JP7052832B2 - Zoom lenses and optics - Google Patents

Description

The present invention relates to a zoom lens and an optical device suitable for a digital still camera or the like.

A zoom lens is often used as a shooting lens in a shooting device (camera) such as a digital still camera or a digital video camera. As a zoom lens having a high magnification ratio, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a positive refractive power arranged in order from the object side along the optical axis. A zoom lens is composed of a third lens group having a positive refractive power and a fourth lens group having a positive refractive power, and the first to fourth lens groups are configured to move along an optical axis at the time of scaling. It has been proposed (see, for example, Patent Document 1). Such a conventional zoom lens is required to have a higher magnification ratio.

Japanese Unexamined Patent Publication No. 2011-33867

The zoom lens according to the first invention has a first lens group having a positive refractive force, a second lens group having a negative refractive force, and a positive refractive force arranged in order from the object side along the optical axis. The third lens group having the The second lens group, the third lens group, and the fourth lens group move along the optical axis, the distance between adjacent lens groups changes, and when the lens is in focus, the fourth lens group moves. Moving along the optical axis, the first lens group has at least one negative lens and satisfies the following conditional expression.
8.60 <β2t / β2w <11.00
30.0 <νd1 <34.0
0.60 <TLt / ft <0.70
0.090 <f3 / ft <0.109
however,
β2t: Magnification of the second lens group in the telephoto end state,
β2w: Magnification of the second lens group in the wide-angle end state,
νd1: Abbe number of the negative lens arranged on the object side among the negative lenses constituting the first lens group,
TLt: Overall length of the zoom lens in the telephoto end state,
ft: Focal length of the zoom lens in the telephoto end state,
f3: Focal length of the third lens group.
The zoom lens according to the second invention includes a first lens group having a positive refractive force, a second lens group having a negative refractive force, and a positive refractive force arranged in order from the object side along the optical axis. The third lens group having the The second lens group, the third lens group, and the fourth lens group move along the optical axis, the distance between adjacent lens groups changes, and when the lens is in focus, the fourth lens group moves. Moving along the optical axis, the first lens group has at least one negative lens and a plurality of positive lenses, and satisfies the following conditional expression.
8.60 <β2t / β2w <11.00
30.0 <νd1 <34.0
83.0 <νd2 <96.0
however,
β2t: Magnification of the second lens group in the telephoto end state,
β2w: Magnification of the second lens group in the wide-angle end state,
νd1: Abbe number of the negative lens arranged on the object side among the negative lenses constituting the first lens group,
νd2: Abbe number of the positive lens arranged on the object side of the positive lenses constituting the first lens group.

The zoom lens according to the third invention includes a first lens group having a positive refractive force, a second lens group having a negative refractive force, and a positive refractive force arranged in order from the object side along the optical axis. The third lens group having the The second lens group, the third lens group, and the fourth lens group move along the optical axis, the distance between adjacent lens groups changes, and when the lens is in focus, the fourth lens group moves. Moving along the optical axis, the first lens group has at least one negative lens and satisfies the following conditional expression.
8.60 <β2t / β2w <11.00
32.0 <νd1 <33.0
0.090 <f3 / ft <0.109
however,
β2t: Magnification of the second lens group in the telephoto end state,
β2w: Magnification of the second lens group in the wide-angle end state,
νd1: Abbe number of the negative lens arranged on the object side among the negative lenses constituting the first lens group,
f3: Focal length of the third lens group,
ft: Focal length of the zoom lens in the telephoto end state.
The zoom lens according to the fourth invention has a first lens group having a positive refractive force, a second lens group having a negative refractive force, and a positive refractive force arranged in order from the object side along the optical axis. The third lens group having the The second lens group, the third lens group, and the fourth lens group move along the optical axis, the distance between adjacent lens groups changes, and when the lens is in focus, the fourth lens group moves. Moving along the optical axis, the first lens group has at least one negative lens and satisfies the following conditional expression.
9.50 <β2t / β2w <11.00
30.0 <νd1 <33.0
0.090 <f3 / ft <0.109
however,
β2t: Magnification of the second lens group in the telephoto end state,
β2w: Magnification of the second lens group in the wide-angle end state,
νd1: Abbe number of the negative lens arranged on the object side among the negative lenses constituting the first lens group,
f3: Focal length of the third lens group,
ft: Focal length of the zoom lens in the telephoto end state.

Further, the optical device according to the present invention is an optical device provided with a zoom lens for forming an image of an object on a predetermined surface, and the zoom lens according to the present invention is used as the zoom lens.

It is a lens block diagram of the zoom lens which concerns on 1st Embodiment. (A) is an aberration diagram at infinity focusing in the wide-angle end state of the zoom lens according to the first embodiment, and (b) is an aberration diagram at infinity focusing in an intermediate focal length state. (C) is an aberration diagram at the time of infinity focusing in the telephoto end state. It is a lens block diagram of the zoom lens which concerns on 2nd Embodiment. (A) is an aberration diagram at infinity focusing in the wide-angle end state of the zoom lens according to the second embodiment, and (b) is an aberration diagram at infinity focusing in an intermediate focal length state. (C) is an aberration diagram at the time of infinity focusing in the telephoto end state. (A) is a front view of the digital still camera, and (b) is a rear view of the digital still camera. It is sectional drawing which follows the arrow AA'in FIG. 5A. It is a flowchart which shows the manufacturing method of a zoom lens.

Hereinafter, preferred embodiments of the present application will be described with reference to the drawings. A digital still camera CAM equipped with a zoom lens according to the present application is shown in FIGS. 5 and 6. 5A and 5B show a front view of the digital still camera CAM, and FIG. 5B shows a rear view of the digital still camera CAM. FIG. 6 shows a cross-sectional view taken along the arrow AA'in FIG. 5 (a).

In the digital still camera CAM shown in FIG. 5, when the power button (not shown) is pressed, the shutter (ZL) (ZL) (not shown) is released, and the light from the subject (object) is focused by the taking lens (ZL). The image is formed on the image pickup element C (for example, CCD, CMOS, etc.) arranged on the image plane I shown in FIG. The subject image formed on the image sensor C is displayed on the liquid crystal monitor M arranged behind the digital still camera CAM. After deciding the composition of the subject image while looking at the liquid crystal monitor M, the photographer presses the release button B1 to take a picture of the subject image with the image sensor, and records and saves the subject image in a memory (not shown).

The photographing lens is composed of the zoom lens ZL according to the embodiment described later. Further, in the digital still camera CAM, the auxiliary light emitting unit DL that emits auxiliary light when the subject is dark and the photographing lens (zoom lens ZL) are zoomed (changed) from the wide-angle end state (W) to the telephoto end state (T). A wide (W) -tele (T) button B2 for double), a function button B3 used for setting various conditions of the digital still camera CAM, and the like are arranged.

As shown in FIG. 1, for example, the zoom lens ZL includes a first lens group G1 having a positive refractive power and a second lens group G2 having a negative power, which are arranged in order from the object side along the optical axis. A third lens group G3 having a positive refractive power and a fourth lens group G4 having a positive refractive power are provided. Then, during zooming from the wide-angle end state to the telescopic end state, the distance between the first lens group G1 and the second lens group G2 changes, and the second lens group G2 and the third lens group G3 The first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 are arranged so that the distance changes and the distance between the third lens group G3 and the fourth lens group G4 changes. It is designed to move along the optical axis. According to such a configuration, a zoom lens ZL and an optical device (digital still camera CAM) having high optical performance with astigmatism and chromatic aberration well corrected while having a small size and a high magnification ratio can be obtained. Can be done.

At the time of zooming, the image plane fluctuation due to zooming is corrected by the movement of the fourth lens group G4. Further, when focusing from an infinite distance object to a close range object (finite distance object), the fourth lens group G4 moves along the optical axis.

In the zoom lens ZL having such a configuration, it is preferable to satisfy the condition represented by the following conditional expression (1).

8.60 <β2t / β2w <11.00 ... (1)
however,
β2t: Magnification of the second lens group G2 in the telephoto end state,
β2w: Magnification of the second lens group G2 in the wide-angle end state.

The conditional expression (1) is a conditional expression that defines an appropriate range for the relationship between the magnification β2t of the second lens group G2 in the telephoto end state and the magnification β2w of the second lens group G2 in the wide-angle end state. If the condition is less than the lower limit of the conditional expression (1), it becomes difficult to correct coma and astigmatism, which is not preferable. On the other hand, if the condition exceeds the upper limit of the conditional expression (1), it becomes difficult to correct the coma aberration, which is not preferable.

In order to exert the effect of this embodiment satisfactorily, it is desirable to set the lower limit value of the conditional expression (1) to 9.00. Further, in order to better exert the effect of this embodiment, it is desirable to set the lower limit value of the conditional expression (1) to 9.50. On the other hand, in order to exert the effect of this embodiment satisfactorily, it is desirable to set the upper limit value of the conditional expression (1) to 10.70. Further, in order to better exert the effect of this embodiment, it is desirable to set the upper limit value of the conditional expression (1) to 10.40.

In the zoom lens ZL having such a configuration, it is preferable to satisfy the condition represented by the following conditional expression (2).

0.60 <TLt / ft <0.75 ... (2)
however,
TLt: Overall length of the zoom lens ZL in the telephoto end state,
ft: Focal length of the zoom lens ZL in the telephoto end state.

The conditional expression (2) is a conditional expression for defining an appropriate range for the ratio of the focal length ft of the zoom lens ZL in the telephoto end state and the total length TLt of the zoom lens ZL in the telephoto end state. If the condition is less than the lower limit of the conditional expression (2), it becomes difficult to correct chromatic aberration of magnification, coma, and astigmatism, which is not preferable. On the other hand, if the condition exceeds the upper limit of the conditional expression (2), it becomes difficult to correct the coma aberration, which is not preferable.

In order to exert the effect of this embodiment satisfactorily, it is desirable to set the lower limit value of the conditional expression (2) to 0.62. Further, in order to better exert the effect of this embodiment, it is desirable to set the lower limit value of the conditional expression (2) to 0.64. On the other hand, in order to exert the effect of this embodiment satisfactorily, it is desirable to set the upper limit value of the conditional expression (2) to 0.73. Further, in order to better exert the effect of this embodiment, it is desirable to set the upper limit value of the conditional expression (2) to 0.70.

In the zoom lens ZL having such a configuration, it is preferable to satisfy the condition represented by the following conditional expression (3).

0.30 <f1 / ft <0.42 ... (3)
however,
f1: Focal length of the first lens group G1
ft: Focal length of the zoom lens ZL in the telephoto end state.

The conditional expression (3) is a conditional expression for defining an appropriate range for the ratio of the focal length ft of the zoom lens ZL in the telephoto end state to the focal length f1 of the first lens group G1. If the condition is less than the lower limit of the conditional expression (3), it becomes difficult to correct coma, astigmatism, and chromatic aberration of magnification, which is not preferable. On the other hand, if the condition exceeds the upper limit of the conditional expression (3), it becomes difficult to correct astigmatism, which is not preferable.

In order to exert the effect of this embodiment satisfactorily, it is desirable to set the lower limit value of the conditional expression (3) to 0.32. Further, in order to better exert the effect of this embodiment, it is desirable to set the lower limit value of the conditional expression (3) to 0.35. On the other hand, in order to exert the effect of this embodiment satisfactorily, it is desirable to set the upper limit value of the conditional expression (3) to 0.40. Further, in order to better exert the effect of this embodiment, it is desirable to set the upper limit value of the conditional expression (3) to 0.38.

In the zoom lens ZL having such a configuration, it is preferable to satisfy the condition represented by the following conditional expression (4).

6.80 <f1 / (-f2) <9.00 ... (4)
however,
f1: Focal length of the first lens group G1
f2: Focal length of the second lens group G2.

The conditional expression (4) is a conditional expression for defining an appropriate range for the ratio between the focal length f2 of the second lens group G2 and the focal length f1 of the first lens group G1. If the condition is less than the lower limit of the conditional expression (4), it becomes difficult to correct coma and astigmatism, which is not preferable. Further, even when the condition exceeds the upper limit of the conditional expression (4), it becomes difficult to correct the coma aberration and the astigmatism, which is not preferable.

In order to exert the effect of this embodiment satisfactorily, it is desirable to set the lower limit value of the conditional expression (4) to 6.90. Further, in order to better exert the effect of this embodiment, it is desirable to set the lower limit value of the conditional expression (4) to 7.00. On the other hand, in order to exert the effect of this embodiment satisfactorily, it is desirable to set the upper limit value of the conditional expression (4) to 8.50. Further, in order to better exert the effect of this embodiment, it is desirable to set the upper limit value of the conditional expression (4) to 8.00.

In the zoom lens ZL having such a configuration, it is preferable to satisfy the condition represented by the following conditional expression (5).

0.020 <(-f2) / ft <0.060 ... (5)
however,
f2: Focal length of the second lens group G2,
ft: Focal length of the zoom lens ZL in the telephoto end state.

The conditional expression (5) is a conditional expression for defining an appropriate range for the ratio between the focal length ft of the zoom lens ZL in the telephoto end state and the focal length f2 of the second lens group G2. If the condition is less than the lower limit of the conditional expression (5), it becomes difficult to correct coma and astigmatism, which is not preferable. Further, even when the condition exceeds the upper limit of the conditional expression (5), it becomes difficult to correct the coma aberration and the astigmatism, which is not preferable.

In order to exert the effect of this embodiment satisfactorily, it is desirable to set the lower limit of the conditional expression (5) to 0.030. Further, in order to better exert the effect of this embodiment, it is desirable to set the lower limit value of the conditional expression (5) to 0.040. On the other hand, in order to exert the effect of this embodiment satisfactorily, it is desirable to set the upper limit value of the conditional expression (5) to 0.055. Further, in order to better exert the effect of this embodiment, it is desirable to set the upper limit value of the conditional expression (5) to 0.053.

In the zoom lens ZL having such a configuration, it is preferable to satisfy the condition represented by the following conditional expression (6).

0.17 <f4 / ft <0.25 ... (6)
however,
f4: Focal length of the 4th lens group G4,
ft: Focal length of the zoom lens ZL in the telephoto end state.

The conditional expression (6) is a conditional expression for defining an appropriate range for the ratio of the focal length ft of the zoom lens ZL in the telephoto end state to the focal length f4 of the fourth lens group G4. If the condition is less than the lower limit of the conditional expression (6), it becomes difficult to correct the coma aberration, which is not preferable. Further, even when the condition exceeds the upper limit of the conditional expression (6), it becomes difficult to correct the coma aberration, which is not preferable.

In order to exert the effect of this embodiment satisfactorily, it is desirable to set the lower limit value of the conditional expression (6) to 0.18. Further, in order to better exert the effect of this embodiment, it is desirable to set the lower limit value of the conditional expression (6) to 0.19. On the other hand, in order to exert the effect of this embodiment satisfactorily, it is desirable to set the upper limit value of the conditional expression (6) to 0.24. Further, in order to better exert the effect of this embodiment, it is desirable to set the upper limit value of the conditional expression (6) to 0.23.

In the zoom lens ZL having such a configuration, it is preferable to satisfy the condition represented by the following conditional expression (7).

0.090 <f3 / ft <0.109 ... (7)
however,
f3: Focal length of the third lens group G3,
ft: Focal length of the zoom lens ZL in the telephoto end state.

The conditional expression (7) is a conditional expression for defining an appropriate range for the ratio of the focal length ft of the zoom lens ZL in the telephoto end state to the focal length f3 of the third lens group G3. If the condition is less than the lower limit of the conditional expression (7), it becomes difficult to correct the coma aberration, which is not preferable. Further, even when the condition exceeds the upper limit of the conditional expression (7), it becomes difficult to correct the coma aberration, which is not preferable.

In order to exert the effect of this embodiment satisfactorily, it is desirable to set the lower limit value of the conditional expression (7) to 0.095. Further, in order to better exert the effect of this embodiment, it is desirable to set the lower limit value of the conditional expression (7) to 0.100. On the other hand, in order to exert the effect of this embodiment satisfactorily, it is desirable to set the upper limit value of the conditional expression (7) to 0.107. Further, in order to better exert the effect of this embodiment, it is desirable to set the upper limit value of the conditional expression (7) to 0.105.

In the zoom lens ZL having such a configuration, it is preferable that the first lens group G1 has at least one negative lens and satisfies the condition represented by the following conditional expression (8).

30.0 <νd1 <35.0 ... (8)
however,
νd1: Abbe number of the negative lens arranged on the object side among the negative lenses constituting the first lens group G1.

The conditional expression (8) is a conditional expression for defining an appropriate range for the Abbe number νd1 of the negative lens arranged on the object side most among the negative lenses constituting the first lens group G1. If the condition is less than the lower limit of the conditional expression (8), it becomes difficult to correct the axial chromatic aberration and the chromatic aberration of magnification, which is not preferable. Further, even when the condition exceeds the upper limit of the conditional expression (8), it becomes difficult to correct the axial chromatic aberration and the chromatic aberration of magnification, which is not preferable.

In order to exert the effect of this embodiment satisfactorily, it is desirable to set the lower limit value of the conditional expression (8) to 31.0. Further, in order to better exert the effect of this embodiment, it is desirable to set the lower limit value of the conditional expression (8) to 32.0. On the other hand, in order to exert the effect of this embodiment satisfactorily, it is desirable to set the upper limit value of the conditional expression (8) to 34.0. Further, in order to better exert the effect of this embodiment, it is desirable to set the upper limit value of the conditional expression (8) to 33.0.

In the zoom lens ZL having such a configuration, it is preferable that the first lens group G1 has a plurality of positive lenses and satisfies the condition represented by the following conditional expression (9).

75.0 <νd2 <96.0 ... (9)
however,
νd2: Abbe number of the positive lens arranged on the object side among the positive lenses constituting the first lens group G1.

The conditional expression (9) is a conditional expression for defining an appropriate range for the Abbe number νd2 of the positive lens arranged on the object side most among the positive lenses constituting the first lens group G1. If the condition is less than the lower limit of the conditional expression (9), it becomes difficult to correct the axial chromatic aberration and the chromatic aberration of magnification, which is not preferable. Further, even when the condition exceeds the upper limit of the conditional expression (9), it becomes difficult to correct the axial chromatic aberration and the magnifying chromatic aberration, which is not preferable.

In order to exert the effect of this embodiment satisfactorily, it is desirable to set the lower limit value of the conditional expression (9) to 77.0. Further, in order to better exert the effect of this embodiment, it is desirable to set the lower limit value of the conditional expression (9) to 81.5. Further, in order to better exert the effect of this embodiment, it is desirable to set the lower limit value of the conditional expression (9) to 83.0. On the other hand, in order to exert the effect of this embodiment satisfactorily, it is desirable to set the upper limit value of the conditional expression (9) to 95.5. Further, in order to better exert the effect of this embodiment, it is desirable to set the upper limit value of the conditional expression (9) to 95.1. Further, in order to better exert the effect of this embodiment, it is desirable to set the upper limit value of the conditional expression (9) to 90.0.

In the zoom lens ZL having such a configuration, it is preferable that the first lens group G1 has a plurality of positive lenses and satisfies the condition represented by the following conditional expression (10).

65.0 <νd3 <83.0 ... (10)
however,
νd3: Abbe number of the positive lens arranged on the image side among the positive lenses constituting the first lens group G1.

The conditional expression (10) is a conditional expression for defining an appropriate range for the Abbe number νd3 of the positive lens arranged on the image side of the positive lenses constituting the first lens group G1. If the condition is less than the lower limit of the conditional expression (10), it becomes difficult to correct the axial chromatic aberration and the chromatic aberration of magnification, which is not preferable. Further, even when the condition exceeds the upper limit of the conditional expression (10), it becomes difficult to correct the axial chromatic aberration and the chromatic aberration of magnification, which is not preferable.

In order to exert the effect of this embodiment satisfactorily, it is desirable to set the lower limit value of the conditional expression (10) to 67.0. On the other hand, in order to exert the effect of this embodiment satisfactorily, it is desirable to set the upper limit value of the conditional expression (10) to 82.0. Further, in order to better exert the effect of this embodiment, it is desirable to set the upper limit value of the conditional expression (10) to 80.0.

In the zoom lens ZL having such a configuration, it is preferable that the fourth lens group G4 is composed of one positive lens and one negative lens. According to such a configuration, various aberrations such as coma aberration, curvature of field, distortion, and chromatic aberration of magnification can be satisfactorily corrected.

In the zoom lens ZL having such a configuration, it is preferable to satisfy the condition represented by the following conditional expression (11).

0.50 <ωt <7.00 ... (11)
however,
ωt: Half angle of view (unit: degree) in the telephoto end state of the zoom lens ZL.

The conditional expression (11) is a conditional expression for defining an appropriate range for the half angle of view ωt in the telephoto end state of the zoom lens ZL. By satisfying this conditional equation (11), various aberrations such as coma aberration, curvature of field, and distortion can be satisfactorily corrected.

In order to exert the effect of this embodiment satisfactorily, it is desirable to set the lower limit value of the conditional expression (11) to 0.70. Further, in order to better exert the effect of this embodiment, it is desirable to set the lower limit value of the conditional expression (11) to 0.90. Further, in order to better exert the effect of this embodiment, it is desirable to set the lower limit value of the conditional expression (11) to 1.10. On the other hand, in order to exert the effect of this embodiment satisfactorily, it is desirable to set the upper limit value of the conditional expression (11) to 6.00. Further, in order to better exert the effect of this embodiment, it is desirable to set the upper limit value of the conditional expression (11) to 5.00. Further, in order to better exert the effect of this embodiment, it is desirable to set the upper limit value of the conditional expression (11) to 4.00. Further, in order to better exert the effect of this embodiment, it is desirable to set the upper limit value of the conditional expression (11) to 3.00. Further, in order to better exert the effect of this embodiment, it is desirable to set the upper limit value of the conditional expression (11) to 2.00.

In the zoom lens ZL having such a configuration, it is preferable to satisfy the condition represented by the following conditional expression (12).

15.00 <ωw <80.00 ... (12)
however,
ωw: Half angle of view (unit: degree) in the wide-angle end state of the zoom lens ZL.

The conditional expression (12) is a conditional expression for defining an appropriate range for the half angle of view ωw in the wide-angle end state of the zoom lens ZL. By satisfying this conditional expression (12), it is possible to satisfactorily correct various aberrations such as coma aberration, curvature of field, and distortion while having a wide angle of view.

In order to exert the effect of this embodiment satisfactorily, it is desirable to set the lower limit value of the conditional expression (12) to 17.00. Further, in order to better exert the effect of this embodiment, it is desirable to set the lower limit value of the conditional expression (12) to 20.00. Further, in order to better exert the effect of this embodiment, it is desirable to set the lower limit value of the conditional expression (12) to 25.00. Further, in order to better exert the effect of this embodiment, it is desirable to set the lower limit value of the conditional expression (12) to 30.00. Further, in order to better exert the effect of this embodiment, it is desirable to set the lower limit value of the conditional expression (12) to 35.00. On the other hand, in order to exert the effect of this embodiment satisfactorily, it is desirable to set the upper limit value of the conditional expression (12) to 70.00. Further, in order to better exert the effect of this embodiment, it is desirable to set the upper limit value of the conditional expression (12) to 60.00. Further, in order to better exert the effect of this embodiment, it is desirable to set the upper limit value of the conditional expression (12) to 50.00.

Here, a method of manufacturing the zoom lens ZL having the above-described configuration will be described with reference to FIG. 7. First, in the cylindrical lens barrel, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a third lens having a positive refractive power. The group G3 and the fourth lens group G4 having a positive refractive power are incorporated (step ST10). Then, by moving the first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 along the optical axis, scaling from the wide-angle end state to the telephoto end state (zooming). ) Is performed so that the first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 can be driven (step ST20).

In step ST10 for incorporating the lens, the first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 are arranged so as to satisfy the above-mentioned predetermined conditional expression. Further, in step ST20 for making each lens group driveable, focusing (focusing) from an infinity object to a close-range object (finite-distance object) by moving the fourth lens group G4 along the optical axis. ) Is done. According to such a manufacturing method, it is possible to obtain a zoom lens ZL having high optical performance in which astigmatism and chromatic aberration are well corrected while having a small size and a high magnification ratio.

(First Example)
Hereinafter, each embodiment of the present application will be described with reference to the accompanying drawings. First, the first embodiment of the present application will be described with reference to FIGS. 1 to 2 and Table 1. FIG. 1 is a lens configuration diagram of the zoom lens ZL (ZL1) according to the first embodiment in a wide-angle end state. The zoom lens ZL1 according to the first embodiment has a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and an aperture, which are arranged in order from the object side along the optical axis. It is composed of an aperture S, a third lens group G3 having a positive refractive power, and a fourth lens group G4 having a positive refractive power.

Then, when scaling from the wide-angle end state to the telescopic end state (zooming), the distance between the first lens group G1 and the second lens group G2 increases, and the second lens group G2 and the third lens group G3 The first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 are arranged so that the distance decreases and the distance between the third lens group G3 and the fourth lens group G4 increases. It is configured to move along the optical axis. More specifically, during zooming, the first lens group G1 moves toward the object along the optical axis, the second lens group G2 moves toward the image plane I along the optical axis, and the third lens group G3 moves. It is configured to move to the object side along the optical axis, and the fourth lens group G4 moves to the object side once along the optical axis and then moves to the image plane I side.

The correction of the image plane fluctuation due to zooming is performed by moving the fourth lens group G4 along the optical axis. Further, focusing from an infinity object to a close-range object (finite-distance object) is performed by moving the fourth lens group G4 toward the object side along the optical axis.

The first lens group G1 has a meniscus-shaped negative lens L11 having a convex surface facing the object side, a biconvex first positive lens L12, and a convex surface toward the object side, which are arranged in order from the object side along the optical axis. It is composed of a second positive lens L13 having a meniscus shape. In the first lens group G1, the negative lens L11 and the first positive lens L12 are bonded lenses bonded to each other. The second lens group G2 includes a meniscus-shaped first negative lens L21 having a concave surface facing the image plane I side, a biconcave second negative lens L22, and an object arranged in order from the object side along the optical axis. It is composed of a meniscus-shaped positive lens L23 with a convex surface facing to the side.

The third lens group G3 includes a biconvex first positive lens L31 arranged in order from the object side along the optical axis, a meniscus-shaped second positive lens L32 with a convex surface facing the object side, and an image plane I. It is composed of a meniscus-shaped negative lens L33 with a concave surface facing side and a biconvex-shaped third positive lens L34. In the third lens group G3, the lens surfaces on both sides of the first positive lens L31 are aspherical. Further, the second positive lens L32 and the negative lens L33 are bonded lenses bonded to each other. The fourth lens group G4 is composed of a biconvex positive lens L41 and a biconcave negative lens L42 arranged in order from the object side along the optical axis. In the fourth lens group G4, the lens surface on the object side of the positive lens L41 is an aspherical surface.

The aperture diaphragm S for adjusting the amount of light is arranged between the second lens group G2 and the third lens group G3 (near the object side of the third lens group G3), and is telephoto from the wide-angle end state. When scaling to the end state, it moves in the same orbit as the third lens group G3. Further, the filter group FL arranged between the fourth lens group G4 and the image plane I is, in order from the object side, a filter such as a low-pass filter or an infrared cut filter, and a cover glass (protective glass of the image plane I). It is composed of and.

Tables 1 and 2 are shown below, and these are tables in which the values of the specifications of the zoom lenses according to the first and second embodiments are listed. In the [Overall specifications] of each table, the focal length f of the zoom lens ZL in each state of the wide-angle end state, the intermediate focal length state, and the telephoto end state, the aperture aperture diameter φ, the F number Fno, and the half angle of view ω (units). : Degree), back focal length BF, and total length TL (air equivalent length from the first optical surface of the zoom lens ZL to the final optical surface (image plane I)) are shown. Further, in [Lens Specifications], the first column (plane number) is the order of the lens planes from the object side along the traveling direction of the light rays, the second column R is the radius of curvature of the lens planes, and the third column. D is the plane spacing which is the distance on the optical axis from the lens surface to the next lens surface, the fourth column nd is the refractive index with respect to the d line (wavelength λ = 587.6 nm), and the fifth column νd is the d line. The Abbe numbers for (wavelength λ = 587.6 nm) are shown respectively. Note that * attached to the right of the first column (plane number) indicates that the lens surface is an aspherical surface. Further, the radius of curvature "∞" indicates a plane or an opening, and the description of the refractive index nd = 1.000000 of air is omitted.

The aspherical coefficient shown in [Aspherical surface data] is the distance along the optical axis from the tangent plane at the apex of the aspherical surface to the position on the aspherical surface at the height y, where y is the height in the direction perpendicular to the optical axis. When (sag amount) is S (y), the radius of curvature (near-axis radius of curvature) of the reference sphere is r, the conical constant is κ, and the aspherical coefficient of the nth order (n = 4, 6) is An. , Expressed by the following equation (A). note that,
In each embodiment, the second-order aspherical coefficient A2 is 0, and the description is omitted. Further, in [aspherical data], "En" indicates "× 10 ^-n ". For example, "1.234E-05" indicates "1.234 × 10 ^-5 ".

S (y) = (y ² / r) / {1 + (1-κ × y ² / r ² ) ^1/2 } + A4 × y ⁴ + A6 × y ⁶
… (A)

[Variable interval data] shows the variable interval values of the zoom lens ZL in each of the wide-angle end state, the intermediate focal length state, and the telephoto end state (at infinity in focus). [Lens group focal length] indicates the value of the focal length of each lens group. [Conditional expression corresponding value] indicates the corresponding value of each conditional expression.

In addition, although "mm" is generally used as the unit of the focal length f, the radius of curvature R, and other lengths listed in all the following specification values, the optical system may be expanded or contracted proportionally. It is not limited to this because the same optical performance can be obtained. Further, in the specification values of the second embodiment described later, the same reference numerals as those of the present embodiment are used.

Table 1 below shows the specifications of the first embodiment. The radius of curvature R of the first surface to the 27th surface in Table 1 corresponds to the reference numerals R1 to R27 attached to the first surface to the 27th surface in FIG. Further, the group numbers G1 to G4 in Table 1 correspond to the respective lens groups G1 to G4 in FIG. 1. Further, in the first embodiment, each lens surface of the thirteenth surface, the fourteenth surface, and the twentieth surface is formed in an aspherical shape.

(Table 1)
[Overall specifications]
Zoom ratio = 33
Wide-angle end state Intermediate focal length state Telephoto end state f 5.0 28.7 165.0
φ 6.84 6.84 6.84
Fno 3.2 4.9 6.7
ω 43.52 9.06 1.55
BF 0.56 0.56 0.56
TL 75.87 92.86 111.99
[Lens specifications]
Surface number R D nd νd
1 55.1766 1.1287 1.9537 32.32
2 35.8769 4.7404 1.4970 81.61
3 -1070.6 0.1129
4 35.6702 3.6982 1.4970 81.61
5 204.2966 D1
6 325.5942 0.7901 1.8348 42.73
7 7.5066 4.4018
8 -23.9398 0.5643 1.7550 52.33
9 28.4177 0.1129
10 15.8188 1.9515 1.9459 17.98
11 73.3626 D2
12 ∞ 0.8465 (Aperture aperture)
13 * 7.4066 2.3702 1.5533 71.68
14 * -41.6775 0.1129
15 7.3201 1.9187 1.5174 52.2
16 98.9731 0.4515 1.9027 35.72
17 5.532 0.7901
18 23.0299 1.0158 1.5182 58.82
19 -634.425 D3
20 * 15.969 2.3356 1.5311 56.15
21 -40.7204 0.2257
22 -47.7471 0.5643 1.8467 23.8
23 492.2301 D4
24 ∞ 0.3386 1.5168 63.88
25 ∞ 0.5643
26 ∞ 0.5643 1.5168 63.88
27 ∞ BF
[Aspherical data]
Page 13 κ = 0.3975, A4 = 4.424E-05, A6 = 3.609E-07
Surface 14 κ = 1.0000, A4 = 1.059E-04, A6 = -6.927E-07
Side 20 κ = 2.2564, A4 = -4.142E-05, A6 = -9.991E-08
[Variable interval data]
Wide-angle end state Intermediate focal length state Telephoto end state D1 0.621 24.769 42.882
D2 31.649 8.935 1.693
D3 8.536 11.190 34.741
D4 5.209 18.113 2.822
[Lens group focal length]
Group number Group first surface Group focal length (f1 to f4)
G1 1 60.8
G2 6 -8.0
G3 13 17.0
G4 20 36.5
[Conditional expression correspondence value]
Conditional expression (1) β2t / β2w = 10.048
Conditional expression (2) TLt / ft = 0.679
Conditional expression (3) f1 / ft = 0.368
Conditional expression (4) f1 / (-f2) = 7.557
Conditional expression (5) (-f2) / ft = 0.049
Conditional expression (6) f4 / ft = 0.221
Conditional expression (7) f3 / ft = 0.103
Conditional expression (8) νd1 = 32.320
Conditional expression (9) νd2 = 81.610
Conditional expression (10) νd3 = 81.610
Conditional expression (11) ωt = 1.55
Conditional expression (12) ωw = 43.52

As described above, in this embodiment, it can be seen that all of the above conditional expressions (1) to (12) are satisfied.

FIG. 2 is an aberration diagram of the zoom lens ZL1 according to the first embodiment. Here, FIG. 2A is an aberration diagram at infinity focusing in the wide-angle end state (f = 5.0 mm), and FIG. 2B is an intermediate focal length state (f = 28.7 mm). It is the aberration diagram at the time of infinity focusing, and FIG. 2C is the aberration diagram at the time of infinity focusing in the telephoto end state (f = 165.0mm). In each aberration diagram, FNO indicates an F number and A indicates a half angle of view. Further, in each aberration diagram, d indicates the aberration at the d line (λ = 587.6 nm), and g indicates the aberration at the g line (λ = 435.8 nm). Further, in the aberration diagram showing astigmatism, the solid line shows the sagittal image plane and the broken line shows the meridional image plane. Further, in the aberration diagram showing coma, a meridional coma is shown. As described above, the description of the aberration diagram is the same in the other embodiments.

From each aberration diagram, it can be seen that in the first embodiment, various aberrations are satisfactorily corrected in each focal length state from the wide-angle end state to the telephoto end state, and the optical performance is excellent. As a result, by mounting the zoom lens ZL1 of the first embodiment, excellent optical performance can be ensured even in the digital still camera CAM. It should be noted that the distortion amount can be sufficiently corrected by image processing after imaging with the aberration amount shown in FIG. 2, and therefore optical correction is not necessary.

(Second Example)
Hereinafter, the second embodiment of the present application will be described with reference to FIGS. 3 to 4 and Table 2. FIG. 3 is a lens configuration diagram of the zoom lens ZL (ZL2) according to the second embodiment in a wide-angle end state. The zoom lens ZL2 according to the second embodiment has a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and an aperture, which are arranged in order from the object side along the optical axis. It is composed of an aperture S, a third lens group G3 having a positive refractive power, and a fourth lens group G4 having a positive refractive power.

Then, when scaling from the wide-angle end state to the telescopic end state (zooming), the distance between the first lens group G1 and the second lens group G2 increases, and the second lens group G2 and the third lens group G3 The first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 are arranged so that the distance decreases and the distance between the third lens group G3 and the fourth lens group G4 increases. It is configured to move along the optical axis. More specifically, during zooming, the first lens group G1 moves toward the object along the optical axis, the second lens group G2 moves toward the image plane I along the optical axis, and the third lens group G3 moves. It is configured to move to the object side along the optical axis, and the fourth lens group G4 moves to the object side once along the optical axis and then moves to the image plane I side.

The correction of the image plane fluctuation due to zooming is performed by moving the fourth lens group G4 along the optical axis. Further, focusing from an infinity object to a close-range object (finite-distance object) is performed by moving the fourth lens group G4 toward the object side along the optical axis.

The first lens group G1 has a meniscus-shaped negative lens L11 having a convex surface facing the object side, a biconvex first positive lens L12, and a convex surface toward the object side, which are arranged in order from the object side along the optical axis. It is composed of a second positive lens L13 having a meniscus shape. In the first lens group G1, the negative lens L11 and the first positive lens L12 are bonded lenses bonded to each other. The second lens group G2 includes a meniscus-shaped first negative lens L21 having a concave surface facing the image plane I side, a biconcave second negative lens L22, and an object arranged in order from the object side along the optical axis. It is composed of a meniscus-shaped positive lens L23 with a convex surface facing to the side.

The third lens group G3 includes a biconvex first positive lens L31 arranged in order from the object side along the optical axis, a meniscus-shaped second positive lens L32 with a convex surface facing the object side, and an image plane I. It is composed of a meniscus-shaped negative lens L33 with a concave surface facing the side and a meniscus-shaped third positive lens L34 with a convex surface facing the object side. In the third lens group G3, the lens surfaces on both sides of the first positive lens L31 are aspherical. Further, the second positive lens L32 and the negative lens L33 are bonded lenses bonded to each other. The fourth lens group G4 is composed of a biconvex positive lens L41 arranged in order from the object side along the optical axis, and a meniscus-shaped negative lens L42 with a concave surface facing the object side. In the fourth lens group G4, the lens surface on the object side of the positive lens L41 is an aspherical surface.

The aperture diaphragm S for adjusting the amount of light is arranged between the second lens group G2 and the third lens group G3 (near the object side of the third lens group G3), and is telephoto from the wide-angle end state. When scaling to the end state, it moves in the same orbit as the third lens group G3. Further, the filter group FL arranged between the fourth lens group G4 and the image plane I is, in order from the object side, a filter such as a low-pass filter or an infrared cut filter, and a cover glass (protective glass of the image plane I). It is composed of and.

Table 2 below shows the specifications of the second embodiment. The radius of curvature R of the first surface to the 27th surface in Table 2 corresponds to the reference numerals R1 to R27 attached to the first surface to the 27th surface in FIG. Further, the group numbers G1 to G4 in Table 2 correspond to the respective lens groups G1 to G4 in FIG. Further, in the second embodiment, each lens surface of the thirteenth surface, the fourteenth surface, and the twentieth surface is formed in an aspherical shape.

(Table 2)
[Overall specifications]
Zoom ratio = 33
Wide-angle end state Intermediate focal length state Telephoto end state f 5.0 28.7 165.0
φ 6.95 6.95 6.95
Fno 3.2 4.9 6.7
ω 43.52 9.06 1.55
BF 0.56 0.56 0.56
TL 75.52 92.90 111.48
[Lens specifications]
Surface number R D nd νd
1 67.28292 1.12867 1.9538 32.32
2 39.75503 5.00362 1.4370 95.1
3 -201.336 0.11287
4 35.47148 3.83747 1.5928 68.62
5 172.5767 D1
6 430.6508 0.79007 1.8348 42.73
7 7.60361 4.40188
8 -24.0196 0.56433 1.7550 52.33
9 32.26023 0.11287
10 16.19498 1.92057 1.9460 17.98
11 73.36343 D2
12 ∞ 0.8465 (Aperture aperture)
13 * 7.44178 2.35489 1.5533 71.68
14 * -38.3744 0.11287
15 7.05695 2.14432 1.5174 52.2
16 185.2265 0.45147 1.9027 35.72
17 5.32685 0.79007
18 25.41322 1.0158 1.5182 58.82
19 1259.654 D3
20 * 15.29177 2.26696 1.5311 56.15
21 -30.8592 0.22573
22 -35.4324 0.56433 1.8467 23.8
23 -590.173 D4
24 ∞ 0.3386 1.5168 63.88
25 ∞ 0.56433
26 ∞ 0.56433 1.5168 63.88
27 ∞ BF
[Aspherical data]
Surface 13 κ = 0.4099, A4 = 4.933E-05, A6 = 2.721E-07
14th surface κ = 1.0000, A4 = 1.168E-04, A6 = -8.574E-07
Side 20 κ = 1.7508, A4 = -2.284E-05, A6 = -9.990E-08
[Variable interval data]
Wide-angle end state Intermediate focal length state Telephoto end state D1 0.621 25.088 42.511
D2 31.965 9.286 1.693
D3 7.492 11.463 34.825
D4 5.587 17.209 2.596
[Lens group focal length]
Group number Group first surface Group focal length (f1 to f4)
G1 1 59.9
G2 6 -8.3
G3 13 17.1
G4 20 33.3.
[Conditional expression correspondence value]
Conditional expression (1) β2t / β2w = 9.944
Conditional expression (2) TLt / ft = 0.676
Conditional expression (3) f1 / ft = 0.363
Conditional expression (4) f1 / (-f2) = 7.229
Conditional expression (5) (-f2) / ft = 0.050
Conditional expression (6) f4 / ft = 0.202
Conditional expression (7) f3 / ft = 0.104
Conditional expression (8) νd1 = 32.320
Conditional expression (9) νd2 = 95.100
Conditional expression (10) νd3 = 68.620
Conditional expression (11) ωt = 1.55
Conditional expression (12) ωw = 43.52

As described above, in this embodiment, it can be seen that all of the above conditional expressions (1) to (12) are satisfied.

FIG. 4 is an aberration diagram of the zoom lens ZL2 according to the second embodiment. Here, FIG. 4A is an aberration diagram at infinity focusing in the wide-angle end state (f = 5.0 mm), and FIG. 4B is an intermediate focal length state (f = 28.7 mm). FIG. 4C is an aberration diagram at the time of infinity focusing, and FIG. 4C is an aberration diagram at the time of infinity focusing in the telephoto end state (f = 165.0 mm). From each aberration diagram, it can be seen that in the second embodiment, various aberrations are satisfactorily corrected in each focal length state from the wide-angle end state to the telephoto end state, and the optical performance is excellent. As a result, by mounting the zoom lens ZL2 of the second embodiment, excellent optical performance can be ensured even in the digital still camera CAM. It should be noted that the distortion amount can be sufficiently corrected by image processing after imaging with the aberration amount shown in FIG. 4, and therefore optical correction is not necessary.

As described above, according to each embodiment, it is possible to realize a zoom lens and an optical device (digital still camera) having high optical performance in which astigmatism and chromatic aberration are well corrected while being compact and having a high magnification ratio. Can be done.

In the above-described embodiment, the contents described below can be appropriately adopted as long as the optical performance is not impaired.

In each of the above-described embodiments, the four-group configuration is shown as the zoom lens, but it can also be applied to other group configurations such as the five-group configuration. Further, a configuration in which a lens or a lens group is added on the most object side or a configuration in which a lens or a lens group is added on the image side may be used. Further, the lens group refers to a portion having at least one lens separated by an air interval that changes at the time of scaling.

Further, a single lens group, a plurality of lens groups, or a partial lens group may be moved in the optical axis direction to form a focusing lens group for focusing from an infinite object to a short-range object. This in-focus lens group can also be applied to autofocus, and is also suitable for driving a motor for autofocus (using an ultrasonic motor or the like). In particular, it is preferable to use the fourth lens group as the in-focus lens group.

In addition, the lens group or partial lens group is moved so as to have a component in the direction perpendicular to the optical axis, or is rotationally moved (swinged) in the in-plane direction including the optical axis to cause image blur caused by camera shake. It may be a group of anti-vibration lenses to be corrected. In particular, it is preferable that at least a part of the second lens group or the third lens group is an anti-vibration lens group.

Further, the lens surface may be formed of a spherical surface or a flat surface, or may be formed of an aspherical surface. When the lens surface is spherical or flat, lens processing and assembly adjustment are facilitated, and deterioration of optical performance due to processing and assembly adjustment errors can be prevented, which is preferable. Further, even if the image plane is displaced, the deterioration of the depiction performance is small, which is preferable. When the lens surface is an aspherical surface, the aspherical surface is an aspherical surface formed by grinding, a glass mold aspherical surface formed by forming glass into an aspherical surface shape, or a composite aspherical surface formed by forming resin on the glass surface into an aspherical surface shape. Any aspherical surface may be used. Further, the lens surface may be a diffraction surface, and the lens may be a refractive index distribution type lens (GRIN lens) or a plastic lens.

Further, the aperture diaphragm is preferably arranged in the vicinity of the third lens group, but the role may be substituted by the frame of the lens without providing the member as the aperture diaphragm.

Further, in order to reduce flare and ghost and achieve high optical performance with high contrast, each lens surface may be provided with an antireflection film having high transmittance in a wide wavelength range.

Further, the zoom lens (variable optical system) of the present embodiment has a magnification ratio of about 28 to 40.

Further, although the zoom lens (variable magnification optical system) of the present embodiment is used for a digital still camera, the present invention is not limited to this, and the zoom lens (variable optical system) can also be used for an optical device such as a digital video camera.

CAM digital still camera (optical equipment)
ZL Zoom Lens G1 1st Lens Group G2 2nd Lens Group G3 3rd Lens Group G4 4th Lens Group S Aperture Aperture I Image Plane

Claims (16)

The first lens group having a positive refractive power, the second lens group having a negative refractive power, the third lens group having a positive refractive power, and the positive ones arranged in order from the object side along the optical axis . It consists of substantially four lens groups due to the fourth lens group having an optical power.
When scaling from the wide-angle end state to the telephoto end state, the first lens group, the second lens group, the third lens group, and the fourth lens group move along the optical axis and are adjacent to each other. The distance between the lens groups changes,
At the time of focusing, the fourth lens group moves along the optical axis, and the fourth lens group moves along the optical axis.
The first lens group has at least one negative lens.
A zoom lens characterized by satisfying the following conditional expressions.
8.60 <β2t / β2w <11.00
30.0 <νd1 <34.0
0.60 <TLt / ft <0.70
0.090 <f3 / ft <0.109
however,
β2t: Magnification of the second lens group in the telephoto end state,
β2w: Magnification of the second lens group in the wide-angle end state,
νd1: Abbe number of the negative lens arranged on the object side among the negative lenses constituting the first lens group,
TLt: Overall length of the zoom lens in the telephoto end state,
ft: Focal length of the zoom lens in the telephoto end state,
f3: Focal length of the third lens group. The first lens group having a positive refractive power, the second lens group having a negative refractive power, the third lens group having a positive refractive power, and the positive ones arranged in order from the object side along the optical axis. It consists of substantially four lens groups due to the fourth lens group having an optical power.
When scaling from the wide-angle end state to the telephoto end state, the first lens group, the second lens group, the third lens group, and the fourth lens group move along the optical axis and are adjacent to each other. The distance between the lens groups changes,
At the time of focusing, the fourth lens group moves along the optical axis, and the fourth lens group moves along the optical axis.
The first lens group has at least one negative lens and a plurality of positive lenses.
A zoom lens characterized by satisfying the following conditional expressions.
8.60 <β2t / β2w <11.00
30.0 <νd1 <34.0
83.0 <νd2 <96.0
however,
β2t: Magnification of the second lens group in the telephoto end state,
β2w: Magnification of the second lens group in the wide-angle end state,
νd1: Abbe number of the negative lens arranged on the object side among the negative lenses constituting the first lens group,
νd2: Abbe number of the positive lens arranged on the object side of the positive lenses constituting the first lens group. The first lens group having a positive refractive power, the second lens group having a negative refractive power, the third lens group having a positive refractive power, and the positive ones arranged in order from the object side along the optical axis. It consists of substantially four lens groups due to the fourth lens group having an optical power.
When scaling from the wide-angle end state to the telephoto end state, the first lens group, the second lens group, the third lens group, and the fourth lens group move along the optical axis and are adjacent to each other. The distance between the lens groups changes,
At the time of focusing, the fourth lens group moves along the optical axis, and the fourth lens group moves along the optical axis.
The first lens group has at least one negative lens.
A zoom lens characterized by satisfying the following conditional expressions.
8.60 <β2t / β2w <11.00
32.0 <νd1 <33.0
0.090 <f3 / ft <0.109
however,
β2t: Magnification of the second lens group in the telephoto end state,
β2w: Magnification of the second lens group in the wide-angle end state,
νd1: Abbe number of the negative lens arranged on the object side among the negative lenses constituting the first lens group,
f3: Focal length of the third lens group,
ft: Focal length of the zoom lens in the telephoto end state. The first lens group having a positive refractive power, the second lens group having a negative refractive power, the third lens group having a positive refractive power, and the positive ones arranged in order from the object side along the optical axis. It consists of substantially four lens groups due to the fourth lens group having an optical power.
When scaling from the wide-angle end state to the telephoto end state, the first lens group, the second lens group, the third lens group, and the fourth lens group move along the optical axis and are adjacent to each other. The distance between the lens groups changes,
At the time of focusing, the fourth lens group moves along the optical axis, and the fourth lens group moves along the optical axis.
The first lens group has at least one negative lens.
A zoom lens characterized by satisfying the following conditional expressions.
9.50 <β2t / β2w <11.00
30.0 <νd1 <33.0
0.090 <f3 / ft <0.109
however,
β2t: Magnification of the second lens group in the telephoto end state,
β2w: Magnification of the second lens group in the wide-angle end state,
νd1: Abbe number of the negative lens arranged on the object side among the negative lenses constituting the first lens group,
f3: Focal length of the third lens group,
ft: Focal length of the zoom lens in the telephoto end state. The zoom lens according to any one of claims 2 to 4 , wherein the zoom lens satisfies the following conditional expression.
0.60 <TLt / ft <0.75
however,
TLt: Overall length of the zoom lens in the telephoto end state,
ft: Focal length of the zoom lens in the telephoto end state. The first lens group has a plurality of positive lenses and has a plurality of positive lenses.
The zoom lens according to any one of claims 1, 3, and 4 , wherein the zoom lens satisfies the following conditional expression.
75.0 <νd2 <96.0
however,
νd2: Abbe number of the positive lens arranged on the object side of the positive lenses constituting the first lens group. The zoom lens according to claim 2 , wherein the zoom lens satisfies the following conditional expression.
0.090 <f3 / ft <0.109
however,
f3: Focal length of the third lens group,
ft: Focal length of the zoom lens in the telephoto end state. The zoom lens according to any one of claims 1 to 7 , wherein the zoom lens satisfies the following conditional expression.
0.30 <f1 / ft <0.42
however,
f1: Focal length of the first lens group,
ft: Focal length of the zoom lens in the telephoto end state. The zoom lens according to any one of claims 1 to 8 , wherein the zoom lens satisfies the following conditional expression.
6.80 <f1 / (-f2) <9.00
however,
f1: Focal length of the first lens group,
f2: Focal length of the second lens group. The zoom lens according to any one of claims 1 to 9 , wherein the zoom lens satisfies the following conditional expression.
0.020 <(-f2) / ft <0.060
however,
f2: Focal length of the second lens group,
ft: Focal length of the zoom lens in the telephoto end state. The zoom lens according to any one of claims 1 to 10 , wherein the zoom lens satisfies the following conditional expression.
0.17 <f4 / ft <0.25
however,
f4: Focal length of the fourth lens group,
ft: Focal length of the zoom lens in the telephoto end state. The first lens group has a plurality of positive lenses and has a plurality of positive lenses.
The zoom lens according to any one of claims 1 to 11 , wherein the zoom lens satisfies the following conditional expression.
65.0 <νd3 <83.0
however,
νd3: Abbe number of the positive lens arranged on the image side among the positive lenses constituting the first lens group. The zoom lens according to any one of claims 1 to 12 , wherein the fourth lens group is composed of one positive lens and one negative lens. The zoom lens according to any one of claims 1 to 13 , wherein the zoom lens satisfies the following conditional expression.
0.50 <ωt <7.00
however,
ωt: Half angle of view (unit: degree) in the telephoto end state of the zoom lens. The zoom lens according to any one of claims 1 to 14 , wherein the zoom lens satisfies the following conditional expression.
15.00 <ωw <80.00
however,
ωw: Half angle of view (unit: degree) in the wide-angle end state of the zoom lens. An optical device equipped with a zoom lens that forms an image of an object on a predetermined surface.
An optical device according to any one of claims 1 to 15 , wherein the zoom lens is the zoom lens.

Images