Zoom lens system and photographing apparatus

1. A zoom lens system comprising, sequentially from an object side to an image side:

a first lens group having positive refractive power;

a second lens group having negative refractive power;

a third lens group having positive refractive power; and

a fourth lens group having positive refractive power,

wherein the first lens group comprises one negative lens, the second lens group comprises one positive lens, the third lens group comprises a positive lens, the fourth lens group comprises at least one positive lens, and a first condition, 0.03<|f 2 /f t |<0.08, is satisfied,

wherein f 2 denotes a focal length of the second lens group and f t denotes a focal length of the zoom lens system in a telephoto position,

wherein the first lens group comprises the one negative lens and three first group positive lenses sequentially from the object side to the image side, the second lens group comprises at least three second group negative lenses and the one positive lens, the third lens group comprises the positive lens and a third group cemented lens comprising a third group positive lens and a third group negative lens sequentially provided from the object side to the image side, the fourth lens group comprises the at least one positive lens and at least one negative lens, and

wherein a zoom ratio of the zoom lens system is greater than 28.

2. The zoom lens system of claim 1 , wherein the first and third lens groups are fixed in an optical axis direction, the second lens group is configured to move from the object side to the image side, and the fourth lens group is configured to move in the optical axis direction to compensate for the movement of the second lens group during variable magnification from a wide-angle position to the telephoto position.

3. The zoom lens system of claim 2 , wherein the third lens group compensates for off-axis aberration generated during the variable magnification by including at least one surface having an aspherical surface shape.

4. The zoom lens system of claim 3 , wherein the fourth lens group compensates for axial aberration generated during the variable magnification by including a cemented lens of a fourth positive lens and a fourth negative lens.

5. The zoom lens system of claim 1 , wherein a second condition 5.8<|f 1 /f 2 |<8.0, is satisfied,

wherein f 1 denotes a focal length of the first lens group and f 2 denotes the focal length of the second lens group.

6. The zoom lens system of claim 5 , wherein the fourth lens group comprises a fourth group cemented lens of a fourth group positive lens and a fourth group negative lens sequentially from the object side to the image side, the fourth group positive lens comprises at least one surface having an aspherical surface, and another condition, 0.08<|f 4 /f t |<0.25, is satisfied,

wherein f 4 denotes a focal length of the fourth lens group and f t denotes the focal length of the zoom lens system in the telephoto position.

7. The zoom lens system of claim 1 , wherein the positive lens of the third lens group comprises at least one surface having an aspherical surface, a cemented surface of the third group cemented lens is convex to the object side, and following conditions

0.15<|f 3 /f t |<0.35 and 0.4<|f 31 /f 3 |<0.8, are satisfied,

wherein f 3 denotes a focal length of the third lens group, f 31 denotes a focal length of the positive lens in the third lens group closest to the object side, and f t denotes the focal length of the zoom lens system in the telephoto position.

8. The zoom lens system of claim 7 , wherein at least one of the three first group positive lenses uses a glass material having an Abbe number greater than or equal to 80.

9. The zoom lens system of claim 7 , wherein the one positive lens in the second lens group comprises a convex surface facing the object side, and the second lens group comprises, sequentially from the object side to the image side, a first and a second negative lenses and a second group cemented lens of the one positive lens and a third negative lens.

10. The zoom lens system of claim 1 , wherein at least one of the three first group positive lenses uses a glass material having an Abbe number greater than or equal to 80.

11. The zoom lens system of claim 1 , wherein the one positive lens in the second lens group comprises a convex surface facing the object side, and the second lens group comprises, sequentially from the object side to the image side, a first and a second negative lenses and a second group cemented lens of the one positive lens and a third negative lens.

12. The zoom lens system of claim 1 , wherein the fourth lens group comprises a fourth group cemented lens of a fourth group positive lens and a fourth group negative lens sequentially from the object side to the image side, the fourth group positive lens comprises at least one surface having an aspherical surface, and another condition, 0.08<|f 4 /f t |<0.25, is satisfied,

wherein f 4 denotes a focal length of the fourth lens group and f t denotes the focal length of the zoom lens system in the telephoto position.

13. The zoom lens system of claim 1 , wherein the fourth lens group comprises a fourth group cemented lens of a fourth group positive lens and a fourth group negative lens sequentially from the object side to the image side, the fourth group positive lens comprises at least one surface having an aspherical surface, and another condition, 0.08<|f 4 /f t |<0.25, is satisfied,

wherein f 4 denotes a focal length of the fourth lens group and f t denotes the focal length of the zoom lens system in the telephoto position.

14. The zoom lens system of claim 1 further comprising an aperture fixed to an image plane disposed between the second lens group and the third lens group.

15. A photographing apparatus comprising the zoom lens system of claim 1 .

16. The zoom lens system of claim 1 , wherein each of at least two of the three first group positive lenses uses a glass material having an Abbe number greater than or equal to 80.

17. A zoom lens system comprising, sequentially from an object side to an image side:

a first lens group having positive refractive power;

a second lens group having negative refractive power;

a third lens group having positive refractive power; and

a fourth lens group having positive refractive power,

wherein the first lens group comprises one negative lens, the second lens group comprises one positive lens, the third lens group comprises a positive lens, the fourth lens group comprises at least one positive lens, and a first condition, 0.03<|f 2 /f t |<0.08, is satisfied,

wherein f 2 denotes a focal length of the second lens group and f t denotes a focal length of the zoom lens system in a telephoto position, and

wherein the one positive lens in the second lens group comprises a convex surface facing the object side, and the second lens group comprises, sequentially from the object side to the image side, first and second negative lenses and a second group cemented lens of the one positive lens and a third negative lens, and

wherein a zoom ratio of the zoom lens system is greater than 28.

18. The zoom lens system of claim 17 , wherein the first lens group comprises the one negative lens and three first group positive lenses sequentially from the object side to the image side, and

wherein each of at least two of the three first group positive lenses uses a glass material having an Abbe number greater than or equal to 80.