Zoom lens and camera with zoom lens

Abstract

There is provided a zoom lens of variable power ratio of the order of 3 in which the whole of the zoom lens is made up of three lens elements groups and the power configuration of each of the groups has an arrangement of negative, positive and negative, whereby the reduction in overall length of its optical system is enabled, so that a compact zoom lens and a camera with it can be provided.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing the configuration of lens elements of a first embodiment of a zoom lens of the invention.

FIG. 2 is a diagram showing aberrations of the first embodiment.

FIG. 3 is a diagram showing the configuration of lens elements of a second embodiment of a zoom lens of the invention.

FIG. 4 is a diagram showing aberrations of the second embodiment.

FIG. 5 is a diagram showing the configuration of lens elements of a third embodiment of a zoom lens of the invention.

FIG. 6 is a diagram showing aberrations of the third embodiment.

FIG. 7 is a diagram showing the configuration of lens elements of a fourth embodiment of a zoom lens of the invention.

FIG. 8 is a diagram showing aberrations of the fourth embodiment.

FIG. 9 is a diagram showing the configuration of lens elements of a fifth embodiment of a zoom lens of the invention.

FIG. 10 is a diagram showing aberrations of the fifth embodiment.

FIG. 11 is a diagram showing the configuration of lens elements of a sixth embodiment of a zoom lens of the invention.

FIG. 12 is a diagram showing aberrations of the sixth embodiment.

FIG. 13 is a diagram showing the configuration of lens elements of a seventh embodiment of a zoom lens of the invention.

FIG. 14 is a diagram showing aberrations of the seventh embodiment.

FIG. 15 is a diagram showing the configuration of lens elements of an eighth embodiment of a zoom lens of the invention.

FIG. 16 is a diagram showing aberrations of the eighth embodiment.

FIG. 17 is a diagram showing the configuration of lens elements of a ninth embodiment of a zoom lens of the invention.

FIG. 18 is a diagram showing aberrations of the ninth embodiment.

FIG. 19 is a diagram showing the configuration of lens elements of a tenth embodiment of a zoom lens of the invention.

FIG. 20 is a diagram showing aberrations of the tenth embodiment.

FIG. 21 is a diagram showing the configuration of lens elements of an 11th embodiment of a zoom lens of the invention.

FIG. 22 is a diagram showing aberrations of the 11th embodiment.

FIG. 23 is a diagram showing the configuration of lens elements of a 12th embodiment of a zoom lens of the invention.

FIG. 24 is a diagram showing aberrations of the 12th embodiment.

FIG. 25 is a diagram showing the configuration of lens elements of a 13th embodiment of a zoom lens of the invention.

FIG. 26 is a diagram showing aberrations of the 13th embodiment.

FIG. 27 is a diagram showing the configuration of lens elements of a 14th embodiment of a zoom lens of the invention.

FIG. 28 is a diagram showing aberrations of the 14th embodiment.

FIG. 29 is a diagram showing the configuration of lens elements of a 15th embodiment of a zoom lens of the invention.

FIG. 30 is a diagram showing aberrations of the 15th embodiment.

FIG. 31 is a diagram showing the configuration of lens elements of a 16th embodiment of a zoom lens of the invention.

FIG. 32 is a diagram showing aberrations of the 16th embodiment.

FIG. 33 is a diagram showing the configuration of lens elements of a 17th embodiment of a zoom lens of the invention.

FIG. 34 is a diagram showing aberrations of the 17th embodiment.

FIG. 35 is a diagram showing the configuration of lens elements of an 18th embodiment of a zoom lens of the invention.

FIG. 36 is a diagram showing aberrations of the 18th embodiment.

FIG. 37 is a diagram showing the configuration of lens elements of a 19th embodiment of a zoom lens of the invention.

FIG. 38 is a diagram showing aberrations of the 19th embodiment.

FIG. 39 is a diagram showing the configuration of lens elements of a 20th embodiment of a zoom lens of the invention.

FIG. 40 is a diagram showing aberrations of the 20th embodiment.

FIG. 41 is a diagram showing the configuration of lens elements of a 21st embodiment of a zoom lens of the invention.

FIG. 42 is a diagram showing aberrations of the 21st embodiment.

FIG. 43 is a diagram showing the configuration of lens elements of a 22nd embodiment of a zoom lens of the invention.

FIG. 44 is a diagram showing aberrations of the 22nd embodiment.

FIG. 45 is a diagram showing the configuration of lens elements of a 23rd embodiment of a zoom lens of the invention.

FIG. 46 is a diagram showing aberrations of the 23rd embodiment.

FIG. 47 is a diagram showing the configuration of lens elements of a 24th embodiment of a zoom lens of the invention.

FIG. 48 is a diagram showing aberrations of the 24th embodiment.

Claims

1. zoom lens comprising, sequentially from an object side thereof, a first lens elements group having a negative refraction power as a whole, a second lens elements group having a positive refraction power as a whole and a third lens element group having a negative refraction power as a whole, wherein a variable power is realized by shifting the positions of the first lens elements group and the second lens elements group in a direction of an optical axis thereof, or so shifting, in addition to the first lens elements group and the second lens elements group, the position of the third lens element group, and wherein the zoom lens satisfies the following conditional expression (1) with respect to the power that the first lens element group possesses, the following conditional expression (2) with respect to the size of the whole lens system, and the following conditional expression (3) with respect to the power that the third lens element group possesses. −0.8≦fw/fI≦−0.45   (1)4.5≦TLw/fw−7.5   (2)−0.55≦fw/fIII≦0   (3)

2. The zoom lens according to claim 1, wherein the first lens elements group is made up by disposing, sequentially from an object side thereof, a first lens element which is a lens having a negative refraction power (hereinafter referred to as a negative lens), a second lens element which is a lens having a positive refraction power (hereinafter, referred to as a positive lens) and a third lens element which is a negative lens, and wherein the zoom lens satisfies the following conditional expression (4) with respect to the power that the second lens element possesses, the following conditional expression (5) with respect to the dispersion properties that are distributed to each lens element of the first lens elements group, and the following conditional expression (6) with respect to the refractive index of the second lens element. 0.22≦fw/f2≦0.55   (4)15≦(υ1+υ3)/2−υ2   (5)1.65≦n2   (6)

3. The zoom lens according to claim 1, wherein the first lens element which makes up the first lens elements group is an aspherical lens, and wherein the zoom lens satisfies the following conditional expression (7) with respect to the configuration of an image side surface thereof and also satisfies the following conditional expression (8) with respect to a relative characteristic on configuration between the image side surface of the first lens element and an object side surface of the second lens element which makes up the first lens elements group. 0.4≦fw/r2≦1.4   (7)0≦r2/r3≦1.5   (8)

4. The zoom lens according to claim 2, wherein the first lens element which makes up the first lens elements group is an aspherical lens, and wherein the zoom lens satisfies the following conditional expression (7) with respect to the configuration of an image side surface thereof and also satisfies the following conditional expression (8) with respect to a relative characteristic on configuration between the object side surface of the first lens element and an object side surface of the second lens element which makes up the first lens elements group. 0.4≦fw/r2≦1.4   (7)0≦r2/r3≦1.5   (8)

5. The zoom lens according to claim 1, wherein the second lens elements group is made up by disposing, sequentially from an object side thereof, a fourth lens element which is a positive lens, a fifth lens element which is a positive lens, a sixth lens element which is a negative lens and a seventh lens element which is a positive lens, and wherein the zoom lens satisfies the following conditional expression (9) with respect to a positive composite power that the fourth lens element and the fifth lens element possess, the following conditional expression (10) with respect to the negative power that the sixth lens element possesses, the following conditional expression (11) with respect to the dispersion properties that are distributed to the fourth lens element, the fifth lens element and the sixth lens element which are disposed closer to the object side in the second lens elements group, and the following conditional expression (12) with respect to the refractive index that each of the similar lens elements possesses. 0.5≦fw/f4,5≦1.5   (9)−1.5≦fw/f6≦0.25   (10)28≦(υ4+υ5)/2−υ6   (11)(n4+n5)/2−n6≦−0.24   (12)

6. The zoom lens according to claim 1, wherein of refracting surfaces of each lens element which makes up the second lens elements group, at least one of the refracting surfaces is formed into an aspherical shape, and wherein the zoom lens satisfies the following conditional expression (13) with respect to the configuration of an object side surface of the fourth lens element and the following conditional expression (14) with respect to an image side surface of the sixth lens element. 0.2≦fw/r7≦1.0   (13)0.4≦fw/r12≦1.6   (14)

7. The zoom lens according to claim 5, wherein of refracting surfaces of each lens element which makes up the second lens elements group, at least one of the refracting surfaces is formed into an aspherical shape, and wherein the zoom lens satisfies the following conditional expression (13) with respect to the configuration of an object side surface of the fourth lens element and the following conditional expression (14) with respect to an image side surface of the sixth lens element. 0.2≦fw/r7≦1.0   (13)0.4≦fw/r12≦1.6   (14)

8. The zoom lens according to claim 1, wherein the third lens element group is made up of only an eighth lens element which is a negative lens, and wherein the zoom lens satisfies the following conditional expression (15) with respect to the configuration of the object side surface of the eighth lens element. −2.0≦fw/r15≦0.2   (15)

9. A zoom lens comprising, sequentially from an object side thereof, a first lens elements group having a negative refraction power as a whole, a second lens elements group having a positive refraction power as a whole and a third lens element group having a negative refraction power as a whole, wherein the first lens elements group being made up by disposing three lens elements which include a first lens element which is a negative lens, a second lens element which is a positive lens and a third lens element which is a negative lens, the second lens elements group being made up by disposing four lens elements which include a fourth lens element which is a positive lens, a fifth lens element which is a positive lens, a sixth lens element which is a negative lens and a seventh lens element which is a positive lens, and the third lens element group being made up by disposing an eighth lens element which is a negative lens, wherein a variable power is realized by shifting the positions of the first lens elements group and the second lens elements group in a direction of an optical axis thereof, or so shifting, in addition to the first lens elements group and the second lens elements group, the position of the third lens element group, wherein a configuration of positive/negative powers of the individual lens elements of the whole lens system is made to be a configuration of negative, positive, negative, positive, positive, negative, positive, negative which is symmetrical with respect to a boundary between the fourth lens element and the fifth lens element, and wherein a distribution of volumes of the powers of the constituent lens elements is also made to be substantially symmetrical in the similar manner.

10. A camera which installs thereon the zoom lens according to claim 1.

11. A camera which installs thereon the zoom lens according to claim 9.

12. A zoom lens comprising, sequentially from an object side thereof, a first lens elements group having a negative refraction power as a whole, a second lens elements group having a positive refraction power as a whole and a third lens element group having a negative refraction power as a whole, the first lens elements group having a negative refraction power as a whole and being made up by disposing a first lens element which is a lens having a negative refraction power (hereinafter referred to as a negative lens) and which has a meniscus configuration which is convex on an object side surface thereof, a second lens element which is a lens having a positive refraction power (hereinafter, referred to as a positive lens) and which has a meniscus configuration which is convex on an object side surface thereof, and a third lens element which is a negative lens, the second lens elements group having a positive refraction power as a whole and being made up by disposing a fourth lens element which is a positive lens, a fifth lens element which is a negative lens and which has a meniscus configuration which is convex on an object side surface thereof, and a sixth lens element which is a positive lens, and the third lens element group having a negative refraction power as a whole and being made up by disposing a seventh lens element which is a negative lens, wherein a variable power is realized by shifting the positions of the first lens elements group and the second lens elements group in a direction of an optical axis thereof, or so shifting, in addition to the first lens elements group and the second lens elements group, the position of the third lens element group, and wherein the zoom lens satisfies the following conditional expression (16) with respect to the power that the first lens element group possesses, the following conditional expression (17) with respect to the size of the whole lens system, and the following conditional expression (18) with respect to the power that the third lens element group possesses. −0.8≦fw/fI≦−0.4   (16)4.5≦TLw/fw≦7.5   (17)−0.6≦fw/fIII≦0   (18)

13. The zoom lens according to claim 12, wherein the first lens element which makes up the first lens elements group is an aspherical lens, and the zoom lens satisfies the following conditional expression (19) with respect to the power that the second lens element possesses, the following conditional expression (20) with respect to the dispersion properties that are distributed to each lens element of the first lens elements group, the following conditional expression (21) with respect to the refractive index of the second lens element, the following conditional expression (22) with respect to the configuration of the image side surface of the first lens element, and satisfies the following conditional expression (23) with respect to a relative characteristic on configuration between the image side surface of the first lens element and the object side surface of the second lens element. 0.25≦fw/f2≦0.55   (19)15≦(υ1+υ3)/2−υ2   (20)1.65≦n2   (21)0.8≦fw/r21.5   (22)0.45≦r2/r3≦0.85   (23)

14. The zoom lens according to claim 12, wherein of refracting surfaces of each lens element which makes up the second lens elements group, at least one of the refracting surfaces is formed into an aspherical shape, and wherein the zoom lens satisfies the following conditional expression (24) with respect to the positive power that the fourth lens element possesses, the following conditional expression (25) with respect to the negative power that the fifth lens element possesses, and the following conditional expression (26) with respect the dispersion properties that are distributed to each lens element which makes up the second lens elements group, the following conditional expression (27) with respect to the refractive index that each of the similar lens elements possesses, the following conditional expression (28) with respect to the configuration of the object side surface of the fourth lens element and the following conditional expression (29) with respect to a relative relationship between the configuration of an object side surface of the fourth lens element and the configuration of an image side surface of the sixth lens element. 0.65≦fw/f4≦1.05   (24)−0.5≦fw/f5≦−0.3   (25)25≦(υ4+υ6)/2−υ5   (26)−0.45≦(n4+n6)/2−n5≦−0.20   (27)0.8≦fw/r7≦1.3   (28)−1.1≦r7/r12≦−0.7   (29)

15. The zoom lens according to claim 12, satisfying the following conditional expression (30) with respect to the configuration of the object side surface of the seventh lens element which makes up the third lens element group. −1.2≦fw/r13≦0.4   (30)

16. A zoom lens comprising, sequentially from an object side thereof, a first lens elements group having a negative refraction power as a whole, a second lens elements group having a positive refraction power as a whole and a third lens element group having a negative refraction power as a whole, wherein the first lens elements group being made up by disposing three lens elements which include a first lens element which is a negative lens and which has a meniscus configuration which is convex on an object side surface thereof, a second lens element which is a positive lens and which has a meniscus configuration which is convex on an object side surface thereof and a third lens element which is a negative lens, the second lens elements group being made up by disposing three lens elements which include a fourth lens element which is a positive lens, a fifth lens element which is a negative lens and which has a meniscus configuration which is convex on an object side surface thereof and a sixth lens element which is a positive lens, and the third lens element group being made up by disposing a seventh lens element which is a negative lens, wherein a variable power is realized by shifting the positions of the first lens elements group and the second lens elements group in a direction of an optical axis thereof, or so shifting, in addition to the first lens elements group and the second lens elements group, the position of the third lens element group, wherein a configuration of positive/negative powers of the individual lens elements of the whole lens system is made to be a configuration of negative, positive, negative, positive, negative, positive, negative which is symmetrical with respect to the fourth lens element which constitutes the center of the configuration, and wherein a distribution of volumes of the powers of the constituent lens elements is also made to be substantially symmetrical in the similar manner.

17. A camera which installs thereon the zoom lens according to claim 12.

18. A camera which installs thereon the zoom lens according to claim 16.