Zoom lens

Claim 2

A zoom lens which is compact and light in weight, which has a large aperture ratio of about 1:1.2 to 1:1.6, and which has a high zoom ratio of about 6 to 10, comprising, a magnification changing system including, in succession from the object side, a first lens means as a focusing portion having a positive refractive power, a second lens means as a variator portion having a negative refractive power and movable along the optical axis to thereby change chiefly the focal length, and a third lens means as a compensator portion having a negative refractive power and maintaining the image plane fluctuated by movement of said variator portion at a predetermined position, and a relay lens system succeeding said magnification changing system, consisting essentially of a fourth lens means as a forward relay group having a positive refractive power and a fifth lens means as a rearward relay group having a positive refractive power, said fourth lens means consisting of, in succession from the object side, a positive lens component having its surface of sharper curvature facing the image side, a biconvex cemented positive lens component having a cemented surface convex to the image side and a positive lens component having its surface of sharper curvature facing the object side, said fifth lens means consisting of a cemented positive lens component having a cemented surface convex to the object side and a positive lens component, wherein said zoom lens satisfies the following conditions: ##EQU7## where R A represents the radius of curvature of the cemented surface of the cemented lens component in said fourth lens means, ν AP and ν AN represent the Abbe numbers of a positive lens and a negative lens, respectively, forming said cemented lens component in said fourth lens means, R B represents the radius of curvature of the cemented surface of the cemented lens component in said fifth lens means, ν BP and ν BN represent the Abbe numbers of a positive lens and a negative lens, respectively, forming said cemented lens component in said fifth lens means, F W represents the focal length of the entire system at the wide angle end, f 5 represents the focal length of said fifth lens means, D represents the principal plane spacing between said fourth lens means and said fifth lens means, Rc represents the radius of curvature of the object side surface of the positive lens component in said fifth lens means, and Bf represents the back focal length.

Claim 3

A zoom lens according to claim 1, wherein said first lens means has a cemented positive lens component having a cemented surface convex to the object side and a positive meniscus lens component having its convex surface facing the object side, said second lens means has a negative meniscus lens component having its convex surface facing the object side, and a cemented negative lens component having a cemented surface convex to the object side, said third lens means has a negative lens component having its surface of sharper curvature facing the object side.

Claim 4

The zoom lens recited in claim 2, wherein said zoom lens further satisfies the following conditions: ##EQU8## where f 1 , f 2 , f 3 , f 4 and f 5 represent the focal lengths of said first, second, third, fourth and fifth lens means, respectively, F T represents the focal length of the entire system at the telephoto end, and r a and r b represent the radii of curvature of the forward and rearward surfaces, respectively, of the positive meniscus lens component in said first lens means.

Claim 5

The zoom lens recited in claim 3, wherein said zoom lens further satisfies the following conditions: 5.0F.sub.W <f.sub.1 <8.0F.sub.W ( 11) 1.0F.sub.W <|f.sub.2 |<2.0F.sub.W ( 12) 3.0F.sub.W <|f.sub.3 |<5.0F.sub.W ( 13) 1.5F.sub.W <f.sub.4 <2.5F.sub.W ( 14) 2.5F.sub.W <f.sub.5 <5.5F.sub.W ( 15) where F W represents the focal length of the entire system at the wide angle end.

Claim 6

The zoom lens recited in claim 4, wherein numerical data are as follows: __________________________________________________________________________ Focal length 11.5˜69.0, Zoom ratio 6, F-number 1.2 __________________________________________________________________________ Radius of Center thickness Refractive Abbe curvature and air space index number __________________________________________________________________________ r.sub.1 82.283 d.sub.1 1.3 n.sub.1 1.80518 ν.sub.1 25.5 L.sub.1 r.sub.2 41.208 d.sub.2 11.7 n.sub.2 1.71300 ν.sub.2 53.9 r.sub.3 -395.394 d.sub.3 0.1 G.sub.1 r.sub.4 42.755 d.sub.4 5.7 n.sub.3 1.51680 ν.sub.3 64.2 L.sub.2 r.sub.5 92.175 d.sub.5 Variable r.sub.6 122.416 d.sub.6 1.0 n.sub.4 1.74443 ν.sub.4 49.4 L.sub.3 r.sub.7 15.859 d.sub.7 6.5 r.sub.8 -20.060 d.sub.8 1.0 n.sub.5 1.60311 ν.sub.5 60.7 G.sub.2 L.sub.4 r.sub.9 22.337 d.sub.9 3.5 n.sub.6 1.80518 ν.sub.6 25.5 r.sub.10 -6704.737 d.sub.10 Variable r.sub.11 -21.619 d.sub.11 1.0 n.sub.7 1.60311 ν.sub.7 60.7 L.sub.5 } G.sub.3 r.sub.12 -189.609 d.sub.12 Variable r.sub.13 -42.947 d.sub.13 3.9 n.sub.8 1.71300 ν.sub.8 53.9 L.sub.6 r.sub.14 -22.593 d.sub.14 0.1 r.sub.15 158.920 d.sub.15 9.0 n.sub.9 1.56384 ν.sub.9 60.8 L.sub.7 G.sub.4 r.sub.16 -21.084 d.sub.16 1.0 n.sub.10 1.74000 ν.sub.10 28.2 r.sub.17 -46.347 d.sub.17 0.2 r.sub.18 44.489 d.sub.18 3.8 n.sub.11 1.74000 ν.sub.11 44.9 L.sub.8 r.sub.19 362.562 d.sub.19 1.8 r.sub.20 ∞ d.sub.20 10.0 n.sub.12 1.57501 ν.sub.12 41.3 Prism P r.sub.21 ∞ d.sub.21 25.1 r.sub.22 144.303 d.sub.22 1.0 n.sub.13 1.74000 ν.sub.13 28.2 L.sub.9 r.sub.23 17.591 d.sub.23 6.0 n.sub.14 1.56384 ν.sub.14 60.8 r.sub.24 -52.016 d.sub.24 0.2 G.sub.5 r.sub.25 19.770 d.sub.25 4.0 n.sub.15 1.51680 ν.sub.15 64.2 L.sub.10 r.sub.26 136.874 Bf 16.54 __________________________________________________________________________ Focal length F.sub.W = 11.5 F.sub.M = 28.0 F.sub.T = 69.0 __________________________________________________________________________ d.sub.5 1.96 20.04 31.05 d.sub.10 32.71 12.06 4.00 d.sub.12 3.42 6.99 3.05 __________________________________________________________________________ f.sub.1 =63.3 f.sub.2 =-15.0 f.sub.3 =-40.5 f.sub.4 =24.8 f.sub.5 =34.3 Principal plane spacing between the fourth and the fifth lens means D=42.36 ##EQU9##

Claim 7

The zoom lens recited in claim 4, wherein numerical data are as follows: __________________________________________________________________________ Focal length 11.0˜88.0, Zoom ratio 8, F-number 1.6 __________________________________________________________________________ Radius of Center thickness Refractive curvature and air space index Abbe number __________________________________________________________________________ r.sub.1 87.625 d.sub.1 1.3 n.sub.1 1.80518 ν.sub.1 25.5 L.sub.1 r.sub.2 47.000 d.sub.2 10.3 n.sub.2 1.65160 ν.sub.2 58.5 r.sub.3 -401.700 d.sub.3 0.1 G.sub.1 r.sub.4 49.638 d.sub.4 5.4 n.sub.3 1.51660 ν.sub.3 64.2 L.sub.2 r.sub.5 129.555 d.sub.5 variable r.sub.6 89.890 d.sub.6 1.0 n.sub.4 1.71300 ν.sub.4 53.9 L.sub.3 r.sub.7 15.414 d.sub.7 5.8 G.sub.2 r.sub.8 -20.393 d.sub.8 1.0 n.sub.5 1.58913 ν.sub.5 61.2 L.sub.4 r.sub.9 18.054 d.sub.9 3.9 n.sub.6 1.71736 ν.sub. 6 29.5 r.sub.10 -299.105 d.sub.10 variable r.sub.11 -23.883 d.sub.11 1.0 n.sub.7 1.60311 ν.sub.7 60.7 L.sub.5 } G.sub.3 r.sub.12 -237.505 d.sub.12 variable r.sub.13 -153.412 d.sub.13 3.2 n.sub.8 1.71300 ν.sub.8 53.9 L.sub.6 r.sub.14 -29.058 d.sub.14 0.1 r.sub.15 56.397 d.sub.15 6.5 n.sub.9 1.58913 ν.sub.9 61.2 L.sub.7 G.sub.4 r.sub.16 -22.050 d.sub.16 1.0 n.sub.10 1.75520 ν.sub.10 27.5 r.sub.17 -68.139 d.sub.17 0.1 r.sub.18 37.710 d.sub.18 2.5 n.sub.11 1.71300 ν.sub.11 53.9 L.sub.8 r.sub.19 114.270 d.sub.19 21.9 r.sub.20 83.072 d.sub.20 1.0 n.sub.12 1.74950 ν.sub.12 25.0 L.sub.9 r.sub.21 11.546 d.sub.21 4.3 n.sub.13 1.56823 ν.sub.13 56.0 r.sub.22 -98.731 d.sub.22 1.0 G.sub.5 r.sub.23 50.000 d.sub.23 2.0 n.sub.14 1.74400 ν.sub.14 44.9 L.sub.10 r.sub.24 -130.371 Bf 14.95 __________________________________________________________________________ Focal length F.sub.W = 11.0 F.sub.M = 31.0 F.sub.T = 88.0 __________________________________________________________________________ d.sub.5 0.89 26.77 40.85 d.sub.10 41.97 13.27 3.26 d.sub.12 4.53 8.35 4.27 __________________________________________________________________________ f.sub.1 =72.1 f.sub.2 =-16.4 f.sub.3 =-44.3 f.sub.4 =22.2 f.sub.5 =49.7 Principal plane spacing between the fourth and the fifth lens means D=51.19 ##EQU10##

Claim 8

The zoom lens recited in claim 4, wherein numerical data are as follows: __________________________________________________________________________ Focal length 10.5˜105.0, Zoom ratio 10, F-number 1.6 __________________________________________________________________________ Radius of Center thickness Refractive Abbe curvature and air space index number __________________________________________________________________________ r.sub.1 97.177 d.sub.1 1.3 n.sub.1 1.80518 ν.sub.1 25.5 L.sub.1 r.sub.2 53.212 d.sub.2 12.5 n.sub.2 1.65160 ν.sub.2 58.5 r.sub.3 -799.589 d.sub.3 0.1 G.sub.1 r.sub.4 55.667 d.sub.4 7.0 n.sub.3 1.51860 ν.sub.3 70.1 L.sub.2 r.sub.5 172.998 d.sub.5 variable r.sub.6 167.781 d.sub.6 1.0 n.sub.4 1.65160 ν.sub.4 58.5 L.sub.3 r.sub.7 16.132 d.sub.7 6.1 G.sub.2 r.sub.8 -23.692 d.sub.8 1.0 n.sub.5 1.58913 ν.sub.5 61.2 L.sub.4 r.sub.9 18.905 d.sub.9 4.0 n.sub.6 1.72825 ν .sub.6 28.3 r.sub.10 330.951 d.sub.10 variable r.sub.11 -24.955 d.sub.11 1.0 n.sub.7 1.60311 ν.sub.7 60.7 L.sub.5 } G.sub.3 r.sub.12 -349.908 d.sub.12 variable r.sub.13 -211.000 d.sub.13 3.4 n.sub.8 1.74443 ν.sub.8 49.4 L.sub.6 r.sub.14 -30.530 d.sub.14 0.1 r.sub.15 66.041 d.sub.15 6.8 n.sub.9 1.58913 ν.sub.9 61.2 L.sub.7 G.sub.4 r.sub.16 -24.732 d.sub.16 1.1 n.sub.10 1.78470 ν.sub.10 26.1 r.sub.17 -83.595 d.sub.17 0.1 r.sub.18 40.841 d.sub.18 2.6 n.sub.11 1.71300 ν.sub.11 53.9 L.sub.8 r.sub.19 167.230 d.sub.19 30.0 r.sub.20 48.248 d.sub.20 1.0 n.sub.12 1.74950 ν.sub.12 35.0 L.sub.9 r.sub.21 10.845 d.sub.21 5.0 n.sub.13 1.56883 ν.sub.13 56.0 r.sub.22 -115.462 d.sub.22 1.0 G.sub.5 r.sub.23 60.000 d.sub.23 2.1 n.sub.14 1.79631 ν.sub.14 40.8 L.sub.10 r.sub.24 -336.344 Bf 13.45 __________________________________________________________________________ Focal length F.sub.W = 10.5 F.sub.M = 33.0 F.sub.T = 105.0 __________________________________________________________________________ d.sub.5 0.96 30.80 46.55 d.sub.10 50.07 15.74 4.48 d.sub.12 5.12 9.61 5.12 __________________________________________________________________________ f.sub.1 =80.5 f.sub.2 =-16.5 f.sub.3 =-44.6 f.sub.4 =23.4 f.sub.5 =51.7 Principal plane spacing between the fourth and fifth lens means D=39.65 ##EQU11##

Claim 9

A zoom lens which is compact and light in weight, which has a large aperture ratio of about 1:1.6, and which has a high zoom ratio of about 8 comprising, a magnification changing system including, in succession from the object side, a first lens means as a focusing portion having a positive refractive power, a second lens means as a variator portion having a negative refractive power and movable along the optical axis to thereby change chiefly the focal length, and a third lens means as a compensator portion having a negative refractive power and maintaining the image plane fluctuated by movement of said variator portion at a predetermined position, and a relay lens system succeeding said magnification changing system, consisting essentially of a fourth lens means as a forward relay group having a positive refractive power and a fifth lens means as a rearward relay group having a positive refractive power, said fourth lens means consisting of, in succession from the object side, a positive lens component having its surface of sharper curvature facing the image side, a biconvex cemented positive lens component having a cemented surface convex to the image side and a positive lens component having its surface of sharper curvature facing the object side, said fifth lens means consisting of a cemented positive lens component having a cemented surface convex to the object side, wherein said zoom lens satisfies the following conditions: ##EQU12## where R A represents the radius of curvature of the cemented surface of the cemented lens component in said fourth lens means, ν AP and ν AN represent the Abbe numbers of a positive lens and a negative lens, respectively, forming said cemented lens component in said fourth lens means, R B represents the radius of curvature of the cemented surface of the cemented lens component in said fifth lens means, ν BP and ν BN represent the Abbe numbers of a positive lens and a negative lens, respectively, forming said cemented lens component in said fifth lens means, F W represents the focal length of the entire system at the wide angle end, f 5 represents the focal length of said fifth lens means, D represents the principal plane spacing between said fourth lens means and said fifth lens means, Rc represents the radius of curvature of the object side surface of the positive lens component in said fifth lens means, and Bf represents the back focal length.

Claim 10

A zoom lens which is compact and light in weight, which has a large aperture ratio of about 1:1.6, and which has a high zoom ratio of about 8 comprising, a magnification changing system including, in succession from the object side, a first lens means as a focusing portion having a positive refractive power, a second lens means as a variator portion having a negative refractive power and movable along the optical axis to thereby change chiefly the focal length, and a third lens means as a compensator portion having a negative refractive power and maintaining the image plane fluctuated by movement of said variator portion at a predetermined position, and a relay lens system succeeding said magnification changing system, consisting essentially of a fourth lens means as a forward relay group having a positive refractive power and a fifth lens means as a rearward relay group having a positive refractive power, said fourth lens means consisting of, in succession from the object side, a positive lens component having its surface of sharper curvature facing the image side, a biconvex cemented positive lens component having a cemented surface convex to the image side and a positive lens component having its surface of sharper curvature facing the object side, said fifth lens means consisting of a cemented positive lens component having a cemented surface convex to the object side, wherein said zoom lens satisfies the following conditions: ##EQU12## where R A represents the radius of curvature of the cemented surface of the cemented lens component in said fourth lens means, ν AP and ν AN represent the Abbe numbers of a positive lens and a negative lens, respectively, forming said cemented lens component in said fourth lens means, R B represents the radius of curvature of the cemented surface of the cemented lens component in said fifth lens means, ν BP and ν BN represent the Abbe numbers of a positive lens and a negative lens, respectively, forming said cemented lens component in said fifth lens means, F W represents the focal length of the entire system at the wide angle end, f 5 represents the focal length of said fifth lens means, D represents the principal plane spacing between said fourth lens means and said fifth lens means, Rc represents the radius of curvature of the object side surface of the positive lens component in said fifth lens means, and Bf represents the back focal length.

Claim 11

A zoom lens according to claim 8, wherein said first lens means has a cemented positive lens component having a cemented surface convex to the object side and a positive meniscus lens component having its convex surface facing the object side, said second lens means has a negative meniscus lens component having its convex surface facing the object side, and a cemented negative lens component having a cemented surface convex to the object side, said third lens means has a negative lens component having its surface of sharper curvature facing the object side.

Claim 12

The zoom lens recited in claim 9, wherein numerical data are as follows: __________________________________________________________________________ Focal length 11.0˜88.0, Zoom ratio 8, F-number 1.6 __________________________________________________________________________ Radius of Center thickness Refractive Abbe curvature and air space index number __________________________________________________________________________ r.sub.1 87.620 d.sub.1 1.3 n.sub.1 1.80518 ν.sub.1 25.5 L.sub.1 r.sub.2 47.000 d.sub.2 10.3 n.sub.2 1.65160 ν.sub.2 58.5 r.sub.3 -401.700 d.sub.3 0.1 G.sub.1 r.sub.4 49.640 d.sub.4 5.4 n.sub.3 1.5168 ν.sub.3 64.2 L.sub.2 r.sub.5 129.551 d.sub.5 variable r.sub.6 89.890 d.sub.6 1.0 n.sub.4 1.71300 ν.sub.4 53.9 L.sub.3 r.sub.7 15.410 d.sub.7 5.8 G.sub.2 r.sub.8 -20.400 d.sub.8 1.0 n.sub.5 1.58913 ν.sub.5 61.2 L.sub.4 r.sub.9 18.050 d.sub.9 3.9 n.sub.6 1.71736 ν.sub.6 29.5 r.sub.10 -298.366 d.sub.10 variable r.sub.11 -23.880 d.sub.11 1.0 n.sub.7 1.60311 ν.sub.7 60.7 L.sub.5 } G.sub.3 r.sub.12 -227.227 d.sub.12 variable r.sub.13 -158.642 d.sub.13 3.2 n.sub.8 1.71300 ν.sub.8 53.9 L.sub.6 r.sub.14 -29.277 d.sub.14 0.1 r.sub.15 61.016 d.sub.15 5.9 n.sub.9 1.58913 ν.sub.9 61.2 L.sub.7 r.sub.16 -22.400 d.sub.16 1.0 n.sub.10 1.80518 ν.sub.10 25.5 G.sub.4 r.sub.17 -50.736 d.sub.17 0.3 r.sub.18 ∞ d.sub.18 10.0 n.sub.11 1.57501 ν.sub.11 41.3 Prism P r.sub.19 ∞ d.sub.19 4.0 r.sub.20 40.658 d.sub.20 2.5 n.sub.12 1.74443 ν.sub.12 49.4 L.sub.8 r.sub.21 103.601 d.sub.21 29.7 r.sub.22 16.288 d.sub.22 1.0 n.sub.13 1.75520 ν.sub.13 27.5 L.sub.9 G.sub.5 r.sub.23 8.967 d.sub.23 6.0 n.sub.14 1.56883 ν.sub.14 56.0 r.sub.24 -1564.799 Bf 11.43 __________________________________________________________________________ Focal length F.sub.W = 11.0 F.sub.M = 31.0 F.sub.T = 88.0 __________________________________________________________________________ d.sub.5 0.89 25.76 39.85 d.sub.10 41.97 13.27 3.26 d.sub.12 2.11 5.93 1.86 __________________________________________________________________________ f.sub.1 =72.1 f.sub.2 =-16.4 f.sub.3 =-44.3 f.sub.4 =21.5 f.sub.5 =37.8 Principal plane spacing between the fourth and the fifth lens means D=34.02 ##EQU13##