Zoom lens, lens barrel, and imaging apparatus

Abstract

To provide a zoom lens, a lens barrel, and an imaging apparatus that can reduce a variation in aberration associated with a change in photographic distance.SOLUTION: A zoom lens has a positive first lens group, a negative second lens group, and a rear group, and in magnification variation from a wide end to a telephoto end, the interval between the adjacent lens groups is changed. The rear group has at least one negative lens group and one positive lens group. Of the negative lens groups included in the rear group, the lens group having the largest negative refractive power is a focusing lens group GF that moves to an image side during focusing from infinity to a close range. Of the positive lens groups included in the rear group, the positive lens group GFF arranged adjacent to an object side of the focusing lens group GF has a positive lens component L1 located on the most image side. The positive lens component L1 has a positive lens L1P, and satisfies the following conditional expression (1). (1) 1.85<NdL1 P, wherein NdL1P is the refractive index of the positive lens L1P.SELECTED DRAWING: Figure 1

Claims

1. The lens has, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a rear lens group; When changing magnification from the short focal length end to the long focal length end, the spacing between adjacent lens groups changes. the rear group has at least one lens group having a negative refractive power and at least one lens group having a positive refractive power; Among the lens groups having negative refractive power included in the rear group, the lens group having the strongest negative refractive power is a focusing lens group GF that moves toward the image side during focusing from infinity to a close distance, Among the lens groups having positive refractive power included in the rear group, a lens group GFF having positive refractive power arranged adjacent to the object side of the focusing lens group GF has a positive lens component L1 located closest to the image side, The positive lens component L1 has a positive lens L1P, The following condition (1) is satisfied: A zoom lens characterized by: (1) 1.85<NdL1P however, NdL1P: the refractive index of the positive lens L1P.

2. The following condition (2) is satisfied:

2. The zoom lens according to claim 1. (2) 25<νdL1P however, νdL1P: the Abbe number of the positive lens L1P.

3. The following condition (3) is satisfied:

3. The zoom lens according to claim 1 or 2. (3) -5<fGFF / fGF<-0.7 however, fGFF: the focal length of the lens group GFF having the positive refractive power, fGF: the focal length of the focusing lens group GF.

4. a positive or negative lens component L2 located adjacent to the object side of the positive lens component L1; The lens component L2 is composed of a cemented lens of a negative lens L2N and a positive lens L2P, The following condition (4) is satisfied:

4. The zoom lens according to claim 1, wherein the first and second lenses are arranged in a first and second directions. (4) 1.0<NdL2N / NdL2P<1.6 however, NdL2N: the refractive index of the negative lens L2N, NdL2P: the refractive index of the positive lens L2P.

5. a positive or negative lens component L2 located adjacent to the object side of the positive lens component L1; The lens component L2 is composed of a cemented lens of a negative lens L2N and a positive lens L2P, The following condition (5) is satisfied:

5. The zoom lens according to claim 1, wherein the first and second lenses are arranged in a first direction and a second direction. (5) 0.2<νdL2N / νdL2P<0.7 however, νdL2P: Abbe number of the positive lens L2P, νdL2N: the Abbe number of the negative lens L2N.

6. The following condition (6) is satisfied:

6. The zoom lens according to claim 1, wherein the first and second lenses are arranged in a first and second directions. (6) 0.5<fL1 / fGFF<5 however, fL1: the focal length of the positive lens component L1, fGFF: the focal length of the lens group GFF having the positive refractive power.

7. The following condition (7) is satisfied:

6. The zoom lens according to claim 1, 4 or 5. (7) 0.5<|fL2| / fL1<20 however, fL1: the focal length of the positive lens component L1, fL2: the focal length of the lens component L2.

8. The following condition (8) is satisfied:

8. The zoom lens according to claim 1, wherein the first and second lenses are arranged in a first direction and a second direction. (8) 0.1<TLT / fT<0.95 however, TLT: total lens length at the long focal length end when focused on infinity, fT: focal length of the entire system when focused at infinity at the long focal length end.

9. The following condition (9) is satisfied:

9. The zoom lens according to claim 1, wherein the first and second lenses are arranged in a first and second directions. (9) 0.1<f1 / fT<1 however, f1: the focal length of the first lens group, fT: focal length of the entire system when focused at infinity at the long focal length end.

10. The following condition (10) is satisfied:

10. The zoom lens according to claim 1, wherein the first and second lenses are arranged in a first direction and a second direction. (10) 0.3<f2 / fGF<3.0 however, f2: the focal length of the second lens group, fGF: the focal length of the focusing lens group GF.

11. The following condition (11) is satisfied:

11. The zoom lens according to claim 1. (11)-8<f1 / f2<-2 however, f1: the focal length of the first lens group, f2: the focal length of the second lens group.

12. a position of the first lens group or the second lens group in the optical axis direction is fixed during zooming from the short focal length end to the long focal length end; 12. The zoom lens according to claim 1, wherein the first and second lenses are arranged in a first direction and a second direction.

13. the focusing lens group GF has at least one negative lens, The following condition (12) is satisfied:

13. The zoom lens according to claim 1, wherein the first and second lenses are arranged in a first direction and a second direction. (12) 35<νdGFN however, νdGFN: the Abbe number of the negative lens GFN having the largest Abbe number among the negative lenses included in the focusing lens group GF.

14. the focusing lens group GF has at least one negative lens and at least one positive lens, The following condition (13) is satisfied:

14. The zoom lens according to claim 1, (13) -10<fGFP / fGFN<-0.5 however, fGFP: the focal length of the positive lens GFP having the smallest Abbe number among the positive lenses included in the focusing lens group GF, fGFN: the focal length of the negative lens GFN having the largest Abbe number among the negative lenses included in the focusing lens group GF.

15. the focusing lens group GF has at least one negative lens and at least one positive lens, The following condition (14) is satisfied:

15. The zoom lens according to claim 1, (14) 0.2<νdGFP / νdGFN<0.7 however, νdGFP: the Abbe number of the positive lens GFP having the smallest Abbe number among the positive lenses included in the focusing lens group GF, νdGFN: the Abbe number of the negative lens GFN having the largest Abbe number among the negative lenses included in the focusing lens group GF.

16. at least one lens group located on the image side of the focusing lens group GF; 16. The zoom lens according to claim 1,

17. at least one lens group located on the image side of the focusing lens group GF; The following condition (15) is satisfied:

17. The zoom lens according to claim 1. (15) 0.1<TLT / DGFRT<0.5 however, TLT: total lens length at the long focal length end when focused on infinity, DGFRT: the distance on the optical axis from the refractive surface closest to the image of the lens group GFF having positive refractive power when focusing on infinity at the long focal length end to the refractive surface closest to the object of the lens group that is closer to the image than the focusing lens group GF.

18. at least one lens group located on the image side of the focusing lens group GF; The following condition (16) is satisfied:

18. The zoom lens according to claim 1. (16) |fGFRT| / fGF<-1.5 however, fGFRT: composite focal length of the lens group on the image side of the focusing lens group GF when focusing on infinity at the long focal length end, fGF: the focal length of the focusing lens group GF.

19. A lens barrel comprising the zoom lens according to any one of claims 1 to 18.

20. 19. An imaging device comprising the zoom lens according to claim 1.

Images