Three-group zoom lens

Claim 2

A three-group zoom lens having, in succession from a remoter imaging conjugate plane side, a convergent first group, a divergent second group and a convergent third group and in which by moving said second group and said third group in different manners of movement, the focal length of the entire system can be varied while maintaining the image plane constant, characterized in that said second group has, in succession from said first group side, a first component including at least one negative meniscus lens having its convex surface facing said first group, a second component which is a positive meniscus lens having its concave surface facing said first group, a third component which is a negative lens, and a fourth component which is a positive lens, and further characterized in that said zoom lens satisfies the following conditions: ##EQU2## where f A represents the focal length of the positive meniscus lens which is the second component, R A .sbsb.1 represents the radius of curvature of the surface of said second component which is adjacent to said first group, R A .sbsb.2 represents the radius of curvature of the surface of said second component which is adjacent to said third group, and f II represents the combined focal length of said second group.

Claim 3

A zoom lens according to claim 1, further characterized in that it satisfies the following conditions: ##EQU3## where R B .sbsb.1 represents the radius of curvature of the first group side surface of the negative lens which is the third component in said second group, D represents the air space between the second component and the third component in said second group, and R C .sbsb.1 represents the radius of curvature of the first group side surface of the positive lens which is the fourth component in said second group.

Claim 4

A zoom lens according to claim 2, further characterized in that said first group has two positive lens components, one of which has a negative lens and a positive lens cemented together or separated from each other.

Claim 5

A zoom lens according to claim 3, further characterized in that it satisfies the following condition: 0.3f.sub.I <R.sub.D.sbsb.1 <0.8f.sub.I where R D .sbsb.1 represents the radius of curvature of the first surface of the positive lens of said first group which is most adjacent to said second group, and f I represents the combined focal length of said first group.

Claim 6

A zoom lens according to claim 2, further characterized in that said third group has, in succession from the second group side, a positive first component, a negative second component and a positive third component, said positive first component includes at least two positive lenses, said negative second component includes a single or cemented negative lens, and said positive third component includes at least one positive lens.

Claim 7

A zoom lens according to claim 3, further characterized in that numerical data are as follows: __________________________________________________________________________ First Embodiment __________________________________________________________________________ f = 50 mm˜135 mm Aperture ratio 1:4.5 r.sub.1 = 533.59 d.sub.1 = 1.5 Nd.sub.1 = 1.8052 νd.sub.1 = 25.4 r.sub.2 = 84.07 d.sub.2 = 6.0 Nd.sub.2 = 1.6700 νd.sub.2 = 47.1 r.sub.3 = -377.89 d.sub.3 = 0.1 G.sub.1 r.sub.4 = 64.57 d.sub.4 = 5.0 Nd.sub.3 = 1.1 νd.sub.3 = 48.1 r.sub.5 = 196.59 d.sub.5 = variable r.sub.6 = 119.01 d.sub.6 = 1.1 Nd.sub.4 = 1.744 νd.sub.4 = 45.1 C.sub.1 r.sub.7 = 26.94 d.sub.7 = 7.15 r.sub.8 = -108.42 d.sub.8 = 3.1 Nd.sub.5 = 1.7234 νd.sub.5 = 38.0 C.sub.2 r.sub.9 = -35.11 d.sub.9 = 1.5 G.sub.2 r.sub.10 = -29.88 d.sub.10 = 1.15 Nd.sub.6 = 1.713 νd.sub.6 = 54.0 C.sub.3 r.sub.11 = 50.31 d.sub.11 = 1.35 r.sub.12 = 42.32 d.sub.12 = 3.0 Nd.sub.7 = 1.795 νd.sub.7 = 28.6 C.sub.4 r.sub.13 = 498.92 d.sub.13 = variable r.sub.14 = 59.35 d.sub.14 = 2.3 Nd.sub.8 = 1.5891 νd.sub.8 = 61.2 r.sub.15 = -2202.0 d.sub.15 = 0.2 r.sub.16 = 29.18 d.sub.16 = 3.45 Nd.sub.9 = 1.5112 νd.sub.9 = 50.9 r.sub.17 = 24.17 d.sub.17 = 0.2 r.sub.18 = 24.17 d.sub.18 = 3.8 Nd.sub.10 = 1.5168 νd.sub.10 = 64.1 G.sub.3 r.sub.19 = 39.33 d.sub.19 = 5.4 r.sub.20 = 173.54 d.sub.20 = 1.85 Nd.sub.11 = 1.8052 νd.sub.11 = 25.4 r.sub.21 = 19.91 d.sub.21 = 6.0 r.sub.22 = 44.01 d.sub.22 = 4.1 Nd.sub.12 = 1.6127 νd.sub.12 = 44.4 r.sub.23 = -62.20 S' f.sub.A = 70.52 f.sub.I = 108.0 f.sub.II = -35.5 f.sub.III = 48.5 S': Back focal length Focal length d.sub.5 d.sub.13 S' 50.0 2.495 35.69 66.409 95.46 24.064 13.347 76.818 135.0 33.615 0.535 81.427 __________________________________________________________________________ where r 1 , r 2 , r 3 , . . . , represent the radii of curvature of the refracting surfaces of the successive lenses from the object side, d 1 , d 2 , d 3 , . . . , represent the center thicknesses and air spaces of the respective lenses, Nd 1 , Nd 2 , Nd 3 , . . . , represent the refractive indices of the respective lenses for d-line (λ=587.6 nm), and νd 1 , νd 2 , νd 3 , . . . , represent the Abbe numbers of the respective lenses.

Claim 8

A zoom lens according to claim 2, further characterized in that numerical data are as follows: __________________________________________________________________________ Second Embodiment __________________________________________________________________________ f = 32 mm˜92 mm Effective aperture ratio Fe 1:5.9˜1:20.1 Magnification 0.086˜0.308 r.sub.1 = 98.265 d.sub.1 = 2.0 Nd.sub.1 = 1.80518 νd.sub.4 = 25.4 r.sub.2 = 56.371 d.sub.2 = 7.0 Nd.sub.2 = 1.67025 νd.sub.2 = 57.6 r.sub.3 = 294.111 d.sub.3 = 0.1 G.sub.1 r.sub.4 = 50.950 d.sub.4 = 4.3 Nd.sub.3 = 1.713 νd.sub.3 = 54.0 r.sub.5 = 86.420 d.sub.5 = variable r.sub.6 = 51.013 d.sub.6 = 1.0 Nd.sub.4 = 1.744 νd.sub.4 = 45.1 C.sub.1 r.sub.7 = 16.136 d.sub.7 = 4.6 r.sub.8 = -64.087 d.sub.8 = 2.75 Nd.sub.5 = 1.71736 ν d.sub.5 = 29.5 C.sub.2 r.sub.9 = -32.942 d.sub.9 = 1.4 G.sub.2 r.sub.10 = -31.525 d.sub.10 = 1.0 Nd.sub.6 = 1.6223 νd.sub.6 = 53.1 C.sub.3 r.sub.11 = 56.459 d.sub.11 = 1.2 r.sub.12 = 28.476 d.sub.12 = 3.2 Nd.sub.7 = 1.71736 νd.sub.7 = 29.5 C.sub.4 r.sub.13 = 109.727 d.sub.13 = variable r.sub.14 = 34.938 d.sub.14 = 2.6 Nd.sub.8 = 1.62041 νd.sub.8 = 60.3 r.sub.15 = -38.235 d.sub.15 = 0.9 Nd.sub.9 = 1.80518 νd.sub.9 = 25.4 r.sub.16 = -97.810 d.sub.16 = 0.1 r.sub.17 = 17.003 d.sub.17 = 3.0 Nd.sub.10 = 1.56384 νd.sub.10 = 60.8 r.sub.18 = 37.067 d.sub.18 = 4.0 r.sub.19 = 294.676 d.sub.19 = 3.8 Nd.sub.11 = 1.78797 νd.sub.11 = 47.5 G.sub.3 r.sub.20 = 15.549 d.sub.20 = 3.3 r.sub.21 = 348.245 d.sub.21 = 1.8 Nd.sub.12 = 1.49782 νd.sub.12 = 82.3 r.sub.22 = -34.381 d.sub.22 = 0.1 r.sub.23 = 23.524 d.sub.23 = 2.7 Nd.sub.13 = 1.49782 νd.sub.13 = 82.3 r.sub.24 = 62.146 S' f.sub.A = 91.130 f.sub.I = 105.00 f.sub.II = -31.932 f.sub.III = 36.385 S' = Back focal length Magnification d.sub.5 d.sub.13 S' 0.086 . 1.716 36.947 43.015 0.118 12.516 26.147 48.542 0.183 24.516 14.147 58.399 0.308 35.516 3.147 75.707 __________________________________________________________________________ where r 1 , r 2 , r 3 , . . . , represent the radii of curvature of the refracting surfaces of the successive lenses from the object side, d 1 , d 2 , d 3 , . . . , represent the center thicknesses and air spaces of the respective lenses, Nd 1 , Nd 2 , Nd 3 , . . . , represent the refractive indices of the respective lenses for d-line (λ=587.6 nm), and νd 1 , νd 2 , νd 3 , . . . , represent the Abbe numbers of the respective lenses.

Claim 9

A zoom lens according to claim 2, further characterized in that numerical data are as follows: __________________________________________________________________________ Third Embodiment __________________________________________________________________________ f = 32 mm˜ 94 mm Effective aperture ratio Fe 1:5.9˜1:21 Magnification 0.086˜0.308 r.sub.1 = 131.806 d.sub.1 = 2.0 Nd.sub.1 = 1.71736 νd.sub.1 = 29.5 r.sub.2 = 56.247 d.sub.2 = 11.0 Nd.sub.2 = 1.67025 νd.sub.2 = 57.6 r.sub.3 = 208.885 d.sub.3 = 1.0 r.sub.4 = -149.871 d.sub.4 = 2.0 Nd.sub.3 = 1.54814 νd.sub.3 = 45.9 G.sub.1 r.sub.5 = 434.555 d.sub.5 = 0.1 r.sub.6 = 48.661 d.sub.6 = 4.0 Nd.sub.4 = 1.717 νd.sub.4 = 48.1 r.sub.7 = 82.614 d.sub.7 = variable r.sub.8 = 27.655 d.sub.8 = 0.9 Nd.sub.5 = 1.55115 νd.sub.5 = 49.6 r.sub.9 = 14.510 d.sub.9 = 3.7 C.sub.1 r.sub.10 = 62.590 d.sub.10 = 0.9 Nd.sub.6 = 1.55115 νd.sub.6 = 49.6 r.sub.11 = 22.908 d.sub.11 = 3.2 r.sub.12 = -51.007 d.sub.12 = 2.0 Nd.sub.7 = 1.71736 νd.sub.7 = 29.5 C.sub.2 G.sub.2 r.sub.13 = -26.403 d.sub.13 = 1.4 r.sub.14 = -24.720 d.sub.14 = 0.9 Nd.sub.8 = 1.6223 νd.sub.8 = 53.1 C.sub.3 r.sub.15 = 296.098 d.sub.15 = 0.1 r.sub.16 = 26.790 d.sub.16 = 2.0 Nd.sub.9 = 1.71736 νd.sub.9 = 29.5 C.sub.4 r.sub.17 = 61.177 d.sub.17 = variable r.sub.18 = 40.653 d.sub.18 = 3.0 Nd.sub.10 = 1.62041 νd.sub.10 = 60.4 r.sub.19 = -34.546 d.sub.19 = 0.9 Nd.sub.11 = 1.80518 νd.sub.11 = 25.4 r.sub.20 = -64.772 d.sub.20 = 0.1 r.sub.21 = 17.153 d.sub.21 = 1.7 Nd.sub.12 = 1.60311 νd.sub.12 = 60.7 r.sub.22 = 38.274 d.sub.22 = 4.2 r.sub.23 = -172.190 d.sub.23 = 1.9 Nd.sub.13 = 1.78797 νd.sub.13 = 47.5 G.sub.3 r.sub.24 = 18.932 d.sub.24 = 2.2 r.sub.25 = -68.879 d.sub.25 = 0.9 Nd.sub.14 = 1.61266 νd.sub.14 = 44.5 r.sub.26 = 30.859 d.sub.26 = 3.1 Nd.sub.15 = 1.51823 νd.sub.15 = 59.0 r.sub.27 = -21.455 d.sub.27 = 0.1 r.sub.28 = 30.206 d.sub.28 = 2.1 Nd.sub.16 = 1.51860 νd.sub.16 = 70.1 r.sub.29 = 180.423 S' f.sub.A = 73.80 f.sub.I = 109.85 f.sub.II =-31.25 f.sub.III = 36.48 S': Back focal length Magnification d.sub.7 d.sub.17 S' 0.086 1.548 37.525 47.654 0.118 12.233 26.840 53.259 0.181 24.216 14.856 63.520 0.308 35.201 3.872 82.256 __________________________________________________________________________ where r 1 , r 2 , r 3 , . . . , represent the radii of curvature of the refracting surfaces of the successive lenses from the object side, d 1 , d 2 , d 3 , . . . , represent the center thicknesses and air spaces of the respective lenses, Nd 1 , Nd 2 , Nd 3 , . . . , represent the refractive indices of the respective lenses for d-line (λ=587.6 nm), and νd 1 , νd 2 , νd 3 , . . . , represent the Abbe numbers of the respective lenses.

Claim 10

A zoom lens according to claim 2, further characterized in that numerical data are as follows: __________________________________________________________________________ Fourth Embodiment __________________________________________________________________________ f = 32 mm˜ 80 mm Effective aperture ratio Fe 1:8.3˜1:11.3 Magnification 0.04˜0.105 r.sub.1 = 103.75 d.sub.1 = 2.4 Nd.sub.1 = 1.8052 νd.sub.1 = 25.4 r.sub.2 = 60.68 d.sub.2 = 11.0 Nd.sub.2 = 1.6703 νd.sub.2 = 57.6 r.sub.3 = 468.51 d.sub.3 = 0.1 G.sub.1 r.sub.4 = 43.06 d.sub.4 = 0.4 Nd.sub.3 = 1.717 νd.sub.4 = 48.1 r.sub.5 = 57.29 d.sub.5 = variable r.sub.6 = 42.81 d.sub.6 = 1.2 Nd.sub.4 = 1.4978 νd.sub.4 = 82.3 r.sub.7 = 19.56 d.sub.7 = 10.0 C.sub.1 r.sub.8 = 576.60 d.sub.8 = 1.2 Nd.sub.5 = 1.4978 νd.sub.5 = 82.3 r.sub.9 = 24.60 d.sub.9 = 7.5 r.sub.10 = -76.36 d.sub.10 = 3.5 Nd.sub.6 = 1.7234 νd.sub.4 = 38.0 C.sub.2 G.sub.2 r.sub.11 = -39.20 d.sub.11 = 1.8 r.sub.12 = -40.87 d.sub.12 = 1.2 Nd.sub.7 = 1.6223 νd.sub.7 = 53.1 C.sub.3 r.sub.13 = -123.32 d.sub.13 = 0.1 r.sub.14 = 20.55 d.sub.14 = 2.6 Nd.sub.8 = 1.7283 νd.sub.8 = 28.3 C.sub.4 r.sub.15 = 22.48 d.sub.15 = variable r.sub.16 = 31.18 d.sub.16 = 2.1 Nd.sub.9 = 1.6237 νd.sub.9 = 47.1 r.sub.17 = -98.50 d.sub.17 = 1.0 Nd.sub. 10 = 1.795 νd.sub.10 = 28.6 r.sub.18 = 91.80 d.sub.18 = 0.1 r.sub.19 = 20.74 d.sub.19 = 1.9 Nd.sub.11 = 1.6204 νd.sub.11 = 60.3 r.sub.20 = 62.37 d.sub.20 = 4.5 r.sub.21 = -44.93 d.sub.21 = 1.1 Nd.sub.12 = 1.717 νd.sub.12 = 48.1 G.sub.3 r.sub.22 = 24.86 d.sub.22 = 1.8 r.sub.23 = -1197.33 d.sub.23 = 3.0 Nd.sub.13 = 1.4978 ν.sub.13 = 82.3 r.sub.24 = -21.98 d.sub.24 = 0.1 r.sub.25 = 39.91 d.sub.25 = 2.1 Nd.sub.14 = 1.4978 νd.sub.14 = 82.3 r.sub.26 = -168.56 S' f.sub.A = 107.10 f.sub.I = 114.10 f.sub.II = -32.30 f.sub. III = -40.85 S': Back focal length Magnification d.sub.5 d.sub.15 S' 0.04 2.515 43.313 53.782 0.06 14.072 25.056 60.482 0.08 18.818 13.030 67.763 0.105 17.139 1.868 80.604 __________________________________________________________________________ where r 1 , r 2 , r 3 , . . . , represent the radii of curvature of the refracting surfaces of the successive lenses from the object side, d 1 , d 2 , d 3 , . . . , represent the center thicknesses and air spaces of the respective lenses, Nd 1 , Nd 2 , Nd 3 , . . . , represent the refractive indices of the respective lenses for d-line (λ=587.6 nm) and νd 1 , νd 2 , νd 3 , . . . , represent the Abbe numbers of the respective lenses.

Claim 11

A zoom lens according to claim 2, further characterized in that numerical data are as follows: __________________________________________________________________________ Fifth Embodiment __________________________________________________________________________ f = 45.5 mm˜91.0 mm Effective aperture ratio Fe 1:6.3˜1:15.4 Magnification 0.127˜0.308 r.sub.1 = 64.21 d.sub.1 = 1.7 Nd.sub.1 = 1.8052 νd.sub.1 = 25.4 r.sub.2 = 39.50 d.sub.2 = 6.0 Nd.sub.2 = 1.6703 νd.sub.2 = 57.6 r.sub.3 = 171.73 d.sub.3 = 0.1 G.sub.1 r.sub.4 = 41.31 d.sub.4 = 3.3 Nd.sub.3 = 1.713 νd.sub.3 = 54.0 r.sub.5 = 62.29 d.sub.5 = variable r.sub.6 = 31.09 d.sub.6 = 0.9 Nd.sub.4 = 1.5512 νd.sub.4 = 49.6 r.sub.7 = 15.22 d.sub.7 = 3.2 C.sub.1 r.sub.8 = 77.26 d.sub. 8 = 0.9 Nd.sub.5 = 1.5512 νd.sub.5 = 49.6 r.sub.9 = 27.29 d.sub.9 = 2.9 r.sub.10 = -57.16 d.sub.10 = 2.1 Nd.sub.6 = 1.7174 νd.sub.6 = 29.5 C.sub.2 G.sub.2 r.sub.11 = -27.49 d.sub.11 = 1.5 r.sub.12 = -23.66 d.sub.12 = 0.9 Nd.sub.7 = 1.6223 νd.sub.7 = 53.1 C.sub.3 r.sub.13 = 371.78 d.sub.13 = 0.1 r.sub.14 = 30.22 d.sub.14 = 2.1 Nd.sub.8 = 1.7174 νd.sub.4 = 29.5 C.sub.4 r.sub.15 = 80.73 d.sub.15 = variable r.sub.16 = 38.44 d.sub.16 = 2.5 Nd.sub.9 = 1.6204 νd.sub.9 = 60.3 r.sub.17 = -35.07 d.sub.17 = 1.0 Nd.sub.10 = 1.8052 νd.sub.10 = 25.4 r.sub.18 = -64.96 d.sub.18 = 0.1 r.sub.19 = 18.76 d.sub.19 = 1.9 Nd.sub.11 = 1.6031 νd.sub.11 = 60.7 r.sub.20 = 35.56 d.sub.20 = 4.6 r.sub.21 = -3930.79 d.sub.21 = 2.1 Nd.sub.12 = 1.7880 νd.sub.12 = 47.5 r.sub.22 = 19.04 d.sub.22 = 2.4 G.sub.3 r.sub.23 = -72.39 d.sub.23 = 1.0 Nd.sub.13 = 1.6127 νd.sub.13 = 44.4 r.sub.24 = 39.08 d.sub.24 = 3.8 Nd.sub.14 = 1.5182 νd.sub.14 = 59.0 r.sub.25 = -26.93 d.sub.25 = 0.1 r.sub.26 = 32.53 d.sub.26 = 2.3 Nd.sub.15 = 1.5186 νd.sub.15 = 70.1 r.sub.27 = 298.36 S' f.sub.A = 71.70 f.sub.I = 87.184 f.sub.II = -32.482 f.sub.III = 40.069 S': Back focal length Magnification d.sub.5 d.sub.15 S' 0.127 1.117 28.201 57.760 0.173 10.236 19.082 63.789 0.241 18.855 10.464 71.272 0.308 24.667 4.652 77.622 __________________________________________________________________________ where r 1 , r 2 , r 3 , . . . , represent the radii of curvature of the refracting surfaces of the successive lenses from the object side, d 1 , d 2 , d 3 , . . . , represent the center thicknesses and air spaces of the respective lenses, Nd 1 , Nd 2 , Nd 3 , . . . , represent the refractive indices of the respective lenses for d-line (λ=587.6 nm), and νd 1 , νd 2 , νd 3 , . . . , represent the Abbe numbers of the respective lenses.