Wide angle zoom lens
View Patent ↗A wide angle zoom lens system in a three lens group N-P-P configuration wherein the first lens group, the second lens group, and the third lens group are arranged in an order from an object side to an image side, and wherein, when variable power operation is performed from a wide angle to a telephoto position, the distance between the first lens group and the second lens group is reduced, and the second lens group is moved toward the object side, and the distance between the second lens group and the third lens group is increased, and wherein the zoom lens has a large view angle at the wide angle position.
1. A wide angle zoom lens comprising:
a first lens group having a negative refractive power;
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 arranged in an order from an object side to an image side, and
wherein, during zooming from the wide angle position to the telephoto position, the distance between the first lens group and the second lens group is reduced, and the second lens group is moved toward the object side, and the distance between the second lens group and the third lens group is increased, and wherein the second lens group comprises four lenses having respectively positive, positive, negative and positive refractive power, and
the wide angle zoom lens satisfies the following expression:
86°≦wfov≦110°
where wfov is the viewing angle at the wide angle position.
2. The wide angle zoom lens of claim 1 , wherein the zoom lens satisfies the following expression:
ft/fw > 4
where ft is the focal length at the telephoto position and fw is the focal length at the wide angle position.
3. The wide angle zoom lens of claim 1 , wherein the first lens group comprises at least one positive lens and satisfies the following expression:
nG2>1.9
where nG 2 is the refractive index of the positive lens disposed closest to the image side of the first lens group.
4. The wide angle zoom lens of claim 1 , wherein the third lens group performs focusing.
5. The wide angle zoom lens of claim 1 , wherein the third lens group comprises a single lens.
6. The wide angle zoom lens of claim 1 , wherein the zoom lens satisfies the following expression at the telephoto position
15>Dt12>0.5 (mm)
where Dt 12 is the distance between the first lens group and the second lens group at the telephoto position.
7. The wide angle zoom lens of claim 1 , wherein the zoom lens satisfies the following expression at the wide angle position
30>Dw12>10 (mm)
where Dw 12 is the distance between the first lens group and the second lens group at the wide angle position.
8. The wide angle zoom lens of claim 1 , wherein the zoom lens satisfies the following expression
25>L2>10 (mm)
where L 2 is the maximum distance the second lens group moves.
9. The wide angle zoom lens of claim 1 , wherein an aperture stop is disposed closest to the image side of the second lens group.
10. The wide angle zoom lens of claim 1 , wherein the second lens group comprises a triple cemented lens.
11. The wide angle zoom lens of claim 10 , wherein the triple cemented lens satisfies the following expression
nC2max>1.9
where nC 2 max is the maximum refractive index of a lens included in the triple cemented lens.
12. The wide angle zoom lens of claim 10 , wherein the triple cemented lens satisfies the following expression
vC2max>80
where vC 2 max is the maximum Abbe number of the lens included in the triple cemented lens.
13. A wide angle zoom lens comprising:
a first lens group having a negative refractive power;
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 arranged in an order from an object side to an image side;
during zooming from the wide angle position to a telephoto position:
the distance between the first lens group and the second lens group is reduced;
the second lens group is moved toward the object side; and
the distance between the second lens group and the third lens group is increased;
the first lens group comprises two lenses, and
the wide angle zoom lens satisfies the following expressions:
86°≦wfov≦110°
where wfov is the view angle at the wide angle position; and
ft/fw> 4
where ft is the focal length at the telephoto position and fw is the focal length at the wide angle position.
14. The wide angle zoom lens of claim 13 , wherein the first lens group comprises at least one positive lens and satisfies the following expression:
nG2>1.9
where nG 2 is the refractive index of the positive lens disposed closest to the image side of the first lens group.
15. The wide angle zoom lens of claim 13 , wherein the third lens group performs focusing.
16. The wide angle zoom lens of claim 13 , wherein the zoom lens satisfies the following expression at the telephoto position
15>Dt12>0.5 (mm)
where Dt 12 is the distance between the first lens group and the second lens group at the telephoto position.
17. The wide angle zoom lens of claim 13 , wherein the zoom lens satisfies the following expression at the wide angle position
30>Dw12>10 (mm)
where Dw 12 is the distance between the first lens group and the second lens group at the wide angle position.
18. A wide angle zoom lens comprising:
a first lens group having a negative refractive power;
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 arranged in an order from an object side to an image side;
during zooming from the wide angle position to a telephoto position:
the distance between the first lens group and the second lens group is reduced;
the second lens group is moved toward the object side; and
the distance between the second lens group and the third lens group is increased;
the first lens group comprises two lenses;
the wide angle zoom lens satisfies the following expression:
86°≦wfov≦110°
where wfov is the view angle at the wide angle position; and
the second lens group comprises a triple cemented lens.
19. The wide angle zoom lens of claim 18 , wherein the triple cemented lens satisfies the following expression
nC2max>1.9
where nC 2 max is the maximum refractive index of a lens included in the triple cemented lens.
20. The wide angle zoom lens of claim 18 , wherein the triple cemented lens satisfies the following expression
vC2max>80
where vC 2 max is the maximum Abbe number of the lens included in the triple cemented lens.
21. A wide angle zoom lens comprising:
a first lens group having a negative refractive power;
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 arranged in an order from an object side to an image side;
during zooming from the wide angle position to a telephoto position:
the distance between the first lens group and the second lens group is reduced;
the second lens group is moved toward the object side; and
the distance between the second lens group and the third lens group is increased;
the first lens group comprises two lenses;
the wide angle zoom lens satisfies the following expressions:
86°≦wfov≦110°
where wfov is the view angle at the wide angle position; and
25>L2>10 (mm)
where L 2 is the distance the second lens group moves.