Zoom lens

Claim 2

A zoom lens comprising, in succession from the object side, a first lens group having a positive refractive power, a second lens group having a negative power, a third lens group having a positive refractive power, and a fourth lens group having a positive refractive power, said zoom lens being designed such that during the magnification change from the wide angle end to the telephoto end, the air space between said first lens group and said second lens group is enlarged, the air space between said second lens group and said third lens group is reduced and further, the air space between said third lens group and said fourth lens group is varied, said second lens group comprising, in succession from the object side, a negative meniscus lens having its convex surface facing the object side, a biconcave negative lens, and a cemented positive lens consisting of a biconvex positive lens and a biconcave negative lens cemented together, said second lens group being designed to satisfy the following conditions: ##EQU9## where f w : the focal length of the zoom lens at the wide angle end f 2 : the focal length of the second lens group ν 21 : the Abbe number of the negative meniscus lens in the second lens group ν 22 : the Abbe number of the biconcave negative lens in the second lens group ν 231 : the Abbe number of the biconvex positive lens in the cemented positive lens in second lens group ν 232 : the Abbe number of the biconcave negative lens in the cemented positive lens in the second lens group r S1 : the radius of curvature of the cemented surface of the cemented positive lens in the second lens group.

Claim 3

A zoom lens according to claim 1, wherein said second lens group is further designed to satisfy the following condition in order to correct various aberrations such as spherical aberration, curvature of image field and coma sufficiently: 0.45<|fz/fw|<0.475.

Claim 4

A zoom lens according to claim 1, wherein the radius of curvature r S1 of said cemented positive lens in said second lens group is designed to satisfy the following condition in order to correct spherical aberration of g-line better balancedly: ##EQU10##

Claim 5

A zoom lens according to claim 1, wherein one of the surfaces of the plurality of lenses constituting said second lens group is formed into an aspherical surface whose negative refractive power progressively becomes stronger from the optic axis toward the margin.

Claim 6

A zoom lens according to claim 4, wherein the object side surface of said negative meniscus lens in said second lens group which is located most adjacent to the object side is formed into an aspherical surface which satisfies the following condition: ##EQU11## l : maximum image height y : the height from the optic axis X(y) : the distance along the direction of the optic axis from the tangential plane at the vertex of the aspherical surface to the position on the aspherical surface at the height y X O (y) the distance along the direction of the optic axis from the tangential plane at the vertex of the aspherical surface to the position on the paraxial reference spherical surface of the aspherical surface at the height y R : the radius of curvature of the paraxial reference spherical surface C n : aspherical surface coefficient (n=4, 6, 8, 10).

Claim 7

A zoom lens according to claim 1, wherein said second lens group is designed to satisfy the following condition: 0.3<D/fw<0.4 where D is the total on-axis thickness of said second lens group.

Claim 8

A zoom lens according to claim 1, wherein said third lens group comprises, in succession from the object side, a biconvex single lens having a positive refractive power, and a cemented lens consisting of a biconvex positive lens and a biconcave negative lens cemented together.

Claim 9

A zoom lens according to claim 7, wherein when the refractive indices of said biconvex positive lens and said biconcave negative lens in said cemented lens in said third lens group for d-line (587.6 nm) are n 321 and n 322 , respectively and further, the focal length of said third lens group is f 3 and the radius of curvature of the cemented surface of said cemented lens is said third lens group is r S2 , said cemented lens in said third lens group is designed to satisfy the following conditions: 0.27<n322-n321 -0.75<rs2/f3<-0.5.

Claim 10

A zoom lens according to claim 1, wherein said fourth lens group comprises, in succession from the object side, a positive lens, a biconvex positive lens and a negative lens having its surface of sharper curvature facing the object side.

Claim 11

A zoom lens according to claim 1, which is constructed in accordance with the following data: ______________________________________ r d ν n ______________________________________ 1 116.278 1.50 23.0 1.86074 2 58.806 7.30 69.9 1.51860 3 -124.613 0.10 4 33.356 3.80 55.6 1.69680 5 52.494 (d5) 6 75.327 1.50 55.6 1.69680 7 13.051 5.40 8 -24.719 1.20 55.6 1.69680 9 109.615 0.20 10 29.74l 3.30 25.5 1.80458 11 -75.999 1.20 43.3 1.84042 12 158.365 (d12) 13 45.324 3.20 64.1 1.51680 14 -38.885 0.10 15 21.606 6.20 69.9 1.51860 16 -21.375 3.00 39.6 1.80454 17 54.807 (d17) 18 375.899 4.50 60.1 1.62041 19 -23.234 0.10 20 74.386 3.30 50.8 1.65844 21 -56.208 2.40 22 -20.007 1.20 39.6 1.80454 23 -829.763 (Bf) ______________________________________ f 35.9981 59.9964 103.0187 d5 1.5844 12.4303 23.1397 d12 14.6271 8.5396 2.5286 d17 9.1990 7.8301 7.4701 Bf 41.3233 51.1822 59.7216 ______________________________________ Sixth surface (aspherical surface) R = 75.327 C.sub.4 = -0.2279E-05, C.sub.6 = -0.8209E-07 C.sub.8 = 0.6910E-09, C.sub.10 = -0.2805E-11 ______________________________________ wherein the numbers at the left end represent the order from the object side, r represents the radius of curvature of each lens surface, d represents the thickness of each lens and the spacing between the lens surfaces, n represents the refractive index for d-line, and f represents focal length of the zoom lens and wherein, the shape of the aspherical surface provided on the object side surface of the positive meniscus lens L 21 located most adjacent to the object side of the second lens group G2 is shown by the aspherical surface equation given below. ##EQU12## where X(y) represents the distance along the direction of the optic axis from the tangential plane at the vertex of the aspherical surface to the position on the aspherical surface at a height y, R represents the paraxial radius of curvature, and Cn represents the aspherical surface coefficient with 10 -n as E-n.

Claim 12

A zoom lens according to claim 1, which is constructed in accordance with the following data: ______________________________________ r d ν n ______________________________________ 1 118.343 1.50 23.0 1.86074 2 58.652 7.30 69.9 1.51860 3 -122.366 0.10 4 33.396 3.80 55.6 1.69680 5 52.877 (d5) 6 73.858 1.50 53.3 1.69350 7 12.899 5.10 8 -23.692 1.20 55.6 1.69680 9 120.425 0.20 10 29.938 3.30 25.5 1.80458 11 -61.989 1.20 43.3 1.84042 12 189.256 (d12) 13 47.033 3.50 64.1 1.51680 14 -38.870 0.10 15 20.876 6.20 56.4 1.50137 16 -21.570 3.00 33.9 1.80384 17 59.932 (d17) 18 356.270 4.50 54.0 1.61720 19 -22.902 0.10 20 78.513 3.30 58.5 1.65160 21 -56.099 2.40 22 -19.489 1.20 40.9 1.79631 23 -387.670 (Bf) ______________________________________ f 36.0332 60.0354 103.0147 d5 1.7714 12.6172 23.3267 d12 14.4840 8.3965 2.3855 d17 9.1067 7.7378 7.3778 Bf 41.4136 51.2588 59.7464 ______________________________________ Sixth surface (aspherical surface) R = 73.858 C.sub.4 = -0.2036E-05, C.sub.6 = -0.8148E-07 C.sub.8 = 0.6559E-09, C.sub.10 = -0.2684E-11 ______________________________________ wherein the numbers at the left end represent the order from the object side, r represents the radius of curvature of each lens surface, d represents the thickness of each lens and the spacing between the lens surfaces, n represents the refractive index for d-line, and f represents focal length of the zoom lens and wherein, the shape of the aspherical surface provided on the object side surface of the positive meniscus lens L 21 located most adjacent to the object side of the second lens group G2 is shown by the aspherical surface equation given below. ##EQU13## where X(y) represents the distance along the direction of the optic axis from the tangential plane at the vertex of the aspherical surface to the position on the aspherical surface at a height y, R represents the paraxial radius of curvature, and Cn represent the aspherical surface coefficient with 10 -n as E-n.

Claim 13

A zoom lens according to claim 1, which is constructed in accordance with the following data: ______________________________________ r d ν n ______________________________________ 1 120.145 1.50 25.5 1.80458 2 52.949 7.90 69.9 1.51860 3 -110.566 0.10 4 31.984 3.80 55.6 1.69680 5 48.957 (d5) 6 49.087 1.80 46.5 1.80411 7 13.558 5.40 8 -26.793 1.20 46.5 1.80411 9 114.932 0.20 10 30.047 3.30 23.0 1.86074 11 -114.188 1.20 49.4 1.77279 12 110.881 (d12) 13 52.088 3.20 60.3 1.51835 14 -42.661 0.10 15 19.984 6.20 64.1 1.51680 16 -25.974 3.00 33.9 1.80384 17 49.762 (d17) 18 100.778 3.50 37.9 1.72342 19 -31.102 0.10 20 146.905 3.00 33.9 1.80384 21 -60.597 2.50 22 -20.403 1.20 25.5 1.80458 23 -3247.710 (Bf) ______________________________________ f 35.9988 59.9982 102.9942 d5 1.1646 11.9945 22.1327 d12 14.8379 8.6437 2.3302 d17 10.3479 9.6336 9.4800 Bf 40.5897 49.8335 58.4844 ______________________________________ Sixth surface (aspherical surface) R = 49.087 C.sub.4 = -0.6974E-05, C.sub.6 = -0.4332E-07 C.sub.8 = 0.2560E-09, C.sub.10 = -0.1310E-11 ______________________________________ wherein the numbers at the left end represent the order from the object side, r represents the radius of curvature of each lens surface, d represents the thickness of each lens and the spacing between the lens surfaces, n represents the refractive index for d-line, and f represents focal length of the zoom lens and wherein, the shape of the aspherical surface provided on the object side surface of the positive meniscus lens L 21 located most adjacent to the object side of the second lens group G2 is shown by the aspherical surface equation given below. ##EQU14## where X(y) represents the distance along the direction of the optic axis from the tangential plane at the vertex of the aspherical surface to the position on the aspherical surface at a height y, R represents the paraxial radius of curvature, and Cn represents the aspherical surface coefficient with 10 -n as E-n.

Claim 14

A zoom lens according to claim 1, which is constructed in accordance with the following data: ______________________________________ r d ν n ______________________________________ 1 99.956 1.50 23.0 1.86074 2 54.213 .50 3 53.257 7.30 69.9 1.51860 4 -134.947 0.10 5 33.368 3.80 55.6 1.69680 6 50.215 (d5) 7 74.980 1.50 55.6 1.69680 8 12.950 5.10 9 -24.122 1.20 55.6 1.69680 10 116.302 0.20 11 29.623 3.30 25.5 1.80458 12 -79.429 1.20 43.3 1.84042 13 162.147 (d12) 14 42.225 3.50 64.1 1.51680 15 -42.225 0.10 16 21.790 6.20 56.4 1.50137 17 -21.790 3.00 33.9 1.80384 18 66.364 (d18) 19 1646.746 4.50 54.0 1.61720 20 -23.205 0.10 21 61.237 3.30 58.5 1.65160 22 -61.237 2.40 23 -20.217 1.20 40.9 1.79631 24 -1314.012 (Bf) ______________________________________ f 36.0362 60.1034 103.0141 d6 1.7713 12.6171 23.3266 d13 14.4840 8.3965 2.3855 d18 9.1067 7.7378 7.3778 Bf 41.2895 51.0141 59.0757 ______________________________________ Seventh surface (aspherical surface) R = 74.980 C.sub.4 = -0.1862E-05, C.sub.6 = -0.8809E-07 C.sub.8 = 0.7091E-09, C.sub.10 = -0.2741E-11 ______________________________________ wherein the numbers at the left end represent the order from the object side, r represents the radius of curvature of each lens surface, d represents the thickness of each lens and the spacing between the lens surfaces, n represents the refractive index for d-line, and f represents focal length of the zoom lens and wherein, the shape of the aspherical surface provided on the object side surface of the positive meniscus lens L 21 located most adjacent to the object side of the second lens group G2 is shown by the aspherical surface equation given below. ##EQU15## where X(y) represents the distance along the direction of the optic axis from the tangential plane at the vertex of the aspherical surface to the position on the aspherical surface at a height y, R represents the paraxial radius of curvature, and Cn represents the aspherical surface coefficient with 10 -n as E-n.

Claim 15

A zoom lens comprising, in succession from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens group having a positive refractive power, said zoom lens being designed such that during the magnification change from the wide angle and to the telephoto end, the air space between said first lens group and said second lens group is enlarged, the air space between said second lens group and said third lens group is reduced and further, the air space between said third lens group and said fourth lens group is varied, said second lens group comprising, in succession from the object side, a negative meniscus lens having its convex surface facing the object side, a cemented negative lens consisting of a positive lens and a negative lens cemented together, and a positive meniscus lens having its convex surface facing the object side, said second lens group being designed to satisfy the following conditions:

Claim 16

A zoom lens comprising, in succession from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens group having a positive refractive power, said zoom lens being designed such that during the magnification change from the wide angle and to the telephoto end, the air space between said first lens group and said second lens group is enlarged, the air space between said second lens group and said third lens group is reduced and further, the air space between said third lens group and said fourth lens group is varied, said second lens group comprising, in succession from the object side, a negative meniscus lens having its convex surface facing the object side, a cemented negative lens consisting of a positive lens and a negative lens cemented together, and a positive meniscus lens having its convex surface facing the object side, said second lens group being designed to satisfy the following conditions:

Claim 17

-0. 6<f2/fw <-0.4 -1.1<f22/fw<-0.5 ν22n-ν22p >19 where f w : the focal length of the zoom 1ens at the wide angle end f 2 : the focal length of the second lens group f 22 : the focal length of the cemented negative lens in the second lens group ν 22n : the Abbe number of the negative lens in the cemented negative lens in the second lens group ν 22p : the Abbe number of the positive lens in the cemented negative lens in the second lens group.

Claim 18

-0. 6<f2/fw <-0.4 -1.1<f22/fw<-0.5 ν22n-ν22p >19 where f w : the focal length of the zoom 1ens at the wide angle end f 2 : the focal length of the second lens group f 22 : the focal length of the cemented negative lens in the second lens group ν 22n : the Abbe number of the negative lens in the cemented negative lens in the second lens group ν 22p : the Abbe number of the positive lens in the cemented negative lens in the second lens group.

Claim 19

A zoom lens according to claim 14, wherein said second lens group is designed to further satisfy the following condition in order to make the zoom lens more compact: -0.5<f2/fw<-0.4.

Claim 20

A zoom lens according to claim 14, wherein said cemented negative lens in said second lens group comprises, in succession from the object side, a positive meniscus lens having its convex surface facing the image side, and a negative lens cemented to said positive meniscus lens and having its surface of sharper curvature facing the object side, and is designed to satisfy the following condition: -0.65<rs1/fw<-0.3 where r S1 is the radius of curvature of the cemented surface of said cemented negative lens in said second lens group.

Claim 21

A zoom lens according to claim 14, wherein said cemented negative lens in said second lens group comprises, in succession from the object side, a biconcave negative lens, and a positive lens cemented to said negative lens and having its surface of sharper curvature facing the object side, and is designed to satisfy the following condition: 0.79<rs1/fw<2 where r S1 is the radius of curvature of the cemented surface of said cemented negative lens in said second lens group.

Claim 22

A zoom lens according to claim 14, wherein said third lens group and said fourth lens group are designed to satisfy the following conditions: -3<f3/f2<-2 -4.2<f4/f2<-2.9 where f 3 is the focal length of said third lens group, and f 4 is the focal length of said fourth lens group.

Claim 23

A zoom lens according to claim 14, wherein said negative single lens and said cemented negative lens in said second lens group are designed to satisfy the following condition: 1<f22/f21<1.6. where f 21 is the focal length of said negative single lens in said second lens group, and f 22 is the focal length of said cemented negative lens in said second lens group.

Claim 24

A zoom lens according to claim 14, wherein one of the surfaces of the plurality of lenses constituting said second lens group is formed into an aspherical surface whose negative refractive power progressively becomes stronger from the optic axis toward the margin.

Claim 25

A zoom lens according to claim 20, wherein one of said negative meniscus lens and said cemented negative lens in said second lens group has its object side surface constructed of an aspherical surface which satisfies the following condition: ##EQU16## l : maximum image height y : the height from the optic axis R : the radius of curvature of the paraxial reference spherical surface C i : aspherical surface coefficient (i=4, 6, 8, 10) X(y) : the distance along the direction of the optic axis from the tangential plane at the vertex of the aspherical surface to the position on the aspherical surface at the height y X O (y) : the distance along the direction of the optic axis from the tangential plane at the vertex of the aspherical surface to the position on the paraxial reference spherical surface of the aspherical surface at the height y.

Claim 26

A zoom lens according to claim 14, wherein said third lens group comprises in succession from the object side, a biconvex positive single lens and a cemented lens consisting of a biconvex positive lens and a biconcave negative lens cemented together, and satisfies the following conditions: 0.26<n32n-n32p -1.1<rs2/f3<-0.46 where n 32p : the refractive index of the biconvex positive lens in the cemented lens in the third lens group for d-line (587.6 nm) n 32n : the refractive index of the biconcave negative lens in the cemented lens in the third lens group for d-line (587.6 nm) r S2 : the radius of curvature of the cemented surface of the cemented lens in the third lens group.

Claim 27

A zoom lens according to claim 14, wherein said fourth lens group comprises, in succession from the object side, a positive lens, a biconvex positive lens and a negative lens having its surface of sharper curvature facing the object side.

Claim 28

A zoom lens according to claim 14, which is constructed in accordance with the following data: ______________________________________ r d Abbe n ______________________________________ 1 118.343 1.50 23.0 1.86074 2 58.652 7.30 69.9 1.51860 3 -122.366 0.10 4 33.634 3.80 51.1 1.73350 5 51.679 1.55 6 51.492 1.50 52.3 1.74810 7 13.662 5.10 8 -24.720 2.80 25.5 1.80458 9 -14.348 1.20 49.4 1.77279 10 418.286 0.20 11 30.648 1.90 25.5 1.80458 12 64.282 14.33 13 48.210 3.50 64.1 1.51680 14 -37.593 0.10 15 21.267 6.20 56.4 1.50137 16 -21.285 3.00 33.9 1.80384 17 62.757 9.63 18 340.249 4.50 53.9 1.71300 19 -23.909 0.10 20 91.716 3.30 58.5 1.65160 21 -72.874 2.40 22 -19.349 1.20 40.9 1.79631 23 -285.532 41.20 ______________________________________ f 36.0328 60.0346 103.0120 d5 1.5511 12.3969 23.1064 d12 14.3330 8.2455 2.2345 d17 9.6254 8.2565 7.8965 Bf 41.2000 51.0445 59.5303 ______________________________________ Sixth surface (aspherical surface) C.sub.4 = -0.3616E-05, C.sub.6 = -0.8343E-07 C.sub.8 = 0.6907E-09, C.sub.10 = -0.2864E-11 ______________________________________ wherein the numbers at the left end represent the order from the object side, r represents the radius of curvature of each lens surface, d represents the thickness of each lens and the spacing between the lens surfaces, n represents the refractive index for d-line, and f represents focal length of the zoom lens and wherein, the shape of the aspherical surface provided on the object side surface of the positive meniscus lens L 21 located most adjacent to the object side of the second lens group G2 is shown by the aspherical surface equation given below. ##EQU17## where X(y) represents the distance along the direction of the optic axis from the tangential plane at the vertex of the aspherical surface to the position on the aspherical surface at a height y, R represents the paraxial radius of curvature, and Cn represents the aspherical surface coefficient with 10 -n as E-n.

Claim 29

A zoom lens according to claim 14, which is constructed in accordance with the following data: ______________________________________ r d Abbe n ______________________________________ 1 118.343 1.50 23.0 1.86074 2 58.652 7.30 69.9 1.51860 3 -122.366 0.10 4 33.396 3.80 55.6 1.69680 5 52.877 1.79 6 85.328 1.50 57.5 1.67025 7 13.626 5.10 8 -24.265 2.40 25.5 1.80458 9 -13.985 1.20 47.5 1.78797 10 -1196.567 0.20 11 31.517 2.30 25.5 1.80458 12 70.772 14.26 13 47.033 3.50 64.1 1.51680 14 -38.870 0.10 15 20.876 6.20 56.4 1.50137 16 -21.570 3.00 33.9 1.80384 17 59.933 9.11 18 356.270 4.50 54.0 1.61720 19 -22.902 0.10 20 78.513 3.30 58.5 1.65160 21 -56.099 2.40 22 -19.489 1.20 40.9 1.79631 23 -387.656 41.41 ______________________________________ f 36.0329 60.0347 103.0125 d5 1.7902 12.6360 23.3455 d12 14.2575 8.1700 2.1590 d17 9.1067 7.7378 7.3778 Bf 41.4128 51.2574 59.7436 ______________________________________ Eighth surface (aspherical surface) C.sub.4 = -0.3808E-05, C.sub.6 = -0.1145E-06 C.sub.8 = 0.1538E-08, C.sub.10 = -0.1336E-10 ______________________________________ wherein the numbers at the left end represent the order from the object side, r represents the radius of curvature of each lens surface, d represents the thickness of each lens and the spacing between the lens surfaces, n represents the refractive index for d-line, and f represents focal length of the zoom lens and wherein, the shape of the aspherical surface provided on the object side surface of the positive meniscus lens L 21 located most adjacent to the object side of the second lens group G2 is shown by the aspherical surface equation given below. ##EQU18## where X(y) represents the distance along the direction of the optic axis from the tangential plane at the vertex of the aspherical surface to the position on the aspherical surface at a height y, R represents the paraxial radius of curvature, and Cn represents the aspherical surface coefficient with 10 -n as E-n.

Claim 30

A zoom lens according to claim 14, which is constructed in accordance with the following data: ______________________________________ r d Abbe n ______________________________________ 1 118.343 1.50 23.0 1.86074 2 58.652 7.30 69.9 1.51860 3 -122.366 0.10 4 33.396 3.80 55.6 1.69680 5 52.877 1.82 6 61.938 1.50 55.6 1.69680 7 13.009 5.10 8 -24.778 2.40 25.5 1.80458 9 -16.249 1.20 52.3 1.74810 10 172.526 0.20 11 29.980 2.30 25.5 1.80458 12 80.762 14.47 13 42.555 3.50 64.1 1.51680 14 -38.088 0.10 15 21.789 6.20 56.4 1.50137 16 -21.658 3.00 33.9 1.80384 17 56.880 8.80 18 293.077 4.50 54.0 1.61720 19 -22.932 0.10 20 80.751 3.30 58.5 1.65160 21 -61.128 2.40 22 -19.591 1.20 40.9 1.79631 23 -274.524 41.49 ______________________________________ f 36.0329 59.9997 102.9999 d5 1.8185 14.9331 25.9585 d12 14.4699 8.8867 2.4707 d17 8.7976 7.5612 8.2439 Bf 41.4869 48.3064 54.0396 ______________________________________ Sixth surface (aspherical surface) C.sub.4 = -0.4308E-05, C.sub.6 = -0.9156E-07 C.sub.8 = 0.7541E-09, C.sub.10 = -0.3154E-11 ______________________________________ wherein the numbers at the left end represent the order from the object side, r represents the radius of curvature of each lens surface, d represents the thickness of each lens and the spacing between the lens surfaces, n represents the refractive index for d-line, and f represents focal length of the zoom lens and wherein, the shape of the aspherical surface provided on the object side surface of the positive meniscus lens L 21 located most adjacent to the object side of the second lens group G2 is shown by the aspherical surface equation given below. ##EQU19## where X(y) represents the distance along the direction of the optic axis from the tangential plane at the vertex of the aspherical surface to the position on the aspherical surface at a height y, R represents the paraxial radius of curvature, and Cn represents the aspherical surface coefficient with 10 -n as E-n.

Claim 31

A zoom lens according to claim 14, which is constructed in accordance with the following data: ______________________________________ r d Abbe n ______________________________________ 1 113.125 1.50 23.0 1.86074 2 57.134 7.30 69.9 1.51860 3 -126.031 0.10 4 33.040 3.80 58.5 1.65160 5 54.293 1.33 6 52.180 1.50 57.5 1.67025 7 12.713 5.10 8 -24.918 1.10 52.3 1.74810 9 32.898 2.30 23.0 1.86074 10 167.263 0.10 11 27.406 1.90 25.5 1.80458 12 52.450 15.02 13 51.155 3.50 69.9 1.51860 14 -38.045 0.10 15 20.881 6.20 56.4 1.50137 16 -21.302 3.00 33.9 1.80384 17 64.699 8.89 18 -7924.511 4.50 50.8 1.65844 19 -23.176 0.10 20 78.513 3.30 57.0 1.62280 21 -51.820 2.40 22 -19.489 1.20 40.9 1.79631 23 -325.859 41.74 ______________________________________ f 36.0327 60.0344 103.0112 d5 1.3272 12.1730 22.8825 d12 15.0199 8.9324 2.9214 d17 8.8935 7.5246 7.1646 Bf 41.7425 51.5867 60.0720 ______________________________________ Sixth surface (aspherical surface) C.sub.4 = -0.3724E-05, C.sub.6 = -0.6826E-07 C.sub.8 = 0.4312E-09, C.sub.10 = -0.1677E-11 ______________________________________ wherein the numbers at the left end represent the order from the object side, r represents the radius of curvature of each lens surface, d represents the thickness of each lens and the spacing between the lens surfaces, n represents the refractive index for d-line, and f represents focal length of the zoom lens and wherein, the shape of the aspherical surface provided on the object side surface of the positive meniscus lens L 21 located most adjacent to the object side of the second lens group G2 is shown by the aspherical surface equation given below. ##EQU20## where X(y) represents the distance along the direction of the optic axis from the tangential plane at the vertex of the aspherical surface to the position on the aspherical surface at a height y, R represents the paraxial radius of curvature, and Cn represents the aspherical surface coefficient with 10 -n as E-n.

Claim 32

A zoom lens according to claim 14, which is constructed in accordance with the following data: ______________________________________ r d Abbe n ______________________________________ 1 117.146 1.50 23.0 1.86074 2 59.914 7.30 69.9 1.51860 3 -129.995 0.10 4 34.324 3.80 58.5 1.65160 5 58.817 1.42 6 48.701 1.50 57.5 1.67025 7 12.637 5.10 8 -24.441 1.10 52.3 1.74810 9 34.076 2.30 23.0 1.86074 10 155.098 0.10 11 27.849 1.90 25.5 1.80458 12 55.884 14.95 13 40.866 3.50 69.9 1.51860 14 -42.729 0.10 15 22.791 6.20 56.4 1.50137 16 -20.659 3.00 33.9 1.80384 17 76.686 8.81 18 -10952.961 4.50 50.8 1.65844 19 -23.332 0.10 20 79.500 3.30 57.0 1.62280 21 -51.786 2.40 22 -19.555 1.20 40.9 1.79631 23 -297.866 41.82 ______________________________________ f 36.0325 60.0339 103.0097 d5 1.4211 12.2669 22.9764 d12 14.9469 8.8594 2.8484 d17 8.8131 7.4442 7.0842 Bf 41.8181 51.6619 60.1462 ______________________________________ Sixth surface (aspherical surface) C.sub.4 = -0.3743E-05, C.sub.6 = -0.6955E-07 C.sub.8 = 0.5633E-09, C.sub.10 = -0.2637E-11 ______________________________________ wherein the numbers at the left end represent the order from the object side, r represents the radius of curvature of each lens surface, d represents the thickness of each lens and the spacing between the lens surfaces, n represents the refractive index for d-line, and f represents focal length of the zoom lens and wherein, the shape of the aspherical surface provided on the object side surface of the positive meniscus lens L 21 located most adjacent to the object side of the second lens group G2 is shown by the aspherical surface equation given below. ##EQU21## where X(y) represents the distance along the direction of the optic axis from the tangential plane at the vertex of the aspherical surface to the position on the aspherical surface at a height y, R represents the paraxial radius of curvature, and Cn represents the aspherical surface coefficient with 10 -n as E-n.