Zoom lens system
View Patent ↗Provided is a zoom lens system including: a first lens group having a positive refractive power; a second lens group having a negative refractive power; a third lens group having a positive refractive power; and a fourth lens group having a negative refractive power sequentially from an object side to an image side, wherein a zooming operation is performed by moving the second lens group and the fourth lens group.
1. A zoom lens system comprising, sequentially from an object side to an image side:
a first lens group having a positive refractive power;
a second lens group having a negative refractive power;
a third lens group having a positive refractive power; and
a fourth lens group having a negative refractive power,
wherein a zooming operation is performed by moving the second lens group and the fourth lens group under a following condition:
0.25< f 1 /f t <0.31,
where f 1 denote a focal length of the first lens group, and f t denotes a focal length of the zoom lens system at a telephoto end,
wherein the fourth lens group comprises a cemented lens and an independent lens having at least one aspherical surface.
2. The zoom lens system of claim 1 , wherein the fourth lens group satisfies a following condition:
0.12 <|f 43 /f 4142 |<0.35,
where f 43 denotes a focal length of the independent lens of the fourth lens group, and f 4142 denotes a focal length of the cemented lens of the fourth lens group.
3. The zoom lens system of claim 1 , wherein the fourth lens group satisfies a following condition:
V T4 <50,
where V T4 denotes an average value of Abbe's numbers of the lenses included in the fourth lens group.
4. A zoom lens system comprising, sequentially from an object side to an image side:
a first lens group having a positive refractive power;
a second lens group having a negative refractive power;
a third lens group having a positive refractive power; and
a fourth lens group having a negative refractive power,
wherein a zooming operation is performed by moving the second lens group and the fourth lens group under a following condition:
0.25< f 1 /ft <0.31,
where f1 denote a focal length of the first lens group, and ft denotes a focal length of the zoom lens system at a telephoto end,
wherein the second lens group comprises a first negative lens, a second negative lens, and a positive lens having at least one aspherical surface.
5. The zoom lens system of claim 4 , wherein the first negative lens, the second negative lens, and the positive lens are respectively independent lenses.
6. The zoom lens system of claim 4 , wherein the first negative lens, the second negative lens, and the positive lens of the second lens group satisfy a following condition:
0.8<( V 21 +V 23 )/ V 22 <1.2,
where V 21 denotes an Abbe's number of the first negative lens, V 22 denotes an Abbe's number of the second negative lens, and V 23 denotes an Abbe's number of the positive lens.
7. The zoom lens system of claim 1 , wherein a focal length of the second lens group satisfies a following condition:
1.0 <|f 2 /f w |<2.0,
where f 2 denotes a focal length of the second lens group, and f w denotes a focal length of the zoom lens system at a wide-angle end.
8. The zoom lens system of claim 1 , wherein the first lens group comprises at least four lenses.
9. The zoom lens system of claim 8 , wherein the third lens group comprises at least three lenses.
10. The zoom lens system of claim 1 , wherein the zoom lens system satisfies a following condition:
30≦ f t /f w ,
where f t denotes a focal length of the zoom lens system in a telephoto end, and f w denotes a focal length of the zoom lens in a wide-angle end.
11. A zoom lens system comprising, sequentially from an object side to an image side:
a first lens group having a positive refractive power;
a second lens group having a negative refractive power;
a third lens group having a positive refractive power; and
a fourth lens group having a negative refractive power,
wherein a zooming operation is performed by moving the second lens group and the fourth lens group, and the fourth lens group comprises a cemented lens and an independent lens and satisfies a following condition:
0.12 <|f 43 /f 4142 |<0.35,
where f 43 denotes a focal length of the independent lens of the fourth lens group, and f 4142 denotes a focal length of the cemented lens of the fourth lens group.
12. The zoom lens system of claim 11 , wherein the independent lens of the fourth lens group comprises at least one aspherical surface.
13. The zoom lens system of claim 11 , wherein the fourth lens group satisfies a following condition:
V T4 <50,
where V T4 denotes an average value of Abbe's numbers of the lenses included in the fourth lens group.
14. The zoom lens system of claim 11 , wherein the first lens group satisfies a following condition:
0.25< f 1 /f t <0.31,
where f 1 denote a focal length of the first lens group, and f t denotes a focal length of the zoom lens system at a telephoto end.
15. The zoom lens system of claim 11 , wherein the second lens group comprises a first negative lens, a second negative lens, and a positive lens having at least one aspherical surface, and the first negative lens, the second negative lens, and the positive lens are respectively independent lenses and satisfy a following condition:
0.8<( V 21 +V 23 )/ V 22 <1.2,
where V 21 denotes an Abbe's number of the first negative lens, V 22 denotes an Abbe's number of the second negative lens, and V 23 denotes an Abbe's number of the positive lens.
16. The zoom lens system of claim 11 , wherein a focal length of the second lens group satisfies a following condition:
1.0 <|f 2 /f w |<2.0,
where f 2 denotes a focal length of the second lens group, and f w denotes a focal length of the zoom lens system at a wide-angle end.
17. The zoom lens system of claim 11 , wherein the first lens group comprises at least four lenses.
18. The zoom lens system of claim 11 , wherein the third lens group comprises a plurality of lenses.
19. The zoom lens system of claim 11 , wherein the zoom lens system satisfies a following condition:
30≦ f t /f w ,
where f t denotes a focal length of the zoom lens system in a telephoto end, and f w denotes a focal length of the zoom lens in a wide-angle end.