Wide angle zoom lens

Claim 2

A wide angle zoom lens having an angle of view of 90 degrees or greater at the wide angle end and a zoom ratio of 1.6 or greater and consisting of two lens groups which are, in succession from the object side, a divergent lens group and a convergent lens group, and in which magnification change is effected by relative movement of said two lens groups, said divergent lens group comprising at least two negative lenses and a positive lens disposed most adjacent to the image side, one of said negative lenses being formed of a low-index high-dispersion material having a refractive index of 1.5 or less and an Abbe number of 62 or less, said negtive lens formed of the low-index high-dispersion material having a non-spherical surface in which the difference in thickness between the central portion and the marginal edge portion is small, said wide angle zoom lens being characterized in that when said non-spherical surface is approximated by ##EQU2## said zoom lens satisfies the following conditions for coefficients C 8 an C 10 : <| C.sub.8 |<0.025fw×10.sup.-7 0<|C.sub.10 |<0.05fw×10.sup.-9, where y is the distance from the optical axis, x is the distance from the tangential plane of the vertex of the non-spherical surface, C 0 is the paraxial curvature (the inverse number of the radius of paraxial curvature) at the vertex of the non-spherical surface, C 4 to C 10 are the fourth-order, sixth-order, eigth-order and tenth-order non-spherical surface coefficients, and fw is the focal length of the lens system at the wide angle end thereof.

Claim 3

A wide angle zoom lens according to claim 1, characterized in that the second negative lens from the object side in said divergent lens group has said non-spherical surface.

Claim 4

A wide angle zoom lens according to claim 2, characterized in that said second negative lens is a negative meniscus lens having its convex surface facing the object side, and said non-spherical surface is that surface of said negative meniscus lens which is adjacent to the object side.

Claim 5

A wide angle zoom lens having an angle of view of 90 degrees or greater at the wide angle end and a zoom ratio of 1.6 or greater and consisting of two lens groups which are, in succession from the object side, a divergent lens group and a convergent lens group, and in which magnification change is effected by relative movement of said two lens groups, said divergent lens group comprising at least two negative lenses and a positive lens disposed most adjacent to the image side, one of said negative lenses being formed of a low-index high-dispersion material having a refractive index of 1.5 or less and an Abbe number of 62 or less, said zoom lens being characterized in that said negative lens formed of the low-index high-dispersion material has a non-spherical surface in which the difference in thickness beteween the central portion and the marginal edge portion is small, in that when said non-spherical surface is approximated by ##EQU3## said zoom lens satisfies the following conditions for coefficients C 8 and C 10 : 0<|C.sub.8 |<0.025fw×10.sup.-7 <| C.sub.10 |<0.05fw×10.sup.-9, where y is the distance from the optical axis, x is the distance from the tangential plane of the vertex of the non-spherical surface, C 0 is the paraxial curvature (the inverse number of the radius of paraxial curvature) at the vertex of the non-spherical surface, C 4 to C 10 are the fourth-order, sixth-order, eighth-order and tenth-order non-spherical surface coefficients, and fw is the focal length of the lens system at the wide angle end thereof, in that the second negative lens from the object side in said divergent lens group has said non-spherical surface, in that said second negative lens is a negative meniscus lens having its convex surface facing the object side, and said non-spherical surface is that surface of said negative meniscus lens which is adjacent to the object side, and in that said zoom lens satisfies the following condition: 0.02<P.sub.2 /Pa<0.7 where P 2 is the refractive power of said negative meniscus lens and Pa is the refractive power of said divergent lens group.

Claim 6

A wide angle zoom lens having an angle of view of 90 degrees or greater at the wide angle end and a zoom ratio of 1.6 or greater and consisting of two lens groups which are, in succession from the object side, a divergent lens group and a convergent lens group, and in which magnification change is effected by relative movement of said two lens groups, said divergent lens group comprising at least two negative lenses and a positive lens disposed most adjacent to the image side, one of said negative lenses being formed of a low-index high-dispersion material having a refractive index of 1.5 or less and an Abbe number of 62 or less, said zoom lens being characterized in that said negative lens formed of the low-index high-dispersion material has a non-spherical surface in which the difference in thickness beteween the central portion and the marginal edge portion is small, in that when said non-spherical surface is approximated by ##EQU3## said zoom lens satisfies the following conditions for coefficients C 8 and C 10 : 0<|C.sub.8 |<0.025fw×10.sup.-7 <| C.sub.10 |<0.05fw×10.sup.-9, where y is the distance from the optical axis, x is the distance from the tangential plane of the vertex of the non-spherical surface, C 0 is the paraxial curvature (the inverse number of the radius of paraxial curvature) at the vertex of the non-spherical surface, C 4 to C 10 are the fourth-order, sixth-order, eighth-order and tenth-order non-spherical surface coefficients, and fw is the focal length of the lens system at the wide angle end thereof, in that the second negative lens from the object side in said divergent lens group has said non-spherical surface, in that said second negative lens is a negative meniscus lens having its convex surface facing the object side, and said non-spherical surface is that surface of said negative meniscus lens which is adjacent to the object side, and in that said zoom lens satisfies the following condition: 0.02<P.sub.2 /Pa<0.7 where P 2 is the refractive power of said negative meniscus lens and Pa is the refractive power of said divergent lens group.

Claim 7

A wide angle zoom lens having an angle of view of 90 degrees or greater at the wide angle end and a zoom ratio of 1.6 or greater and consisting of two lens groups which are, in succession from the object side, a divergent lens group and a convergent lens group, and in which magnification change is effected by relative movement of said two lens groups, said divergent lens group comprising at least two negative lenses and a positive lens disposed most adjacent to the image side, one of said negative lenses being formed of a low-index high-dispersion material having a refractive index of 1.5 or less and an Abbe number of 62 or less, said zoom lens being characterized in that said divergent lens group has, in succession from the object side, three negative meniscus lenses having their convex surfaces facing the object side, and a positive lens, said convergent lens group has, in succession from the object side, a positive lens, a positive lens having a center thickness greater than that of the preceding positive lens, a biconcave negative lens, a positive meniscus lens having its convex surface facing the image side, and a biconvex positive lens, and said zoom lens satisfies the following conditions: ______________________________________ 0.9|Pa| < |P.sub.1 | < |Pa.ve rtline., P.sub.1 < 0 0.02 |Pa| < |P.sub.2 | <0.6 |Pa|, P.sub.2 < 0 0.4|Pa| < |P.sub.3 | <0.9 |Pa|, P.sub.3 < 0 0.65 |Pa| <P.sub.4 <0.85 |Pa| 0.3Pb<P.sub.5 <0.5 Pb 0.7Pb<P.sub.6 <0.9 Pb 1.6Pb< |P.sub.7 | <2.4 Pb, P.sub.7 < 0 0.5Pb<P.sub.8 <1.6 Pb 0.4Pb<P.sub.9 <0.9 Pb ______________________________________ where P 1 , P 2 , P 3 , . . . are the refractive powers of the successive lenses from the object side, Pa is the refractive power of said divergent lens group, and Pb is the refractive power of said convergent lens group.

Claim 8

A wide angle zoom lens having an angle of view of 90 degrees or greater at the wide angle end and a zoom ratio of 1.6 or greater and consisting of two lens groups which are, in succession from the object side, a divergent lens group and a convergent lens group, and in which magnification change is effected by relative movement of said two lens groups, said divergent lens group comprising at least two negative lenses and a positive lens disposed most adjacent to the image side, one of said negative lenses being formed of a low-index high-dispersion material having a refractive index of 1.5 or less and an Abbe number of 62 or less, said zoom lens being characterized in that said divergent lens group has, in succession from the object side, three negative meniscus lenses having their convex surfaces facing the object side, and a positive lens, said convergent lens group has, in succession from the object side, a positive lens, a positive lens having a center thickness greater than that of the preceding positive lens, a biconcave negative lens, a positive meniscus lens having its convex surface facing the image side, and a biconvex positive lens, and said zoom lens satisfies the following conditions: ______________________________________ 0.9|Pa| < |P.sub.1 | < |Pa.ve rtline., P.sub.1 < 0 0.02 |Pa| < |P.sub.2 | <0.6 |Pa|, P.sub.2 < 0 0.4|Pa| < |P.sub.3 | <0.9 |Pa|, P.sub.3 < 0 0.65 |Pa| <P.sub.4 <0.85 |Pa| 0.3Pb<P.sub.5 <0.5 Pb 0.7Pb<P.sub.6 <0.9 Pb 1.6Pb< |P.sub.7 | <2.4 Pb, P.sub.7 < 0 0.5Pb<P.sub.8 <1.6 Pb 0.4Pb<P.sub.9 <0.9 Pb ______________________________________ where P 1 , P 2 , P 3 , . . . are the refractive powers of the successive lenses from the object side, Pa is the refractive power of said divergent lens group, and Pb is the refractive power of said convergent lens group.

Claim 9

A wide angle zoom lens according to claim 5, characterized in that numerical data are as follows: ______________________________________ f = 21.5˜34.5 F-number 3.5 ______________________________________ R D nd νd ______________________________________ 1 84.542 2.40 1.79668 45.5 G.sub.1 2 19.410 4.35 3 29.211(*) 2.00 1.49823 59.2 G.sub.2 4 23.432 4.00 A 5 50.770 2.00 1.79668 45.5 G.sub.3 6 22.769 4.02 7 31.521 5.00 1.72825 28.3 G.sub.4 8 422.700 d.sub.8 (variable) 9 83.264 3.50 1.67025 57.6 G.sub.5 10 -127.798 1.00 11 .000 2.00 12 22.500 10.00 1.48749 70.2 G.sub.6 13 -194.056 6.00 14 -24.176 1.50 1.79504 28.6 G.sub.7 B 15 35.085 2.00 16 -131.908 3.50 1.50137 56.5 G.sub.8 17 -16.629 .40 18 67.766 3.00 1.51680 64.1 G.sub.9 19 -45.769 B.F ______________________________________ Pa= -0.029 (*)Non-spherical surface coefficient Pb =0.028 C.sub.4 = 1.947 × 10.sup.-5 P.sub.1 = -0.031 C.sub.6 = 2.18 × 10.sup.-8 P.sub.2 = -0.0041 C.sub.8 = 6.129 × 10.sup.-11 P.sub.3 = -0.019 C.sub.10 = 4.3 × 10.sup.-13 P.sub.4 =0.021 d.sub.8 = 22.84˜0.84 P.sub.5 =0.013 B.F = 36.63˜49.99 P.sub.6 =0.024 P.sub.7 = -0.056 P.sub.8 =0.027 P.sub.9 =0.019 where the numbers at the left end of the table indicate the order from the object side, R represents the radius of curvature of each lens surface, D represents the center thickness and air space of each lens, nd and νd represent the refractive index and the Abbe number, respectively, of each lens for d-line.

Claim 10

A wide angle zoom lens having an angle of view of 90 degrees or greater at the wide angle end and a zoom ratio of 1.6 or greater and consisting of two lens groups which are, in succession from the object side, a divergent lens group and a convergent lens group, and in which magnification change is effected by relative movement of said two lens groups, said divergent lens group comprising at least two negative lenses and a positive lens disposed most adjacent to the image side, one of said negative lenses being formed of a low-index high-dispersion material having a refractive index of 1.5 or less and an Abbe number of 62 or less, said zoom lens being characterized in that said divergent lens group has, in succession from the object side, two negative meniscus lenses having their convex surfaces facing the object side and a positive meniscus lens having its convex surface facing the object side, said convergent lens group has, in succession from the object side, a positive lens, a negative meniscus lens having its convex surface facing the object side, a biconvex positive lens, a biconcave negative lens, a positive meniscus lens having its convex surface facing the image side, and a positive lens, and said zoom lens satisfies the following conditions: ______________________________________ 0.4|Pa| < |P.sub.1 | < 1.1|Pa |, P.sub.1 < 0 0.04 |Pa| < |P.sub.2 | < 0.7| a|, P.sub.2 < 0 0.05 |Pa| <P.sub.3 < 0.6|Pa| 0.4Pb<P.sub.4 < 0.9Pb -0.5Pb<P.sub.5 < 0.2Pb 1.1Pb<P.sub.6 < 1.9Pb 1.7Pb< |P.sub.7 | < 2.6Pb, P.sub.7 < 0 0.4Pb<P.sub.8 < 0.95Pb 0.35Pb<P.sub.9 < 0.8Pb ______________________________________ where P 1 , P 2 , P 3 , . . . are the refractive powers of the successive lenses from the object side, Pa is the refractive power of said divergent lens group, and Pb is the refractive power of said convergent lens group.

Claim 11

A wide angle zoom lens having an angle of view of 90 degrees or greater at the wide angle end and a zoom ratio of 1.6 or greater and consisting of two lens groups which are, in succession from the object side, a divergent lens group and a convergent lens group, and in which magnification change is effected by relative movement of said two lens groups, said divergent lens group comprising at least two negative lenses and a positive lens disposed most adjacent to the image side, one of said negative lenses being formed of a low-index high-dispersion material having a refractive index of 1.5 or less and an Abbe number of 62 or less, said zoom lens being characterized in that said divergent lens group has, in succession from the object side, two negative meniscus lenses having their convex surfaces facing the object side and a positive meniscus lens having its convex surface facing the object side, said convergent lens group has, in succession from the object side, a positive lens, a negative meniscus lens having its convex surface facing the object side, a biconvex positive lens, a biconcave negative lens, a positive meniscus lens having its convex surface facing the image side, and a positive lens, and said zoom lens satisfies the following conditions: ______________________________________ 0.4|Pa| < |P.sub.1 | < 1.1|Pa |, P.sub.1 < 0 0.04 |Pa| < |P.sub.2 | < 0.7| a|, P.sub.2 < 0 0.05 |Pa| <P.sub.3 < 0.6|Pa| 0.4Pb<P.sub.4 < 0.9Pb -0.5Pb<P.sub.5 < 0.2Pb 1.1Pb<P.sub.6 < 1.9Pb 1.7Pb< |P.sub.7 | < 2.6Pb, P.sub.7 < 0 0.4Pb<P.sub.8 < 0.95Pb 0.35Pb<P.sub.9 < 0.8Pb ______________________________________ where P 1 , P 2 , P 3 , . . . are the refractive powers of the successive lenses from the object side, Pa is the refractive power of said divergent lens group, and Pb is the refractive power of said convergent lens group.

Claim 12

A wide angle zoom lens according to claim 7, characterized in that numerical data are as follows: ______________________________________ f = 21.5˜34.5 F-number 3.5 ______________________________________ R D nd νd ______________________________________ 1 64.919 2.40 1.79797 47.5 G.sub.1 2 20.920 6.00 3 33.477(*) 2.00 1.49108 57.6 G.sub.2 A 4 20.822 6.00 5 54.472 3.00 1.72825 28.3 G.sub.3 6 88.146 d.sub.6 (variable) 7 66.935 1.80 1.67270 57.6 G.sub.4 8 -90.139 1.00 9 .000 2.00 10 29.859 4.50 1.62588 35.6 G.sub.5 11 -17.539 1.00 1.79668 45.5 12 34.344 .10 13 22.330 9.50 1.54739 53.6 G.sub.6 B 14 -25.976 2.00 15 -33.725 1.50 1.80518 25.4 G.sub.7 16 23.194 2.00 17 -53.782 3.50 1.50137 56.5 G.sub.8 18 -18.255 .40 19 35.814 3.50 1.51860 70.1 G.sub.9 20 -700.199 B.F ______________________________________ Pa= -0.029 (*)Non-spherical surface coefficient Pb=0.028 C.sub.4 = 1.7 × 10.sup.-5 P.sub.1 = -0.025 C.sub.6 =-4.521 × 10.sup.-10 P.sub.2 =0.008 C.sub.8 = -3.719 × 10.sup.-14 P.sub.3 =0.005 C.sub.10 = 3.4 × 10.sup.-13 P.sub.4 =0.017 d.sub.6 = 37.28˜15.27 P.sub.5 = -0.010 B.F = 36.76˜50.11 P.sub.6 =0.042 P.sub.7 = -0.059 P.sub.8 =0.019 P.sub.9 =0.015 where the numbers at the left end of the table indicate the order from the object side, R represents the radius of curvature of each lens surface, D represents the center thickness and air space of each lens, nd and νd represent the refractive index and the Abbe number, respectively, of each lens for d-line.

Claim 13

A wide angle zoom lens having an angle of view of 90 degrees or greater at the wide angle end and a zoom ratio of 1.6 or greater and consisting of two lens groups which are, in succession from the object side, a divergent lens group and a convergent lens group, and in which magnification change is effected by relative movement of said two lens groups, said divergent lens group comprising at least two negative lenses and a positive lens disposed most adjacent to the image side, one of said negative lenses being formed of a low-index high-dispersion material having a refractive index of 1.5 or less and an Abbe number of 62 or less, said zoom lens being characterized in that said divergent lens group has, in succession from the object side, two negative meniscus lenses having their convex surfaces facing the object side and a positive meniscus lens having its convex surface facing the object side, said convergent lens group has, in succession from the object side, a positive lens, a positive lens having a center thickness greater than that of the preceding positive lens, a biconcave negative lens, a positive meniscus lens having its convex surface facing the image side, and a biconvex positive lens, and said zoom lens satisfies the following conditions: ______________________________________ 0.9 |Pa| < |P.sub.1 | < 0.98 |Pa|, P.sub.1 < 0 0.3 |Pa| < |P.sub.2 | < 0.5|P a|, P.sub.2 < 0 0.2 |Pa| <P.sub.3 < 0.35 |Pa| 0.3Pb<P.sub.4 < 1.3Pb 0.7Pb<P.sub.5 < 1.2Pb 1.8Pb< |P.sub.6 | < 2.3Pb, P.sub.6 < 0 0.5Pb<P.sub.7 < 0.9Pb 0.5Pb<P.sub.8 < 0.9Pb ______________________________________ where P 1 , P 2 , P 3 , . . . are the refractive powers of the successive lenses from the object side, Pa is the refractive power of said divergent lens group, and Pb is the refractive power of said convergent lens group.

Claim 14

A wide angle zoom lens having an angle of view of 90 degrees or greater at the wide angle end and a zoom ratio of 1.6 or greater and consisting of two lens groups which are, in succession from the object side, a divergent lens group and a convergent lens group, and in which magnification change is effected by relative movement of said two lens groups, said divergent lens group comprising at least two negative lenses and a positive lens disposed most adjacent to the image side, one of said negative lenses being formed of a low-index high-dispersion material having a refractive index of 1.5 or less and an Abbe number of 62 or less, said zoom lens being characterized in that said divergent lens group has, in succession from the object side, two negative meniscus lenses having their convex surfaces facing the object side and a positive meniscus lens having its convex surface facing the object side, said convergent lens group has, in succession from the object side, a positive lens, a positive lens having a center thickness greater than that of the preceding positive lens, a biconcave negative lens, a positive meniscus lens having its convex surface facing the image side, and a biconvex positive lens, and said zoom lens satisfies the following conditions: ______________________________________ 0.9 |Pa| < |P.sub.1 | < 0.98 |Pa|, P.sub.1 < 0 0.3 |Pa| < |P.sub.2 | < 0.5|P a|, P.sub.2 < 0 0.2 |Pa| <P.sub.3 < 0.35 |Pa| 0.3Pb<P.sub.4 < 1.3Pb 0.7Pb<P.sub.5 < 1.2Pb 1.8Pb< |P.sub.6 | < 2.3Pb, P.sub.6 < 0 0.5Pb<P.sub.7 < 0.9Pb 0.5Pb<P.sub.8 < 0.9Pb ______________________________________ where P 1 , P 2 , P 3 , . . . are the refractive powers of the successive lenses from the object side, Pa is the refractive power of said divergent lens group, and Pb is the refractive power of said convergent lens group.

Claim 15

A wide angle zoom lens according to claim 9, characterized in that numerical data are as follows: ______________________________________ f = 21.5˜34.5 F-number 3.5 ______________________________________ R D nd νd ______________________________________ 1 67.667 2.40 1.78797 47.5 G.sub.1 2 19.923 3.00 3 32.887(*) 2.00 1.49108 57.6 G.sub.2 A 4 19.102 14.95 5 30.337 5.00 1.72825 28.3 G.sub.3 6 41.162 d.sub.6 (variable) 7 66.543 3.50 1.67270 32.2 G.sub.4 8 -152.688 1.00 9 .000 2.00 10 19.809 10.00 1.48749 70.2 G.sub.5 11 -125.581 3.16 12 -22.325 1.50 1.79504 28.6 G.sub.6 B 13 31.687 2.00 14 -48.870 3.50 1.50137 56.5 G.sub.7 15 -15.939 .40 16 67.545 5.00 1.51860 70.1 G.sub.8 17 -37.800 B.F ______________________________________ Pa= -0.029 (*)Non-spherical surface coefficient Pb =0.028 C.sub.4 = 2.14 × 10.sup.-5 P.sub.1 = -0.027 C.sub.6 = 1.23 × 10.sup.-8 P.sub.2 = -0.010 C.sub.8 = -5.72 × 10.sup.-11 P.sub.3 =0.008 C.sub.10 = 5.823 × 10.sup.-13 P.sub.4 =0.014 d.sub.6 = 22.6˜0.6 P.sub.5 =0.028 B.F = 38.06˜51.4 P.sub.6 = -0.061 P.sub.7 =0.022 P.sub.8 =0.021 ______________________________________ where the numbers at the left end of the table indicate the order from the object side, R represents the radius of curvature of each lens surface, D represents the center thickness and air space of each lens, and nd and νd represent the refractive index and the Abbe number, respectively, of each lens for d-line.

Claim 16

A wide angle zoom lens having an angle of view of 90 degrees or greater at the wide angle end and a zoom ratio of 1.6 or greater and consisting of two lens groups which are, in succession from the object side, a divergent lens group and a convergent lens group, and in which magnification change is effected by relative movement of said two lens groups, said divergent lens group comprising at least two negative lenses and a positive lens disposed most adjacent to the image side, one of said negative lenses being formed of a low-index high-dispersion material having a refractive index of 1.5 or less and an Abbe number of 62 or less, said zoom lens being characterized in that said divergent lens group has, in succession from the object side, three negative meniscus lenses having their convex surfaces facing the object side and a positive lens having its convex surface facing the object side, said convergent lens group having, in succession from the object side, a positive lens, a negative meniscus lens comprising a cemented lens and having its convex surface facing the object side, a biconvex positive lens comprising a cemented lens, a biconcave negative lens, a positive meniscus lens having its convex surface facing the image side, and a positive lens, and said zoom lens satisfies the following conditions: ______________________________________ 0.3|Pa| < |P.sub.1 | < 1.2 |Pa|, P.sub.1 < 0 0.02 |Pa| < |P.sub.2 | < 0.9 |Pa|, P.sub.2 < 0 0.3|Pa| < |P.sub.3 | < 0.9 |Pa|, P.sub.3 < 0 0.2|Pa| <P.sub.4 < 0.8 |Pa| 0.3Pb<P.sub.5 < 1.3Pb -0.5Pb<P.sub.6 < 0.5Pb 0.7Pb<P.sub.7 < 1.4Pb 1.4Pb< |P.sub.8 | < 2.2Pb, P.sub.8 < 0 0.3Pb<P.sub.9 < 1.0Pb 0.3Pb<P.sub.10 < 0.8Pb ______________________________________ where P 1 , P 2 , P 3 , . . . are the refractive powers of the successive lenses from the object side, Pa is the refractive power of said divergent lens group, and Pb is the refractive power of said convergent lens group.

Claim 17

A wide angle zoom lens having an angle of view of 90 degrees or greater at the wide angle end and a zoom ratio of 1.6 or greater and consisting of two lens groups which are, in succession from the object side, a divergent lens group and a convergent lens group, and in which magnification change is effected by relative movement of said two lens groups, said divergent lens group comprising at least two negative lenses and a positive lens disposed most adjacent to the image side, one of said negative lenses being formed of a low-index high-dispersion material having a refractive index of 1.5 or less and an Abbe number of 62 or less, said zoom lens being characterized in that said divergent lens group has, in succession from the object side, three negative meniscus lenses having their convex surfaces facing the object side and a positive lens having its convex surface facing the object side, said convergent lens group having, in succession from the object side, a positive lens, a negative meniscus lens comprising a cemented lens and having its convex surface facing the object side, a biconvex positive lens comprising a cemented lens, a biconcave negative lens, a positive meniscus lens having its convex surface facing the image side, and a positive lens, and said zoom lens satisfies the following conditions: ______________________________________ 0.3|Pa| < |P.sub.1 | < 1.2 |Pa|, P.sub.1 < 0 0.02 |Pa| < |P.sub.2 | < 0.9 |Pa|, P.sub.2 < 0 0.3|Pa| < |P.sub.3 | < 0.9 |Pa|, P.sub.3 < 0 0.2|Pa| <P.sub.4 < 0.8 |Pa| 0.3Pb<P.sub.5 < 1.3Pb -0.5Pb<P.sub.6 < 0.5Pb 0.7Pb<P.sub.7 < 1.4Pb 1.4Pb< |P.sub.8 | < 2.2Pb, P.sub.8 < 0 0.3Pb<P.sub.9 < 1.0Pb 0.3Pb<P.sub.10 < 0.8Pb ______________________________________ where P 1 , P 2 , P 3 , . . . are the refractive powers of the successive lenses from the object side, Pa is the refractive power of said divergent lens group, and Pb is the refractive power of said convergent lens group.

Claim 18

A wide angle zoom lens according to claim 11, characterized in that numerical data are as follows: ______________________________________ f = 21.5˜40.43 F-number 3.5˜4.5 ______________________________________ R D nd νd ______________________________________ 1 64.000 2.40 1.78797 47.5 G.sub.1 2 25.000 4.35 3 32.377(*) 2.00 1.49823 59.2 G.sub.2 4 20.597 4.00 A 5 52.000 2.00 1.78797 47.5 G.sub.3 6 23.391 8.00 7 30.761 3.00 1.72825 28.3 G.sub.4 8 73.742 d.sub.8 (variable) 9 66.015 1.80 1.66446 35.9 G.sub.5 10 -83.552 1.00 11 .000 2.00 12 28.422 3.00 1.62230 53.1 G.sub.6 13 -19.165 1.00 1.79668 45.5 14 33.767 .10 15 21.715 1.00 1.54739 53.6 G.sub.7 B 16 16.010 4.00 1.54814 45.9 17 -52.192 3.10 18 -41.838 1.50 1.80518 25.4 G.sub.8 19 25.090 2.00 20 -49.505 3.50 1.50137 56.5 G.sub.9 21 -18.307 .40 22 323.983 2.80 1.51835 60.3 G.sub.10 23 -32.421 B.F ______________________________________ Pa= -0.029 (*)Non-spherical surface coefficient Pb=0.028 C.sub.4 = 1.365 × 10.sup.-5 P.sub.1 = -0.019 C.sub.6 = 1.277 × 10.sup.-9 P.sub.2 = -0.008 C.sub.8 = 4.86 × 10.sup.-11 P.sub.3 = -0.018 C.sub.10 = 7 × 10.sup.-14 P.sub.4 =0.014 d.sub.8 = 27.79˜0.45 P.sub.5 = 0.018 B.F = 41.11˜60.55 P.sub.6 = -0.009 P.sub.7 =0.035 P.sub.8 = -0.052 P.sub.9 =0.018 P.sub.10 =0.018 where the numbers at the left end of the table indicate the order from the object side, R represents the radius of curvature of each lens surface, D represents the center thickness and air space of each lens, nd and νd represent the refractive index and the Abbe number, respectively, of each lens for d-line.

Claim 19

A wide angle zoom lens having an angle of view of 90 degrees or greater at the wide angle end and a zoom ratio of 1.6 or greater and consisting of two lens groups which are, in succession from the object side, a divergent lens group and a convergent lens group, and in which magnification change is effected by relative movement of said two lens groups, said divergent lens group comprising at least two negative lenses and a positive lens disposed most adjacent to the image side, one of said negative lenses being formed of a low-index high-dispersion material havinng a refractive index of 1.5 or less and an Abbe number of 62 or less, said zoom lens being characterized in that said divergent lens group has, in succession from the object side, three negative meniscus lenses having their convex surfaces facing the object side and a positive lens, said convergent lens group has, in succession from the object side, a biconvex positive lens, a negative meniscus lens comprising a cemented lens and having its convex surface facing the object side, a positive lens, a negative lens having its concave surface of sharper curvature facing the image side, and a positive lens having its convex surface of sharper curvature facing the image side, and said zoom lens satisfies the following conditions: ______________________________________ 0.3 |Pa| < |P.sub.1 | < 0.9 |Pa|, P.sub.1 < 0 0.1 |Pa| < |P.sub.2 | < 0.8 |Pa|, P.sub.2 < 0 0.2 |Pa| < |P.sub.3 | < 0.8 |Pa|, P.sub.3 < 0 0.3 |Pa| <P.sub.4 < 0.7 |Pa| 0.4Pb<P.sub.5 < 1.1Pb -0.4Pb<P.sub.6 < 0.4Pb 0.3Pb<P.sub.7 < 1.2Pb 0.7Pb<P.sub.8 < 1.9Pb 0.7Pb<P.sub.9 < 1.6Pb ______________________________________ where P 1 , P 2 , P 3 , . . . are the refractive powers of the successive lenses from the object side, Pa is the refractive power of said divergent lens group, and Pb is the refractive power of said convergent lens group.

Claim 20

A wide angle zoom lens having an angle of view of 90 degrees or greater at the wide angle end and a zoom ratio of 1.6 or greater and consisting of two lens groups which are, in succession from the object side, a divergent lens group and a convergent lens group, and in which magnification change is effected by relative movement of said two lens groups, said divergent lens group comprising at least two negative lenses and a positive lens disposed most adjacent to the image side, one of said negative lenses being formed of a low-index high-dispersion material havinng a refractive index of 1.5 or less and an Abbe number of 62 or less, said zoom lens being characterized in that said divergent lens group has, in succession from the object side, three negative meniscus lenses having their convex surfaces facing the object side and a positive lens, said convergent lens group has, in succession from the object side, a biconvex positive lens, a negative meniscus lens comprising a cemented lens and having its convex surface facing the object side, a positive lens, a negative lens having its concave surface of sharper curvature facing the image side, and a positive lens having its convex surface of sharper curvature facing the image side, and said zoom lens satisfies the following conditions: ______________________________________ 0.3 |Pa| < |P.sub.1 | < 0.9 |Pa|, P.sub.1 < 0 0.1 |Pa| < |P.sub.2 | < 0.8 |Pa|, P.sub.2 < 0 0.2 |Pa| < |P.sub.3 | < 0.8 |Pa|, P.sub.3 < 0 0.3 |Pa| <P.sub.4 < 0.7 |Pa| 0.4Pb<P.sub.5 < 1.1Pb -0.4Pb<P.sub.6 < 0.4Pb 0.3Pb<P.sub.7 < 1.2Pb 0.7Pb<P.sub.8 < 1.9Pb 0.7Pb<P.sub.9 < 1.6Pb ______________________________________ where P 1 , P 2 , P 3 , . . . are the refractive powers of the successive lenses from the object side, Pa is the refractive power of said divergent lens group, and Pb is the refractive power of said convergent lens group.

Claim 21

A wide angle zoom lens according to claim 13, characterized in that numerical data are as follows: ______________________________________ f = 21.5˜40.43 F-number 3.5˜4.5 ______________________________________ R D nd νd ______________________________________ 1 64.249 2.40 1.78797 47.5 G.sub.1 2 23.675 4.35 3 44.977(*) 2.00 1.49823 59.2 G.sub.2 4 22.143 4.00 A 5 38.293 2.00 1.78797 47.5 G.sub.3 6 23.472 8.85 7 30.745 3.00 1.72825 28.3 G.sub.4 8 64.848 d.sub.8 (variable) 9 82.520 1.80 1.67270 32.2 G.sub.5 10 -82.687 1.00 11 .000 2.00 12 27.869 3.00 1.62230 53.1 G.sub.6 13 -20.530 1.00 1.79631 41.0 14 39.101 .10 B 15 27.071 5.00 1.54739 53.6 G.sub.7 16 -285.620 4.17 17 125.878 1.50 1.80518 25.4 G.sub.8 18 21.151 2.00 19 186.118 5.00 1.62041 60.3 G.sub.9 20 -24.269 B.F ______________________________________ Pa= -0.029 (*)Non-spherical surface coefficient Pb =0.028 C.sub.4 = 1.345 × 10.sup.-5 P.sub. 1 = -0.020 C.sub.6 = 2.447 × 10.sup.-9 P.sub.2 = -0.011 C.sub.8 = 3.162 × 10.sup.-11 P.sub.3 = -0.012 C.sub.10 = 3.393 × 10.sup.-14 P.sub.4 =0.013 d.sub.8 = 28.13˜0.79 P.sub.5 =0.016 B.F = 41.18˜60.62 P.sub.6 = -0.005 P.sub.7 =0.022 P.sub.8 = -0.031 P.sub.9 =0.029 where the numbers at the left end of the table indicate the order from the object side, R represents the radius of curvature of each lens surface, D represents the center thickness and air space of each lens, nd and νd represent the refractive index and the Abbe number, respectively, of each lens for d-line.

Claim 22

A wide angle zoom lens having an angle of view of 90 degrees or greater at the wide angle end and a zoom ratio of 1.6 or greater and consisting of two lens groups which are, in succession from the object side, a divergent lens group and a convergent lens group, and in which magnification change is effected by relative movement of said two lens groups, said divergent lens group comprising at least two negative lenses and a positive lens disposed most adjacent to the image side, one of said negative lenses being formed of a low-index high-dispersion material having a refractive index of 1.5 or less and an Abbe number of 62 or less, said zoom lens being characterized in that said divergent lens group has, in succession from the object side, three negative meniscus lenses having their convex surfaces facing the object side, and a positive lens, said convergent lens group has, in succession from the object side, a positive lens, a negative meniscus lens comprising a cemented lens and having its convex surface facing the object side, a biconvex positive lens, a biconcave negative lens, a positive meniscus lens having its convex surface facing the image side, and a positive lens, and said zoom lens satisfies the following conditions: ______________________________________ 0.5|Pa| < |P.sub.1 | < 1.5 |Pa|, P.sub.1 < 0 0.02 |Pa| < |P.sub.2 | < 0.5 |Pa|, P.sub.2 < 0 0.3|Pa| < |P.sub.3 | < 0.9 |Pa|, P.sub.3 < 0 0.3|Pa| <P.sub.4 < 0.9 |Pa| 0.4Pb<P.sub.5 < 1.2Pb -0.6Pb<P.sub.6 < 0.6Pb 0.7Pb<P.sub.7 < 1.5Pb 1.1Pb< |P.sub.8 | < 2.4Pb, Pb.sub.8 < 0 0.3Pb<P.sub.9 < 1.1Pb 0.4Pb<P.sub.10 < 1.1Pb ______________________________________ where P 1 , P 2 , P 3 , . . . are the refractive powers of the successive lenses from the object side, Pa is the refractive power of said divergent lens group, and Pb is the refractive power of said convergent lens group.

Claim 23

A wide angle zoom lens having an angle of view of 90 degrees or greater at the wide angle end and a zoom ratio of 1.6 or greater and consisting of two lens groups which are, in succession from the object side, a divergent lens group and a convergent lens group, and in which magnification change is effected by relative movement of said two lens groups, said divergent lens group comprising at least two negative lenses and a positive lens disposed most adjacent to the image side, one of said negative lenses being formed of a low-index high-dispersion material having a refractive index of 1.5 or less and an Abbe number of 62 or less, said zoom lens being characterized in that said divergent lens group has, in succession from the object side, three negative meniscus lenses having their convex surfaces facing the object side, and a positive lens, said convergent lens group has, in succession from the object side, a positive lens, a negative meniscus lens comprising a cemented lens and having its convex surface facing the object side, a biconvex positive lens, a biconcave negative lens, a positive meniscus lens having its convex surface facing the image side, and a positive lens, and said zoom lens satisfies the following conditions: ______________________________________ 0.5|Pa| < |P.sub.1 | < 1.5 |Pa|, P.sub.1 < 0 0.02 |Pa| < |P.sub.2 | < 0.5 |Pa|, P.sub.2 < 0 0.3|Pa| < |P.sub.3 | < 0.9 |Pa|, P.sub.3 < 0 0.3|Pa| <P.sub.4 < 0.9 |Pa| 0.4Pb<P.sub.5 < 1.2Pb -0.6Pb<P.sub.6 < 0.6Pb 0.7Pb<P.sub.7 < 1.5Pb 1.1Pb< |P.sub.8 | < 2.4Pb, Pb.sub.8 < 0 0.3Pb<P.sub.9 < 1.1Pb 0.4Pb<P.sub.10 < 1.1Pb ______________________________________ where P 1 , P 2 , P 3 , . . . are the refractive powers of the successive lenses from the object side, Pa is the refractive power of said divergent lens group, and Pb is the refractive power of said convergent lens group.

Claim 24

A wide angle zoom lens according to claim 15, characterized in that numerical data are as follows: ______________________________________ f = 21.5˜34.5 F-number 3.5 ______________________________________ R D nd νd ______________________________________ 1 76.293 2.40 1.79668 45.5 G.sub.1 2 20.705 4.35 3 31.590(*) 2.00 1.49823 59.2 G.sub.2 4 21.102 4.00 A 5 48.496 2.00 1.79668 45.5 G.sub.3 6 24.910 5.58 7 30.883 3.00 1.72825 28.3 G.sub.4 8 124.590 d.sub.8 (variable) 9 63.647 1.80 1.67270 32.2 G.sub.5 10 -84.941 1.00 11 .000 2.00 12 28.866 4.50 1.62230 53.1 G.sub.6 13 -18.391 1.00 1.79668 45.5 14 33.240 .10 15 24.396 3.50 1.54739 53.6 G.sub.7 B 16 -38.669 1.78 17 -44.091 7.00 1.80518 25.4 G.sub.8 18 26.739 2.00 19 -69.572 3.50 1.50137 56.5 G.sub.9 20 -19.213 .40 21 183.998 2.80 1.62041 60.3 .sub. G.sub.10 22 -53.387 B.F ______________________________________ Pa= - 0.029 (*)Non-spherical surface coefficient Pb=0.028 C.sub.4 = 1.956 × 10.sup.-5 P.sub.1 = -0.027 C.sub.6 = 1.5 × 10.sup.-8 P.sub.2 = -0.007 C.sub.8 = 2.614 × 10.sup.-11 P.sub.3 = -0.015 C.sub.10 = 2.83 × 10.sup.-13 P.sub.4 =0.018 d.sub.8 = 26.53˜4.52 P.sub.5 =0.018 B.F = 39.3˜52.65 P.sub.6 = -0.010 P.sub.7 =0.036 P.sub.8 = -0.051 P.sub.9 =0.019 P.sub.10 =0.015 where the numbers at the left end of the table indicate the order from the object side, R represents the radius of curvature of each lens surface, D represents the center thickness and air space of each lens, nd and νd represent the refractive index and the Abbe number, respectively, of each lens for d-line.

Claim 25

A wide angle zoom lens having an angle of view of 90 degrees or greater at the wide angle end and a zoom ratio of 1.6 or greater and consisting of two lens groups which are, in succession from the object side, a divergent lens group and a convergent lens group, and in which magnification change is effected by relative movement of said two lens groups, said divergent lens group comprising at least two negative lenses and a positive lens disposed most adjacent to the image side, one of said negative lenses being formed of a low-index high-dispersion material having a refractive index of 1.5 or less and an Abbe number of 62 or less, said zoom lens being characterized in that said divergent lens group has, in succession from the object side, three negative meniscus lenses having their convex surfaces facing the object side and a positive lens, said convergent lens group has, in succession from the object side, a positive lens, a positive lens having a center thickness greater than that of the preceding positive lens, a negative lens, and two positive meniscus lenses having their convex surfaces facing the image side, and said zoom lens satisfies the following conditions: ______________________________________ 0.4|Pa| < |P.sub.1 | < 1.3|Pa |, P.sub.1 < 0 0.1|Pa| < |P.sub.2 | < 0.5|Pa |, P.sub.2 < 0 0.3|Pa| < |P.sub.3 | < 0.9|Pa |, P.sub.3 < 0 0.45 |Pa| <P.sub.4 < 0.95 |Pa| 0.3Pb<P.sub.5 < 0.9Pb 0.4Pb<P.sub.6 < 1.3Pb 1.0Pb< |P.sub.7 | < 2.3Pb, P.sub.7 < 0 0.4Pb<P.sub.8 < 1.2Pb 0.4Pb<P.sub.9 < 1.2Pb ______________________________________ where P 1 , P 2 , P 3 , . . . are the refractive powers of the successive lenses from the object side, Pa is the refractive power of said divergent lens group, and Pb is the refractive power of said convergent lens group.

Claim 26

A wide angle zoom lens having an angle of view of 90 degrees or greater at the wide angle end and a zoom ratio of 1.6 or greater and consisting of two lens groups which are, in succession from the object side, a divergent lens group and a convergent lens group, and in which magnification change is effected by relative movement of said two lens groups, said divergent lens group comprising at least two negative lenses and a positive lens disposed most adjacent to the image side, one of said negative lenses being formed of a low-index high-dispersion material having a refractive index of 1.5 or less and an Abbe number of 62 or less, said zoom lens being characterized in that said divergent lens group has, in succession from the object side, three negative meniscus lenses having their convex surfaces facing the object side and a positive lens, said convergent lens group has, in succession from the object side, a positive lens, a positive lens having a center thickness greater than that of the preceding positive lens, a negative lens, and two positive meniscus lenses having their convex surfaces facing the image side, and said zoom lens satisfies the following conditions: ______________________________________ 0.4|Pa| < |P.sub.1 | < 1.3|Pa |, P.sub.1 < 0 0.1|Pa| < |P.sub.2 | < 0.5|Pa |, P.sub.2 < 0 0.3|Pa| < |P.sub.3 | < 0.9|Pa |, P.sub.3 < 0 0.45 |Pa| <P.sub.4 < 0.95 |Pa| 0.3Pb<P.sub.5 < 0.9Pb 0.4Pb<P.sub.6 < 1.3Pb 1.0Pb< |P.sub.7 | < 2.3Pb, P.sub.7 < 0 0.4Pb<P.sub.8 < 1.2Pb 0.4Pb<P.sub.9 < 1.2Pb ______________________________________ where P 1 , P 2 , P 3 , . . . are the refractive powers of the successive lenses from the object side, Pa is the refractive power of said divergent lens group, and Pb is the refractive power of said convergent lens group.

Claim 27

A wide angle zoom lens according to claim 17, characterized in that numerical data are as follows: ______________________________________ f = 21.5˜34.5 F-number 3.5 ______________________________________ R D nd νd ______________________________________ 1 84.326 2.40 1.79668 45.5 G.sub.1 2 20.368 4.35 3 31.281(*) 2.00 1.49823 59.2 G.sub.2 4 21.508 4.00 A 5 61.688 2.00 1.79668 45.5 G.sub.3 6 26.543 5.64 7 33.660 3.00 1.72825 28.3 G.sub.4 8 312.886 d.sub.8 (variable) 9 64.509 1.80 1.67270 32.2 G.sub.5 10 -92.241 1.00 11 .000 2.00 12 29.037 4.50 1.62230 53.1 G.sub.6 13 -19.720 4.50 1.79886 34.0 14 -61.925 2.11 B 15 -44.877 7.00 1.80518 25.4 G.sub.7 16 27.045 2.00 17 -62.708 3.50 1.50137 56.5 G.sub.8 18 -20.201 .40 19 -135.756 2.80 1.62299 58.2 G.sub.9 20 -29.338 B.F ______________________________________ Pa= -0.029 (*)Non-spherical surface coefficient Pb =0.028 C.sub.4 = 2.088 × 10.sup.-5 P.sub.1 = -0.029 C.sub.6 = 1.798 × 10.sup.-8 P.sub.2 = -0.007 C.sub.8 = 3.644 × 10.sup.-11 P.sub.3 = -0.017 C.sub.10 = 2.63 × 10.sup.-13 P.sub.4 =0.019 d.sub.8 = 23.84˜1.84 P.sub.5 =0.018 B.F = 39.54˜52.89 P.sub.6 =0.025 P.sub.7 = -0.050 P.sub.8 =0.017 P.sub.9 =0.017 where the numbers at the left end of the table indicate the order from the object side, R represents the radius of curvature of each lens surface, D represents the center thickness and air space of each lens, nd and νd represent the refractive index and the Abbe number, respectively, of each lens for d-line.