Zoom lens having a long back focal length with vibration reduction function

• US 6,285,501 B1
• Filed: 01/27/2000
• Issued: 09/04/2001
• Est. Priority Date: 01/27/1999
• Status: Expired due to Term

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Suzuki, Kenzaburo
• Primary Examiner(s): Sugarman, Scott J.
• Assistant Examiner(s): Lucas, Michael A.
• Application Number:
  US09/492,179
• Time in Patent Office: 586 Days
• Field of Search: 359/554, 359/557, 359/676, 359/682, 359/683, 359/684, 359/680
• US Class Current: 359/554
• CPC Class Codes: G02B 15/145125 arranged +--++
• CPC Class Codes: G02B 27/646 compensating for small deviations, e.g. due to vibration or shake movement of one or more optical elements for control of motion blur in cameras, projectors or printers G03B2205/0007; image stabilisation in cameras peculiar to the presence or use of an electronic image sensor H04N23/68

Abstract

A high-performance zoom lens having a long back focal length and thus ideally suitable to electronic imaging equipment. The zoom lens comprises a first lens group G1 having a positive refractive power, a second lens group G2 having a, negative refractive power, a third lens group G3 having a negative refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a positive refractive power. When zooming from the wide-angle end to the telephoto end, the air gap between the first lens group G1 and the second lens group G2 increases, the air gap between the second lens group G2 and the third lens group G3 changes, and the air gap between the fourth lens group G4 and the fifth lens group G5 changes.

Vibration reduction is attained by displacing (shifting) a vibration reduction lens group G4v consisting of the fourth lens group G4 or a partial lens group in said fourth lens group in a direction substantially perpendicular to the optical axis.

Claims

1. A zoom lens having a long back focal length comprising, in order from an object 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 negative refractive power;

a fourth lens group a having a positive refractive power; and

a fifth lens group a having positive refractive power;

wherein the zoom lens is designed such that when zooming is effected from the wide-angle end to the telephoto end, the interval between said first lens group and said second lens group increases, the interval between said second lens group and said third lens group changes linearly or non-linearly, and the interval between said fourth lens group and said fifth lens group changes linearly or non-linearly;

wherein vibration reduction is attained by shifting a vibration reduction lens group consisting of said fourth lens group or a partial lens group of said fourth lens group in a direction substantially perpendicular to an optical axis; and

wherein the following conditional formulae are satisfied;

2. A zoom lens according to claim 1, further satisfying the following conditional formulae:

3. A zoom lens according to claim 2, further satisfying the following conditional formulae:

4. A zoom lens according to claim 3, wherein said first lens group and said fourth lens group is fixed during zooming from the wide-angle end to the telephoto end, and the following (condition is satisfied:

5. A zoom lens according to claim 4, wherein said fifth lens group includes a cemented lens having a divergent convex cemented surface facing to the image side.

6. A zoom lens, according to claim 5, further satisfying the following conditional formula:

7. A zoom lens according to claim 6, further satisfying the following conditional formulae:

8. A zoom lens according to claim 6,

wherein the fourth lens group includes a positive lens arranged at the most object side and negative lens arranged at the most image side;

the fifth lens group include a cemented lens having a divergent convex cemented surface facing to the image side; and

the following conditional formula is satisfied;

9. A zoom lens according to claim 6, further satisfying the following conditional formula:

10. A zoom lens according to claim 2, wherein said fifth lens group includes a cemented lens having a divergent convex cemented surface facing to the image side.

11. A zoom lens according to claim 10, further satisfying the following conditional formula:

12. A zoom lens according to claim 10, further satisfying the following conditional formulae:

13. A zoom lens according to claim 10,

wherein the fourth lens group includes a positive lens arranged at the most object side and a negative lens arranged at the most image side;

the fifth lens group include a cemented lens having a divergent convex cemented surface facing to the image side; and

the following conditional formula is satisfied;

14. A zoom lens according to claim 10, further satisfying the following conditional formula:

15. A zoom lens according to claim 1, wherein said first lens group and said fourth lens group is fixed during zooming from the wide-angle end to the telephoto end, and the following condition is satisfied:

16. A zoom lens according to claim 15, wherein said fifth lens group includes a cemented lens having a divergent convex cemented surface facing to the image side.

17. A zoom lens according to claim 15, further satisfying the following conditional formula:

18. A zoom lens according to claim 17, further satisfying the following conditional formulae:

19. A zoom lens according to claim 17,

wherein the fourth lens group includes a positive lens arranged at the most object side and a negative lens arranged at the most image side;

the fifth lens group include a cemented lens having a divergent convex cemented surface facing to the image side; and

the following conditional formula is satisfied;

20. A zoom lens according to claim 17, further satisfying the following conditional formula:

21. A zoom lens according to claim 15, further satisfying the following conditional formulae: