Zoom lens system
A zoom lens system according to an example embodiment includes, sequentially from an object side to an image plane side along an optical axis, a first lens group having a negative refractive power and including at least one doublet lens, the doublet lens including two lenses, a second lens group having a positive refractive power, and a third lens group having a positive refractive power, wherein the first lens group and the second lens group are configured to move along the optical axis to perform zooming and focusing, and the zoom lens system satisfies 3.0<Vdf/Vdr<6.0, where Vdf denotes an Abbe number of a lens arranged at the object side in a doublet lens, and Vdr denotes an Abbe number of a lens arranged at the image plane side in a doublet lens.
1. A zoom lens system comprising:
a first lens group having a negative refractive power and comprising at least one doublet lens, the doublet lens comprising two lenses;
a second lens group having a positive refractive power; and
a third lens group having a positive refractive power,
wherein the first lens group, the second lens group, and the third lens group are sequentially disposed from an object side to an image plane side along an optical axis of the zoom lens system,
wherein the first lens group and the second lens group are configured to move along the optical axis to perform zooming and focusing, and
wherein
3.0< Vdf/Vdr< 6.0,
where Vdf denotes an Abbe number of a lens arranged at the object side in the doublet lens, and Vdr denotes an Abbe number of a lens arranged at the image plane side in the doublet lens.
2. The zoom lens system of claim 1 , wherein the first lens group comprises five lenses, and the five lenses comprise:
a first lens having a negative refractive power;
a second lens having a negative refractive power;
a third lens having a negative refractive power;
a fourth lens having a positive refractive power; and
a fifth lens having a negative refractive power,
wherein a surface of the third lens and a surface of the fourth lens are attached to form the doublet lens.
3. The zoom lens system of claim 2 , wherein
Vd1<60,
Vd2<25, and
Vd5<50,
where Vd1, Vd2, and Vd5 respectively denote Abbe numbers of the first lens, the second lens, and the fifth lens.
4. The zoom lens system of claim 1 , wherein the second lens group comprises five lenses, and the five lenses comprise:
a sixth lens having a positive refractive power;
a seventh lens having a positive refractive power;
an eighth lens having a negative refractive power;
a ninth lens having a positive refractive power; and
a tenth lens having a negative refractive power.
5. The zoom lens system of claim 4 , wherein the sixth lens and the tenth lens each comprise an aspherical surface, respectively, and
wherein
Vd6>40, and
Vd10>70,
where Vd6 and Vd10 respectively denote Abbe numbers of the sixth lens and the tenth lens.
6. The zoom lens system of claim 1 , wherein the third lens group comprises an eleventh lens having a positive refractive power and a twelfth lens having a negative refractive power, a surface of the eleventh lens and a surface of the twelfth lens being attached to each other and form a doublet lens, and
wherein
Vd 11/ Vd 12<0.9,
where Vd11 and Vd12 respectively denote Abbe numbers of the eleventh lens and the twelfth lens.
7. The zoom lens system of claim 1 , wherein
0.9<Fno<1.1,
where Fno denotes an F-number of the zoom lens system.
8. The zoom lens system of claim 1 , wherein
0.8<− f 1/ f 2<1, and
f 2/ f 3<0.5,
where f1 denotes a focal distance of the first lens group, f2 denotes a focal distance of the second lens group, and f3 denotes a focal distance of the third lens group.
9. The zoom lens system of claim 1 , wherein a total number of lenses included in the first to third lens groups is at least twelve.
10. A zoom lens system comprising:
a first lens group having a negative refractive power and comprising at least five lenses;
a second lens group having a positive refractive power; and
a third lens group having a positive refractive power,
wherein the first lens group, the second lens group, and the third lens group are sequentially disposed from an object side to an image plane side along an optical axis of the zoom lens system,
wherein the first lens group and the second lens group are configured to move along the optical axis to perform zooming and focusing, and
wherein
0.9<Fno<1.2,
where Fno denotes an F-number of the zoom lens system.
11. The zoom lens system of claim 10 , wherein the at least five lenses comprise, sequentially from the object side to the image plane side:
a first lens having a negative refractive power;
a second lens having a negative refractive power;
a third lens having a negative refractive power;
a fourth lens having a positive refractive power; and
a fifth lens having a negative refractive power.
12. The zoom lens system of claim 11 , wherein a surface of the third lens and a surface of the fourth lens are attached to each other and form a doublet lens, and
wherein
3.0< Vdf/Vdr< 6.0,
where Vdf denotes an Abbe number of a lens arranged at the object side in the doublet lens, and Vdr denotes an Abbe number of a lens arranged at the image plane side in the doublet lens.
13. The zoom lens system of claim 10 , wherein
0.8<− f 1/ f 2<1, and
f 2/ f 3<0.5,
where f1 denotes a focal distance of the first lens group, f2 denotes a focal distance of the second lens group, and f3 denotes a focal distance of the third lens group.
14. The zoom lens system of claim 10 , wherein the second lens group comprises at least five lenses.
15. The zoom lens system of claim 14 , wherein the five lenses included in the second lens group comprise:
a sixth lens having a positive refractive power;
a seventh lens having a positive refractive power;
an eighth lens having a negative refractive power;
a ninth lens having a positive refractive power; and
a tenth lens having a negative refractive power.
16. The zoom lens system of claim 15 , wherein a surface of the eighth lens and a surface of the ninth lens are attached to each other and form a doublet lens.
17. The zoom lens system of claim 15 , wherein a surface on the object side of the sixth lens and a surface on the image plane side of the tenth lens comprise an aspherical surface, respectively.
18. The zoom lens system of claim 10 , wherein a total number of lenses included in the first to third lens groups is at least twelve.