Zoom lens system

Claim 2

A zoom lens system comprising: a first lens group of a negative refractive power including a first sub-group located at the front of the zoom lens system and a second sub-group located at the image side of the first sub-group with a first variable air space formed between the first and second sub-groups; and a second lens group of a positive refractive power located at the image side of the first lens group with a second variable air space formed between the first and second lens groups, the first and second lens groups being shiftable along the optical axis with the second variable air space varying in zooming operation, and the first lens group being shiftable along the optical axis with the first variable air space varying in focusing operation, wherein the first sub-group includes a negative component at the image side end thereof so that the first variable air space is directly next to the negative component.

Claim 3

The invention of claim 1, wherein the second sub-group includes a negative component at the object side end thereof so that the first variable air space is directly next to the negative component of the second sub-group.

Claim 4

The invention of claim 1, wherein the negative component has a concave surface facing the first variable air space.

Claim 5

A zoom lens system comprising: a first lens group of a negative refractive power including a first sub-group located at the front of the zoom lens system and a second sub-group located at the image side of the first sub-group with a first variable air space formed between the first and second sub-groups; and a second lens group of a positive refractive power located at the image side of the first lens group with a second variable air space formed between the first and second lens groups, the first and second lens groups being shiftable along the optical axis with the second variable air space varying during a zooming operation, and the first lens group being shiftable along the optical axis with the first variable air space varying during a focusing operation, wherein the first sub-group includes a negative component and the second sub-group includes a negative component, and wherein the first sub-group further includes a positive component located at the front of the zoom lens system.

Claim 6

A zoom lens system comprising: a first lens group of a negative refractive power including a first sub-group located at the front of the zoom lens system and a second sub-group located at the image side of the first sub-group with a first variable air space formed between the first and second sub-groups; and a second lens group of a positive refractive power located at the image side of the first lens group with a second variable air space formed between the first and second lens groups, the first and second lens groups being shiftable along the optical axis with the second variable air space varying during a zooming operation, and the first lens group being shiftable along the optical axis with the first variable air space varying during a focusing operation, wherein the first sub-group includes a negative component and the second sub-group includes a negative component, and wherein the first sub-group further includes a positive component located at the front of the zoom lens system.

Claim 7

A zoom lens system comprising: a first lens group of a negative refractive power including a first sub-group located at the front of the zoom lens system and a second sub-group located at the image side of the first sub-group with a first variable air space formed between the first and second sub-groups, the first sub-group includes a positive component and a negative component located at the image side of the positive component; and a second lens group of a positive refractive power located at the image side of the first lens group with a second variable air space formed between the first and second lens groups, the first and second lens groups being shiftable along the optical axis with the second variable air space varying in a zooming operation, and the first lens group being shiftable along the optical axis with the first variable air space varying in a focusing operation, wherein the lens system fulfills the following conditions: 1.4<|f.sub.I.sbsb.1 |/f.sub.S <3.0, f.sub.I.sbsb.1 <0 0.3<d/f.sub.S <0.8 wherein: f I .sbsb.1 represents the focal length of the first sub-group; d represents the axial width of the first variable air space with the zoom lens system focused to infinity; and f S represents the focal length of the whole zoom lens system in the shorts focal length condition.

Claim 8

A zoom lens system comprising: a first lens group of a negative refractive power including a first sub-group located at the front of the zoom lens system and a second sub-group located at the image side of the first sub-group with a first variable air space formed between the first and second sub-groups, the first sub-group includes a positive component and a negative component located at the image side of the positive component; and a second lens group of a positive refractive power located at the image side of the first lens group with a second variable air space formed between the first and second lens groups, the first and second lens groups being shiftable along the optical axis with the second variable air space varying in a zooming operation, and the first lens group being shiftable along the optical axis with the first variable air space varying in a focusing operation, wherein the lens system fulfills the following conditions: 1.4<|f.sub.I.sbsb.1 |/f.sub.S <3.0, f.sub.I.sbsb.1 <0 0.3<d/f.sub.S <0.8 wherein: f I .sbsb.1 represents the focal length of the first sub-group; d represents the axial width of the first variable air space with the zoom lens system focused to infinity; and f S represents the focal length of the whole zoom lens system in the shorts focal length condition.

Claim 9

A zoom lens system comprising: a first lens group of a negative refractive power including a first sub-group located at the front of the zoom lens system and a second sub-group located at the image side of the first sub-group, wherein the first sub-group includes a negative component at the image side end thereof, and the second sub-group includes a negative component at the object side end thereof and a first variable air space is formed between the two negative components, and a second lens group of a positive refractive power located at the image side of the first lens group with a second variable air space formed between the first and second lens groups, the first and second lens groups being shiftable along the optical axis with the second variable air space varying in a zooming operation, and the first lens group being shiftable along the optical axis with the first variable air space varying in a focusing operation, wherein the lens system fulfills the following conditions: 1.4<|f.sub.I.sbsb.1 |/f.sub.S <3.0, f.sub.I.sbsb.1 <0 0.3<d/f.sub.S <0.8 wherein: f I .sbsb.1 represents the focal length of the first sub-group; d represents the axial width of the first variable air space with the zoom lens system focused to infinity; and f S represents the focal length of the whole zoom lens system in the shortest focal length condition.

Claim 10

A zoom lens system comprising: a first lens group of a negative refractive power including a first sub-group located at the front of the zoom lens system and a second sub-group located at the image side of the first sub-group, wherein the first sub-group includes a negative component at the image side end thereof, and the second sub-group includes a negative component at the object side end thereof and a first variable air space is formed between the two negative components, and a second lens group of a positive refractive power located at the image side of the first lens group with a second variable air space formed between the first and second lens groups, the first and second lens groups being shiftable along the optical axis with the second variable air space varying in a zooming operation, and the first lens group being shiftable along the optical axis with the first variable air space varying in a focusing operation, wherein the lens system fulfills the following conditions: 1.4<|f.sub.I.sbsb.1 |/f.sub.S <3.0, f.sub.I.sbsb.1 <0 0.3<d/f.sub.S <0.8 wherein: f I .sbsb.1 represents the focal length of the first sub-group; d represents the axial width of the first variable air space with the zoom lens system focused to infinity; and f S represents the focal length of the whole zoom lens system in the shortest focal length condition.

Claim 11

A zoom lens system comprising: a first lens group of a negative refractive power including a first sub-group located at the front of the zoom lens system and a second sub-group located at the image side of the first sub-group with the first variable air space formed between the first and second sub-groups, the first sub-group includes, consecutively from the object side, a front positive component and a first negative component and the second sub-group has a second negative component located at the image side of the first sub-group, wherein the first variable air space is located between the first and second negative components; and a second lens group of a positive refractive power located at the image side of the first lens group with a second variable air space formed between the first and second lens groups, the first and second lens groups being shiftable along the optical axis with the second variable air space varying in a zooming operation, and the first lens group being shiftable along the optical axis with the first variable air space varying in a focusing operation, wherein the lens system fulfills the following conditions: 1.4<|f.sub.I.spsb.1 |/f.sub.S <3.0, f.sub.I.spsb.1 <0 0.3<d/f.sub.S <0.8 wherein; f I .spsb.1 represents the focal length of the first sub-group; d represents the axial width of the first variable air space with the zoom lens system focused to infinity; and f S represents the focal length of the whole zoom lens system in the shortest focal length condition.

Claim 12

A zoom lens system comprising: a first lens group of a negative refractive power including a first sub-group located at the front of the zoom lens system and a second sub-group located at the image side of the first sub-group with the first variable air space formed between the first and second sub-groups, the first sub-group includes, consecutively from the object side, a front positive component and a first negative component and the second sub-group has a second negative component located at the image side of the first sub-group, wherein the first variable air space is located between the first and second negative components; and a second lens group of a positive refractive power located at the image side of the first lens group with a second variable air space formed between the first and second lens groups, the first and second lens groups being shiftable along the optical axis with the second variable air space varying in a zooming operation, and the first lens group being shiftable along the optical axis with the first variable air space varying in a focusing operation, wherein the lens system fulfills the following conditions: 1.4<|f.sub.I.spsb.1 |/f.sub.S <3.0, f.sub.I.spsb.1 <0 0.3<d/f.sub.S <0.8 wherein; f I .spsb.1 represents the focal length of the first sub-group; d represents the axial width of the first variable air space with the zoom lens system focused to infinity; and f S represents the focal length of the whole zoom lens system in the shortest focal length condition.

Claim 13

A zoom lens system comprising: a first lens group of a negative refractive power including a first sub-group located at the front of the zoom lens system and a second sub-group located at the image side of the first sub-group with a first variable air space formed between the first and second sub-groups, the first sub-group includes a negative component at the image side and thereof so that the first variable air space is directly next to the negative component, and a second lens group of a positive refractive power located at the image side of the first lens group with a second variable air space formed between the first and second lens groups, the first and second lens groups being shiftable along the optical axis with the second variable air space varying in a zooming operation, and the first lens group being shiftable along the optical axis with the first variable air space varying in a focusing operation, wherein the lens system fulfills the following conditions: 1.4<|f.sub.I.spsb.1 |/f.sub.S <3.0, F.sub.I.spsb.1 <0 0.3<d/f.sub.S <0.8 wherein: f I .spsb.1 represents the focal length of the first sub-group; d represents the axial width of the first variable air space with the zoom lens system focused to infinity; and f S represents the focal length of the whole zoom lens system in the shortest focal length condition.

Claim 14

A zoom lens system comprising: a first lens group of a negative refractive power including a first sub-group located at the front of the zoom lens system and a second sub-group located at the image side of the first sub-group with a first variable air space formed between the first and second sub-groups, the first sub-group includes a negative component at the image side and thereof so that the first variable air space is directly next to the negative component, and a second lens group of a positive refractive power located at the image side of the first lens group with a second variable air space formed between the first and second lens groups, the first and second lens groups being shiftable along the optical axis with the second variable air space varying in a zooming operation, and the first lens group being shiftable along the optical axis with the first variable air space varying in a focusing operation, wherein the lens system fulfills the following conditions: 1.4<|f.sub.I.spsb.1 |/f.sub.S <3.0, F.sub.I.spsb.1 <0 0.3<d/f.sub.S <0.8 wherein: f I .spsb.1 represents the focal length of the first sub-group; d represents the axial width of the first variable air space with the zoom lens system focused to infinity; and f S represents the focal length of the whole zoom lens system in the shortest focal length condition.

Claim 15

The invention of claim 8, wherein the condition for d/fs is as follows: 0.35<d/fs<0.8.

Claim 16

A zoom lens system comprising: a first lens group of a negative refractive power including a first sub-group located at the front of the zoom lens system and a second sub-group located at the image side of the first sub-group with a first variable air space formed between the first and second sub-groups; and a second lens group of a positive refractive power located at the image side of the first lens group with a second variable air space formed between the first and second lens grops, the first and second lens groups being shiftable along the optical axis with the second variable air space varying in a zooming operation, and the first lens group being shiftable along the optical axis with the first variable air space varying in a focusing operation, wherein the first sub-group includes a negative component at the image side end thereof so that the first variable air space is directly next to the negative component, wherein the lens system comprises the following design parameters: ______________________________________ f = 24˜ 35 mm F/3.5 2ω = 84° ˜ 63° Radius of Axial Refractive Abbe Curvature Distance Index Number ______________________________________ r.sub.1 74.01 d.sub.1 6.00 N.sub.1 1.6031 ν.sub.1 60.7 r.sub.2 244.99 I.sub.1 d.sub.2 0.20 r.sub.3 50.03 d.sub.3 1.50 N.sub.2 1.7725 ν.sub.2 49.8 r.sub.4 18.04 d.sub.4 * 12.00 r.sub.5 691.03 d.sub.5 1.50 N.sub.3 1.7545 ν.sub.3 51.6 I r.sub.6 32.39 d.sub.6 3.50 r.sub.7 111.30 d.sub.7 4.00 N.sub.4 1.7106 ν.sub.4 43.3 I.sub.2 r.sub.8 -93.67 d.sub.8 1.00 N.sub.5 1.6405 ν.sub.5 60.1 r.sub.9 70.10 d.sub.9 2.50 r.sub.10 32.38 d.sub.10 3.00 N.sub.6 1.7174 ν.sub.6 29.4 r.sub.11 64.64 d.sub.11 ** 13.33 -1.50 r.sub.12 75.56 d.sub.12 2.50 N.sub.7 1.5173 ν.sub.7 69.4 r.sub.13 -96.23 d.sub.13 0.10 r.sub.14 21.90 d.sub.14 3.36 N.sub.8 1.5173 ν.sub.8 69.4 r.sub.15 301.11 d.sub.15 0.10 r.sub.16 24.01 d.sub. 16 2.00 N.sub.9 1.5173 ν.sub.9 69.4 r.sub.17 51.82 d.sub.17 5.29 II r.sub.18 -52.25 d.sub.18 2.00 N.sub.10 1.8052 ν.sub.10 25.4 r.sub.19 -24.83 d.sub.19 0.80 N.sub.11 1.7569 ν.sub.11 29.7 r.sub.20 18.78 d.sub.20 2.03 r.sub.21 -69.23 d.sub.21 2.00 N.sub.12 1.5168 ν.sub.12 64.1 r.sub.22 -22.60 d.sub.22 0.10 r.sub.23 38.07 d.sub.23 2.30 N.sub.13 1.5168 ν.sub.13 64.1 r.sub.24 -55.97 ______________________________________

Claim 17

A zoom lens system comprising: a first lens group of a negative refractive power including a first sub-group located at the front of the zoom lens system and a second sub-group located at the image side of the first sub-group with a first variable air space formed between the first and second sub-groups; and a second lens group of a positive refractive power located at the image side of the first lens group with a second variable air space formed between the first and second lens grops, the first and second lens groups being shiftable along the optical axis with the second variable air space varying in a zooming operation, and the first lens group being shiftable along the optical axis with the first variable air space varying in a focusing operation, wherein the first sub-group includes a negative component at the image side end thereof so that the first variable air space is directly next to the negative component, wherein the lens system comprises the following design parameters: ______________________________________ f = 24˜ 35 mm F/3.5 2ω = 84° ˜ 63° Radius of Axial Refractive Abbe Curvature Distance Index Number ______________________________________ r.sub.1 74.01 d.sub.1 6.00 N.sub.1 1.6031 ν.sub.1 60.7 r.sub.2 244.99 I.sub.1 d.sub.2 0.20 r.sub.3 50.03 d.sub.3 1.50 N.sub.2 1.7725 ν.sub.2 49.8 r.sub.4 18.04 d.sub.4 * 12.00 r.sub.5 691.03 d.sub.5 1.50 N.sub.3 1.7545 ν.sub.3 51.6 I r.sub.6 32.39 d.sub.6 3.50 r.sub.7 111.30 d.sub.7 4.00 N.sub.4 1.7106 ν.sub.4 43.3 I.sub.2 r.sub.8 -93.67 d.sub.8 1.00 N.sub.5 1.6405 ν.sub.5 60.1 r.sub.9 70.10 d.sub.9 2.50 r.sub.10 32.38 d.sub.10 3.00 N.sub.6 1.7174 ν.sub.6 29.4 r.sub.11 64.64 d.sub.11 ** 13.33 -1.50 r.sub.12 75.56 d.sub.12 2.50 N.sub.7 1.5173 ν.sub.7 69.4 r.sub.13 -96.23 d.sub.13 0.10 r.sub.14 21.90 d.sub.14 3.36 N.sub.8 1.5173 ν.sub.8 69.4 r.sub.15 301.11 d.sub.15 0.10 r.sub.16 24.01 d.sub. 16 2.00 N.sub.9 1.5173 ν.sub.9 69.4 r.sub.17 51.82 d.sub.17 5.29 II r.sub.18 -52.25 d.sub.18 2.00 N.sub.10 1.8052 ν.sub.10 25.4 r.sub.19 -24.83 d.sub.19 0.80 N.sub.11 1.7569 ν.sub.11 29.7 r.sub.20 18.78 d.sub.20 2.03 r.sub.21 -69.23 d.sub.21 2.00 N.sub.12 1.5168 ν.sub.12 64.1 r.sub.22 -22.60 d.sub.22 0.10 r.sub.23 38.07 d.sub.23 2.30 N.sub.13 1.5168 ν.sub.13 64.1 r.sub.24 -55.97 ______________________________________

Claim 18

A zoom lens system comprising: a first lens group of a negative refractive power including a first sub-group located at the front of the zoom lens system and a second sub-group located at the image side of the first sub-group with a first variable air space formed between the first and second sub-groups, and a second lens group of a positive refractive power located at the image side of the first lens group with a second variable air space formed between the first and second lens groups, the first and second lens groups being shiftable along the optical axis with the second variable air space varying in a zooming operation, and the first lens group being shiftable along the optical axis with the first variable air space varying in a focusing operation, wherein the first sub-group includes a negative component at the image side end thereof so that the first variable air space is directly next to the negative component, wherein the lens system comprises the following design parameters: ______________________________________ f = 20˜ 28 mm F/4.0 2ω = 94° ˜ 75° Radius of Axial Refractive Abbe Curvature Distance Index Number ______________________________________ r.sub.1 49.83 d.sub.1 7.00 N.sub.1 1.6031 ν.sub.1 60.7 r.sub.2 146.93 I.sub.1 d.sub.2 0.20 r.sub.3 36.34 d.sub.3 1.50 N.sub.2 1.7725 ν.sub.2 49.8 r.sub.4 14.78 d.sub.4 * 12.00 r.sub.5 691.03 d.sub.5 1.50 N.sub.3 1.7545 ν.sub.3 51.6 I r.sub.6 22.50 d.sub.6 3.50 r.sub.7 -1130.81 d.sub.7 2.00 N.sub.4 1.7106 ν.sub.4 43.3 I.sub.2 r.sub.8 -100.57 d.sub.8 1.00 N.sub.5 1.6405 ν.sub.5 60.1 r.sub.9 75.01 d.sub.9 0.15 r.sub.10 25.69 d.sub.10 3.00 N.sub.6 1.7174 ν.sub.6 29.4 r.sub.11 98.99 d.sub.11 ** 9.24 -1.00 r.sub.12 221.86 d.sub.12 1.50 N.sub.7 1.5176 ν.sub.7 53.5 r.sub.13 -76.93 d.sub.13 0.10 r.sub.14 29.40 d.sub.14 2.00 N.sub.8 1.5176 ν.sub.8 53.5 r.sub.15 854.04 d.sub.15 0.10 r.sub.16 17.24 d.sub. 16 2.00 N.sub.9 1.5176 ν.sub.9 53.5 r.sub.17 103.13 d.sub.17 3.29 II r.sub.18 -27.45 d.sub.18 2.00 N.sub.10 1.8052 ν.sub.10 25.4 r.sub.19 -25.61 d.sub.19 0.80 N.sub.11 1.7569 ν.sub.11 29.7 r.sub.20 20.55 d.sub.20 2.03 r.sub.21 -112.10 d.sub.21 1.50 N.sub.12 1.5168 ν.sub.12 64.1 r.sub.22 -21.36 d.sub.22 0.10 r.sub.23 73.05 d.sub.23 2.55 N.sub.13 1.5168 ν.sub.13 64.1 r.sub.24 -19.53 ______________________________________

Claim 19

A zoom lens system comprising: a first lens group of a negative refractive power including a first sub-group located at the front of the zoom lens system and a second sub-group located at the image side of the first sub-group with a first variable air space formed between the first and second sub-groups, and a second lens group of a positive refractive power located at the image side of the first lens group with a second variable air space formed between the first and second lens groups, the first and second lens groups being shiftable along the optical axis with the second variable air space varying in a zooming operation, and the first lens group being shiftable along the optical axis with the first variable air space varying in a focusing operation, wherein the first sub-group includes a negative component at the image side end thereof so that the first variable air space is directly next to the negative component, wherein the lens system comprises the following design parameters: ______________________________________ f = 20˜ 28 mm F/4.0 2ω = 94° ˜ 75° Radius of Axial Refractive Abbe Curvature Distance Index Number ______________________________________ r.sub.1 49.83 d.sub.1 7.00 N.sub.1 1.6031 ν.sub.1 60.7 r.sub.2 146.93 I.sub.1 d.sub.2 0.20 r.sub.3 36.34 d.sub.3 1.50 N.sub.2 1.7725 ν.sub.2 49.8 r.sub.4 14.78 d.sub.4 * 12.00 r.sub.5 691.03 d.sub.5 1.50 N.sub.3 1.7545 ν.sub.3 51.6 I r.sub.6 22.50 d.sub.6 3.50 r.sub.7 -1130.81 d.sub.7 2.00 N.sub.4 1.7106 ν.sub.4 43.3 I.sub.2 r.sub.8 -100.57 d.sub.8 1.00 N.sub.5 1.6405 ν.sub.5 60.1 r.sub.9 75.01 d.sub.9 0.15 r.sub.10 25.69 d.sub.10 3.00 N.sub.6 1.7174 ν.sub.6 29.4 r.sub.11 98.99 d.sub.11 ** 9.24 -1.00 r.sub.12 221.86 d.sub.12 1.50 N.sub.7 1.5176 ν.sub.7 53.5 r.sub.13 -76.93 d.sub.13 0.10 r.sub.14 29.40 d.sub.14 2.00 N.sub.8 1.5176 ν.sub.8 53.5 r.sub.15 854.04 d.sub.15 0.10 r.sub.16 17.24 d.sub. 16 2.00 N.sub.9 1.5176 ν.sub.9 53.5 r.sub.17 103.13 d.sub.17 3.29 II r.sub.18 -27.45 d.sub.18 2.00 N.sub.10 1.8052 ν.sub.10 25.4 r.sub.19 -25.61 d.sub.19 0.80 N.sub.11 1.7569 ν.sub.11 29.7 r.sub.20 20.55 d.sub.20 2.03 r.sub.21 -112.10 d.sub.21 1.50 N.sub.12 1.5168 ν.sub.12 64.1 r.sub.22 -21.36 d.sub.22 0.10 r.sub.23 73.05 d.sub.23 2.55 N.sub.13 1.5168 ν.sub.13 64.1 r.sub.24 -19.53 ______________________________________

Claim 20

A zoom lens system comprising: a first lens group of a negative refractive power including a first sub-group located at the front of the zoom lens system and a second sub-group located at the image side of the first sub-group with a first variable air space formed between the first and second sub-groups; and a second lens group of a positive refractive power located at the image side of the first lens group with a second variable air space formed between the first and second lens groups, the second variable air space being varied with the first variable air space being maintained in a zooming operation and both the first and second variable air spaces being varied in a focusing operation, wherein the first sub-group includes a positive component and a negative component located at the image side of the positive component.

Claim 21

A zoom lens system comprising: a first lens group of a negative refractive power including a first sub-group located at the front of the zoom lens system and a second sub-group located at the image side of the first sub-group with a first variable air space formed between the first and second sub-groups; and a second lens group of a positive refractive power located at the image side of the first lens group with a second variable air space formed between the first and second lens groups, the second variable air space being varied with the first variable air space being maintained in a zooming operation and both the first and second variable air spaces being varied in a focusing operation, wherein the first sub-group includes a positive component and a negative component located at the image side of the positive component.

Claim 22

The invention of claim 12 wherein the lens system fulfills the following conditions: 1.4<|f.sub.I1 |/f.sub.S <3.0, f.sub.I1 <0 0.3<d/f.sub.S <0.8 wherein: f I1 represents the focal length of the first subgroup; d represents the axial width of the first variable air space with the zoom lens system focused to infinity; and f S represents the focal length of the whole zoom lens system in the shortest focal length condition.

Claim 23

A zoom lens system comprising: a first lens group of a negative refractive power including a first sub-group located at the front of the zoom lens system and a second sub-group located at the image side of the first sub-group with a first variable air space formed between the first and second sub-groups; and a second lens group of a positive refractive power located at the image side of the first lens group with a second variable air space formed between the first and second lens groups, the second variable air space being varied with the first variable air space being maintained during a zooming operation and both the first and second variable air spaces being varied during a focusing operation, wherein the first sub-group includes a negative component at the image side end thereof so that the first variable air space is directly next to the negative component.

Claim 24

A zoom lens system comprising: a first lens group of a negative refractive power including a first sub-group located at the front of the zoom lens system and a second sub-group located at the image side of the first sub-group with a first variable air space formed between the first and second sub-groups; and a second lens group of a positive refractive power located at the image side of the first lens group with a second variable air space formed between the first and second lens groups, the second variable air space being varied with the first variable air space being maintained during a zooming operation and both the first and second variable air spaces being varied during a focusing operation, wherein the first sub-group includes a negative component at the image side end thereof so that the first variable air space is directly next to the negative component.

Claim 25

The invention of claim 14, wherein the second sub-group includes a negative component at the object side end thereof so that the negative component of the second sub-group is directly next to the first variable air space.

Claim 26

The invention of claim 14 wherein the lens system fulfills the following conditions: 1.4<|f.sub.I1 |/f.sub.S <3.0, f.sub.I1 <0 0.3<d/f.sub.S <0.8 wherein: f I1 represents the focal length of the first subgroup; d represents the axial width of the first variable air space with the zoom lens system focused to infinity; and f S represents the focal length of the whole zoom lens system in the shortest focal length condition.

Claim 27

A zoom lens system comprising: a first lens group of a negative refractive power including a first sub-group located at the front of the zoom lens system and a second sub-group located at the image side of the first sub-group with a first variable air space formed between the first and second sub-groups; and a second lens group of a positive refractive power located at the image side of the first lens group with a second variable air space formed between the first and second lens groups, the second variable air space being varied with the first variable air space being maintained in a zooming operation and both the first and second variable air spaces being varied in a focusing operation, wherein the first sub-group includes a negative component and the second sub-group includes a negative component, and wherein the first sub-group further includes a positive component located at the front of the zoom lens system.

Claim 28

A zoom lens system comprising: a first lens group of a negative refractive power including a first sub-group located at the front of the zoom lens system and a second sub-group located at the image side of the first sub-group with a first variable air space formed between the first and second sub-groups; and a second lens group of a positive refractive power located at the image side of the first lens group with a second variable air space formed between the first and second lens groups, the second variable air space being varied with the first variable air space being maintained in a zooming operation and both the first and second variable air spaces being varied in a focusing operation, wherein the first sub-group includes a negative component and the second sub-group includes a negative component, and wherein the first sub-group further includes a positive component located at the front of the zoom lens system.

Claim 29

The invention of claim 17 wherein the lens system fulfills the following conditions: 1.4<|f.sub.I1 |/f.sub.S <3.0, f.sub.I1 <0 0.3<d/f.sub.S <0.8 wherein: f I1 represents the focal length of the first subgroup; d represents the axial width of the first variable air space with the zoom lens system focused to infinity; and f S represents the focal length of the whole zoom lens system in the shortest focal length condition.