JP2880786B2 - Zoom lens for compact cameras covering a wide angle - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens which is suitable for a compact camera and has a back focus restriction smaller than that for a single-lens reflex camera. However, the present invention relates to a small-sized and low-cost two-group type zoom lens that covers a wide angle of 36 ° to 37 ° with a half angle of view on the short focal length side.

"Conventional technology" As a zoom lens for a compact camera, (A) 2
There is a group type, (B) a three-group type or a four-group type.

The type (B) has a feature that the amount of movement is smaller than that of the two-group type, but has a large lens system and a complicated structure, and is clearly different from the two-group type as in the present invention. Details are omitted.

In comparison, the two-group type has a slightly larger travel distance,
The lens configuration and mechanical structure are simple, and miniaturization is easy.

Examples of such two-group type zoom lenses include: (A-1) JP-A-56-128911; JP-A-57-201213;
No. 48009, No. 60-170816, No. 60-191216 (A-2) JP-A Nos. 62-90611 and 64-57222 (A-3) JP-A Nos. 62-113120 and 62-264019 No. etc. are conventionally known.

In the present invention, the first lens is constituted by a negative lens. However, the first lens of the first lens group of the telephoto type two-unit zoom lens is described in JP-A-63-2760 assuming that the first lens is a negative lens.
There is No. 13.

"Problem to be Solved by the Invention" However, the camera of (A-1) has a problem that the camera as a whole cannot be made compact because the back focus is small and the rear lens diameter is large. There is also a problem that internal reflection and the like easily occur between the film surface and the final surface.

In order to solve such a problem, the applicant of the present application has proposed a two-group type zoom lens having a relatively large back focus for a compact camera (A-2).
With a zoom ratio of 1.5 to 1.6 and a configuration of 6 elements in 5 groups, (A-
3) The magnification ratio is about 1.7 to 2.5 times, the zoom ratio is about 1.5 to 1.6 times, and the zoom ratio is about 1.5 to 1.6 times. The short-focus side has a half angle of view of about 30 °, which is insufficient for the demand for wide-angle photography with a compact camera for landscape photography. was there. In addition, there is a problem that the demand for a smaller and less expensive zoom lens for a compact camera cannot be satisfied.

In JP-A-63-276013, as in the present invention,
Although a negative lens is used as the first lens, since it uses a gradient index lens, it is still expensive in current technology, and it is difficult to reduce the cost. There were challenges.

The present invention has been made in order to solve the above-mentioned problem, and further improves the above-mentioned type (A-2) of JP-A-64-57222. 57222
Approximately the same as the above, but with the objective of providing a wide-angle zoom lens that widens the half-angle of view on the short focus side to 36 ° to 37 ° and is suitable for small and inexpensive compact cameras. I do.

[Means for Solving the Problems] A zoom lens for a compact camera having a wide angle according to the present invention includes, in order from the object side, a first lens group having a positive focal length and a second lens group having a negative focal length. Wherein the first lens group includes, from the object side, a 1a lens group having a negative focal length, and a positive lens group, wherein the first lens group has a negative focal length. A 1b lens group having a focal length, the 1a lens group having a negative first lens disposed on the object side, a convex surface having a large curvature on the image side and a concave surface having a large curvature on the object side on the image side. (1) -0.5 <f _1G / f ₁ ≦ 0 In order to achieve higher performance in such a zoom lens,
The 1a lens unit is characterized in that at least one aspheric surface having a divergent aspheric amount with respect to a paraxial curvature radius that satisfies (2) −50 <ΣΔI _1a <0 is provided.

Further, in the above-mentioned zoom lens, the first lens group 1b
The lens group includes a biconvex lens having a diverging surface bonded surface and a negative meniscus lens.

In the above zoom lens, the further _{(3) 0.7 <h 1 /} h 1aMAX <1.0 (4) -0.5 < Conditions of _{f 1G / f 1a <0.0 (} 5) 0.1 <d 2~a / f s <0.4 It is characterized by satisfaction.

In addition, in the above-mentioned zoom lens, one or both of the negative first lens on the object side and the meniscus lens on the image side of the 1a lens group are made of plastic, and when the first lens is plastic, (6) (m _{1a -2}・ m _1b・ m _2L ) ² <0.3 When the image-side meniscus lens is plastic, (7) (m _1b・ m _2L −m _1a-2・ m _1b・ m _2L ) ² <0.3 When both the first negative lens and the meniscus lens on the image side are plastic, the condition (8) (m _1b · m _2L ) ² <0.3 is satisfied.

In the zoom lens, the second lens group includes a positive meniscus 2-1 having a convex surface facing the image side from the object side.
The second of the lens and the negative meniscus with the concave surface facing the object side
(9) N _2G-1 <1.65 Characterized by satisfying the following conditions.

Further, in the zoom lens in which the meniscus lens on the image side in the 1a-th lens group is made of plastic, the 2-1 lens of the second lens group is made of plastic, and (11) (m _2-2L −m _2L ) ² < It satisfies the condition of 0.5.

 Here, each of the above symbols is determined as follows.

f _1G : Focal length of the first lens group f ₁ : Focal length of the first lens in the 1a lens group ΣΔI _1a : Third order spherical aberration coefficient due to the aspherical surface in the 1a lens group H ₁ : height of the paraxial ray passing through the first surface h _1aMAX : paraxial axis passing through the 1a lens group maximum value f _1a of the height of the ray: the 1a lens group having a focal length d _{2 to a:} distance f _s from the second surface of the 1a lens group to the last surface of the 1a lens group, the whole system at the short focal end _{M 1a-2} : lateral magnification of the meniscus lens on the image side in the 1a lens group m _1b : lateral magnification of the 1b lens group m _2L : lateral magnification of the second lens group on the long focal length N _2G-1 : D-line refractive index of the 2-1 lens of the second lens group f _2G : focal length of the second lens group f _2G-1 : focal length of the 2-1 lens of the second lens group m _2-2L : The second lens group on the long focal length side 2-2 Lateral Magnification of Lens "Operation and Effect of the Invention" The first lens of the conventional two-group type compact camera zoom lens is almost a positive lens. In order to increase the back focus to some extent, it is a great feature that the first lens is a negative lens (including a lens having no power) while being a telephoto type two-unit zoom lens.

Incidentally, Japanese Patent Application Laid-Open No. 63-63, in which a negative lens is used as the first lens.
In Japanese Patent No. 276013, the first lens group is composed of a negative gradient index lens and a positive gradient index lens. Therefore, as compared with the present invention, the negative first lens group composed of at least two lenses is provided. It can be said that the positive 1b lens group including the lens group and at least two lenses respectively correspond to each other.

Further, the image-side meniscus lens of the 1a-th lens unit of the present invention preferably has a concave surface on the object side and a convex surface on the image side, which has a large curvature (in particular, conditional expression (3) can be easily achieved). This is necessary for widening the angle.

In order to further increase the zoom ratio, it is preferable to divide the meniscus lens on the image side of the 1a-th lens unit into two negative and positive lenses.

The present invention is a zoom lens for a compact camera,
While the back focus is relatively large, the wide angle on the short focal length side is measured, and the overall length of the lens is further reduced. In addition, the use of an aspherical surface allows the performance to be satisfactorily corrected, and the cost can be reduced by using inexpensive glass and plastic.

Condition (1) relates to the power of the first lens, which is the most significant feature of the present invention. If the upper limit is exceeded, the first lens does not have a negative focal length, and wide angle cannot be achieved. Conversely, if the lower limit is exceeded, the negative power becomes too large and the first lens group as a whole is positive. Therefore, the burden on the positive second b lens group becomes too large, and higher-order aberrations are generated. It becomes difficult to correct aberrations in one lens group, and since the second lens group is a magnifying lens, the aberration generated in the first lens group increases, which is not preferable.

The condition (2) relates to the aspherical surface in the 1a lens group. The divergence (the divergence means that the radius of curvature decreases as the diameter increases for a concave surface and decreases for a convex surface) By using an aspherical surface having an aspherical amount of (the larger the radius is, the larger the radius of curvature becomes),
The correction of the spherical aberration in the lens group can be satisfactorily corrected, and the amount of change of the spherical aberration due to zooming can be reduced. Note that the upper limit of the condition (1) includes the equation (power 0), but having the divergent aspherical amount of the condition (2) is equivalent to having negative power. When the value exceeds the upper limit of the condition (2), the effect of the aspherical surface is small, and it becomes difficult to satisfactorily correct the aberration.
Higher order aberrations occur, which is not preferable.

Here, the amount of change of the third-order aberration coefficient due to the aspherical surface will be supplemented. The aspherical shape is generally represented as follows.

Converting this to a focal length f = 1.0, If you replace it with Becomes

The second term and below give the amount of the aspherical surface.
Factor A ₄ terms are related, such as the third-order aspheric coefficient φ follows.

φ = 8 (N′−N) A ₄ where N: refractive index before aspherical surface N ′: refractive index after aspherical surface Aspherical coefficient φ is next to third-order aberration coefficient of aberration ring Resulting in the indicated change.

^{ΔI = h 4 φ ΔII = h} 3 φ ΔIII = h 2 2 φ ΔIV = h 2 2 φ ΔV = h 3 φ However I: spherical aberration coefficient II: coma aberration coefficient III: astigmatism coefficient IV: Tamaketsuzo surface Curvature coefficient V: Distortion aberration coefficient h: Height of paraxial on-axis ray passing through each lens surface: Height of paraxial off-axis ray passing through the center of the pupil passing through each lens surface Note that as an aspherical surface expression There are various expressions using conic coefficients and odd-order terms, but when y is smaller than the paraxial radius of curvature, only even-order terms can be sufficiently approximated. Therefore, simply changing the expression of the aspherical shape does not depart from the application of the present invention.

Conditions (3), (4) and (5) relate to the 1a-th lens unit. However, the present invention is basically a telephoto-type two-unit zoom lens as described above, and the first lens unit is a negative lens. This is a preceding retro type, and the condition (3) is a conditional expression of a ratio of the height of the paraxial on-axis ray on the first surface to the maximum value of the height of the paraxial on-axis ray in the 1a lens group. Yes, condition (4) is No. 1a
This is the condition of the power of the lens group.

If both of the conditions (3) and (4) exceed the upper limits, the first lens unit does not become retro type, it is difficult to widen the angle, and it is disadvantageous to increase the back focus. If the lower limit is exceeded, on the contrary, the negative power of the 1a-th lens unit increases, so that the first lens unit as a whole is positive.
The burden on the positive first lens group becomes too large, and it becomes difficult to correct aberrations in the first lens group.

The condition (5) is as follows: from the second surface of the diverging surface of the first lens to the 1a
This is a condition of the distance to the final surface of the lens group, and is also related to the conditions (3) and (4). If the upper limit is exceeded, it becomes easy to enter the range of the conditions (3) and (4), and aberration correction is performed. Although the above is advantageous, the overall length of the lens is increased, which is contrary to the reduction in size and weight. If the lower limit is exceeded, it becomes easy to violate the lower limits of the conditions (3) and (4) in order to obtain a retro type, and the above-described problem occurs.

Further, if plastic is used for a lens having relatively low power in each lens group, focus movement and change in performance with respect to temperature and humidity are small, and weight reduction can be achieved. Therefore, an improvement in performance can be achieved.

Here, a supplementary explanation will be given on the focus movement with respect to the temperature or humidity change of the plastic lens. The change in the coefficient of linear expansion or refractive index of plastic with respect to temperature or humidity is
It is about 10 times larger than ordinary glass, but the amount of change in the focal length of the lens is Δf, and the lateral magnification of the lens group behind it without the plastic lens is m ′. ) Assuming that the lateral magnification up to the rear lens group is m, the focus movement amount Δp is Δp = Δf (m′−m) ² .

Accordingly, when the negative first lens on the object side of the 1a lens group of _{plastics, m '= m 1a-2} · m 1b · m 2L, from the m = 0, the upper limit of the condition (6) If it exceeds, the focus shift with respect to temperature and humidity becomes large, which is not preferable.

When the meniscus lens on the image side of the 1a lens group is plastic, m ′ = m _1b · m _2L and m = m _1a−2 · m _1b · m _2L
If the upper limit of conditional expression (7) is exceeded, the focus shift with respect to temperature and humidity is large, which is not preferable.

Further, when the first lens group is composed of a negative lens and a positive meniscus lens, it is preferable to use plastic for both, since the signs of the focus movements are opposite to each other, so that they cancel each other. In this case, m ′ = m _1b · m _2L and m = 0. If the upper limit of conditional expression (8) is exceeded, the focus shift with respect to temperature and humidity is large, which is not preferable. At this time, it is preferable to satisfy the conditional expressions (6) and (7) at the same time, because the influence of plastic deformation and the like is small. However, when the first lens is made of plastic, it is preferable to protect the first lens with a coat or a filter, since appearance problems such as scratches are likely to occur.

Up to now, the first lens group has been described, but the present invention uses glass and plastic having a low refractive index also for the second lens group. Conditions (9) and (10) relate to the (2-1) -th positive meniscus lens on the object side of the second lens group. If the upper limit of condition (9) is exceeded, the inexpensive zoom lens which is the object of the present invention can be obtained. Contrary to what you get. The condition (1
If the upper limit of (0) is exceeded, the power becomes too large, and as will be described later, when plastic is used, focus movement due to changes in temperature and humidity and deterioration of performance are caused, which is not preferable. Conversely, when the value goes below the lower limit of the condition (10), the positive power becomes too small, and it becomes difficult to correct the chromatic aberration in the second lens unit.

When plastic is used for the 2-1 positive meniscus lens, it is better to combine the negative lens (second lens) of the 1a lens group with a plastic lens, and conditional expression (11)
If the upper limit is exceeded, the focus shift with respect to changes in temperature and humidity becomes undesirably large.

"Examples" Hereinafter, Examples 1 to 6 of the present invention will be described. Where f
Focal length, omega denotes a half angle, f _B designates the back focal distance, r is the radius of curvature of each lens surface, d is the lens thickness or spacing between adjacent lens surfaces, N is the refractive index of the d-line of each lens, [nu each lens Is the Abbe number of Α ₄ , α ₆ , α ₈ are the fourth order, 6
These are the eighth and eighth order aspherical coefficients.

[Example 1] F _NO = 1: 4.5 to 6.3 to 7.8 f = 28.8 to 40.0 to 50.0 ω = 36.5 to 28.9 to 23.8 f _B = 9.52 to 21.82 to 32.80 Surface No. rd N ν 1 −1155.862 2.00 1.50137 56.4 2 44.414 1.83 3 * −20.974 4.16 1.49186 57.4 4 * −24.155 3.83 5 28.793 3.18 1.49831 65.0 6 −8.263 1.30 1.80518 25.4 7 −11.036 9.60 to 5.44 to 3.30 8 * −19.003 2.24 1.58547 29.9 9 −13.790 5.22 10 −9.774 1.40 1.71700 47.9 11 −62.017 Third surface aspheric surface Fourth surface aspheric surface α ₄ = −0.13199124 × 10 ⁻³ α ₄ = 0.66259188 × 10 ⁻⁴ α ₆ = 0.33020762 × 10 ⁻⁵ α ₆ = 0.43519870 × 10 ⁻⁵ α ₈ = −0.20227944 × 10 ⁻⁷ α ₈ = −0.19786341 × 10 ⁻⁷ 8th surface aspherical surface α ₄ = −0.19537588 × 10 ⁻⁴ α ₆ = 0.27364726 × 10 ⁻⁶ α ₈ = −0.68890548 × 10 ⁻⁸ [Example 2 ] F _NO = 1: 4.5 to 6.3 to 7.8 f = 28.8 to 40.0 to 50.0 ω = 36.7 to 28.9 to 23.9 f _B = 9.96 to 22.51 to 33.78 Surface No. rd N ν 1 112.851 1.25 1.51633 64.1 2 28.043 2.45 3 * −21.667 4.35 1.49186 57.4 4 * −23.688 3.77 5 31.551 3.25 1.498 31 65.0 6 −8.000 1.30 1.80518 25.4 7 −10.707 9.70 to 5.49 to 3.31 8 * −19.000 2.19 1.58547 29.9 9 −13.771 5.28 10 −9.974 1.40 1.71700 47.9 11 −65.191 Third surface aspheric surface Fourth surface aspheric surface α ₄ = − 0.16196547 × 10 ^-3 α ₄ = 0.55028021 × 10 ^-4 α ₆ = 0.33966042 × 10 ^-5 α ₆ = 0.42858951 × 10 ^-5 α ₈ = −0.17979629 × 10 ^-7 α ₈ = −0.94133470 × 10 ^-8 Surface 8 Aspherical surface α ₄ = 0.16193380 × 10 ⁻⁴ α ₆ = −0.31705545 × 10 ⁻⁶ α ₈ = 0.65675921 × 10 ⁻⁸ [Example 3] F _NO = 1: 4.5 to 6.3 to 7.8 f = 28.9 to 40.0 to 50.0 ω = 36.3~28.8~23.8 f _B = 9.54~23.00~35.09 surface No. r d N ν 1 32.610 1.40 1.49186 57.4 2 * 32.148 1.53 3 -15.741 6.50 1.69350 53.2 4 -25.191 0.20 5 30.247 3.08 1.56883 56.3 6 -8.589 1.30 1.80518 25.4 7 -13.414 11.00～5.90～3.26 8 -23.303 2.36 1.80518 25.4 9 -15.670 4.15 10 -11.281 1.40 1.78590 44.2 11 -92.130 second surface aspherical ^{_{α 4 = 0.13465738 × 10 -3 α}} 6 = 0.91656704 × 10 -6 α ₈ = 0.93247586 × 10 ^-7 [施例_{4] F NO = 1: 4.5~6.3~7.8} f = 28.9~40.0~50.0 ω = 36.2~28.9~23.9 f B = 9.60~23.00~35.10 surface No. r d N ν 1 380.713 1.40 1.49186 57.4 2 * 48.823 1.43 3 −15.135 5.52 1.49186 57.4 4 * −16.582 0.20 5 27.684 3.04 1.51633 64.1 6 −9.347 1.30 1.80518 25.4 7 −13.603 11.00 to 5.91 to 3.26 8 −22.373 2.43 1.80518 25.4 9 −14.854 4.14 10 −10.842 1.40 1.80610 40.9 11 − 71.900 second surface aspherical fourth surface aspherical ^{_{α 4 = 0.21730709 × 10 -3 α}} 4 = -0.50524256 × 10 -4 α 6 = -0.98794356 × 10 -6 α 6 = 0.12890886 × 10 -5 α 8 = 0.13733039 × _{^{10 -6 α 8 = -0.50335244 × 10}} -7 [ example _{5] F NO = 1: 4.5~6.3~7.8} f = 29.0~40.0~50.0 ω = 36.4~29.0~23.9 f B = 9.70~22.89~34.88 surface No. rd N ν 1 −74.523 1.30 1.49186 57.4 2 * 81.780 1.49 3 −16.509 4.50 1.49186 57.4 4 * −16.696 0.18 5 28.958 3.04 1.51633 64.1 6 −9.060 1.30 1.80518 25.4 7 −12.538 10.61 to 5.81 to 3.27 8 * −20.254 2.56 1.58547 29.9 9 -13.083 4 .06 10 −9.993 1.40 1.74400 44.8 11 −54.034 2nd surface aspheric surface 4th surface aspheric surface α ₄ = 0.26099530 × 10 ⁻³ α ₄ = −0.51010293 × 10 ⁻⁴ α ₆ = −0.13475431 × 10 ⁻⁵ α ₆ = 0.15071552 × 10 ^-5 α ₈ = 0.15814110 × 10 ^-6 α ₈ = −0.52968803 × 10 ^-7 Eighth surface aspheric surface α ₄ = 0.14960324 × 10 ^-4 α ₆ = −0.32608025 × 10 ^-6 α ₈ = 0.69066771 × 10 ^-8 [example _{6] F NO = 1: 3.6~5.0~6.8} f = 28.9~40.0~55.0 ω = 36.4~28.6~21.7 f B = 8.38~20.22~36.20 surface No. r d N ν 1 -82.758 1.50 1.73101 40.3 2 * 79.204 1.13 3 −17.282 3.28 1.80610 40.9 4 −17.854 0.12 5 35.828 5.18 1.51633 64.1 6 −7.863 1.49 1.80518 25.4 7 −10.490 10.15 to 6.14 to 3.29 8 −28.665 2.64 1.80518 25.4 9 −15.537 3.03 10 −12.410 1.50 1.83400 37.2 11 −29.126 1.66 12 −16.209 1.50 1.83400 37.2 13 −59.144 Second surface aspheric surface α ₄ = 0.19804673 × 10 ^-3 α ₆ = 0.11076836 × 10 ^-5 α ₈ = 0.75 126 600 × 10 ^-7 Conditional expressions in the above embodiments The following table shows the values corresponding to

[Brief description of the drawings]

FIG. 1, FIG. 3, FIG. 5, FIG. 7, FIG. 9, FIG.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a short-focus side lens system configuration diagram of Examples 1, 2, 3, 4, 5, and 6 of the present invention. 2, 4, 6, 8, 10, and 12,
In each aberration diagram of Examples 1, 2, 3, 4, 5, 6 of the present invention,
(A) shows the state on the short focal side, (b) shows the state on the intermediate side, and (c) shows the state on the long focal side.

Claims (9)

(57) [Claims] 1. A lens system comprising a first lens unit having a positive focal length and a second lens unit having a negative focal length in order from the object side, wherein the distance between the first and second lens units is changed. In the zoom lens that performs magnification, the first lens group includes, from the object side, a first lens group having a negative focal length, and a first lens group having a positive focal length.
The lens group includes at least two lenses in which a negative first lens is disposed on the object side, and a convex meniscus lens having a concave surface having a large curvature on the image side and a convex surface having a large curvature on the image side is disposed on the image side; and 1) −0.5 <f _1G / f ₁ ≦ 0, where f _{1G is} the focal length of the first lens group, f _{1 is} the focal length of the first lens in the 1a-th lens group. A comprehensive zoom lens for compact cameras. 2. The zoom lens according to claim 1, wherein
In the 1a lens group, (2) -50 <ΣΔI _1a <0 where ΣΔI _1a : the third-order spherical aberration coefficient due to the aspheric surface in the 1a lens group (when the focal length of the entire system on the short focal length side is converted to 1.0) A wide-angle zoom lens for a compact camera, comprising at least one aspheric surface having a divergent aspherical amount with respect to a paraxial radius of curvature that satisfies the following equation: 3. The zoom lens according to claim 1, wherein the first lens group of the first lens group includes a biconvex lens having a diverging surface bonded surface and a negative meniscus lens. Zoom lens for compact cameras. 4. The zoom lens according to claim 1, wherein (3) 0.7 <h ₁ / h _1aMAX <1.0 (4) −0.5 <f _1G / f _1a <0.0 (5) 0.1 <d _{2 to a} / f _s <0.4 where h _{1 is} the height of the paraxial axial ray passing through the first surface of the 1a lens group h _1aMAX : the maximum value of the height of the paraxial axial ray passing through the 1a lens group f _1a: the 1a lens group having a focal length d _{2 to a:} distance f _s from the second surface of the 1a lens group to the last surface of the 1a lens group satisfies the conditions of the focal length of the entire system at the short focal end A wide-angle zoom lens for compact cameras. 5. The zoom lens according to claim 1, wherein
The first negative lens on the object side of the 1a lens group is made of plastic, and (6) ( _m1a-2 · _m1b · _m2L ) ² <0.3 where _m1a-2 : the image side of the first 1a lens group. A wide-angle zoom lens for a compact camera, which satisfies the following conditions: lateral magnification of meniscus lens m _1b : lateral magnification of first lens group m _2L : lateral magnification of second lens group on long focal length side. 6. The zoom lens according to claim 1, wherein
The meniscus lens on the image side of the 1a lens group is made of plastic and has a wide angle of view characterized by satisfying the condition of (7) ( _m1b · _m2L− m1a _-2 · _m1b · _m2L ) ² <0.3. A comprehensive zoom lens for compact cameras. 7. The zoom lens according to claim 1, wherein
The negative first lens on the object side and the meniscus lens on the image side of the 1a lens group are both made of plastic, and cover a wide angle characterized by satisfying the condition of (8) (m _1b · m _2L ) ² <0.3. Zoom lens for compact cameras. 8. The zoom lens according to claim 1, wherein the second lens group includes, from the object side, a positive meniscus 2-1 lens having a convex surface facing the image side, and a negative meniscus having a concave surface facing the object side. (9) N _2G-1 <1.65 Where N _2G-1 : refractive index of d-line of the 2-1 lens of the second lens group f _2G : focal length of the second lens group f _2G-1 : focal point of the 2-1 lens of the second lens group A wide-angle zoom lens for compact cameras that satisfies various distance requirements. 9. The zoom lens according to claim 6, wherein the 2-1 lens in the second lens group is made of plastic, and (11) (m _2-2L −m _2L ) ² <0.5 where m _{2− 2L} : A wide-angle zoom lens for compact cameras, which satisfies the condition of the lateral magnification of the 2-2 lens in the second lens group on the long focal length side.