Zooms lens system and photographing apparatus including the same
View Patent ↗A zoom lens system and a photographing apparatus including the same, wherein the zoom lens system includes a first lens group including one or more lenses, and an optical member for changing a path of light, and 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 positive refractive power, wherein zooming is performed by varying air gaps between the first through fourth lens groups.
1. A zoom lens system comprising:
a first lens group comprising one or more lenses, and an optical member for changing a path of light, and 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 positive refractive power,
wherein the first lens group, the second lens group, the third lens group, and the fourth lens group are sequentially arranged from an object side to an image side,
wherein zooming is performed by varying air gaps between the first through fourth lens groups, and
wherein the zoom lens system satisfies the following expressions:
1.8
≤
f
I
f
W
f
T
≤
2.7
,
and
-
1.0
≤
f
II
f
W
f
T
≤
-
0.7
,
where f w indicates an overall focal length at a wide angle end, f T indicates an overall focal length at a telephoto end, f I indicates a focal length of the first lens group, and f II indicates a focal length of the second lens group,
wherein the fourth lens group performs focusing, and wherein an F-number at the wide angle end is equal to or less than 1.8.
2. The zoom lens system of claim 1 , wherein the third lens group comprises an aperture.
3. The zoom lens system of claim 2 , wherein the aperture is disposed at the object side of the third lens group.
4. The zoom lens system of claim 1 , wherein the optical member satisfies the following expression:
n I(P) ≧1.80
where n I(P) indicates a refractive index of the optical member.
5. The zoom lens system of claim 4 , wherein the optical member comprises a prism.
6. The zoom lens system of claim 1 , wherein the first lens group comprises a negative lens, the optical member for changing a path of light that has passed through the negative lens, and a positive lens.
7. The zoom lens system of claim 6 , wherein the negative lens is a meniscus lens having a convex surface toward the object side.
8. The zoom lens system of claim 1 , wherein the fourth lens group comprises a positive lens and a negative lens.
9. The zoom lens system of claim 1 , wherein the third lens group comprises a positive lens, a positive lens, and a negative lens.
10. The zoom lens system of claim 1 , wherein the third lens group comprises two or more lenses.
11. The zoom lens system of claim 1 , wherein at least one of the first through fourth lens groups comprises at least one aspherical lens.
12. The zoom lens system of claim 1 , wherein at least one of the second through fourth lens groups comprises at least one doublet lens.
13. The zoom lens system of claim 1 , wherein the second lens group and the fourth lens group move during zooming.
14. A photographing apparatus comprising:
a zoom lens system; and
an imaging sensor for converting an image formed by the zoom lens system into an electrical signal,
wherein the zoom lens system comprises:
a first lens group comprising one or more lenses, and an optical member for changing a path of light, and 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 positive refractive power,
wherein the first lens group, the second lens group, the third lens group, and the fourth lens group are sequentially arranged from an object side to an image side,
wherein zooming is performed by varying air gaps between the first through fourth lens groups, and
wherein the zoom lens system satisfies the following expressions:
1.8
≤
f
I
f
W
f
T
≤
2.7
,
and
-
1.0
≤
f
II
f
W
f
T
≤
-
0.7
,
where f W indicates an overall focal length at a wide angle end, f T indicates an overall focal length at a telephoto end, f I indicates a focal length of the first lens group, and f II indicates a focal length of the second lens group,
wherein the fourth lens group performs focusing, and wherein an F-number at the wide angle end is equal to or less than 1.8.
15. The photographing apparatus of claim 14 , wherein the third lens group comprises an aperture.
16. The photographing apparatus of claim 15 , wherein the aperture is disposed at the object side of the third lens group.
17. The photographing apparatus of claim 14 , wherein the optical member satisfies the following expression:
n I(P) ≧1.80
where n I(P) indicates a refractive index of the optical member.
18. The photographing apparatus of claim 14 , wherein the first lens group comprises a negative lens, the optical member for changing a path of light that has passed through the negative lens, and a positive lens.