Zoom lens and image pickup apparatus using the same
View Patent ↗A zoom lens comprising, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, a fourth lens unit having a negative refractive power, and a fifth lens unit having a positive refractive power. Each distance between the first lens unit and the second lens unit, between the third lens unit and the fourth lens unit, and between the fourth lens unit and the fourth lens unit at the telephoto end is longer than at the wide angle end, and a distance between the second lens unit and the third lens unit at the telephoto end is shorter than at the wide angle end, and the following conditional expressions are satisfied. 2< mg 3t /mg 3w <6 1.2< mg 5t /mg 5w <4 0.02< f 5 /f t <0.12
1. A zoom lens comprising in order from an object side to an image side:
a first lens unit having a positive refractive power;
a second lens unit having a negative refractive power;
a third lens unit having a positive refractive power;
a fourth lens unit having a negative refractive power; and
a fifth lens unit having a positive refractive power, wherein
at the time of zooming, each of the first lens unit, the second lens unit, the third lens unit, the fourth lens unit, and the fifth lens unit moves to change distances between the lens units,
a distance between the first lens unit and the second lens unit at a telephoto end is longer than a distance between the first lens unit and the second lens unit at a wide angle end,
a distance between the third lens unit and the fourth lens unit at the telephoto end is longer than a distance between the third lens unit and the fourth lens unit at the wide angle end,
a distance between the fourth lens unit and the fifth lens unit at the telephoto end is longer than a distance between the fourth lens unit and the fifth lens unit at the wide angle end,
a distance between the second lens unit and the third lens unit at the telephoto end is shorter than a distance between the second lens unit and the third lens unit at the wide angle end, and
the following conditional expression (11) is satisfied:
40< f t /f w <150 (11)
where,
f t denotes the focal length of the overall zoom lens system at the telephoto end, and
f w denotes a focal length of the overall zoom lens system at a wide angle end.
2. The zoom lens according to claim 1 , wherein the following conditional expression (11-1) is satisfied:
45< f t /f w <150 (11-1)
where,
f t denotes the focal length of the overall zoom lens system at the telephoto end, and
f w denotes a focal length of the overall zoom lens system at a wide angle end.
3. The zoom lens according to claim 1 , wherein
the following conditional expression (11-2) is satisfied:
52< f t /f w <150 (11-2)
where,
f t denotes the focal length of the overall zoom lens system at the telephoto end, and
f w denotes a focal length of the overall zoom lens system at a wide angle end.
4. The zoom lens according to claim 1 , wherein
the following conditional expression (11-3) is satisfied:
54.72 ≦f t /f w <150 (11-3)
where,
f t denotes the focal length of the overall zoom lens system at the telephoto end, and
f w denotes a focal length of the overall zoom lens system at a wide angle end.
5. The zoom lens according to claim 1 , wherein
the following conditional expression (11-4) is satisfied:
55.09 ≦f t /f w <150 (11-4)
where,
f t denotes the focal length of the overall zoom lens system at the telephoto end, and
f w denotes a focal length of the overall zoom lens system at a wide angle end.
6. The zoom lens according to claim 1 , wherein
the following conditional expression (11-5) is satisfied:
60.07≦ f t /f w <150 (11-5)
where,
f t denotes the focal length of the overall zoom lens system at the telephoto end, and
f w denotes a focal length of the overall zoom lens system at a wide angle end.
7. The zoom lens according to claim 1 , wherein
the first lens unit includes a cemented lens having a negative lens and a positive lens, and at least one positive lens.
8. The zoom lens according to claim 1 , wherein
the first lens unit includes a cemented lens having a negative lens and a positive lens, and at least one positive lens, and
the following conditional expression (11-3) is satisfied:
54.72 ≦f t /f w <150 (11-3)
where,
f t denotes the focal length of the overall zoom lens system at the telephoto end, and
f w denotes a focal length of the overall zoom lens system at a wide angle end.
9. The zoom lens according to claim 1 , wherein
the first lens unit has three lens elements, and includes in order from an object side, a negative meniscus lens having a convex surface directed toward the object side, a biconvex positive lens, and a positive meniscus lens having a convex surface directed toward the object side, and
the negative meniscus lens of the first lens unit and the biconvex positive lens of the first lens unit are cemented.
10. The zoom lens according to claim 4 , wherein
the first lens unit has three lens elements, and includes in order from an object side, a negative meniscus lens having a convex surface directed toward the object side, a biconvex positive lens, and a positive meniscus lens having a convex surface directed toward the object side, and
the negative meniscus lens of the first lens unit and the biconvex positive lens of the first lens unit are cemented.
11. The zoom lens according to claim 1 , wherein
the first lens unit has three lens elements, and includes in order from an object side, a negative meniscus lens having a convex surface directed toward the object side, a biconvex positive lens, and a positive meniscus lens having a convex surface directed toward the object side,
the negative meniscus lens of the first lens unit and the biconvex positive lens of the first lens unit are cemented, and
the following conditional expression (11-3) is satisfied:
54.72 ≦f t /f w <150 (11-3)
where,
f t denotes the focal length of the overall zoom lens system at the telephoto end, and
f w denotes a focal length of the overall zoom lens system at a wide angle end.
12. The zoom lens according to claim 1 , wherein
the second lens unit includes three negative lenses and one positive lens.
13. The zoom lens according to claim 12 , wherein
the three negative lenses of the second lens unit include a negative meniscus lens having a convex surface directed toward the object side, a biconcave negative lens, and a biconcave negative lens, and
the one positive lens of the second lens unit includes a biconvex positive lens.
14. The zoom lens according to claim 4 , wherein
the second lens unit includes three negative lenses and one positive lens.
15. The zoom lens according to claim 14 , wherein
the three negative lenses of the second lens unit include a negative meniscus lens having a convex surface directed toward the object side, a biconcave negative lens, and a biconcave negative lens, and
the one positive lens of the second lens unit includes a biconvex positive lens.
16. The zoom lens according to claim 1 , wherein
the first lens unit has three lens elements, and includes in order from an object side, a negative meniscus lens having a convex surface directed toward the object side, a biconvex positive lens, and a positive meniscus lens having a convex surface directed toward the object side,
the negative meniscus lens of the first lens unit and the biconvex positive lens of the first lens unit are cemented,
the second lens unit includes three negative lenses and one positive lens, and
the following conditional expression (11-3) is satisfied:
54.72 ≦f t /f w <150 (11-3)
where,
f t denotes the focal length of the overall zoom lens system at the telephoto end, and
f w denotes a focal length of the overall zoom lens system at a wide angle end.
17. The zoom lens according to claim 16 , wherein
the three negative lenses of the second lens unit include a negative meniscus lens having a convex surface directed toward the object side, a biconcave negative lens, and a biconcave negative lens, and
the one positive lens of the second lens unit includes a biconvex positive lens.
18. The zoom lens according to claim 1 , wherein
the third lens unit has four lens elements,
at least two lenses of the four lens elements of the third lens unit are cemented, and
in the third lens unit, a biconvex positive lens is disposed nearest to the object side.
19. The zoom lens according to claim 4 , wherein
the third lens unit has four lens elements,
at least two lenses of the four lens elements of the third lens unit are cemented, and
in the third lens unit, a biconvex positive lens is disposed nearest to the object side.
20. The zoom lens according to claim 1 , wherein
the first lens unit has three lens elements, and includes in order from an object side, a negative meniscus lens having a convex surface directed toward the object side, a biconvex positive lens, and a positive meniscus lens having a convex surface directed toward the object side,
the negative meniscus lens of the first lens unit and the biconvex positive lens of the first lens unit are cemented,
the second lens unit includes three negative lenses and one positive lens,
the three negative lenses of the second lens unit include a negative meniscus lens having a convex surface directed toward the object side, a biconcave negative lens, and a biconcave negative lens,
the one positive lens of the second lens unit includes a biconvex positive lens,
the third lens unit has four lens elements,
at least two lenses of the four lens elements of the third lens unit are cemented,
in the third lens unit, a biconvex positive lens is disposed nearest to the object side, and
the following conditional expression (11-3) is satisfied:
54.72 ≦f t /f w <150 (11-3)
where,
f t denotes the focal length of the overall zoom lens system at the telephoto end, and
f w denotes a focal length of the overall zoom lens system at a wide angle end.
21. The zoom lens according to claim 1 , wherein
the fourth lens unit has two lens elements, and
the two lens elements of the fourth lens unit are cemented.
22. The zoom lens according to claim 4 , wherein
the fourth lens unit has two lens elements, and
the two lens elements of the fourth lens unit are cemented.
23. The zoom lens according to claim 1 , wherein
the first lens unit has three lens elements, and includes in order from an object side, a negative meniscus lens having a convex surface directed toward the object side, a biconvex positive lens, and a positive meniscus lens having a convex surface directed toward the object side,
the negative meniscus lens of the first lens unit and the biconvex positive lens of the first lens unit are cemented,
the second lens unit includes three negative lenses and one positive lens,
the three negative lenses of the second lens unit include a negative meniscus lens having a convex surface directed toward the object side, a biconcave negative lens, and a biconcave negative lens,
the one positive lens of the second lens unit includes a biconvex positive lens,
the third lens unit has four lens elements,
at least two lenses of the four lens elements of the third lens unit are cemented,
in the third lens unit, a biconvex positive lens is disposed nearest to the object side,
the fourth lens unit has two lens elements,
the two lens elements of the fourth lens unit are cemented, and
the following conditional expression (11-3) is satisfied:
54.72 ≦f t /f w <150 (11-3)
where,
f t denotes the focal length of the overall zoom lens system at the telephoto end, and
f w denotes a focal length of the overall zoom lens system at a wide angle end.
24. The zoom lens according to claim 1 , wherein
the fifth lens unit has two lens elements, and
the two lens elements of the fifth lens unit are cemented.
25. The zoom lens according to claim 4 , wherein
the fifth lens unit has two lens elements, and
the two lens elements of the fifth lens unit are cemented.
26. The zoom lens according to claim 1 , wherein
the first lens unit has three lens elements, and includes in order from an object side, a negative meniscus lens having a convex surface directed toward the object side, a biconvex positive lens, and a positive meniscus lens having a convex surface directed toward the object side,
the negative meniscus lens of the first lens unit and the biconvex positive lens of the first lens unit are cemented,
the second lens unit includes three negative lenses and one positive lens,
the three negative lenses of the second lens unit include a negative meniscus lens having a convex surface directed toward the object side, a biconcave negative lens, and a biconcave negative lens,
the one positive lens of the second lens unit includes a biconvex positive lens,
the third lens unit has four lens elements,
at least two lenses of the four lens elements of the third lens unit are cemented,
in the third lens unit, a biconvex positive lens is disposed nearest to the object side,
the fourth lens unit has two lens elements,
the two lens elements of the fourth lens unit are cemented,
the fifth lens unit has two lens elements,
the two lens elements of the fifth lens unit are cemented, and
the following conditional expression (11-3) is satisfied:
54.72 ≦f t /f w <150 (11-3)
where,
f t denotes the focal length of the overall zoom lens system at the telephoto end, and
f w denotes a focal length of the overall zoom lens system at a wide angle end.
27. The zoom lens according to claim 1 , wherein
the first lens unit and the third lens unit are positioned more on the object side at the telephoto end than at the wide angle end, and
the fifth lens unit is positioned more on the image side at the telephoto end than at the wide angle end.
28. The zoom lens according to claim 1 , wherein the second lens unit is positioned more on the image side at the telephoto end than at the wide angle end.
29. The zoom lens according to claim 1 , wherein the following conditional expression (1) is satisfied:
2< mg 3t /mg 3w <6 (1)
where,
mg 3w denotes a lateral magnification of the third lens unit at the wide angle end, and
mg 3t denotes a lateral magnification of the third lens unit at the telephoto end.
30. The zoom lens according to claim 1 , wherein the following conditional expression (3) is satisfied:
0.02< f 5 /f t <0.12 (3)
where,
f 5 denotes a focal length of the fifth lens unit, and
f t denotes a focal length of the overall zoom lens system at the telephoto end.
31. The zoom lens according to claim 1 , wherein the following conditional expression (4) is satisfied:
0.02< f 3 /f t <0.1 (4)
where,
f 3 denotes a focal length of the third lens unit, and
f t denotes the focal length of the overall zoom lens system at the telephoto end.
32. The zoom lens according to claim 1 , wherein the following conditional expression (5) is satisfied:
1.5<(1− mg 3t )× mg 4t ×mg 5t <7.0 (5)
where,
mg 3t denotes the lateral magnification of the third lens unit at the telephoto end,
mg 4t denotes a lateral magnification of the fourth lens unit at the telephoto end, and
mg 5t denotes the lateral magnification of the fifth lens unit at the telephoto end.
33. The zoom lens according to claim 1 , wherein the following conditional expression (6) is satisfied:
νd 1n <50 (6)
where,
νd 1n denotes Abbe's number for a d-line of at least one negative lens in the first lens unit,
Abbe's number νd 1n is indicated by νd 1n =(nd 1n −1)/(nF 1n −nC 1n ), and
nd 1n , ng 1n , nF 1n , and nC 1n are refractive indices for the d-line, the g-line, the F-line, and a C-line respectively, of at least one negative lens in the first lens unit.
34. The zoom lens according to claim 1 , wherein the following conditional expression (7) is satisfied:
80<νd 1p (7)
where,
νd 1p denotes Abbe's number for the d-line of at least one positive lens in the first lens unit,
Abbe's number νd 1p is indicated by νd 1p =(nd 1p −1)/(nF 1p −nC 1p ), and
nd 1p , ng 1p , nF 1p , and nC 1p are refractive indices for the d-line, the g-line, the F-line, and the C-line respectively, of at least one positive lens in the first lens unit.
35. The zoom lens according to claim 1 , wherein the first lens unit includes a negative lens which satisfies the following conditional expression (8):
θ gF 1n <−0.00266 νd 1n +0.68107 (8)
where,
θgF 1n denotes a partial dispersion ratio for a g-line and an F-line of at least one negative lens in the first lens unit,
the partial dispersion ratio θgF 1n is indicated by θgF 1n =(ng 1n −nF 1n )/(nF 1n −nC 1n ), and
nd 1n , ng 1n , nF 1n , and nC 1n are refractive indices for the d-line, the g-line, the F-line, and a C-line respectively, of at least one negative lens in the first lens unit.
36. The zoom lens according to claim 1 , wherein the following conditional expression (10) is satisfied:
0.2< f 1 /f t <0.5 (10)
where,
f 1 denotes a focal length of the first lens unit, and
f t denotes a focal length of the overall zoom lens system at the telephoto end.
37. An image pickup apparatus comprising:
a zoom lens; and
an image pickup element which has an image pickup surface, and which converts an image formed on the image pickup surface by the zoom lens, to an electric image, wherein
the zoom lens is the zoom lens according to claim 1 .
38. The image pickup apparatus according to claim 37 , comprising:
an image converting section, wherein
an electric signal having a distortion due to the zoom lens, is converted to an image signal in which, the distortion is corrected, by an image processing in the image converting section.