JP2017219655A - Zoom lens and imaging device having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zoom lens having a high variable power ratio, high optical performance over the whole zoom range, and little variations in a focus or aberrations even when an environmental temperature changes.SOLUTION: The zoom lens includes, successively from an object side to an image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a rear group composed of two lens groups; and the zoom lens includes at least one resin lens having a positive refractive power in the second lens group or succeeding groups, and at least one resin lens having a negative refractive power in the second lens group or succeeding groups. The refractive power of each resin lens is appropriately set by taking a temperature coefficient of the refractive index and a coefficient of linear expansion into consideration.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a zoom lens and an image pickup apparatus having the same, and is particularly suitable as a photographing optical system such as a digital still camera, a video camera, and a photographic camera.

  In recent years, as a photographic optical system used for interchangeable lenses for single-lens reflex cameras, etc., the lens has a high zoom ratio, a large aperture ratio, a long back focus, and high optical performance over the entire zoom range. Is required. A positive lead type zoom lens in which a lens group having a positive refractive power is disposed on the object side is known as one of lenses that meet these requirements.

  As a positive lead type zoom lens, a zoom lens having a comparatively high zoom ratio is known which is composed of five lens groups having positive, negative, positive and negative refractive powers in order from the object side to the image side (see Patent Document 1). ).

JP 2010-237453 A

  In recent years, zoom lenses having a high zoom ratio and a large aperture ratio and a long back focus and high optical performance over the entire zoom range are required to be low in cost, light in weight, and high in performance.

  The zoom lens of Patent Document 1 is disadvantageous in terms of cost because many glass lenses having a high refractive index are used in order to achieve high optical performance over the entire zoom range with a high zoom ratio. Moreover, since many glass lenses with a large specific gravity are used, an increase in weight is inevitable.

  Use of an organic material such as resin or plastic for the optical element is very effective in realizing cost reduction and weight reduction. In the case of an organic material, since it is easier to manufacture an aspheric shape than a glass material, it is possible to improve optical performance by correcting higher-order aberrations at a low cost.

  However, organic materials such as resins and plastics generally have a large shape change and refractive index change due to temperature changes, and the magnitude of these changes is about 10 to 100 times that of glass. Therefore, in the case of using an optical element in which an organic material has a strong power in order to have an aberration correction effect, it is important to reduce a focus position shift accompanying a change in environmental temperature. In order to reduce the shift of the focus position due to the change in the environmental temperature, it is necessary to reduce the amount of change in the back focus due to the change in the environmental temperature.

  The present invention has a high zoom ratio, corrects aberrations well over the entire zoom range from the wide-angle end to the telephoto end, has high optical performance over the entire zoom range, and is capable of focusing fluctuations even if there is a change in environmental temperature. An object of the present invention is to provide a zoom lens with little aberration fluctuation.

In order to achieve the above object, a zoom lens according to the present invention provides:
In order from the object side to the image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a rear group composed of two lens groups. Including at least one resin lens having a positive refractive power after the second lens group and at least one resin lens having a negative refractive power after the second lens group, and satisfying the following conditional expression: Features.

However, the LPi the i-th plastic lens from the object side, _{n i} is the refractive index at the d-line of the resin lens LPi, _dn i / dT is the temperature coefficient of the refractive index in the vicinity normal temperature of the resin lens LPi, alpha _i is a resin The linear expansion coefficient of the lens LPi, φ _i is the refractive power of the resin lens LPi, φ _W is the refractive power of the entire system at the wide angle end, β _5W is the lateral magnification of the fifth lens group at the wide angle end, and β _5T is the first power at the telephoto end. This is the lateral magnification of the 5 lens group.

  According to the present invention, it is possible to obtain a zoom lens having a high zoom ratio, high optical performance over the entire zoom range, and little focus fluctuation and aberration fluctuation even when the environmental temperature changes.

FIG. 3 is an optical system cross-sectional view at the wide angle end of the zoom lens according to the first exemplary embodiment. FIG. 6 is an aberration diagram for the zoom lens of Example 1 at an environmental temperature of 20 ° C. FIG. 6 is an aberration diagram for the zoom lens of Example 1 at an environmental temperature of 0 ° C. FIG. 4 is an aberration diagram for the zoom lens of Example 1 at an environmental temperature of 40 ° C. 6 is a cross-sectional view of an optical system at a wide angle end of a zoom lens according to Embodiment 2. FIG. FIG. 6 is an aberration diagram for the zoom lens of Example 2 at an environmental temperature of 20 ° C. FIG. 6 is an aberration diagram for the zoom lens of Example 2 at an environmental temperature of 0 ° C. FIG. 6 is an aberration diagram for the zoom lens of Example 2 at an environmental temperature of 40 ° C. 6 is a cross-sectional view of an optical system at a wide angle end of a zoom lens according to Embodiment 3. FIG. FIG. 6 is an aberration diagram for the zoom lens of Example 3 at an environmental temperature of 20 ° C. FIG. 6 is an aberration diagram for the zoom lens of Example 3 at an environmental temperature of 0 ° C. FIG. 6 is an aberration diagram for the zoom lens of Example 3 at an environmental temperature of 40 ° C. It is a principal part schematic of a camera (imaging device) provided with the zoom lens of the present invention.

  Below, each conditional expression in this invention is demonstrated. If resin lenses having an aspherical shape are arranged in two or more lens groups, it is possible to realize high optical performance in the entire zoom range at low cost. However, in order to reduce the shift of the focus position due to the change in the environmental temperature, it is necessary to reduce the amount of change in the back focus due to the change in the environmental temperature. For this purpose, the refractive power of each resin lens must be set so that the amount of change in refractive power of the entire system due to changes in environmental temperature is small.

And LPi the i-th plastic lens from the object side, a refractive index of _{n i} the d-line of the resin lens LPi, the temperature coefficient of the refractive index _dn i / dT in the vicinity normal temperature of the resin lens LPi, alpha _i and resin lens LPi The linear expansion coefficient. Also, φ _i is the refractive power of the resin lens LPi, and φ _W is the refractive power of the entire system at the wide angle end. At this time, the change amount Δφ _i of the refractive power of the resin lens LPi due to the change ΔT of the environmental temperature is given by the following equation.

In general, in an organic material such as resin or plastic, the temperature coefficient dn _i / dT of the refractive index is a negative value, and the linear expansion coefficient α _i is a positive value. Therefore, the entire value in the right parenthesis of the above expression is a negative value. In order to reduce the amount of change in the refractive power of the entire system due to changes in the environmental temperature, it is necessary to use two or more resin lenses having different refractive powers. For this reason, the zoom lens of each embodiment is

Is satisfied. Conditional expression (1) defines the amount of change in the refractive power of the entire system caused by a change in environmental temperature, and is for setting the refractive power of each resin lens optimally. If the upper limit value of conditional expression (1) is exceeded, the amount of change in back focus due to a change in environmental temperature becomes too large, which is not good.

Conditional expression (2) is for appropriately defining the refractive power of each resin lens. If the lower limit value of conditional expression (2) is not reached, the refractive power of the resin lens becomes too small, and the effect of correcting low-order aberrations cannot be obtained sufficiently. _Let β _{5W be} the lateral magnification of the fifth lens group at the wide-angle end, and β _{5T be} the lateral magnification of the fifth lens group at the telephoto end. At this time, the zoom lens of each example is

Is satisfied. Conditional expression (3) relates to the zoom ratio of the fifth lens group, and is for achieving high zoom ratio. If the lower limit of conditional expression (3) is not reached, the zooming effect shared by the fifth lens unit L5 will be small, and it will be difficult to achieve high zooming.

  Next, a preferred embodiment of the present invention will be described in detail.

  The zoom lens according to the present invention includes, in order from the object side to the image side, a first lens group having a positive refractive power (optical power), a second lens group having a negative refractive power, and a third lens having a positive refractive power. And a rear group consisting of two lens groups. Here, the refractive power is the reciprocal of the focal length. The lens group is an aggregate composed of a single lens or a plurality of lenses, and is a lens group that moves independently of adjacent lens groups during zooming.

  In each embodiment, zooming is performed by changing the distance between the i-th lens unit Li and the (i + 1) -th lens unit Li + 1, and zooming from the wide-angle end (short focal length end) to the telephoto end (long focal length end). At this time, each lens group is moved to the object side. Specifically, the first lens unit L1 and the second lens unit L2 move so that the distance between the first lens unit L1 and the second lens unit L2 at the telephoto end is larger than that at the wide-angle end. The distance between the second lens group L2 and the third lens group L3 is small, the distance between the third lens group L3 and the fourth lens group L4 is large, and the distance between the fourth lens group L4 and the fifth lens group L5. The third, fourth, and fifth lens groups move so that becomes smaller.

  In each embodiment, the third lens unit L3 and the fifth lens unit L5 are moved together to the object side. This simplifies the lens barrel structure. In each embodiment, the third lens unit L3 and the fifth lens unit L5 may be moved independently. This facilitates correction of off-axis aberrations such as astigmatism during zooming.

  In each embodiment, focusing from infinity to close is performed by extending the second lens unit L2 toward the object side. Further, the image stabilization is performed by shifting a part of the lens component L4a of the fourth lens unit L4 in a direction perpendicular to the optical axis.

  Next, features of each embodiment will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a sectional view of the optical system at the wide-angle end of the zoom lens according to Embodiment 1 of the present invention.

  In the optical system cross-sectional view shown in FIG. 1, the left side is the front (object side, enlargement side), and the right side is the rear (image side, reduction side). The zoom lens according to the first exemplary embodiment includes, in order from the object side to the image side, a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, a third lens unit L3 having a positive refractive power, and a negative lens unit. The fourth lens unit L4 has a refractive power of 5 and the fifth lens unit L5 has a positive refractive power.

  SP is an aperture stop, which is disposed in the third lens unit L3. IP is an image plane, and when used as a photographing optical system of a digital still camera or a video camera, a photosensitive surface corresponding to an imaging surface of a solid-state imaging device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor is placed.

The arrows indicate the movement trajectory of each lens unit during zooming from the wide angle end to the telephoto end. 2A and 2B are aberration diagrams of the zoom lens of Example 1 at the wide-angle end and the telephoto end when the environmental temperature is 20 ° C., respectively. FIGS. 3 and 4 are aberration diagrams of the zoom lens of Example 1 at an environmental temperature of 0 ° C. and 40 ° C., respectively. The performance of the optical system after the environmental temperature change is evaluated by changing the curvature radius r of the resin lens, the surface distance d on the optical axis, the refractive index nd with respect to the d-line, and the aspheric coefficient A _i of each order according to the following formulas. Went.

Here, r ′ is the radius of curvature of the resin lens after temperature change, d ′ is the surface spacing on the optical axis after temperature change, nd ′ is the refractive index with respect to d-line after temperature change, and A _i ′ is after temperature change. Represents the aspheric coefficient of each order. α represents the linear expansion coefficient of the resin lens, dn / dT represents the temperature coefficient of the refractive index near the normal temperature of the resin lens, and ΔT represents the amount of change in the environmental temperature. Further, the surface interval d on the optical axis was changed by moving the object side surface with respect to the image side surface.

  In the aberration diagrams, d and g represent d-line and g-line. M and S represent the d-line meridional image surface and sagittal image surface. Fno is the F number, and ω is the half angle of view. Each of the lens cross-sectional view and the aberration diagram shows a state when focusing on infinity.

  In Example 1, the second lens unit L2 has a negative refractive power resin lens LP1, the third lens unit L3 has a positive refractive power resin lens LP2, the fourth lens unit L4 has a negative refractive power resin lens LP3, The fifth lens unit L5 includes a resin lens LP4 having a positive refractive power. Each resin lens has an aspheric shape on both the front and rear surfaces. In the resin lenses LP1 and LP4, the on-axis light beam and the off-axis light beam are well separated at the wide-angle end, so that it is possible to effectively correct the aberration with respect to the off-axis light beam.

  On the other hand, in the resin lenses LP2 and LP3, since the light beam of the on-axis light beam is larger than the light beam of the off-axis light beam over the entire zoom range, effective aberration correction for the on-axis light beam is possible. As a result, the zoom lens of Example 1 has a high zoom ratio, high optical performance over the entire zoom range, and a zoom lens in which focus fluctuation and aberration fluctuation due to changes in environmental temperature are sufficiently suppressed. Yes.

  FIG. 5 is a lens cross-sectional view at the wide-angle end of the zoom lens according to the second embodiment of the present invention. FIGS. 6A and 6B are aberration diagrams of the zoom lens of Example 2 at the wide-angle end and the telephoto end when the environmental temperature is 20 ° C., respectively. 7 and 8 are aberration diagrams of the zoom lens of Example 2 at environmental temperatures of 0 ° C. and 40 ° C., respectively.

  In Example 2, a resin lens LP1 having a positive refractive power is provided in the third lens group L3, a resin lens LP2 having a negative refractive power is provided in the fourth lens group L4, and a resin lens LP3 having a negative refractive power is provided in the fifth lens group L5. Contains. In the resin lens LP1, since the light beam of the axial light beam is larger than the light beam of the off-axis light beam over the entire zoom range, it is possible to effectively correct the aberration with respect to the axial light beam.

  On the other hand, in the resin lenses LP2 and LP3, the on-axis light beam and the off-axis light beam are well separated at the wide-angle end, so that effective aberration correction for the off-axis light beam is possible. As a result, the zoom lens of Example 2 has high optical performance over the entire zoom range, and is a zoom lens in which focus fluctuation and aberration fluctuation due to changes in environmental temperature are sufficiently suppressed.

  FIG. 9 is a lens cross-sectional view at the wide-angle end of the zoom lens according to Embodiment 3 of the present invention. FIGS. 10A and 10B are aberration diagrams of the zoom lens of Example 3 at the wide-angle end and the telephoto end at an environmental temperature of 20 ° C., respectively. 11 and 12 are aberration diagrams of the zoom lens of Example 3 at an environmental temperature of 0 ° C. and 40 ° C., respectively.

  In Example 3, the third lens unit L3 includes a resin lens LP1 having a negative refractive power, and the fifth lens unit L5 includes a resin lens LP2 having a positive refractive power. In the resin lens LP1, since the light beam of the axial light beam is larger than the light beam of the off-axis light beam over the entire zoom range, it is possible to effectively correct the aberration with respect to the axial light beam.

  On the other hand, in the resin lens LP2, since the on-axis light beam and the off-axis light beam are well separated at the wide angle end, effective aberration correction for the off-axis light beam is possible. As a result, the zoom lens of Example 3 has high optical performance over the entire zoom range, and is a zoom lens in which focus fluctuation and aberration fluctuation due to changes in environmental temperature are sufficiently suppressed.

Hereinafter, specific numerical data of Numerical Examples 1 to 3 corresponding to Examples 1 to 3 will be shown. In the numerical data of each example, r represents a radius of curvature, d represents a surface interval on the optical axis, nd and vd represent a refractive index with respect to the d line of the optical material, and an Abbe number. Further, in the aspherical shape, X is the amount of displacement from the surface vertex in the optical axis direction, h is the height from the optical axis in the direction perpendicular to the optical axis, r is the paraxial radius of curvature, K is the conic constant, A ₄ , A ₆ , A ₈ ,... Are represented by the following equations, where aspherical coefficients of respective orders are used.

Note that “e ± n” in each aspheric coefficient means “× 10 ^{± n} ”. Tables 1 to 4 show the relationship between the above-described conditional expressions and numerical values in the numerical examples.

Numerical example 1

Unit mm

Surface data surface number rd nd vd Effective diameter
1 ∞ 1.50 62.40
2 126.570 2.00 1.80610 33.3 55.29
3 51.029 9.63 1.49700 81.5 49.89
4 -313.989 0.15 47.75
5 46.574 5.47 1.60311 60.6 43.00
6 203.470 (variable) 42.33
7 77.124 1.20 1.91082 35.3 25.32
8 14.889 5.71 19.95
9 -36.748 0.90 1.83481 42.7 19.37
10 24.964 0.15 18.52
11 23.747 6.30 1.80518 25.4 18.60
12 -22.637 0.52 18.03
13 * -19.767 0.85 1.70000 56.0 17.43
14 * 1058.136 (variable) 16.77
15 (Aperture) ∞ 0.50 16.05
16 * 27.319 2.91 1.53110 55.9 16.90
17 * 136.521 2.11 17.15
18 * 43.043 1.11 1.63550 23.9 17.68
19 * 30.976 0.20 17.51
20 24.680 4.65 1.49700 81.5 17.63
21 -36.757 (variable) 17.56
22 -41.428 0.70 1.71300 53.9 14.63
23 -450.579 1.03 1.80610 33.3 14.59
24 237.410 3.28 14.56
25 -45.084 1.10 1.83481 42.7 14.57
26 -58.725 (variable) 14.75
27 25.085 4.93 1.49700 81.5 19.47
28 -49.536 0.20 19.48
29 * -137.408 5.91 1.53110 55.9 19.34
30 * -16.609 0.20 19.11
31 -18.390 2.08 1.83481 42.7 18.75
32 -209.358 (variable) 19.43
Image plane ∞

Aspherical data 13th surface
K = 0.00000e + 000 A 4 = -1.71187e-005 A 6 = 7.61397e-007 A 8 = -1.75792e-008
A10 = 2.14417e-010 A12 = -1.31439e-012 A14 = 3.26122e-015

14th page
K = 0.00000e + 000 A 4 = -1.34050e-005 A 6 = 6.08500e-007 A 8 = -1.11831e-008
A10 = 8.99998e-011 A12 = -8.75432e-014 A14 = -1.49853e-015

16th page
K = 0.00000e + 000 A 4 = -1.50822e-005 A 6 = 2.18997e-007 A 8 = -8.13233e-009
A10 = 1.39032e-010 A12 = -1.63424e-012 A14 = 6.13104e-015

17th page
K = 0.00000e + 000 A 4 = -2.14463e-005 A 6 = 2.99615e-007 A 8 = -1.86468e-009
A10 = -2.26394e-011 A12 = -2.06772e-013 A14 = 1.46553e-015

18th page
K = 0.00000e + 000 A 4 = -4.10558e-007 A 6 = 5.32203e-007 A 8 = 3.78845e-010
A10 = -6.31146e-011 A12 = 3.92274e-013 A14 = -1.02398e-015

19th page
K = 0.00000e + 000 A 4 = 1.25738e-005 A 6 = 4.74080e-007 A 8 = -2.79081e-009
A10 = 2.31700e-011 A12 = -3.05783e-013 A14 = 9.50446e-016

29th page
K = 0.00000e + 000 A 4 = -1.84149e-005 A 6 = 4.76259e-008 A 8 = -1.01073e-010
A10 = 4.45368e-012 A12 = -6.82727e-015 A14 = 3.57211e-017

30th page
K = 0.00000e + 000 A 4 = 1.89546e-005 A 6 = 5.81065e-008 A 8 = 9.63476e-010
A10 = -1.30471e-011 A12 = 1.30497e-013 A14 = -3.69029e-016

Various data Zoom ratio 10.38
Wide angle Medium telephoto focal length 18.60 49.08 193.00
F number 3.59 4.89 5.88
Angle of view 36.29 15.55 4.05
Image height 13.66 13.66 13.66
Total lens length 145.04 172.07 200.21
BF 38.23 59.69 74.12

d 6 2.16 22.94 48.33
d14 29.01 14.89 2.85
d21 2.56 4.14 8.95
d26 7.78 5.11 0.66
d32 38.23 59.69 74.12

Entrance pupil position 32.69 79.92 245.23
Exit pupil position -40.39 -36.34 -32.11
Front principal point position 46.89 103.91 87.58
Rear principal point position 19.63 10.61 -118.88

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 83.61 18.75 7.64 -5.01
2 7 -12.86 15.62 2.54 -8.28
3 15 24.94 11.49 4.50 -4.55
4 22 -39.70 6.11 0.50 -4.37
5 27 55.14 13.32 -2.77 -10.88

Single lens Data lens Start surface Focal length
1 1 -107.34
2 3 89.10
3 5 98.85
4 7 -20.45
5 9 -17.69
6 11 15.32
7 13 -27.71
8 16 63.72
9 18 -180.34
10 20 30.48
11 22 -64.03
12 23 -192.76
13 25 -241.35
14 27 34.26
15 29 34.98
16 31 -24.27

Numerical example 2

Unit mm

Surface data surface number rd nd vd Effective diameter
1 ∞ 1.50 62.40
2 141.103 2.00 1.80610 33.3 55.67
3 58.909 9.05 1.49700 81.5 50.83
4 -279.517 0.17 49.92
5 50.475 5.86 1.60311 60.6 48.11
6 182.594 (variable) 47.40
7 120.593 1.20 1.83481 42.7 26.67
8 15.415 6.56 20.85
9 -40.246 1.98 1.77250 49.6 19.68
10 40.511 0.15 18.71
11 27.712 6.16 1.80518 25.4 18.68
12 -28.832 0.43 17.63
13 -23.374 0.85 1.77250 49.6 17.45
14 117.614 (variable) 16.71
15 (Aperture) ∞ 0.50 15.42
16 * 21.943 3.87 1.53110 55.9 16.01
17 * -69.158 0.75 15.97
18 66.924 0.90 1.84666 23.9 15.86
19 19.426 0.15 15.56
20 19.426 5.43 1.49700 81.5 15.65
21 -24.891 (variable) 15.70
22 -26.534 0.70 1.72916 54.7 13.76
23 19.720 2.61 1.80518 25.4 13.89
24 -557.711 3.00 14.18
25 * -198.376 1.93 1.63550 23.9 15.26
26 * 532.803 (variable) 15.89
27 27.632 4.51 1.49700 81.5 18.79
28 -51.851 0.24 18.80
29 -46.943 3.92 1.58313 59.4 18.77
30 -33.099 0.15 18.90
31 * -37.571 2.05 1.63550 23.9 18.85
32 * -346.694 (variable) 19.14
Image plane ∞

Aspheric data 16th surface
K = 0.00000e + 000 A 4 = -7.10180e-006 A 6 = -9.98860e-008 A 8 = 1.79036e-009
A10 = -1.67712e-011 A12 = 1.00108e-013

17th page
K = 0.00000e + 000 A 4 = 1.76723e-005 A 6 = -8.86840e-008 A 8 = 2.00984e-009
A10 = -1.73730e-011 A12 = 1.02044e-013

25th page
K = 0.00000e + 000 A 4 = -4.69378e-005 A 6 = 1.37484e-007 A 8 = -1.12028e-009
A10 = 5.31911e-011 A12 = -4.64775e-013

26th page
K = 0.00000e + 000 A 4 = -6.78664e-005 A 6 = -3.52746e-008 A 8 = 3.00797e-009
A10 = -9.16322e-012 A12 = -1.07956e-013

No. 31
K = 0.00000e + 000 A 4 = -1.45679e-005 A 6 = -1.56848e-007 A 8 = 1.57447e-009
A10 = -8.88686e-012 A12 = 1.64173e-014

32nd page
K = 0.00000e + 000 A 4 = 2.64195e-005 A 6 = -4.82876e-008 A 8 = 3.74924e-010
A10 = -2.65891e-013 A12 = -5.61696e-015

Various data Zoom ratio 10.38
Wide angle Medium Telephoto focal length 18.60 49.98 193.00
F number 3.60 5.08 5.88
Angle of view 36.29 15.29 4.05
Image height 13.66 13.66 13.66
Total lens length 143.77 172.29 204.37
BF 38.23 62.40 74.56

d 6 2.16 23.00 53.75
d14 28.51 13.64 2.85
d21 2.50 4.13 5.96
d26 5.76 2.52 0.64
d32 38.23 62.40 74.56

Entrance pupil position 33.52 78.22 285.07
Exit pupil position -39.57 -34.05 -32.00
Front principal point position 47.68 102.30 128.50
Rear principal point position 19.63 12.42 -118.44

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 90.97 18.58 6.93 -5.57
2 7 -13.01 17.32 3.24 -8.24
3 15 23.37 11.59 3.96 -4.76
4 22 -37.04 8.24 0.68 -5.25
5 27 56.49 10.86 0.19 -6.98

Single lens Data lens Start surface Focal length
1 1 -126.83
2 3 98.77
3 5 113.77
4 7 -21.28
5 9 -25.86
6 11 18.45
7 13 -25.18
8 16 31.83
9 18 -32.61
10 20 22.88
11 22 -15.42
12 23 23.70
13 25 -227.23
14 27 36.97
15 29 174.31
16 31 -66.48

Numerical Example 3

Unit mm

Surface data surface number rd nd vd Effective diameter
1 ∞ 1.50 62.40
2 120.134 2.00 1.80610 33.3 54.86
3 47.216 9.76 1.49700 81.5 49.04
4 -396.426 0.18 46.87
5 45.215 5.40 1.60311 60.6 40.76
6 258.748 (variable) 40.05
7 162.647 1.20 1.83481 42.7 25.76
8 15.118 5.65 20.03
9 -37.535 0.90 1.77250 49.6 19.49
10 43.591 0.15 18.79
11 33.351 5.99 1.80518 25.4 18.77
12 -23.085 0.32 17.96
13 -20.825 0.85 1.77250 49.6 17.56
14 159.641 (variable) 16.80
15 (Aperture) ∞ 0.50 16.11
16 32.373 3.38 1.48749 70.2 16.93
17 -88.769 0.18 17.18
18 * 33.778 1.39 1.63550 23.9 17.38
19 * 28.146 0.15 17.15
20 29.911 4.04 1.49700 81.5 17.16
21 -44.831 (variable) 17.02
22 -37.014 0.70 1.71300 53.9 14.36
23 -294.116 1.07 1.80610 33.3 14.35
24 603.359 3.00 14.34
25 -35.597 1.17 1.83481 42.7 14.36
26 -58.873 (variable) 14.63
27 31.363 6.25 1.49700 81.5 21.14
28 -25.096 0.15 21.33
29 * -114.254 5.57 1.53110 55.9 20.81
30 * -19.891 0.15 20.91
31 -20.465 2.06 1.83481 42.7 20.49
32 -181.579 (variable) 21.11
Image plane ∞

Aspheric data 18th surface
K = 0.00000e + 000 A 4 = 1.00370e-007 A 6 = 9.36423e-010 A 8 = 1.50466e-010
A10 = 8.94392e-013 A12 = 1.58339e-015

19th page
K = 0.00000e + 000 A 4 = 1.01526e-006 A 6 = 2.88174e-008 A 8 = 1.56270e-011
A10 = 9.01705e-013 A12 = 1.09599e-014

29th page
K = 0.00000e + 000 A 4 = -3.35405e-005 A 6 = -2.74797e-008 A 8 = -7.41239e-010
A10 = 8.43212e-012 A12 = -6.82830e-014

30th page
K = 0.00000e + 000 A 4 = -5.16595e-006 A 6 = -6.30529e-009 A 8 = -7.00266e-011
A10 = 1.41189e-012 A12 = -2.94316e-014

Various data Zoom ratio 10.38
Wide angle Medium telephoto focal length 18.60 49.00 193.00
F number 3.49 4.75 5.88
Angle of view 36.29 15.58 4.05
Image height 13.66 13.66 13.66
Total lens length 145.36 170.31 197.80
BF 39.27 60.90 76.13

d 6 2.16 21.72 45.58
d14 28.08 14.32 2.85
d21 2.50 3.90 8.56
d26 9.71 5.83 1.04
d32 39.27 60.90 76.13

Entrance pupil position 32.76 77.17 226.81
Exit pupil position -49.28 -39.40 -32.88
Front principal point position 47.45 102.23 78.10
Rear principal point position 20.67 11.90 -116.87

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 80.14 18.84 8.06 -4.69
2 7 -12.70 15.06 2.67 -7.55
3 15 23.71 9.63 3.06 -3.83
4 22 -32.72 5.94 0.94 -3.66
5 27 44.58 14.18 -0.41 -9.34

Single lens Data lens Start surface Focal length
1 1 -97.70
2 3 85.52
3 5 89.99
4 7 -20.04
5 9 -25.98
6 11 17.78
7 13 -23.80
8 16 49.11
9 18 -293.78
10 20 36.76
11 22 -59.45
12 23 -245.16
13 25 -110.38
14 27 29.12
15 29 44.44
16 31 -27.79

  Next, an embodiment of a camera system using the zoom lens of the present invention will be described.

  FIG. 13 is a schematic diagram of a main part of a camera (imaging device) including the zoom lens of the present invention.

  The lens barrel 10 incorporates the zoom lens 11 shown in the first, second, and third embodiments. In the camera body 20, a mirror 21 that reflects upward the light beam captured by the zoom lens 11, a focusing plate 22 on which a subject image is formed by the zoom lens 11, and a pentagon that converts the light beam from the focusing plate 22 into an erect image. A roof prism 23, an eyepiece 24 for observing a subject image formed on the focusing screen 22, a solid-state image sensor (photoelectric conversion element) 25 such as a CCD sensor or a CMOS sensor for receiving a light beam from the zoom lens 11, and the like are provided. It has been.

  FIG. 13 shows an observation state, that is, a photographing standby state. When the photographer operates the release button, the mirror 21 is retracted from the illustrated optical path, and the subject image is captured on the solid-state image sensor 25. Thus, by using the zoom lens shown in Embodiments 1 to 3 for a camera, a camera having high optical performance can be realized. The present invention can be similarly applied to a camera without the mirror 21.

L1 first lens group, L2 second lens group, L3 third lens group, L4 fourth lens group,
L4a anti-vibration lens component, L5 fifth lens group, LPi resin lens, SP aperture,
IP image plane, dd line, g g line, S sagittal ray, M meridional ray,
Fno F number, ω half angle of view

Claims (5)

From the object side to the image side,
A first lens unit having a positive refractive power;
A second lens unit having negative refractive power;
A third lens group having a positive refractive power;
It has a rear group consisting of two lens groups,
Including at least one resin lens having a positive refractive power after the second lens group;
Including at least one resin lens having a negative refractive power after the second lens group;
A zoom lens satisfying the following conditional expression:
However,
LPi is the i-th resin lens from the object side,
n _i is the refractive index of the resin lens LPi with respect to the d-line,
dn _i / dT is a temperature coefficient of the refractive index of the resin lens LPi near room temperature,
α _i is the linear expansion coefficient of the resin lens LPi,
φ _i is the refractive power of the resin lens LPi,
φ _W is the refractive power of the entire system at the wide angle end,
β _5W is the lateral magnification of the fifth lens group at the wide-angle end,
β _5T is the lateral magnification of the fifth lens group at the telephoto end.   2. The zoom lens according to claim 1, wherein the rear group includes a fourth lens group having a negative refractive power and a fifth lens group having a positive refractive power in order from the object side to the image side.   3. The zoom lens according to claim 1, wherein the third lens group includes a resin lens having a negative refractive power, and the fifth lens group includes a resin lens having a positive refractive power. 4.   The third lens group includes a resin lens having a positive refractive power, the fourth lens group includes a resin lens having a negative refractive power, and the fifth lens group includes a resin lens having a negative refractive power. The zoom lens according to any one of claims 1 to 3.   The second lens group includes a resin lens having a negative refractive power, the third lens group includes a resin lens having a positive refractive power, the fourth lens group includes a resin lens having a negative refractive power, The zoom lens according to any one of claims 1 to 3, wherein the five lens groups include a resin lens having a positive refractive power.