Wide angle zoom lens system

Claim 2

A wide angle zoom lens system which comprises a diverging lens group and a converging lens group in the order from the object side and in which both of said groups are movable on the optic axis of the lens system to vary the air space between said two groups so that the magnification of the image is variable while the image plane is being maintained at a fixed position, said diverging lens group comprising, in the order from the object side, a first member which is a negative meniscus lens component convex to the object side, a second member which is a negative meniscus lens component convex to the object side, and a third member which is a positive meniscus lens component convex to the object side, said converging lens group comprising at least four positive lens components which are separate from one another, a positive lens component being closest to the object side and a positive lens component being closest to the image side and a negative lens component disposed among said at least four positive lens components.

Claim 3

A wide angle zoom lens system according to claim 1, wherein said diverging lens group satisfies the following condition: ##EQU3## where f 1 represents the total focal length of said diverging lens group, and D the air space between said second member and said third member.

Claim 4

A wide angle zoom lens system according to claim 2, wherein said diverging lens group further satisfies the following conditions: |f.sub.1 |<|f.sub.11 |<2|f.sub.1 |, |f.sub.1 |<|f.sub.12 |<2|f.sub.1 |, 1.5|f.sub.1 |<|f.sub.13 |<3.0|f.sub.1 | and ##EQU4## where f.sub.11, f.sub.12 and f.sub.13 respectively represent the focal lengths of said first, second and third members in said deverging lens group, and R.sub.1, R.sub.2 ; R.sub.3, R.sub.4 ; R.sub.5, R.sub.6 respectively represent the curvature radii of the successive refracting surfaces in order from the object side.

Claim 5

A wide angle zoom lens system according to claim 3, wherein the respective components of said diverging lens group satisfy the following conditions: ##EQU5## where R 1 , R 2 , . . . , R 6 respectively represent the curvature radii of the successive refracting surfaces, in order from the object side, of said lens components in said diverging lens group.

Claim 6

A wide angle zoom lens system according to claim 4, wherein said converging lens group comprises five components, namely, in order from the object side, a fourth member which is a positive lens component, a fifth member which is a positive lens component, a sixth member which is a positive meniscus lens component convex to the object side, a seventh member which is a negative lens component, and an eighth member which is a positive lens component.

Claim 7

A wide angle zoom lens system according to claim 5, having the following numerical data: Total focal length: 36.023-49.497-68.795 F-number: 3.5 Maximum angle of view: 61.8° Back focal distance: 43.286-52.587-65.909 focal length of divergent group: f 1 =-59.942 focal length of convergent group: f 2 =41.379 ______________________________________ R.sub.1 = 46.411 d.sub.1 = 1.5 n.sub.1 = 1.71300 ν.sub.1 = 53.9 R.sub.2 = 25.766 d.sub.2 = 6.1 R.sub.3 = 136.271 d.sub.3 = 2.3 n.sub.2 = 1.69680 ν.sub.2 = 55.6 f.sub.1 R.sub.4 = 37.166 d.sub.4 = 8.3 R.sub.5 = 34.764 d.sub.5 = 3.8 n.sub.3 = 1.80518 ν.sub.3 = 25.5 R.sub.6 = 51.636 d.sub.6 = 33.561 - 14.818 - 0.761 R.sub.7 = 86.016 d.sub.7 = 3.1 n.sub.4 = 1.46450 ν.sub.4 = 65.8 R.sub.8 = -426.543 d.sub.8 = 0.1 R.sub.9 = 32.028 d.sub.9 = 5.3 n.sub. 5 = 1.52000 ν.sub.5 = 70.1 R.sub.10 = -365.381 d.sub.10 = 0.1 R.sub.11 = 20.985 d.sub.11 = 5.8 n.sub.6 = 1.52000 ν.sub.6 = 70.1 f.sub.2 R.sub.12 = 54.800 d.sub.12 = 4.0 R.sub.13 = -229.491 d.sub.13 = 1.5 n.sub.7 = 1.80518 ν.sub.7 = 25.5 R.sub.14 = 18.432 d.sub.14 = 4.5 R.sub.15 = 103.230 d.sub.15 = 3.6 n.sub.8 = 1.67270 ν.sub.8 = 32.2 R.sub.16 = -40.525 ______________________________________ where R, d, n and νd respectively represent the curvature radii of the refractive surfaces, the center thickness of and the air spaces between the respective lens components, the refractive indices for d-line (wavelength λ=587.6 nm), and the Abbe numbers for d-line (wavelength λ=587.6 nm).

Claim 8

A wide angle zoom lens system according to claim 4, wherein said converging lens group comprises five components, namely, in order from the object side, a fourth member which is a positive lens component, a fifth member which is a positive meniscus lens component convex to the object side, a sixth member which is a negative lens component, a seventh member which is a positive meniscus lens component convex to the image side, and an eighth member which is a positive lens component.

Claim 9

A wide angle zoom lens system according to claim 7, having the following numerical data: Total focal length: 36.023-49.497-68.795 F-number: 3.5 Maximum angle of view: 61.8° Back focal distance: 42.763-52.064-65.385 focal length of divergent group: f 1 =-59.942 focal length of convergent group: f 2 =41.379 ______________________________________ R.sub.1 = 43.640 d.sub.1 = 1.5 n.sub.1 = 1.71300 ν.sub.1 = 53.9 R.sub.2 = 25.862 d.sub.2 = 4.9 R.sub.3 = 97.646 d.sub.3 = 2.3 n.sub.2 = 1.69680 ν.sub.2 = 55.6 f.sub.1 R.sub.4 = 34.089 d.sub.4 = 10.7 R.sub.5 = 32.807 d.sub.5 = 3.8 n.sub.3 = 1.80518 ν.sub.3 = 25.5 R.sub.6 = 43.313 d.sub.6 = 32.854 - 14.110 - 0.054 R.sub.7 = 38.800 d.sub.7 = 8.6 n.sub.4 = 1.62041 ν.sub.4 = 60.3 R.sub.8 = -118.771 d.sub.8 = 2.5 R.sub.9 = 21.150 d.sub.9 = 4.9 n.sub.5 = 1.62041 ν.sub.5 = 60.3 R.sub.10 = 67.565 d.sub.10 = 2.7 R.sub.11 = -111.186 d.sub.11 = 4.2 n.sub.6 = 1.80518 ν.sub.6 = 25.5 f.sub.2 R.sub.12 = 20.265 d.sub.12 = 3.0 R.sub.13 = -100.634 d.sub.13 = 3.2 n.sub.7 = 1.62588 ν.sub.7 = 35.6 R.sub.14 = -29.367 d.sub.14 = 0.1 R.sub.15 = 50.024 d.sub.15 = 2.5 n.sub.8 = 1.62588 ν.sub.8 = 35.6 R.sub.16 = 110.281 ______________________________________ where R, d, n and νd respectively represent the curvature radii of the refractive surfaces, the center thickness of and the air space between the respective lens components, the refractive indices for d-line (wavelength λ=587.6 nm), and the Abbe numbers for d-line (wavelength λ=587.6 nm).

Claim 10

A wide angle zoom lens system according to claim 4, wherein said converging lens group comprises six components, namely, in order from the object side, a fourth member which is a positive lens component, a fifth member which is a positive lens component, a sixth member which is a positive meniscus lens component convex to the object side, a seventh member which is a negative lens component, an eighth member which is a positive meniscus lens component convex to the image side, and a ninth member which is a positive lens component.

Claim 11

A wide angle zoom lens system according to claim 9, having the following numerical data: Total focal length: 36.023-49.497-68.795 F-number: 3.5 Maximum angle of view: 61.8° Back focal distance: 42.981-52.283-65.604 focal length of divergent group: f 1 =-59.942 focal length of convergent group: f 2 =41.379 ______________________________________ R.sub.1 = 43.524 d.sub.1 = 1.5 n.sub.1 = 1.71300 ν.sub.1 = 53.9 R.sub.2 = 26.068 d.sub.2 = 4.9 f.sub.1 R.sub.3 = 98.490 d.sub.3 = 2.3 n.sub.2 = 1.69680 ν.sub.2 = 55.6 R.sub.4 = 34.319 d.sub.4 = 11.4 R.sub.5 = 33.114 d.sub.5 = 3.8 n.sub.3 = 1.80518 ν.sub.3 = 25.5 R.sub.6 = 43.047 d.sub.6 = 32.883 - 14.140 - 0.083 R.sub.7 = 38.412 d.sub.7 = 5.0 n.sub.4 = 1.62041 ν.sub.4 = 60.3 R.sub.8 = -273.441 d.sub.8 = 0.1 R.sub.9 = 301.136 d.sub.9 = 2.4 n.sub.5 = 1.62041 ν.sub.5 = 60.3 R.sub.10 = -777.160 d.sub.10 = 2.5 R.sub.11 = 20.877 d.sub.11 = 5.6 n.sub.6 = 1.62041 ν.sub.6 = 60.3 f.sub.2 R.sub.12 = 53.182 d.sub.12 = 3.0 R.sub.13 = -125.912 d.sub.13 = 2.5 n.sub.7 = 1.80518 ν.sub.7 = 25.5 R.sub.14 = 20.055 d.sub.14 = 2.9 R.sub.15 = -157.736 d.sub.15 = 3.3 n.sub.8 = 1.62588 ν.sub.8 = 35.6 R.sub.16 = -31.259 d.sub.16 = 0.1 R.sub.17 = 58.587 d.sub.17 = 2.5 n.sub.9 = 1.62588 ν.sub.9 = 35.6 R.sub.18 = 168.201 ______________________________________ where R, d, n and νd respectively represent the curvature radii of the refractive surfaces, the center thickness of and the air spaces between the respective lens components, the refractive indices for d-line (wavelength λ=587.6 nm), and the Abbe numbers for d-line (wavelength λ=587.6 nm).

Claim 12

A wide angle zoom lens system according to claim 1, wherein said diverging lens group consists of said three lens components.

Claim 13

A wide angle zoom lens system according to claim 1, wherein said all lens components are spherical lenses.