9 -19.657 (d9) 10 -22.629 2.30 45.4 1.79668 11 -16.126 4.40 12 -12.072 1.30 47.5 1.78797 13 -64.687 (Bf) (Variable Interval Upon Zooming) f 28.8068 37.9904 53.4859 d9 14.5448 9.1528 4.2528 Bf 8.0716 19.8680 39.7720 11th Surface (Aspherical Surface) Cone Constant: k = 1.00 Aspherical Surface Coefficients c2 = 0.0, c4 = -0.3536E-05, c6 = -0.2223E-07, c8 = -0.1381E-09, c10 = -0.1133E-10 (Numerical Values Corresponding to Conditions) .vertline.f.sub.F /f.sub.W .vertline. = 1.698, K/f.sub.W = 0.163, L/f.sub.W = 0.309 ______________________________________
where numerals at the left end in the table represent the order from the object side, r is the radius of curvature of a lens surface, d is the lens surface interval, .nu. is the Abbe's number, n is the refractive index of the d ray (.lambda.=587.6 nm), f is the focal length of the entire system, 2.omega. is the field angle, and F.sub.NO is the f-number;
an aspherical shape is expressed by:
X(h)=(h.sup.2 /r)/[1+(1-kh.sup.2 /r.sup.2).sup.1/2 ]+c2h.sup.2 +c4h.sup.4 +c6h.sup.6 +c8h.sup.8 +c10h.sup.10
where X(h) is the distance along the optical axis direction from a tangent plane of the vertex of each aspherical surface at a height h in the vertical direction from the optical axis, r is the reference paraxial radius of curvature, k is a cone constant, and cn is an nth-order aspherical surface coefficient; and
E-n at the right end in the cone constant k and the nth-order aspherical surface coefficient cn represents 10.sup.-n.

### Claim 12 (depends on 5)

A wide-angle zoom lens according to claim 5, wherein said zoom lens is constituted according to the following data:
______________________________________ 2.omega. = 72.6.degree. to 35.3.degree., F.sub.NO = 3.60 to 8.49 r d .nu. n ______________________________________ 1 25.849 1.40 57.0 1.62280 2 13.482 8.20 3 14.827 3.20 47.1 1.67003 4 232.513 2.00 5 -17.188 3.30 44.7 1.80218 6 13.072 4.70 69.9 1.51860 7 -16.673 0.15 8 44.207 2.70 64.1 1.51680 9 -17.869 (d9) 10 -38.731 3.10 31.6 1.75692 11 -24.465 5.00 12 -11.987 1.30 43.3 1.84042 13 -49.324 (Bf) (Variable Interval Upon Zooming) f 28.8000 45.0000 67.9005 d9 16.2789 8.6414 4.0621 Bf 5.5645 23.4879 48.8245 10th Surface (Aspherical Surface) Cone Constant: k = 1.00 Aspherical Surface Coefficients c2 = 0.0, c4 = 0.2427E-04, c6 = 0.2213E-06, c8 = 0.1675E-09, c10 = 0.4614E-11 (Numerical Values Corresponding to Conditions) .vertline.f.sub.F /f.sub.W .vertline. = 1.642, K/f.sub.W = 0.162, L/f.sub.W = 0.333 ______________________________________
where numerals at the left end in the table represent the order from the object side, r is the radius of curvature of a lens surface, d is the lens surface interval, .nu. is the Abbe's number, n is the refractive index of the d ray (.lambda.=587.6 nm), f is the focal length of the entire system, 2.omega. is the field angle, and F.sub.NO is the f-number;
an aspherical shape is expressed by:
X(h)=(h.sup.2 /r)/[1+(1-kh.sup.2 /r.sup.2).sup.1/2 ]+c2h.sup.2 +c4h.sup.4 +c6h.sup.6 +c8h.sup.8 +c10h.sup.10
where X(h) is the distance along the optical axis direction from a tangent plane of the vertex of each aspherical surface at a height h in the vertical direction from the optical axis, r is the reference paraxial radius of curvature, k is a cone constant, and cn is an nth-order aspherical surface coefficient; and
E-n at the right end in the cone constant k and the nth-order aspherical surface coefficient cn represents 10.sup.-n.

### Claim 13 (depends on 1)

A wide-angle zoom lens according to claim 1, wherein said front group in said first lens group is constituted by a negative meniscus lens with a convex surface facing the object side, said rear group in said first lens group is constituted by a positive meniscus lens with a convex surface facing the object side, a combination lens which has a negative refracting power, is constituted by combining a double-concave negative lens and a double-convex positive lens, and has a meniscus shape with a concave surface facing the object side as a whole, and a double-concave positive lens, said second lens group is constituted by three lenses including a positive meniscus lens with a convex surface facing the image side, a negative lens with a concave surface facing the object side whose curvature is stronger than a surface of that lens facing the image side, and a negative meniscus lens with a concave surface facing the object side, and said first lens group is constituted to satisfy the following conditions:
0.91<.vertline.f.sub.F /f.sub.W .vertline.<4, f.sub.F <0
0.1<K/f.sub.W <0.4
0.1<L/f.sub.W <0.7
where
f.sub.F : the focal length of said front group in said first lens group
f.sub.W : the focal length of said zoom lens at the wide-angle end
K: the axial distance from a lens surface at the extreme image-side end of said first lens group to a rear-side principal point of said first lens group when a direction toward the image side is defined as a positive direction in said first lens group
L: the axial distance from a lens surface at the extreme object-side end of said front group to a lens surface at the extreme object-side end of said rear group in said first lens group.

### Claim 14 (depends on 13)

A wide-angle zoom lens according to claim 13, wherein said rear group in said first lens group is constituted to further satisfy the following conditions:
0.6<f.sub.1 f.sub.W <0.95
0.38<M/f.sub.W <0.86
where
f.sub.l : the focal length of said first lens group
M: the axial distance from a lens surface at the extreme object-side end to a lens surface at the extreme image-side end of said rear group in said first lens group.

### Claim 15 (depends on 13)

A wide-angle zoom lens according to claim 13, wherein said second lens group is constituted to further satisfy the following conditions:
0.7<.vertline.f.sub.2 /f.sub.W .vertline.<1.7, f.sub.2 <0
where
f.sub.2 : the focal length of the second lens group.

### Claim 16 (depends on 13)

A wide-angle zoom lens according to claim 13, wherein said front group in said first lens group is constituted to satisfy the following condition so as to satisfactorily correct a chromatic aberration of magnification:
.nu..sub.d <50
where
.nu..sub.d : the Abbe's number of said negative lens in said front group in said first lens group.

### Claim 17 (depends on 13)

A wide-angle zoom lens according to claim 13, wherein said zoom lens is constituted according to the following data:
______________________________________ 2.omega. = 73.5.degree. to 53.6.degree., F.sub.NO = 3.60 to 5.46 r d .nu. n ______________________________________ 1 25.764 1.40 54.0 1.61720 2 12.978 7.50 3 14.053 2.90 49.4 1.77279 4 60.943 2.00 5 -17.855 2.80 44.7 1.80218 6 12.454 4.70 69.9 1.51860 7 -19.794 0.20 8 54.636 2.20 60.0 1.64000 9 -18.737 (d9) 10 -240.704 3.80 40.9 1.79631 11 -24.842 2.00 12 -19.268 1.00 39.6 1.80454 13 114.664 6.10 14 -16.000 1.20 60.1 1.62041 15 -22.304 (Bf) (Variable Interval Upon Zooming) f 28.8000 35.0001 43.7000 d9 13.3643 8.1607 3.3486 Bf 4.3696 13.8675 27.1950 (Numerical Values Corresponding to Conditions) .vertline.f.sub.F /f.sub.W .vertline. = 1.535, K/f.sub.W = 0.158, L/f.sub.W = 0.309 ______________________________________
where numerals at the left end in the table represent the order from the object side, r is the radius of curvature of a lens surface, d is the lens surface interval, .nu. is the Abbe's number, n is the refractive index of the d ray (.lambda.=587.6 nm), f is the focal length of the entire system, 2.omega. is the field angle, and F.sub.NO is the f-number;
an aspherical shape is expressed by:
X(h)=(h.sup.2 /r)/[1+(1-kh.sup.2 /r.sup.2).sup.1/2 ]+c2h.sup.2 +c4h.sup.4 +c6h.sup.6 +c8h.sup.8 +c10h.sup.10
where X(h) is the distance along the optical axis direction from a tangent plane of the vertex of each aspherical surface at a height h in the vertical direction from the optical axis, r is the reference paraxial radius of curvature, k is a cone constant, and cn is an nth-order aspherical surface coefficient; and
E-n at the right end in the cone constant k and the nth-order aspherical surface coefficient cn represents 10.sup.-n.

### Claim 18 (depends on 13)

A wide-angle zoom lens according to claim 13, wherein said zoom lens is constituted according to the following data:
______________________________________ 2.omega. = 81.4.degree. to 50.1.degree., F.sub.NO = 4.00 to ______________________________________ 7.61 r d .nu. n ______________________________________ 1 20.276 1.40 70.1 1.51860 2 8.605 8.30 3 17.141 3.00 40.4 1.60717 4 -50.434 1.50 5 -18.928 3.30 40.9 1.79631 6 12.348 4.50 70.1 1.51860 7 -15.644 0.20 8 62.738 2.80 70.1 1.51860 9 -15.275 (d9) 10 -242.922 3.00 47.1 1.67003 11 -17.147 0.50 12 -19.696 1.30 52.3 1.74810 13 119.721 6.00 14 -11.661 1.20 55.6 1.69680 15 -25.029 (Bf) (Variable Interval Upon Zooming) f 24.7000 34.9999 47.0006 d9 12.7074 6.8392 3.2462 d13 5.6463 19.6368 35.9368 (Numerical Values Corresponding to Conditions) .vertline.f.sub.F /f.sub.W .vertline. = 1.217, K/f.sub.W 0.295, L/f.sub.W = 0.393 ______________________________________
where numerals at the left end in the table represent the order from the object side, r is the radius of curvature of a lens surface, d is the lens surface interval, .nu. is the Abbe's number, n is the refractive index of the d ray (.lambda.=587.6 nm), f is the focal length of the entire system, 2.omega. is the field angle, and F.sub.NO is the f-number;
an aspherical shape is expressed by:
X(h)=(h.sup.2 /r)/[1+(1-kh.sup.2 /r.sup.2).sup.1/2 ]+c2h.sup.2 +c4h.sup.4 +c6h.sup.6 +c8h.sup.8 +c10h.sup.10
where X(h) is the distance along the optical axis direction from a tangent plane of the vertex of each aspherical surface at a height h in the vertical direction from the optical axis, r is the reference paraxial radius of curvature, k is a cone constant, and cn is an nth-order aspherical surface coefficient; and
E-n at the right end in the cone constant k and the nth-order aspherical surface coefficient cn represents 10.sup.-n.

### Claim 19 (depends on 13)

A wide-angle zoom lens according to claim 13, wherein said zoom lens is constituted according to the following data:
______________________________________ 2.omega. = 81.0.degree. to 49.9.degree., F.sub.NO = 4.01 to 7.63 r d .nu. n ______________________________________ 1 16.304 1.40 55.6 1.69680 2 8.307 7.78 3 18.085 3.00 38.1 1.60342 4 -38.197 1.50 5 -17.064 4.21 40.9 1.79631 6 14.089 3.50 70.1 1.51860 7 -14.116 0.20 8 73.360 2.50 70.1 1.51860 9 -15.127 (d9) 10 -187.630 4.00 48.1 1.71700 11 -17.504 0.50 12 -19.518 1.30 52.3 1.74810 13 119.152 6.00 14 -12.112 1.20 54.0 1.71300 15 -27.416 (Bf) (Variable Interval Upon Zooming) f 24.7000 35.0000 47.0000 d9 12.7137 6.9873 3.4812 Bf 5.8536 19.7293 35.8952 (Numerical Values Corresponding to Conditions) .vertline.f.sub.F /f.sub.W .vertline. = 1.060, K/f.sub.W = 0.326, L/f.sub.W = 0.372 ______________________________________
where numerals at the left end in the table represent the order from the object side, r is the radius of curvature of a lens surface, d is the lens surface interval, .nu. is the Abbe's number, n is the refractive index of the d ray (.lambda.=587.6 nm), f is the focal length of the entire system, 2.omega. is the field angle, and F.sub.NO is the f-number;
an aspherical shape is expressed by:
X(h)=(h.sup.2 /r)/[1+(1-kh.sup.2 /r.sup.2).sup.1/2 ]+c2h.sup.2 +c4h.sup.4 +c6h.sup.6 +c8h.sup.8 +c10h.sup.10
where X(h) is the distance along the optical axis direction from a tangent plane of the vertex of each aspherical surface at a height h in the vertical direction from the optical axis, r is the reference paraxial radius of curvature, k is a cone constant, and cn is an nth-order aspherical surface coefficient; and
E-n at the right end in the cone constant k and the nth-order aspherical surface coefficient cn represents 10.sup.-n.

### Claim 20 (depends on 1)

A wide-angle zoom lens according to claim 1, wherein said front group in said first lens group has a negative lens with a surface facing the image side whose curvature is stronger than a surface of that lens facing the object side, said rear group in said first lens group is constituted by five lenses including two positive lenses with convex surfaces facing the object side, a combination negative lens which is constituted by combining a double-concave negative lens and a double-convex positive lens, and has a meniscus shape with a concave surface facing the object side as a whole, and a double-convex positive lens, and said first lens group is constituted to satisfy the following conditions:
0.91<.vertline.f.sub.F /f.sub.W .vertline.<4, f.sub.F <0
0.1<K/f.sub.W <0.4
0.1<L/f.sub.W <0.7
where
f.sub.F : the focal length of said front group in said first lens group
f.sub.W : the focal length of said zoom lens at the wide-angle end
K: the axial distance from a lens surface at the extreme image-side end of said first lens group to a rear-side principal point of said first lens group when a direction toward the image side is defined as a positive direction in said first lens group
L: the axial distance from a lens surface at the extreme object-side end of said front group to a lens surface at the extreme object-side end of said rear group in said first lens group.

### Claim 21 (depends on 20)

A wide-angle zoom lens according to claim 20, wherein said rear group in said first lens group is constituted to further satisfy the following condition
0.6<f.sub.1 /f.sub.W <0.95
0.38<M/f.sub.W <0.86
where
f.sub.1 : the focal length of said first lens group
M: the axial distance from a lens surface at the extreme image-side end to a lens surface at the extreme image-side end of said rear group in said first lens group.

### Claim 22 (depends on 20)

A wide-angle zoom lens according to claim 20, wherein said second lens group is constituted to further satisfy the following condition:
0.7<.vertline.f.sub.2 /f.sub.W .vertline.<1.7, f.sub.2 <0
where
f.sub.2 : the focal length of the second lens group.

### Claim 23 (depends on 20)

A wide-angle zoom lens according to claim 20, wherein said front group in said first lens group is constituted to satisfy the following condition so as to satisifactorily correct a chromatic aberration of magnification:
.nu..sub.d >50
where
.nu..sub.d : the Abbe's number of said negative lens in said front group in said first lens group.

### Claim 24 (depends on 20)

A wide-angle zoom lens according to claim 20, wherein said zoom lens is constituted according to the following data:
______________________________________ 2 = 73.1.degree. to 44.7.degree., F.sub.NO = 3.60 to 6.68 r d .nu. n ______________________________________ 1 197.859 2.00 69.9 1.51860 2 19.388 7.00 3 24.521 3.00 45.9 1.54814 4 136.978 0.30 5 13.789 2.70 59.0 1.51823 6 31.717 2.70 7 -15.651 2.50 37.3 1.83400 8 17.163 4.30 60.3 1.51835 9 -12.474 0.20 10 24.890 2.00 54.0 1.61720 11 -47.535 (d11) 12 -18.716 1.90 25.5 1.80458 13 -15.044 5.00 14 -12.495 1.30 40.9 1.79631 15 -54.769 (Bf) (Variable Interval Upon Zooming) f 28.8066 37.9897 53.4836 d11 13.7672 8.3752 3.4752 Bf 7.7971 19.5932 39.4958 (Numerical Values Corresponding to Conditions) .vertline.f.sub.F /f.sub.W .vertline. = 1.444, K/f.sub.W = 0.138, L/f.sub.W = 0.312 ______________________________________
where numerals at the left end in the table represent the order from the object side, r is the radius of curvature of a lens surface, d is the lens surface interval, v is the Abbe's number, n is the refractive index of the d ray (.lambda.=587.6 nm), f is the focal length of the entire system, 2.omega. is the field angle, and F.sub.NO is the f-number;
an aspherical shape is expressed by:
X(h)=(h.sup.2 /r)/[1+(1-kh.sup.2 /r.sup.2).sup.1/2 ]+c2h.sup.2 +c4h.sup.4 +c6h.sup.6 +c8h.sup.8 +c10h.sup.10
where X(h) is the distance along the optical axis direction from a tangent plane of the vertex of each aspherical surface at a height h in the vertical direction from the optical axis, r is the reference paraxial radius of curvature, k is a cone constant, and cn is an nth-order aspherical surface coefficient; and
E-n at the right end in the cone constant k and the nth-order aspherical surface coefficient cn represents 10.sup.-n.

### Claim 25 (depends on 20)

A wide-angle zoom lens according to claim 20, wherein said zoom lens is constituted according to the following data:
______________________________________ 2.omega. = 80.9.degree. to 50.1.degree., F.sub.NO = 4.00 to 7.61 r d .nu. n ______________________________________ 1 646.314 1.40 70.1 1.51860 2 14.895 5.94 3 56.368 2.00 60.8 1.56384 4 -394.173 0.45 5 12.463 3.00 40.4 1.60717 6 143.065 1.50 7 -20.295 3.30 40.9 1.79631 8 9.059 4.58 70.1 1.51860 9 -22.896 0.20 10 28.452 2.81 70.1 1.5160 11 -15.372 (d11) 12 -28.348 2.30 33.9 1.80384 13 -17.740 4.17 14 -10.896 1.30 49.4 1.77279 15 -102.351 (Bf) (Variable Interval Upon Zoominq) f 24.7000 35.0000 47.0000 d11 13.6683 8.0201 4.5619 Bf 5.9493 18.3353 32.7656 13th Surface (Aspherical Surface) Cone Constant: k = 1.00 Aspherical Surface Coefficients c2 = 0.0, c4 = -0.1752E-04, c6 = -0.1528E-06, c8 = 0.1863E-08, c10 = -0.2984E-10 (Numerical Values Corresponding to Conditions) .vertline.f.sub.F /f.sub.W .vertline. = 1.191, K/f.sub.W = 0.195, L/f.sub.W = 0.297 ______________________________________
where numerals at the left end in the table represent the order from the object side, r is the radius of curvature of a lens surface, d is the lens surface interval, .nu. is the Abbe's number, n is the refractive index of the d ray (.lambda.=587.6 nm), f is the focal length of the entire system, 2.omega. is the field angle, and F.sub.NO is the f-number;
an aspherical shape is expressed by:
X(h)=(h.sup.2 /r)/[1+(1-kh.sup.2 /r.sup.2).sup.1/2 ]+c2h.sup.2 +c4h.sup.4 +c6h.sup.6 +c8h.sup.8 +c10h.sup.10
where X(h) is the distance along the optical axis direction from a tangent plane of the vertex of each aspherical surface at a height h in the vertical direction from the optical axis, r is the reference paraxial radius of curvature, k is a cone constant, and cn is an nth-order aspherical surface coefficient; and
E-n at the right end in the cone constant k and the nth-order aspherical surface coefficient cn represents 10.sup.-n.

### Claim 26 (depends on 1)

A wide-angle zoom lens according to claim 1, wherein said front group in said first lens group is constituted by two negative lenses including a negative meniscus lens with a convex surface facing the object side, and a double-concave negative lens, and said first lens group is constituted to satisfy the following conditions:
0.91<.vertline.f.sub.F /f.sub.W .vertline.<4, f.sub.F <0
0.1<K/f.sub.W <0.4
0.1<L/f.sub.W <0.7
where
f.sub.F : the focal length of said front group in said first lens group
f.sub.W : the focal length of said zoom lens at the wide-angle end
K: the axial distance from a lens surface at the extreme image-side end of said first lens group to a rear-side principal point of said first lens group when a direction toward the image side is defined as a positive direction in said first lens group
L: the axial distance from a lens surface at the extreme object-side end of said front group to a lens surface at the extreme object-side end of said rear group in said first lens group.

### Claim 27 (depends on 26)

A wide-angle zoom lens according to claim 26, wherein said rear group in said first lens group is constituted to further satisfy the following conditions:
0.6<f.sub.1 /f.sub.W <0.95
0.38<M/f.sub.W <0.86
where
f.sub.1 : the focal length of said first lens group
M: the axial distance from a lens surface at the extreme object-side end to a lens surface at the extreme image-side end of said rear group in said first lens group.

### Claim 28 (depends on 26)

A wide-angle zoom lens according to claim 26, wherein said second lens group is constituted to further satisfy the following conditions:
0.7<.vertline.f.sub.2 /f.sub.W .vertline.<1.7, f.sub.2 <0
where
f.sub.2 : the focal length of the second lens group.

### Claim 29 (depends on 26)

A wide-angle zoom lens according to claim 26, wherein said front group in said first lens group is constituted to satisfy the following condition so as to satisfactorily correct a chromatic aberration of magnification:
.nu..sub.d >50
where
.nu..sub.d : the Abbe's number of said negative lens in said front group in said first lens group.

### Claim 30 (depends on 26)

A wide-angle zoom lens according to claim 26, wherein said zoom lens is constituted according to the following data:
______________________________________ 2.omega. = 72.6.degree. to 44.5.degree., F.sub.NO = 3.60 to 6.69 r d .nu. n ______________________________________ 1 14.054 1.40 55.6 1.69680 2 10.361 6.00 3 -329.940 1.40 60.1 1.62041 4 53.650 1.00 5 14.357 3.30 47.1 1.67003 6 -192.090 1.70 7 -15.831 3.50 37.3 1.83400 8 12.497 4.00 60.3 1.51835 9 -19.372 0.20 10 39.206 2.30 50.8 1.65844 11 -17.082 (d11) 12 -25.204 2.30 25.5 1.80458 13 -18.690 5.10 14 -14.000 1.30 37.3 1.83400 15 -80.772 (Bf) (Variable Interval Upon Zooming) f 28.8067 37.9898 53.4840 d11 13.8391 8.4471 3.5471 Bf 8.0709 19.8670 39.7699 (Numerical Values Corresponding to Conditions) .vertline.f.sub.F /f.sub.W .vertline. = 1.189, K/f.sub.W = 0.162, L/f.sub.W = 0.340 ______________________________________
where numerals at the left end in the table represent the order from the object side, r is the radius of curvature of a lens surface, d is the lens surface interval, .nu. is the Abbe's number, n is the refractive index of the d ray (.lambda.=587.6 nm), f is the focal length of the entire system, 2.omega. is the field angle, and F.sub.NO is the f-number;
an aspherical shape is expressed by:
X(h)=(h.sup.2 /r)/[1+(1-kh.sup.2 /r.sup.2).sup.1/2 ]+c2h.sup.2 +c4h.sup.4 +c6h.sup.6 +c8h.sup.8 +c10h.sup.10
where X(h) is the distance along the optical axis direction from a tangent plane of the vertex of each aspherical surface at a height h in the vertical direction from the optical axis, r is the reference paraxial radius of curvature, k is a cone constant, and cn is an nth-order aspherical surface coefficient; and
E-n at the right end in the cone constant k and the nth-order aspherical surface coefficient cn represents 10.sup.-n.

### Claim 31 (depends on 1)

A wide-angle zoom lens according to claim 1, wherein said front group in said first lens group is constituted by a negative meniscus lens with a convex surface facing the object side, said rear group is constituted by five lenses including two positive lenses, a combination negative lens which is constituted by combining a double-concave negative lens and a double-convex positive lens, and has a meniscus shape with a concave surface facing the object side as a whole, and a double-convex positive lens, said second lens group is constituted by three lenses including a positive lens with a surface facing the image side whose curvature is stronger than a surface of that lens facing the object side, a double-concave negative lens, and a negative meniscus lens with a concave surface facing the object side, and said first lens group is constituted to satisfy the following conditions:
0.91<.vertline.f.sub.F /f.sub.W .vertline.<4, f.sub.F <0
0.1<K/f.sub.W <0.4
0.1<L/f.sub.W <0.7
where
f.sub.F : the focal length of said front group in said first lens group
f.sub.W : the focal length of said zoom lens at the wide-angle end
K: the axial distance from a lens surface at the extreme image-side end of said first lens group to a rear-side principal point of said first lens group when a direction toward the image side is defined as a positive direction in said first lens group
L: the axial distance from a lens surface at the extreme object-side end of said front group to a lens surface at the extreme object-side end of said rear group in said first lens group.

### Claim 32 (depends on 31)

A wide-angle zoom lens according to claim 31, wherein said rear group in said first lens group is constituted to further satisfy the following conditions:
0.6<f.sub.1 /f.sub.W <0.95
0.38<M/f.sub.W 0.86
where
f.sub.1 : the focal length of said first lens group
M: the axial distance from a lens surface at the extreme object-side end to a lens surface at the extreme image-side end of said rear group in said first lens group.

### Claim 33 (depends on 31)

A wide-angle zoom lens according to claim 31, wherein said second lens group is constituted to further satisfy the following conditions:
0.7<.vertline.f.sub.2 .vertline.f.sub.W <1.7, f.sub.2 <0
where
f.sub.2 : the focal length of the second lens group.

### Claim 34 (depends on 31)

A wide-angle zoom lens according to claim 31, wherein said front group in said first lens group is constituted to satisfy the following condition so as to satisfactorily correct a chromatic aberration of magnification:
.nu..sub.d >50
where
.nu..sub.d : the Abbe's number of said negative lens in said front group in said first lens group.

### Claim 35 (depends on 31)

A wide-angle zoom lens according to claim 31, wherein said zoom lens is constituted according to the following data:
______________________________________ 2.omega. = 81.7.degree. to 50.4.degree., F.sub.NO = 4.00 to 7.61 r d .nu. n ______________________________________ 1 48.662 1.40 70.1 1.51860 2 9.559 5.94 3 100.989 2.00 60.8 1.56384 4 1184.828 0.45 5 14.417 3.00 40.4 1.60717 6 -63.718 1.50 7 -20.049 3.30 40.9 1.79631 8 10.814 4.58 70.1 1.51860 9 -18.051 0.20 10 46.580 2.81 70.1 1.51860 11 -15.354 (d11) 12 -139.781 4.00 47.1 1.67003 13 -16.243 0.50 14 -18.624 1.30 52.3 1.74810 15 174.141 6.00 16 -11.049 1.20 49.4 1.77279 15 -20.995 (Bf) (Variable Interval Upon Zooming) f 24.7000 35.0000 47.0000 d11 12.4919 6.8478 3.3921 Bf 5.6032 19.4303 35.5397 (Numerical Values Corresponding to Conditions) .vertline.f.sub.F /f.sub.W .vertline. = 0.940, K/f.sub.W = 0.309, L/f.sub.W = 0.297 ______________________________________
where numerals at the left end in the table represent the order from the object side, r is the radius of curvature of a lens surface, d is the lens surface interval, .nu. is the Abbe's number, n is the refractive index of the d ray (.lambda.=587.6 nm), f is the focal length of the entire system, 2.omega. is the field angle, and F.sub.NO is the f-number;
an aspherical shape is expressed by:
X(h)=(h.sup.2 /r)/[1+(1-kh.sup.2 /r.sup.2).sup.1/2 ]+c2h.sup.2 +c4h.sup.4 +c6h.sup.6 +c8h.sup.8 +c10h.sup.10
where X(h) is the distance along the optical axis direction from a tangent plane of the vertex of each aspherical surface at a height h in the vertical direction from the optical axis, r is the reference paraxial radius of curvature, k is a cone constant, and cn is an nth-order aspherical surface coefficient; and
E-n at the right end in the cone constant k and the nth-order aspherical surface coefficient cn represents 10.sup.-n.

### Claim 36 (depends on 31)

A wide-angle zoom lens according to claim 31, wherein said zoom lens is constituted according to the following data:
______________________________________ 2.omega. = 80.9.degree. TO 50.0.degree., F.sub.NO = 4.00 TO 7.61 r d .nu. n ______________________________________ 1 35.172 1.40 70.1 1.51860 2 11.972 10.00 3 101.444 2.00 60.8 1.56384 4 125.222 0.45 5 15.510 3.00 40.4 1.60717 6 -121.711 1.50 7 -17.264 3.30 40.9 1.79631 8 11.630 4.58 70.1 1.51860 9 -17.516 0.20 10 36.151 2.81 64.1 1.51680 11 -16.330 (d11) 12 -48.833 3.00 45.9 1.54814 13 -21.554 0.50 14 -133.247 0.80 54.0 1.71300 15 92.156 6.30 16 -12.127 1.00 54.0 1.71300 17 -42.017 (Bf) ______________________________________ (Variable Interval Upon Zooming) f 24.6999 34.9998 46.9997 d11 12.8000 7.0459 3.5228 Bf 6.3472 19.8374 35.5542 (Numerical Values Corresponding to Conditions) .vertline.f.sub.F /f.sub.W .vertline. = 1.447, K/f.sub.W = 0.324, L/f.sub.W = 0.462 ______________________________________
where numerals at the left end in the table represent the order from the object side, r is the radius of curvature of a lens surface, d is the lens surface interval, .nu. is the Abbe's number, n is the refractive index of the d ray (.lambda.=587.6 nm), f is the focal length of the entire system, 2.omega. is the field angle, and F.sub.NO is the f-number;
an aspherical shape is expressed by:
X(h)=(h.sup.2 /r)/[1+(1-kh.sup.2 /r.sup.2).sup.1/2 ]+c2h.sup.2 +c4h.sup.4 +c6h.sup.6 +c8h.sup.8 +c10h.sup.10
where X(h) is the distance along the optical axis direction from a tangent plane of the vertex of each aspherical surface at a height h in the vertical direction from the optical axis, r is the reference paraxial radius of curvature, k is a cone constant, and cn is an nth-order aspherical surface coefficient; and
E-n at the right end in the cone constant k and the nth-order aspherical surface coefficient cn represents 10.sup.-n.

### Claim 37 (depends on 1)

A wide-angle zoom lens according to claim 1, wherein said front group in said first lens group is constituted by two lenses including a negative lens with a surface facing the image side whose curvature is stronger than a surface of that lens facing the object side, and a positive lens with a surface facing the object side whose curvature is stronger than a surface of that lens facing the image side, and said first lens group is constituted to satisfy the following conditions:
0.91<.vertline.f.sub.F /f.sub.W .vertline.<4, f.sub.F <0
0.1<K/f.sub.W <0.4
0.1<L/f.sub.W <0.7
where
f.sub.F : the focal length of said front group in said first lens group
f.sub.W : the focal length of said zoom lens at the wide-angle end
K: the axial distance from a lens surface at the extreme image-side end of said first lens group to a rear-side principal point of said first lens group when a direction toward the image side is defined as a positive direction in said first lens group
L: the axial distance from a lens surface at the extreme object-side end of said front group to a lens surface at the extreme object-side end of said rear group in said first lens group.

### Claim 38 (depends on 37)

A wide-angle zoom lens according to claim 37, wherein said rear group in said first lens group is constituted to further satisfy the following conditions:
0.6<f.sub.1 /f.sub.W <0.95
0.38<M/f.sub.W <0.86
where
f.sub.l : the focal length of said first lens group
M: the axial distance from a lens surface at the extreme object-side end to a lens surface at the extreme image-side end of said rear group in said first lens group.

### Claim 39 (depends on 37)

A wide-angle zoom lens according to claim 37, wherein said second lens group is constituted to further satisfy the following conditions:
0.7<.vertline.f.sub.2 /f.sub.W <1.7, f.sub.2 <0
where f.sub.2 : the focal length of the second lens group.

### Claim 40 (depends on 37)

A wide-angle zoom lens according to claim 37, wherein said front group in said first lens group is constituted to satisfy the following condition so as to satisfactorily correct a chromatic aberration of magnification:
.nu..sub.d >50
where
.nu..sub.d : the Abbe's number of said negative lens in said front group in said first lens group.

### Claim 41 (depends on 37)

A wide-angle zoom lens according to claim 37, wherein said zoom lens is constituted according to the following data:
______________________________________ 2.omega. = 81.0.degree. to 50.5.degree., F.sub.NO = 4.01 to 7.63 r d .nu. n ______________________________________ 1 -757.521 1.40 70.1 1.51860 2 14.921 2.63 3 45.833 2.00 56.0 1.56883 4 -1758.247 2.00 5 12.814 3.00 47.1 1.62374 6 92.013 1.50 7 -20.683 3.30 44.7 1.80218 8 8.793 4.58 70.1 1.51860 9 -21.405 1.00 10 23.137 2.81 70.1 1.51860 11 -15.554 (d11) 12 -27.213 2.30 40.9 1.79631 13 -16.225 3.83 14 -10.450 1.30 49.4 1.77279 15 -113.948 (Bf) ______________________________________ (Variable Interval Upon Zooming) f 24.7000 35.0000 47.0000 d11 13.5916 7.9956 4.5693 Bf 6.0474 18.3524 32.6884 13th Surface (Aspherical Surface) Cone Constant: k = 1.00 Aspherical Surface Coefficients c2 = 0.0, c4 = -0.1305E-04, c6 = -0.2596E-06, c8 = 0.5319E-08, c10 = -0.5783E-10 (Numerical Values Corresponding to Conditions) .vertline.f.sub.F /f.sub.W .vertline. = 1.881, K/f.sub.W = 0.184, L/f.sup.W = 0.325 ______________________________________
where numerals at the left end in the table represent the order from the object side, r is the radius of curvature of a lens surface, d is the lens surface interval, .nu. is the Abbe's number, n is the refractive index of the d ray (.lambda.=587.6 nm), f is the focal length of the entire system, 2.omega. is the field angle, and F.sub.NO is the f-number;
an aspherical shape is expressed by:
X(h)=(h.sup.2 /r)/[1+(1-kh.sup.2 /r.sup.2).sup.1/2 ]+c2h.sup.2 +c4h.sup.4 +c6h.sup.6 +c8h.sup.8 +c10h.sup.10
where X(h) is the distance along the optical axis direction from a tangent plane of the vertex of each aspherical surface at a height h in the vertical direction from the optical axis, r is the reference paraxial radius of curvature, k is a cone constant, and cn is an nth-order aspherical surface coefficient; and
E-n at the right end in the cone constant k and the nth-order aspherical surface coefficient cn represents 10.sup.-n.

### Claim 42

A wide-angle zoom lens comprising:
a first lens group having a positive refracting power and a second lens group having a negative refracting power, which are moved relative to each other along an optical axis so as to attain zooming, a lens in the first lens group which is closest to the object side having a convex surface facing the object side,
said first lens group being constituted in turn from the object side by a front group having a negative refracting power and a rear group having a positive refracting power, and being constructed so that the spacing between the front group and the rear group is constant during zooming,
said front group having at least one negative lens,
said rear group having at least two positive lenses, and
said zoom lens being constituted to satisfy the following conditions:
0.1<D.sub.2 /f.sub.W <0.4
0.2<D.sub.3 /f.sub.W <0.4
0.75<.vertline.f.sub.F /f.sub.W .vertline.<4; f.sub.F <0
where f.sub.F is the focal length of said front group in said first lens group, f.sub.W is the focal length of said zoom lens at the wide-angle end, D.sub.2 is the axial distance from a lens surface at the extreme image-side end in said front group to a lens surface at the extreme object-side end in said rear group in said first lens group, and D.sub.3 is the central thickness of said positive lens at the extreme object-side end in said rear group in said first lens group.

### Claim 43 (depends on 42)

A wide-angle zoom lens according to claim 42, wherein said rear group in said first lens group has a positive lens with a convex surface facing the object side, a lens with a concave surface facing the object side, and a positive lens, and is constituted to satisfy the following conditions:
0.6<f.sub.1 /f.sub.W <0.95
0.38<M/f.sub.W <0.86
where
f.sub.1 : the focal length of said first lens group
M: the axial distance from a lens surface at the extreme object-side end to a lens surface at the extreme image-side end of said rear group in said first lens group.

### Claim 44 (depends on 42)

A wide-angle zoom lens according to claim 42, wherein said second lens group has a positive lens with a convex surface facing the image side, and a negative lens with a concave surface facing the object side in turn from the object side, and is constituted to satisfy the following conditions:
0.7<.vertline.f.sub.2 /f.sub.W .vertline.<1.7; f.sub.2 <0
where
f.sub.2 : the focal length of the second lens group.

### Claim 45 (depends on 42)

A wide-angle zoom lens according to claim 42, wherein said front group in said first lens group is constituted to satisfy the following condition so as to satisfactorily correct a chromatic aberration of magnification:
.nu..sub.d >50
where
.nu..sub.d : the Abbe's number of said negative lens in said front group in said first lens group.

### Claim 46 (depends on 42)

A wide-angle zoom lens according to claim 42, wherein said front group in said first lens group is constituted by a negative meniscus lens with a convex surface facing the object side, said rear group in said first lens group is constituted by a double-convex positive lens, a combination negative lens which is a combination lens of a double-concave negative lens and a double-convex positive lens, and has a meniscus shape with a concave surface facing the object side as a whole, and a double-convex positive lens, said second lens group is constituted by a positive meniscus lens with a convex surface facing the image side, and a negative meniscus lens with a concave surface facing the object side, and said first and second lens groups are constituted to satisfy the following conditions:
0.1<D.sub.2 /f.sub.W <0.4
0.2<D.sub.3 /f.sub.W <0.4
0.75<.vertline.f.sub.F /f.sub.W .vertline.<1.12; f.sub.F <0
where
f.sub.F : the focal length of said front group in said first lens group
f.sub.W : the focal length of said zoom lens at the wide-angle end
D.sub.2 : the axial distance from a lens surface at the extreme image-side end in said front group to a lens surface at the extreme object-side end in said rear group in said first lens group
D.sub.3 : the central thickness of said positive lens at the extreme object-side end in said rear group in said first lens group.

### Claim 47 (depends on 46)

A wide-angle zoom lens according to claim 46, wherein said rear group in said first lens group is constituted to satisfy the following conditions:
0.6<f.sub.1 /f.sub.W <0.95
0.38<M/f.sub.W <0.86
where,
f.sub.1 : the focal length of said first lens group
M: the axial distance from a lens surface at the extreme object-side end to a lens surface at the extreme image-side end of said rear group in said first lens group.

### Claim 48 (depends on 46)

A wide-angle zoom lens according to claim 46, wherein said second lens group is constituted to satisfy the following conditions:
0.7<.vertline.f.sub.2 /f.sub.W .vertline.<1.7; f.sub.2 <0
where
f.sub.2 : the focal length of the second lens group.

### Claim 49 (depends on 46)

A wide-angle zoom lens according to claim 46, wherein said front group in said first lens group is constituted to satisfy the following condition so as to satisfactorily correct a chromatic aberration of magnification:
.nu..sub.d >50
where
.nu..sub.d : the Abbe's number of said negative lens in said front group in said first lens group.

### Claim 50 (depends on 46)

A wide-angle zoom lens according to claim 46, wherein said zoom lens is constituted according to the following data:
______________________________________ 2.omega. = 81.3.degree. to 49.9, F.sub.NO = 4.08 to 7.82 r d .nu. n ______________________________________ 1 21.435 1.40 55.6 1.69680 2 8.392 3.30 3 11.239 5.40 41.4 1.57501 4 -29.971 .70 5 -14.229 3.50 40.9 1.79631 6 11.077 3.80 69.9 1.51860 7 -14.555 .20 8 47.678 2.80 69.9 1.51860 9 -13.366 (d9) 10 -27.913 2.60 49.4 1.74240 11 -19.186 4.60 12 -10.455 1.30 60.0 1.64000 13 -95.825 (Bf) ______________________________________ (Variable Interval Upon Zooming) f 24.7000 35.0000 47.0000 d9 13.2523 7.3493 3.7351 d13 6.3891 19.7808 35.3828 10th Surface (Aspherical Surface) Cone Constant: k = .1000 .times. 10 Aspherical Surface Coefficients c2 = .0000, c4 = .3439 .times. 10.sup.-4, c6 = .1040 .times. 10.sup.-6, c8 = .1110 .times. 10.sup.-8, c10 = .1862 .times. 10.sup.-10 (Numerical Values Corresponding to Conditions) D.sub.2 /f.sub.W = 0.133, D.sub.3 /f.sub.W = 0.219, .vertline.f.sub.F /f.sub.W .vertline. = 0.838 ______________________________________
where numerals at the left end in the table represent the order from the object side, r is the radius of curvature of a lens surface, d is the lens surface interval, .nu. is the Abbe's number, n is the refractive index of the d ray (.lambda.=587.6 nm), f is the focal length of the entire system, 2.omega. is the field angle, and F.sub.NO is the f-number;
an aspherical shape is expressed by:
X(h)=(h.sup.2 /r)/[1+(1-kh.sup.2 /r.sup.2).sup.1/2 ]+c2h.sup.2 +c4h.sup.4 +c6h.sup.6 +c8h.sup.8 +c10h.sup.10
where X(h) is the distance along the optical axis direction from a tangent plane of the vertex of each aspherical surface at a height h in the vertical direction from the optical axis, r is the reference paraxial radius of curvature, k is a cone constant, and cn is an nth-order aspherical surface coefficient; and
E-n at the right end in the cone constant k and the nth-order aspherical surface coefficient cn represents 10.sup.-n.

### Claim 51 (depends on 46)

A wide-angle zoom lens according to claim 46, wherein said zoom lens is constituted according to the following data:
______________________________________ 2.omega. = 81.2.degree. to 50.1.degree., F.sub.NO = 4.08 to 7.83 r d .nu. n ______________________________________ 1 23.130 1.40 55.6 1.69680 2 8.440 3.70 3 11.773 6.50 40.7 1.58144 4 -32.846 1.00 5 -14.205 2.50 40.9 1.79631 6 10.542 3.90 69.9 1.51860 7 -14.401 .20 8 41.295 2.40 69.9 1.51860 9 -12.855 (d9) 10 -22.495 2.60 49.4 1.74240 11 -16.826 4.70 12 -10.290 1.30 60.0 1.64000 13 -68.640 (Bf) ______________________________________ (Variable Interval Upon Zooming) f 24.7000 35.0000 47.0000 d9 13.2618 7.3674 3.7585 d13 7.0341 21.0606 37.4022 10th Surface (Aspherical Surface) Cone Constant: k = .1000 .times. 10 Aspherical Surface Coefficients c2 = .0000, c4 = .3149 .times. 10.sup.-4, c6 = .2485 .times. 10.sup.-7, c8 = .3372 .times. 10.sup.-8, c10 = .8716 .times. 10.sup.-11 (Numerical Values Corresponding to Conditions) D.sub.2 /f.sub.W = .150, D.sub.3 /f.sub.W = 0.263, .vertline.f.sub.F /f.sub.W .vertline. = 0.804 ______________________________________
where numerals at the left end in the table represent the order from the object side, r is the radius of curvature of a lens surface, d is the lens surface interval, .nu. is the Abbe's number, n is the refractive index of the d ray (.lambda.=587.6 nm), f is the focal length of the entire system, 2.omega. is the field angle, and F.sub.NO is the f-number;
an aspherical shape is expressed by:
X(h)=(h.sup.2 /r)/[1+(1-kh.sup.2 /r.sup.2).sup.1/2 ]+c2h.sup.2 +c4h.sup.4 +c6h.sup.6 +c8h.sup.8 +c10h.sup.10
where X(h) is the distance along the optical axis direction from a tangent plane of the vertex of each aspherical surface at a height h in the vertical direction from the optical axis, r is the reference paraxial radius of curvature, k is a cone constant, and cn is an nth-order aspherical surface coefficient; and
E-n at the right end in the cone constant k and the nth-order aspherical surface coefficient cn represents 10.sup.-n.

### Claim 52 (depends on 46)

A wide-angle zoom lens according to claim 46, wherein said zoom lens is constituted according to the following data:
______________________________________ 2.omega. = 81.3.degree. to 49.9.degree., F.sub.NO = 4.10 to 7.87 r d .nu. n ______________________________________ 1 23.277 1.40 55.6 1.69680 2 8.166 3.30 3 11.365 5.60 40.7 1.58144 4 -25.499 .70 5 -13.771 3.60 40.9 1.79631 6 10.503 3.50 69.9 1.51860 7 -15.096 .20 8 51.118 2.80 69.9 1.51860 9 -12.204 (d9) 10 -29.253 2.60 49.2 1.74330 11 -19.555 4.80 12 -10.668 1.30 60.0 1.64000 13 -122.254 (Bf) ______________________________________ (Variable Interval Upon Zooming) f 24.7000 35.0000 47.0000 d9 13.3040 7.3914 3.7713 d13 7.0230 20.7253 36.6891 10th Surface (Aspherical Surface) Cone Constant: k = .1000 .times. 10 Aspherical Surface Coefficients c2 = .0000, c4 = .2758 .times. 10.sup.-4, c6 = .1565 .times. 10.sup.-6, c8 = .1325 .times. 10.sup.-8, c10 = .6892 .times. 10.sup.-11 (Numerical Values Corresponding to Conditions) D.sub.2 /f.sub.W = 0.133, D.sub.3 /f.sub.W = 0.227, .vertline.f.sub.F /f.sub.W .vertline. = 0.760 ______________________________________
where numerals at the left end in the table represent the order from the object side, r is the radius of curvature of a lens surface, d is the lens surface interval, .mu. is the Abbe's number, n is the refractive index of the d ray (.lambda.=587.6 nm), f is the focal length of the entire system, 2.omega. is the field angle, and F.sub.NO is the f-number;
an aspherical shape is expressed by:
X(h)=(h.sup.2 /r)/[1+(1-kh.sup.2 /r.sup.2).sup.1/2 ]+c2h.sup.2 +c4h.sup.4 +c6h.sup.6 +c8h.sup.8 +c10h.sup.10
where X(h) is the distance along the optical axis direction from a tangent plane of the vertex of each aspherical surface at a height h in the vertical direction from the optical axis, r is the reference paraxial radius of curvature, k is a cone constant, and cn is an nth-order aspherical surface coefficient; and
E-n at the right end in the cone constant k and the nth-order aspherical surface coefficient cn represents 10.sup.-n.

### Claim 53 (depends on 46)

A wide-angle zoom lens according to claim 46, wherein said zoom lens is constituted according to the following data:
______________________________________ 2.omega. = 81.2.degree. to 49.8.degree., F.sub.NO = 4.08 to 7.82 r d .nu. n ______________________________________ 1 22.065 1.40 55.6 1.69680 2 8.464 3.30 3 11.325 5.74 41.4 1.57501 4 -30.545 .70 5 -14.108 3.61 40.9 1.79631 6 11.555 3.50 69.9 1.51860 7 -14.313 .20 8 46.612 2.80 69.9 1.51860 9 -13.494 (d9) 10 -26.529 2.60 45.0 1.74400 11 -19.655 5.07 12 -10.609 1.30 60.0 1.64000 13 -78.447 (Bf) ______________________________________ (Variable Interval Upon Zooming) f 24.7000 35.0000 47.0000 d9 13.2718 7.3725 3.7606 d13 5.9704 19.2136 34.6425 10th Surface (Aspherical Surface) Cone Constant: k = .1000E .times. 10 Aspherical Surface Coefficients c2 = .0000, c4 = .3207 .times. 10.sup.-4, c6 = .1167 .times. 10.sup.-6, c8 = .1127 .times. 10.sup.-8, c10 = .1492 .times. 10.sup.-10 (Numerical Values Corresponding to Conditions) D.sub.2 /f.sub.W = 0.133, D.sub.3 /f.sub.W = 0.232, .vertline.f.sub.F /f.sub.W .vertline. = 0.833 ______________________________________
where numerals at the left end in the table represent the order from the object side, r is the radius of curvature of a lens surface, d is the lens surface interval, v is the Abbe's number, n is the refractive index of the d ray (.lambda.=587.6 nm), f is the focal length of the entire system, 2.omega. is the field angle, and F.sub.NO is the f-number;
an aspherical shape is expressed by:
X(h)=(h.sup.2 /r)/[1+(1-kh.sup.2 /r.sup.2).sup.1/2 ]+c2h.sup.2 +c4h.sup.4 +c6h.sup.6 +c8h.sup.8 +c10h.sup.10
where X(h) is the distance along the optical axis direction from a tangent plane of the vertex of each aspherical surface at a height h in the vertical direction from the optical axis, r is the reference paraxial radius of curvature, k is a cone constant, and cn is an nth-order aspherical surface coefficient; and
E-n at the right end in the cone constant k and the nth-order aspherical surface coefficient cn represents 10.sup.-n.

### Claim 54 (depends on 46)

A wide-angle zoom lens according to claim 46, wherein said zoom lens is constituted according to the following data:
______________________________________ 2.omega. = 81.2.degree. to 49.7.degree., F.sub.NO = 4.08 to 7.82 r d .nu. n ______________________________________ 1 19.841 1.40 60.1 1.62041 2 7.751 3.30 3 14.418 6.50 40.3 1.60717 4 -23.618 .70 5 -15.309 3.50 39.6 1.80454 6 12.359 3.50 69.9 1.51860 7 -14.332 .20 8 188.925 2.80 69.9 1.51860 9 -11.898 (d9) 10 -27.400 2.60 35.2 1 74950 11 -22.795 5.80 12 -10.233 1.30 60.0 1.64000 13 -41.937 (Bf) ______________________________________ (Variable Interval Upon Zooming) f 24.7000 35.0000 47.0000 d9 13.1481 7.3266 3.7623 d13 5.6707 18.9887 34.5049 10th Surface (Aspherical Surface) Cone Constant: k = .1000 .times. 10 Aspherical Surface Coefficients c2 = .0000, c4 = .3906 .times. 10.sup.-4, c6 = .4141 .times. 10.sup.-6, c8 = -.1854 .times. 10.sup.-8, c10 = .3529 .times. 10.sup.-10 (Numerical Values Corresponding to Conditions) D.sub.2 /f.sub. W = 0.133, D.sub.3 /f.sub.W = 0.263, .vertline.f.sub.F /f.sub.W .vertline. = 0.869 ______________________________________
where numerals at the left end in the table represent the order from the object side, r is the radius of curvature of a lens surface, d is the lens surface interval, .nu. is the Abbe's number, n is the refractive index of the d ray (.lambda.=587.6 nm), f is the focal length of the entire system, 2.omega. is the field angle, and F.sub.NO is the f-number;
an aspherical shape is expressed by:
X(h)=(h.sup.2 /r)/[1+(1-kh.sup.2 /r.sup.2).sup.1/2 ]+c2h.sup.2 +c4h.sup.4 +c6h.sup.6 +c8h.sup.8 +c10h.sup.10
where X(h) is the distance along the optical axis direction from a tangent plane of the vertex of each aspherical surface at a height h in the vertical direction from the optical axis, r is the reference paraxial radius of curvature, k is a cone constant, and cn is an nth-order aspherical surface coefficient; and
E-n at the right end in the cone constant k and the nth-order aspherical surface coefficient cn represents 10.sup.-n.

### Claim 55 (depends on 46)

A wide-angle zoom lens according to claim 46, wherein said zoom lens is constituted according to the following data:
______________________________________ 2.omega. = 80.9.degree. to 49.7.degree. , F.sub.NO = 3.96 to 7.60 r d .nu. n ______________________________________ 1 21.944 1.40 60.7 1.60311 2 9.227 7.41 3 15.248 5.00 42.0 1.66755 4 -63.535 1.50 5 -22.358 3.67 40.9 1.79631 6 10.488 3.50 69.9 1.51860 7 -18.870 .20 8 5.861 2.80 69.9 1.51860 9 -14.283 (d9) 10 -22.342 2.30 29.5 1.71736 11 -17.827 4.95 12 -10.139 1.30 52.3 1.74810 13 -33.026 (Bf) ______________________________________ (Variable Interval Upon Zooming) f 24.6992 35.0000 47.0018 d9 13.3720 7.5415 3.9717 d13 5.6017 18.8215 34.2242 10th Surface (Aspherical Surface) Cone Constant: k = .1000 .times. 10 Aspherical Surface Coefficients c2 = .0000, c4 = .3784 .times. 10.sup.-4, c6 = .6940 .times. 10.sup.-6, c8 = -.4462 .times. 10.sup.-8, c10 = .5012 .times. 10.sup.-10 (Numerical Values Corresponding to Conditions) D.sub.2 /f.sub.W = .300, D.sub.3 /f.sub.W = 0.202, .vertline.f.sub.F /f.sub.W .vertline. = 1.115 ______________________________________
where numerals at the left end in the table represent the order from the object side, r is the radius of curvature of a lens surface, d is the lens surface interval, .nu. is the Abbe's number, n is the refractive index of the d ray (.lambda.=587.6 nm), f is the focal length of the entire system, 2.omega. is the field angle, and F.sub.NO is the f-number;
an aspherical shape is expressed by:
X(h)=(h.sup.2 /r)/[1+(1-kh.sup.2 /r.sup.2).sup.1/2 ]+c2h.sup.2 +c4h.sup.4 +c6h.sup.6 +c8h.sup.8 +c10h.sup.10
where X(h) is the distance along the optical axis direction from a tangent plane of the vertex of each aspherical surface at a height h in the vertical direction from the optical axis, r is the reference paraxial radius of curvature, k is a cone constant, and cn is an nth-order aspherical surface coefficient; and
E-n at the right end in the cone constant k and the nth-order aspherical surface coefficient cn represents 10.sup.-n.

### Claim 56 (depends on 46)

A wide-angle zoom lens according to claim 46, wherein said zoom lens is constituted according to the following data:
______________________________________ 2.omega. = 81.2.degree. to 49.8.degree., F.sub.NO = 4.00 to 7.66 r d .nu. n ______________________________________ 1 22.657 1.40 60.7 1.60311 2 8.748 6.5 3 14.989 6.40 42.0 1.66755 4 -41.143 .70 5 -20.566 3.20 40.9 1.79631 6 10.219 3.50 69.9 1.51860 7 -18.896 .20 8 75.085 2.80 69.9 1.51860 9 -13.115 (d9) 10 -25.378 2.60 29.5 1.71736 11 -20.550 5.40 12 -10.144 1.30 49.5 1.74443 13 -30.682 (Bf) ______________________________________ (Variable Interval Upon Zooming) f 24.7000 35.0002 47.0006 d9 13.3694 7.5413 3.9729 d13 5.6023 18.9256 34.4481 10th Surface (Aspherical Surface) Cone Constant: k = .1000 .times. 10 Aspherical Surface Coefficients c2 = .0000, c4 = .3777 .times. 10.sup.-4, c6 = .8613 .times. 10.sup.-6, c8 = -.7697 .times. 10.sup.-8, c10 = .6687 .times. 10.sup.-10 (Numerical Values Corresponding to Conditions) D.sub.2 /f.sub.W = 0.263, D.sub.3 /f.sub.W = 0.259, .vertline.f.sub.F /f.sub.W .vertline. = 0.994 ______________________________________
where numerals at the left end in the table represent the order from the object side, r is the radius of curvature of a lens surface, d is the lens surface interval, .nu. is the Abbe's number, n is the refractive index of the d ray (.lambda.=587.6 nm), f is the focal length of the entire system, 2.omega. is the field angle, and F.sub.NO is the f-number;
an aspherical shape is expressed by:
X(h)=(h.sup.2 /r)/[1+(1-kh.sup.2 /r.sup.2).sup.1/2 ]+c2h.sup.2 +c4h.sup.4 +c6h.sup.6 +c8h.sup.8 +c10h.sup.10
where X(h) is the distance along the optical axis direction from a tangent plane of the vertex of each aspherical surface at a height h in the vertical direction from the optical axis, r is the reference paraxial radius of curvature, k is a cone constant, and cn is an nth-order aspherical surface coefficient; and
E-n at the right end in the cone constant k and the nth-order aspherical surface coefficient cn represents 10.sup.-n.

### Claim 57

A wide-angle zoom lens consisting of:
a first lens group having a positive refracting power and a second lens group having a negative refracting power, which are moved relative to each other along an optical axis so as to attain zooming,
said first lens group being provided with a lens surface convex to the object side and positioned nearest the object side, and being constituted in turn from the object side by a front group having a negative refracting power and a rear group having a positive refracting power, and being constructed so that the spacing between said front group and said rear group is constant during zooming,
said front group having at least one negative lens,
said rear group having at least two positive lenses, and
said zoom lens being constituted to satisfy the following condition:
0.1<K/f.sub.W <0.4
where f.sub.W is the focal length of said zoom lens at the wide-angle end, and K is the axial distance from a lens surface at the extreme image-side end of said first lens group to a rear-side principal point of said first lens group when a direction toward the image side is defined as a positive direction.