JP2012058660A - Zoom lens and imaging apparatus having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zoom lens and an imaging apparatus having the same which offer high optical performance over the entire zoom range.SOLUTION: The zoom lens includes, in order from an object side to an image side, a first lens group of positive refractive power, a second lens group of negative refractive power, a third lens group of negative refractive power, an aperture stop, and a fourth lens group of positive refractive power. The fourth lens group includes a forty first lens group and a forty second lens group, and the Abbe's number of lenses in the forty second lens group is appropriately specified.

Description

  The present invention relates to a zoom lens and an imaging apparatus having the same.

  In recent years, zoom lenses having a high zoom ratio and high optical performance have been demanded for imaging devices such as a television camera, a digital camera, and a video camera.

  As a zoom lens with a high zoom ratio, there is known a positive lead type four-group zoom lens in which a lens unit having a positive refractive power is arranged closest to the object side and is composed of four lens groups as a whole (Patent Document 1, 2). In these four-group zoom lenses, chromatic aberration is corrected by using an anomalous dispersion optical material, a diffraction element, or the like.

JP 2003-287678 A JP-A-8-146294

  However, as the zoom lens further increases in zoom ratio and the image sensor further increases in pixels, there is a need for further enhancement of the performance of the zoom lens, in particular, further reduction of the amount of axial chromatic aberration in the entire zoom range. It has been.

  Therefore, an object of the present invention is to provide a zoom lens that can satisfactorily reduce lateral chromatic aberration in the entire zoom region even in a zoom lens having a high zoom ratio.

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, a second lens group having a negative refractive power, a third lens group having a negative refractive power, and an aperture stop. And a fourth lens group having a positive refractive power, wherein the fourth lens group is a forty-first lens group having a positive refractive power in order from the object side with the longest air gap in between. And a positive refractive power 42nd lens group, and the Abbe number of the material of the first positive lens having the largest dispersion among the positive lenses included in the 42nd lens group is νm, other than the first positive lens When the average Abbe number of the positive lens material is νrp and the average Abbe number of the negative lens material in the forty-second lens group is νrn,
0.4 <νm / (νrp−νrn) <0.63
It is characterized by satisfying the following condition.

  According to the present invention, it is possible to obtain a zoom lens having high optical performance in the entire zoom range and an imaging apparatus having the same.

FIG. 3 is an optical path diagram at the wide-angle end of the zoom lens according to Embodiment 1 of the present invention when the focus is at infinity. (A) is a longitudinal aberration diagram when the object distance is 2 m at the wide angle end in Numerical Example 1, (B) is a longitudinal aberration diagram when the object distance is 2 m at a focal length of 16.02 mm in Numerical Example 1, and (C). Is a longitudinal aberration diagram when the object distance is 2 m at the telephoto end in Numerical Example 1. FIG. 7 is an optical path diagram at the wide-angle end of the zoom lens according to the second embodiment of the present invention when the focus is at infinity. (A) is a longitudinal aberration diagram when the object distance is 2 m at the wide-angle end in Numerical Example 2, (B) is a longitudinal aberration diagram when the object distance is 2 m at the focal length of 16.02 mm in Numerical Example 2, and (C). Is a longitudinal aberration diagram when the object distance is 2 m at the telephoto end in Numerical Example 2. FIG. 7 is an optical path diagram at the wide-angle end of the zoom lens according to Embodiment 3 of the present invention when the focus is at infinity. (A) is a longitudinal aberration diagram when the object distance is 2 m at the wide-angle end in Numerical Example 3, (B) is a longitudinal aberration diagram when the object distance is 2 m at the focal length of 16.02 mm in Numerical Example 3, and (C). Is a longitudinal aberration diagram when the object distance is 2 m at the telephoto end in Numerical Example 3. FIG. 6 is an optical path diagram at the wide-angle end of the zoom lens according to the fourth exemplary embodiment of the present invention when the focus is at infinity. (A) is a longitudinal aberration diagram when the object distance is 6 m at the wide-angle end in Numerical Example 4, (B) is a longitudinal aberration diagram when the object distance is 6 m at the focal length of 30.29 mm in Numerical Example 4, and (C). Is a longitudinal aberration diagram when the object distance is 6 m at the telephoto end in Numerical Example 4. FIG. 7 is an optical path diagram at the wide-angle end of the zoom lens according to Embodiment 5 of the present invention when the focus is at infinity. (A) is a longitudinal aberration diagram when the object distance is 6 m at the wide angle end in Numerical Example 5, (B) is a longitudinal aberration diagram when the object distance is 6 m at the focal length of 30.29 mm in Numerical Example 5, and (C). Is a longitudinal aberration diagram when the object distance is 6 m at the telephoto end of Numerical Example 5. FIG. 7 is an optical path diagram at the wide-angle end of the zoom lens according to Embodiment 6 of the present invention when the focus is at infinity. (A) is a longitudinal aberration diagram when the object distance is 2 m at the wide-angle end in Numerical Example 6, (B) is a longitudinal aberration diagram when the object distance is 2 m at the focal length of 32.04 mm in Numerical Example 6, and (C). Is a longitudinal aberration diagram when the object distance is 2 m at the telephoto end in Numerical Example 6. Schematic view of main parts of an image pickup apparatus according to Embodiment 7 of the present invention. Chromatic aberration secondary spectrum conceptual diagram

  The zoom lens according to the present exemplary embodiment includes, in order from the object side, a first lens unit U1 having a positive refractive power, a second lens unit U2 having a negative refractive power, a third lens unit U3 having a negative refractive power, an aperture stop SP, The fourth lens unit U4 has a positive refractive power. Here, at least a part (or the whole) of the first lens group moves in the optical axis direction with the focusing operation. The second lens group moves in the optical axis direction with zooming (moves toward the image side with zooming from the wide-angle end to the telephoto end). The third lens group moves in the optical axis direction in order to correct image plane variation (movement in the optical axis direction) due to movement of the second lens group. The fourth lens group does not move for zooming, but may move with the focusing operation (in the embodiment, it does not move during the focusing operation). The fourth lens group includes a forty-first lens group having a positive refractive power and a forty-second lens having a positive refractive power from the object side with the longest air interval among the air intervals between the lenses in the fourth lens group. It is composed of groups.

The zoom lens of the present invention is characterized in that the following conditions are satisfied in the above-described configuration.
0.400 <νm / (νrp−νrn) <0.630 (1)
Here, νm is the Abbe number of the material of the positive lens (first positive lens) Lm having the largest dispersion among the positive lenses included in the forty-second lens group. Further, νrp is an average Abbe number of materials used for positive lenses other than the first positive lens (other than the positive lens Lm) among the positive lenses included in the forty-second lens group, and νrn is the forty-second lens. It is the average Abbe number of the material used for the negative lens included in the group.
Here, the definition of the Abbe number νd for the d-line of the material of the optical element (lens) used in this example is as follows.
νd = (Nd−1) / (NF-NC) (2)
However, the refractive indexes for the F line (486.1 nm), d line (587.6 nm), and C line (656.3 nm) of the Fraunhofer line of the optical element are Ng, NF, Nd, and NC, respectively.

By satisfying this conditional expression (1), it is possible to satisfactorily reduce lateral chromatic aberration in the entire zoom range (all zoom range from the wide-angle end to the telephoto end) of the zoom lens with a high zoom ratio.
Here, 0.540 <νm / (νrp−νrn) <0.629 (1a)
Is more preferable.

  The following conditional expressions (9) to (20) are conditional expressions in which desirable conditions for solving additional problems in the zoom lens of the present invention are set. Specifically, it will be described below.

  In order to obtain high optical performance in such a four-group zoom lens, it is important to satisfactorily correct lateral chromatic aberration at the wide-angle end and axial chromatic aberration at the telephoto end. When both the lateral chromatic aberration at the wide-angle end and the axial chromatic aberration at the telephoto end are satisfactorily corrected, the number of lenses increases or the effective diameter of the lens increases unless an appropriate material is arranged.

  First, the height from the optical axis of the on-axis ray of the i-th lens (thin lens) in paraxial tracking is h_i, and is the height from the optical axis of the off-axis principal ray of the i-th lens in paraxial tracking. Is h_bar_i. Further, the refractive power of the i-th lens in paraxial tracking is φ_i, and the Abbe number and ν_i of the i-th lens in paraxial tracking.

At this time, the axial chromatic aberration coefficient L and lateral chromatic aberration coefficient T of the lens system
L = Σ (h_i × h_i × φ_i / ν_i) (3)
T = Σ (h_i × h_bar_i × φ_i / ν_i) (4)
It can be expressed as. From this equation, it can be seen that the longitudinal chromatic aberration is proportional to the square of the height h, and the lateral chromatic aberration is proportional to the height h and the height h_bar.

  By configuring the fourth lens unit U4 as described above, it is possible to appropriately share the correction ability of axial chromatic aberration and lateral chromatic aberration among the groups in the fourth lens unit. That is, the share of magnification chromatic aberration correction of the forty-second lens group can be increased. Accordingly, in the zoom lens of each embodiment, the chromatic aberration of magnification (especially the chromatic aberration of magnification at the wide angle end) is reduced well by disposing the positive lens (first positive lens) Lm in the forty-second lens group closest to the image plane. can do.

  In each embodiment, an aperture stop SP is disposed close to the object side of the 41st lens group U41 (the aperture stop SP is disposed closer to the fourth lens group than the third lens group). At this time, h_bar in the forty-second lens unit U42 is relatively larger than h_bar in the forty-first lens unit U41. In addition, h_bar in the forty-second lens unit U42 is increased by providing an air gap of an appropriate length between the forty-first lens unit U41 having a positive refractive power and the forty-second lens unit U42 having a positive refractive power. Can do.

In view of these, in order to effectively correct the lateral chromatic aberration, it is necessary to appropriately select the optical material of the positive lens Lm. Hereinafter, the achromatic condition of a lens group having a positive refractive power φ as a whole and having a positive lens and a negative lens will be described. At this time, the refractive power φ (> 0) of the entire lens system is
φ = φ1 + φ2 (5)
It is expressed. Here, φ1 is the refractive power of the positive lens, φ2 is the refractive power of the negative lens, and φ1> 0 and φ2 <0.
This lens group has a positive lens Abbe number of ν1 and a negative lens Abbe number of ν2.
E = φ1 / ν1 + φ2 / ν2 (6)
The chromatic aberration in this lens group can be reduced more favorably as E that can be expressed by Here, if E = 0 is satisfied, the imaging positions of the F-line and the C-line coincide with each other, and primary achromaticity can be achieved.
Here, in the conditional expression (5), since Φ> 0, | φ1 |> | φ2 |. In order to set E = 0 under these conditions, the Abbe number of the positive and negative lenses needs to satisfy ν1> ν2 from the conditional expression (6). That is, it is necessary to configure the lens group (select an optical material of the lens) so that the Abbe number of the positive lens is larger than the Abbe number of the negative lens.

In this way, when the primary achromaticity between the F line and the C line is performed, the imaging position of the g line is shifted from the imaging positions of the F line and the C line. When the partial dispersion ratios of the positive lens and the negative lens are θ1 and θ2, respectively, the shift amount (secondary spectrum) Δ of the imaging position is expressed by the following equation.
Δ = − (1 / φ) (θ1−θ2) / (ν1−ν2) (7)
Here, the definition of the partial dispersion ratio θgF regarding the g-line and the F-line is as follows. Refractive indexes of the optical material Fraunhofer line for g-line (435.8 nm), F-line (486.1 nm), d-line (587.6 nm), and C-line (656.3 nm) are Ng, NF, Let Nd, NC. At this time, the partial dispersion ratio θgF is
θgF = (Ng−NF) / (NF−NC) (8)
It can be expressed as.

  In general, a material having a smaller Abbe number νd tends to have a larger partial dispersion ratio θgF, and therefore tends to satisfy θ1 <θ2. At this time, from the conditional expression (7), the imaging position of the g-line tends to shift to the image plane side on the axis and shift to the high image height direction off the axis (FIG. 14). In order to reduce the secondary spectrum, the numerator (θ1−θ2) in the conditional expression (7) may be reduced and the denominator (ν1−ν2) may be increased.

  Therefore, in the embodiment of the present invention, in order to reduce the numerator of the conditional expression (7), one positive lens Lm is a lens made of a material having a small νd and a large θgF (high anomalous dispersion). Furthermore, in order to increase the denominator of the conditional expression (7) and maintain the primary achromatic condition E = 0, the positive lens other than Lm has a large νd and the negative lens has a small νd. .

  With such a configuration, it is possible to effectively reduce the secondary spectrum of lateral chromatic aberration while satisfactorily correcting axial chromatic aberration.

The average values of the Abbe number and the partial dispersion ratio of the positive lens material (within the 41st lens group) included in the 41st lens group U41 are denoted by νfp and θfp, respectively. Further, the average values of Abbe number and partial dispersion ratio of the negative lens material (within the 41st lens group) included in the 41st lens group are νfn and θfn, respectively. At this time, the 41st lens group
2.1 × 10 ⁻³ <(θfn−θfp) / (νfp−νfn) <3.7 × 10 ⁻³ (9)
Is preferable.

Thus, if both conditional expression (1) and conditional expression (9) are satisfied, both axial chromatic aberration (especially axial chromatic aberration at the telephoto end) and lateral chromatic aberration (especially lateral chromatic aberration at the wide-angle end) are both good. Can be reduced. As described in Equations (3) and (4), since the 41st lens group has a high degree of correction of axial chromatic aberration, the Abbe numbers of the positive and negative lenses in the 41st lens group should be set appropriately. In particular, axial chromatic aberration can be effectively reduced.
Here, 2.11 × 10 ⁻³ <(θfn−θfp) / (νfp−νfn) <2.52 × 10 ⁻³ (9a)
Is more preferable.

Next, when the refractive power of the 41st lens group is φf and the refractive power of the positive lens Lm is φm,
0.20 <φm / φf <1.10 (10)
It is still preferable that the following condition is satisfied.

If this conditional expression (10) is satisfied, the lateral chromatic aberration can be reduced more satisfactorily. If the lower limit of conditional expression (10) is not reached, it will be difficult to reduce lateral chromatic aberration. In particular, when φf becomes larger than φm and falls below the lower limit value of conditional expression (10), it becomes difficult to secure a back focus as a replaceable zoom lens with respect to the imaging apparatus, or correction of chromatic aberration of magnification. It becomes difficult. On the other hand, if φm becomes larger than φf and exceeds the upper limit value of conditional expression (10), it is difficult to reduce axial chromatic aberration. Further, if φf becomes smaller than φm and exceeds the upper limit value of conditional expression (10), the effective diameter of the forty-second group becomes large, making it difficult to reduce the size and weight. In addition, it is difficult to achieve both reduction of longitudinal chromatic aberration and lateral chromatic aberration.
Where
0.21 <φm / φf <0.60 (10a)
Is more preferable.

In the forty-second lens unit U42, the Abbe number and partial dispersion ratio of the positive lens Lm having the largest dispersion included in the forty-second lens unit U42 are set to νm and θm, respectively. At this time, the positive lens Lm is
−1.65 × 10 ⁻³ <(θm−0.652) / νm <0 (11)
15 <νm <30 (12)
Is more preferable.

  Among the positive lenses included in the forty-second lens unit U42, the material of the positive lens Lm having the largest dispersion is more effectively achromatic so as to satisfy the conditional expressions (11) and (12) as described above. ing.

  By using an optical material that satisfies the conditional expression (11) for the forty-second lens unit U42, chromatic aberration is favorably corrected over a wide wavelength band of g-line to C-line. In particular, the lateral chromatic aberration at the wide angle end in the entire optical system is corrected well.

  If the lower limit value of conditional expression (11) is exceeded or the upper limit value of (12) is exceeded, it will be difficult to impart a sufficient achromatic effect to the forty-second lens unit U42 having a positive refractive power. In particular, it becomes difficult to obtain a sufficient correction effect for the lateral chromatic aberration at the wide-angle end in the entire optical system.

Conversely, when the upper limit value of conditional expression (11) is exceeded or below the lower limit value of (12), the primary and secondary achromatic balance in the forty-second lens unit U42 having a positive refractive power is lost. This makes it difficult to achieve both correction of longitudinal chromatic aberration and lateral chromatic aberration in the entire optical system.
Where
−1.45 × 10 ⁻³ <(θm−0.652) / νm <−0.90 × 10 ⁻³ (11a)
22.5 <νm <27.0 (12a)
Is more preferable.

  In addition, it is desirable that the positive lens having the largest dispersion in the forty-second lens group is configured as a single lens. The positive lens arranged as a single lens in the forty-second lens unit U42 can be arranged in the vicinity of a lens having negative refractive power so as to be achromatic.

  The 41st lens group preferably includes one or more positive lenses (single lenses) and a cemented lens of a positive lens and a negative lens.

  The zoom lens is preferably a zoom lens that forms (ties) an image on a photoelectric conversion element (on an image pickup element).

  In order to obtain a chromatic aberration correction effect equivalent to that of the present invention, a method in which an element having a characteristic partial dispersion characteristic is divided into a plurality of lenses having weak refractive power can be considered. In that case, it is possible to improve aberration correction capability such as spherical aberration and coma aberration and to provide a function as an eccentric aberration adjustment mechanism, but it is difficult to achieve a reduction in size and weight.

The air gap D between the forty-first lens group U41 and the forty-second lens group U42 is a variable-magnification optical system unit (extender, IE, EXT) that changes (discontinuously changes) the focal length range of the entire system. The configuration is suitable for insertion / extraction. The length from the first lens surface to the last lens surface of the fourth lens unit U4 is L4, and the axial marginal that passes through the air gap between the 41st lens unit U41 and the 42nd lens unit U42 of the fourth lens unit U4. An inclination angle [unit: degree (°)] formed by the light beam with respect to the optical axis is ξ. Then, the angle formed by the convergent light beam (light beam converging toward the image plane) from the optical axis is +, the angle formed by the divergent light beam (light beam diverging toward the image surface) from the optical axis is −, and the afocal time is ξ. When = 0
0.15 <D / L4 (13)
−5 ° <ξ <+ 5 ° (14)
It is desirable to have a configuration that satisfies at least one of the following.

  If the lower limit of conditional expression (13) is not reached, it will be difficult to secure the air space necessary for inserting and removing the variable magnification optical system unit.

An optical system including a color separation optical system or the like between the final lens surface and the image surface as in each embodiment requires a relatively long back focus, but it is sufficient if the upper limit value of conditional expression (14) is exceeded. It is difficult to ensure a long back focus. If the lower limit of conditional expression (14) is not reached, the divergence angle of the incident light beam becomes too large, and the effective lens performance of the variable magnification optical system unit becomes large, and it becomes difficult to obtain good optical performance. .
Where
0.380 <D / L4 <0.450 (13a)
+ 0.40 ° <ξ <+ 2.80 ° (14a)
It is still more preferable to satisfy at least one of

  Further, if a movable part (a lens group that moves in the optical axis direction during zooming) is provided in the fourth lens unit U4 having a positive refractive power, the effective diameter of the entire lens system increases. Manufacturing becomes difficult.

Next, when the refractive power of the fourth lens group is φ4,
0.20 <φm / φ4 <1.30 (15)
It is preferable to satisfy the following conditions.

  If the conditional expression (15) is satisfied, the lateral chromatic aberration can be reduced more favorably. If the lower limit of conditional expression (15) is not reached, it will be difficult to effectively reduce lateral chromatic aberration. In particular, when φ4 is too large, it is difficult to ensure a sufficiently long back focus. On the other hand, if the upper limit value of conditional expression (15) is exceeded, it will be difficult to achieve both reduction of longitudinal chromatic aberration and lateral chromatic aberration.

Next, when the refractive power of the forty-second lens group is φr,
0.30 <φm / φr <1.30 (16)
It is preferable to satisfy the following conditions.

  If the conditional expression (16) is satisfied, the lateral chromatic aberration can be reduced more favorably. If the lower limit of conditional expression (16) is not reached, it will be difficult to effectively reduce lateral chromatic aberration. In particular, when φr is too large, it is difficult to ensure a sufficiently long back focus. On the other hand, if the upper limit of conditional expression (16) is exceeded, it will be difficult to achieve both reduction of longitudinal chromatic aberration and lateral chromatic aberration.

Next, when the average refractive power of the positive lens in the forty-first lens group is φfp,
0.25 <φm / φfp <1.85 (17)
It is preferable to satisfy the following conditions.

  If the conditional expression (17) is satisfied, the lateral chromatic aberration can be reduced more favorably. If the lower limit of conditional expression (17) is not reached, it will be difficult to effectively reduce lateral chromatic aberration. On the other hand, if the upper limit value of conditional expression (17) is exceeded, it will be difficult to achieve both reduction of longitudinal chromatic aberration and lateral chromatic aberration.

Next, when the average refractive power of the negative lens in the forty-first lens group is φfn,
−1.50 <φm / φfn <−0.30 (18)
It is preferable to satisfy the following conditions.

  If the conditional expression (18) is satisfied, the lateral chromatic aberration can be reduced more favorably. If the lower limit of conditional expression (18) is not reached, it will be difficult to achieve both reduction of longitudinal chromatic aberration and lateral chromatic aberration. On the other hand, if the upper limit value of conditional expression (18) is exceeded, it will be difficult to effectively reduce lateral chromatic aberration.

Next, in the forty-second lens group, when the average refractive power of positive lenses other than the positive lens Lm is φrp,
0.30 <φm / φrp <0.95 (19)
It is preferable to satisfy the following conditions.

  If the conditional expression (19) is satisfied, the lateral chromatic aberration can be reduced more favorably. If the lower limit of conditional expression (19) is not reached, it will be difficult to effectively reduce lateral chromatic aberration. On the other hand, if the upper limit of conditional expression (19) is exceeded, it will be difficult to achieve both reduction of longitudinal chromatic aberration and lateral chromatic aberration.

Next, when the average refractive power of the negative lens in the forty-second lens group is φrn,
−0.60 <φm / φrn <−0.15 (20)
It is preferable to satisfy the following conditions.

  If the conditional expression (20) is satisfied, the lateral chromatic aberration can be reduced more favorably. If the lower limit of conditional expression (20) is not reached, it will be difficult to achieve both reduction of axial chromatic aberration and lateral chromatic aberration. On the other hand, if the upper limit value of conditional expression (20) is exceeded, it will be difficult to effectively reduce lateral chromatic aberration.

  The zoom lens of the present invention achieves a zoom ratio of about 7 to 40 times (preferably up to about 100 times), has a relatively simple lens configuration, and can achieve good aberration correction over the entire zoom range. Zoom type.

  FIG. 1 is a configuration diagram of a zoom lens that is Embodiment 1 (Numerical Embodiment 1) of the present invention and an optical path diagram when focusing on an object at infinity at the wide-angle end. 2A, 2B, and 2C are longitudinal aberration diagrams when focusing on an object having a distance of 2 m at the wide-angle end, the focal length of 16.02 mm, and the telephoto end of Numerical Example 1. FIG.

  However, the values of the focal length and the object distance are values when a numerical example described later is expressed in mm. The object distance is a distance from the image plane. These are all the same in the following embodiments.

  In the lens optical path diagram, the first lens unit U1 does not move during zooming and has a positive refractive power. The first lens unit U1 has a refractive power for focusing, and performs focusing by moving the whole or a part of the lens group having a refractive power.

  The second lens unit U2 is a lens unit (variator lens unit) having negative refractive power that moves during zooming.

  The third lens unit U3 is a lens unit (compensator lens group) having a negative refractive power that moves during zooming. The third lens unit U3 moves on the optical axis in conjunction with the movement of the second group lens unit, and corrects image plane fluctuations accompanying zooming.

  SP is an aperture stop, which is disposed between the third lens unit U3 and the fourth lens unit. U4 is a fourth lens group (relay lens group) that does not move during zooming and has a positive refractive power for image formation.

  The fourth lens unit U4 includes a forty-first lens unit U41 having a positive refractive power and a forty-second lens unit U42 having a positive refractive power with the longest distance between the air as a boundary.

  DG is a color separation prism or an optical filter, and is shown as a glass block. IP is an image plane and corresponds to the imaging plane of a solid-state imaging device (photoelectric conversion device).

  Lm is a lens (optical element) made of an anomalous dispersion material (optical material).

  In the aberration diagrams, spherical aberration indicates g-line, e-line, C-line, and F-line. Astigmatism indicates the e-line meridional image plane (meri) and the e-line sagittal image plane (sagi). The lateral chromatic aberration is represented by g-line, C-line, and F-line. Fno is the F number, and ω is the half angle of view.

  In all aberration diagrams, the spherical aberration is 0.2 mm, the astigmatism is 0.2 mm, the distortion is 5%, and the lateral chromatic aberration is drawn on a scale of 0.05 mm.

  In the following embodiments, the wide-angle end and the telephoto end refer to zoom positions when the second lens unit U2 for zooming is positioned at both ends of the range in which the mechanism can move on the optical axis.

  The lens configuration described above is the same in each embodiment described below.

  Numerical Example 1 corresponding to Example 1 is described in the column of Example 1 in Table 1 when the Abbe number and the partial dispersion ratio are substituted into conditional expressions (1) and (9) to (14). Value, and all conditional expressions are satisfied. As a result, Numerical Example 1 achieves good lateral chromatic aberration at the wide-angle end and good axial chromatic aberration over the entire zoom range.

In Numerical Example 1, the lens Lm made of an optical material having anomalous dispersion is disposed as a positive lens on the most object side of the forty-second lens unit U42. In particular, lateral chromatic aberration is effectively corrected on the wide angle side.
The forty-first lens unit U41 includes a positive lens, a positive lens, and a cemented lens of a positive lens and a negative lens.
The forty-second lens unit U42 includes a positive lens, a cemented lens in which a negative lens and a positive lens are cemented, a cemented lens in which a positive lens and a negative lens are cemented, and a positive lens.

  The distance between the forty-first lens group U41 and the forty-second lens group U42 has a structure suitable for inserting / removing a variable magnification optical system unit that changes the focal length range of the entire system.

  FIG. 3 is an optical path diagram when focusing on an object at infinity at the wide-angle end of the zoom lens that is Embodiment 2 (Numerical Embodiment 2) of the present invention. 4A, 4 </ b> B, and 4 </ b> C are longitudinal aberration diagrams when focusing on an object having a distance of 2 m at the wide-angle end, a focal length of 16.02 mm, and a telephoto end according to Numerical Example 2. FIG.

  Numerical Example 2 corresponding to Example 2 is a value described in the Example 2 column of Table 1 by substituting Abbe numbers and partial dispersion ratio values into conditional expressions (1) and (9) to (14). And all conditional expressions are satisfied. As a result, Numerical Example 2 achieves good lateral chromatic aberration at the wide-angle end and good axial chromatic aberration over the entire zoom range.

  The lens Lm made of an optical material having anomalous dispersion of Numerical Example 2 is arranged as a positive lens on the most object side of the forty-second lens unit U42. In particular, the lateral chromatic aberration is effectively corrected on the wide angle side.

  The lens configurations of the forty-first lens group U41 and the forty-second lens group U42 are the same as those in the first embodiment, but the materials of the lenses having the largest dispersion included in the forty-second lens group U42 are different.

  In numerical example 1, compared with numerical example 2, the partial dispersion ratio of the lens material having the largest dispersion among the positive lenses included in the forty-second lens unit U42 is higher. As a result, the lateral chromatic aberration at the wide-angle end in the entire optical system is corrected more effectively.

  On the other hand, in Numerical Example 2, compared to Numerical Example 1, the dispersion of the lens material having the largest dispersion among the positive lenses included in the forty-second lens unit U42 is low. This achieves a better correction balance especially for axial chromatic aberration and chromatic spherical aberration components of the entire zoom range in the entire optical system.

  The distance between the forty-first lens group U41 and the forty-second lens group U42 has a structure suitable for inserting / removing a variable magnification optical system unit that changes the focal length range of the entire system.

  FIG. 5 is an optical path diagram when focusing on an object at infinity at the wide-angle end of the zoom lens that is Embodiment 3 (Numerical Embodiment 3) of the present invention. 6A, 6 </ b> B, and 6 </ b> C are longitudinal aberration diagrams when focusing on an object having a distance of 2 m at the wide-angle end, the focal length of 16.02 mm, and the telephoto end of Numerical Example 3. FIG.

  Numerical Example 3 corresponding to Example 3 substitutes the Abbe number and partial dispersion ratio values into conditional expressions (1) and (9) to (14), and values described in the Example 3 column of Table 1 And all conditional expressions are satisfied. Thus, Numerical Example 3 achieves good lateral chromatic aberration at the wide-angle end and good axial chromatic aberration over the entire zoom range.

  The lens Lm made of an optical material having anomalous dispersion in Numerical Example 3 is arranged as a positive lens on the most object side of the forty-second lens unit U42. In particular, the lateral chromatic aberration is effectively corrected on the wide angle side.

  The lens configurations of the forty-first lens group U41 and the forty-second lens group U42 are the same as those in the first and second embodiments, and the lens having the largest dispersion included in the forty-second lens group U42 is the same as that in the second embodiment.

  The distance between the forty-first lens group U41 and the forty-second lens group U42 has a structure suitable for inserting / removing a variable magnification optical system unit that changes the focal length range of the entire system.

  FIG. 7 is an optical path diagram when focusing on an object at infinity at the wide-angle end of the zoom lens that is Embodiment 4 (Numerical Embodiment 4) of the present invention. FIGS. 8A, 8B, and 8C are longitudinal aberration diagrams when focusing on an object having a distance of 6 m at the wide-angle end, the focal length of 30.29 mm, and the telephoto end of Numerical Example 4. FIG.

  In numerical example 4 corresponding to example 4, the values described in the column of example 4 in Table 1 are obtained by substituting Abbe numbers and partial dispersion ratio values into conditional expressions (1) and (9) to (14). And all conditional expressions are satisfied. As a result, Numerical Example 4 achieves good lateral chromatic aberration at the wide-angle end and good axial chromatic aberration over the entire zoom range.

  The lens Lm made of an optical material having anomalous dispersion of Numerical Example 4 is arranged as a positive lens on the most image plane side of the forty-second lens unit U42. In particular, the lateral chromatic aberration is effectively corrected on the wide angle side.

  The lens of the fourth embodiment has a zoom ratio smaller than that of the first to third embodiments, and has a zoom type configuration on the telephoto side.

  The lens configuration of the forty-second lens unit U42 is the same as in Examples 1 to 3, but the lens configuration of the forty-first lens unit U41 is a positive lens, a cemented lens of a positive lens and a negative lens, and a cemented lens of a positive lens and a negative lens. Is made up of.

  The distance between the forty-first lens group U41 and the forty-second lens group U42 has a structure suitable for inserting / removing a variable magnification optical system unit that changes the focal length range of the entire system.

  FIG. 9 is an optical path diagram when focusing on an object at infinity at the wide-angle end of the zoom lens that is Embodiment 5 (Numerical Embodiment 5) of the present invention. 10A, 10B, and 10C are longitudinal aberration diagrams when focusing on an object having a distance of 6 m at the wide-angle end, the focal length of 30.29 mm, and the telephoto end according to Numerical Example 5. FIG.

  Numerical Example 5 corresponding to Example 5 is the value described in the column of Example 5 in Table 1 when the Abbe number and the partial dispersion ratio are substituted into conditional expressions (1) and (9) to (14). And all conditional expressions are satisfied. As a result, Numerical Example 5 achieves good lateral chromatic aberration at the wide-angle end and good axial chromatic aberration over the entire zoom range.

  The lens Lm made of an optical material having anomalous dispersion of Numerical Example 5 is arranged as a positive lens on the most image plane side of the forty-second lens unit U42. In particular, the lateral chromatic aberration is effectively corrected on the wide angle side.

  The lens of Example 5 is common to Example 4 from the first group to the third group, and the positive and negative lens configuration of the fourth group is the same.

  The lens of Example 5 has a larger value of conditional expression (6) representing the magnitude of the refractive power of the lens Lm than the lens of Example 4, and corrects lateral chromatic aberration at the wide-angle end more effectively.

  The distance between the forty-first lens group U41 and the forty-second lens group U42 has a structure suitable for inserting / removing a variable magnification optical system unit that changes the focal length range of the entire system.

  FIG. 11 is an optical path diagram when focusing on an object at infinity at the wide angle end of the zoom lens according to Embodiment 6 (Numerical Embodiment 6) of the present invention. 12A, 12B, and 12C are longitudinal aberration diagrams when focusing on an object having a distance of 2 m at the wide-angle end, the focal length of 32.04 mm, and the telephoto end of Numerical Example 6, respectively.

  Numerical Example 6 corresponding to Example 6 has a configuration in which an insertable / removable variable magnification optical system shown as EXT (extender) in FIG. 21 is inserted in the maximum air interval in the fourth group.

  Numerical Example 6 corresponding to Example 6 is a value described in the column of Example 6 in Table 1 when the Abbe number and the partial dispersion ratio are substituted into the conditional expressions (1) and (9) to (14). And all conditional expressions are satisfied. As a result, Numerical Example 6 achieves good lateral chromatic aberration at the wide-angle end and good axial chromatic aberration over the entire zoom range.

  In the aberration diagram of Example 6, the scales of spherical aberration and astigmatism are different from those of the other examples, and both are drawn with a scale of 0.4 mm.

  FIG. 13 is a schematic diagram of a main part of an imaging apparatus 125 (television camera system) of Example 7 using the zoom lens of each example as a photographing optical system. In FIG. 13, reference numeral 101 denotes any one of the zoom lenses according to the first to sixth embodiments. Reference numeral 124 denotes a camera body, and the zoom lens 101 is detachable from the camera body 124. An imaging apparatus (imaging system) 125 is configured by attaching the zoom lens 101 to the camera 124. Here, the zoom lens 101 and the camera body 124 may be integrally configured.

  The zoom lens 101 includes a first lens group F, a zoom unit LZ, and a fourth lens group R for image formation. The first lens group F includes a focusing lens group. The zooming unit LZ includes a second lens group that moves on the optical axis for zooming, and a third lens group that moves on the optical axis to correct image plane fluctuations accompanying zooming.

  SP is an aperture stop. The fourth lens group R has a variable magnification optical system unit (lens unit) IE that can be inserted and removed from the optical path. The variable magnification optical system unit IE (EXT) discontinuously changes the focal length range of the entire zoom lens 101 system.

  Reference numerals 114 and 115 denote driving mechanisms such as helicoids and cams for driving the first lens group F and the zooming portion LZ in the optical axis direction, respectively. Reference numerals 116 to 118 denote motors (drive means) that electrically drive the drive mechanisms 114 and 115 and the aperture stop SP. Reference numerals 119 to 121 denote detectors such as an encoder, a potentiometer, or a photosensor for detecting the position of the first lens group F and the zooming portion LZ on the optical axis and the aperture diameter of the aperture stop SP.

  In the camera body 124, 109 is a glass block corresponding to an optical filter or color separation prism in the camera body 124, and 110 is a solid-state imaging device (photoelectric sensor) such as a CCD sensor or CMOS sensor that receives a subject image formed by the zoom lens 101. Conversion element). Reference numerals 111 and 122 denote CPUs that control various types of driving of the camera body 124 and the zoom lens body 101.

  Thus, by applying the zoom lens of the present invention to a television camera, an imaging device having high optical performance is realized.

  Numerical examples 1 to 6 corresponding to the first to sixth embodiments of the present invention are shown below. In each numerical example, i indicates the order of surfaces from the object side, ri is the radius of curvature of the i-th surface from the object side, di is the i-th and i + 1-th distance from the object side, Ni, νi Are the refractive index and Abbe number of the i-th optical member. The last three surfaces are glass blocks such as filters.

  The aspherical shape is the X axis in the optical axis direction, the H axis in the direction perpendicular to the optical axis, the light traveling direction is positive, R is the paraxial radius of curvature, k is the cone constant, A3, A4, A5, A6, A7, When A8, A9, A10, A11, and A12 are aspheric coefficients, they are expressed by the following equations.

It is represented by For example, “e-Z” means “× 10 ^−Z ”. * Indicates an aspherical surface.

(Numerical example 1)
Surface data surface number rd nd vd θgF Effective diameter
1 * 227.195 2.50 1.77250 49.6 0.5521 87.70
2 33.736 19.76 61.84
3 311.589 1.85 1.75500 52.3 0.5476 61.28
4 80.391 13.54 58.97
5 -80.728 1.75 1.75500 52.3 0.5476 58.73
6 -17642.010 1.30 60.74
7 135.169 6.62 1.80518 25.4 0.6161 63.25
8 -339.711 1.16 63.31
9 328.904 9.40 1.51633 64.1 0.5352 62.99
10 * -74.094 11.86 62.84
11 1211.778 8.57 1.48749 70.2 0.5300 54.63
12 -67.682 1.65 1.88300 40.8 0.5667 54.19
13 -126.215 0.20 54.42
14 182.391 1.65 2.00330 28.3 0.5980 52.89
15 55.727 10.56 1.49700 81.5 0.5375 52.39
16 -405.898 0.20 53.25
17 130.732 9.01 1.49700 81.5 0.5375 54.61
18 -91.216 0.20 54.76
19 57.687 7.79 1.62041 60.3 0.5426 52.65
20 1234.500 (variable) 51.79
21 52.721 0.75 1.88300 40.8 0.5667 21.51
22 13.435 3.29 18.24
23 67.192 0.75 1.88300 40.8 0.5667 18.10
24 36.490 2.83 17.67
25 -48.656 4.75 1.80518 25.4 0.6161 17.46
26 -12.990 0.80 1.88300 40.8 0.5667 17.55
27 -1003.160 0.20 18.01
28 33.652 2.54 1.68893 31.1 0.6003 18.31
29 1299.417 (variable) 18.15
30 -26.243 0.75 1.75 500 52.3 0.5476 18.06
31 52.073 2.45 1.80810 22.8 0.6307 19.53
32 -173.421 (variable) 20.04
33 (Aperture) ∞ 1.40 26.40
34 -2344.389 3.04 1.54814 45.8 0.5685 27.33
35 -52.261 0.20 27.84
36 559.498 2.59 1.72047 34.7 0.5834 28.67
37 -94.784 0.20 28.92
38 90.102 6.95 1.72047 34.7 0.5834 29.17
39 -29.451 1.20 1.92286 18.9 0.6495 29.01
40 -294.678 34.00 29.25
41 114.071 4.00 1.92286 18.9 0.6495 29.48
42 -71.194 6.81 29.30
43 -261.853 1.20 1.88300 40.8 0.5667 23.75
44 21.740 5.13 1.49700 81.5 0.5375 22.37
45 1783.648 0.24 22.20
46 35.748 7.14 1.49700 81.5 0.5375 22.12
47 -19.737 1.20 2.00330 28.3 0.5980 21.88
48 -140.247 0.15 22.89
49 90.253 5.55 1.49700 81.5 0.5375 23.35
50 -26.510 4.00 23.62
51 ∞ 33.00 1.60859 46.4 0.5664 40.00
52 ∞ 13.20 1.51680 64.2 0.5347 40.00
53 ∞ (variable) 40.00
Image plane ∞


Aspheric data 1st surface
K = -5.42173e + 001 A 4 = 1.90661e-006 A 6 = 3.73103e-011 A 8 = -1.91524e-013 A10 = -6.77526e-019
A 3 = -4.12872e-006 A 5 = -1.32181e-008 A 7 = 2.42261e-012 A 9 = 2.44378e-015

10th page
K = -2.28238e + 000 A 4 = -2.08837e-007 A 6 = 2.96604e-011 A 8 = 3.48782e-013 A10 = -1.18721e-016
A 3 = -6.36724e-007 A 5 = 5.61037e-010 A 7 = -1.11164e-011 A 9 = -3.18271e-016

Various data zoom ratio 13.00
Wide angle Medium Telephoto focal length 4.45 16.02 57.85
F number 1.90 1.90 2.80
Angle of view 51.02 18.95 0.00
Image height 5.50 5.50 0.00
Total lens length 300.03 300.03 300.03
BF 38.16 38.16 38.16

d20 0.91 31.10 44.72
d29 42.27 8.63 6.22
d32 9.00 12.46 1.24
d53 4.99 4.99 4.99

Entrance pupil position 34.85 53.95 97.66
Exit pupil position 724.89 724.89 724.89
Front principal point position 39.33 70.32 160.16
Rear principal point position 0.54 -11.03 -52.86

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 26.80 109.58 47.04 36.95
2 21 -16.80 15.91 0.43 -11.92
3 30 -43.80 3.20 -0.39 -2.18
4 33 52.90 131.20 56.46 -113.55

(Numerical example 2)
Surface data surface number rd nd vd θgF Effective diameter
1 * 227.195 2.50 1.77250 49.6 0.5521 87.70
2 33.736 19.76 61.84
3 311.589 1.85 1.75500 52.3 0.5476 61.28
4 80.391 13.54 58.97
5 -80.728 1.75 1.75500 52.3 0.5476 58.73
6 -17642.010 1.30 60.74
7 135.169 6.62 1.80518 25.4 0.6161 63.25
8 -339.711 1.16 63.31
9 328.904 9.40 1.51633 64.1 0.5352 62.99
10 * -74.094 11.86 62.84
11 1211.778 8.57 1.48749 70.2 0.5300 54.63
12 -67.682 1.65 1.88300 40.8 0.5667 54.19
13 -126.215 0.20 54.42
14 182.391 1.65 2.00330 28.3 0.5980 52.89
15 55.727 10.56 1.49700 81.5 0.5375 52.39
16 -405.898 0.20 53.25
17 130.732 9.01 1.49700 81.5 0.5375 54.61
18 -91.216 0.20 54.76
19 57.687 7.79 1.62041 60.3 0.5426 52.65
20 1234.500 (variable) 51.79
21 52.721 0.75 1.88300 40.8 0.5667 21.51
22 13.435 3.29 18.24
23 67.192 0.75 1.88300 40.8 0.5667 18.10
24 36.490 2.83 17.67
25 -48.656 4.75 1.80518 25.4 0.6161 17.46
26 -12.990 0.80 1.88300 40.8 0.5667 17.55
27 -1003.160 0.20 18.01
28 33.652 2.54 1.68893 31.1 0.6003 18.31
29 1299.417 (variable) 18.15
30 -26.243 0.75 1.75 500 52.3 0.5476 18.06
31 52.073 2.45 1.80810 22.8 0.6307 19.53
32 -173.421 (variable) 20.04
33 (Aperture) ∞ 1.40 26.40
34 -6210.608 3.48 1.51742 52.4 0.5564 27.34
35 -43.230 0.20 27.87
36 131.811 2.86 1.51742 52.4 0.5564 28.91
37 -139.192 0.20 29.07
38 60.741 6.91 1.51742 52.4 0.5564 29.31
39 -35.821 1.20 1.80810 22.8 0.6307 29.08
40 -219.130 34.00 29.28
41 71.936 4.28 1.84666 23.8 0.6205 28.71
42 -77.529 6.46 28.41
43 -69.616 1.20 1.88300 40.8 0.5667 23.34
44 24.451 5.56 1.48749 70.2 0.5300 22.36
45 -79.972 0.24 22.39
46 46.903 6.56 1.49700 81.5 0.5375 22.61
47 -23.655 1.20 2.00330 28.3 0.5980 22.46
48 -111.207 0.15 23.22
49 88.163 5.09 1.49700 81.5 0.5375 23.59
50 -31.853 4.00 23.72
51 ∞ 33.00 1.60859 46.4 0.5664 40.00
52 ∞ 13.20 1.51680 64.2 0.5347 40.00
53 ∞ (variable) 40.00
Image plane ∞


Aspheric data 1st surface
K = -5.42173e + 001 A 4 = 1.90661e-006 A 6 = 3.73103e-011 A 8 = -1.91524e-013 A10 = -6.77526e-019
A 3 = -4.12872e-006 A 5 = -1.32181e-008 A 7 = 2.42261e-012 A 9 = 2.44378e-015

10th page
K = -2.28238e + 000 A 4 = -2.08837e-007 A 6 = 2.96604e-011 A 8 = 3.48782e-013 A10 = -1.18721e-016
A 3 = -6.36724e-007 A 5 = 5.61037e-010 A 7 = -1.11164e-011 A 9 = -3.18271e-016

Various data zoom ratio 13.00
Wide angle Medium Telephoto focal length 4.45 16.02 57.85
F number 1.90 1.90 2.80
Angle of view 51.02 18.95 0.00
Image height 5.50 5.50 0.00
Total lens length 300.04 300.04 300.04
BF 38.17 38.17 38.17

d20 0.91 31.10 44.72
d29 42.27 8.63 6.22
d32 9.00 12.46 1.24
d53 5.00 5.00 5.00

Entrance pupil position 34.85 53.95 97.66
Exit pupil position 502.92 502.92 502.92
Front principal point position 39.34 70.48 162.23
Rear principal point position 0.55 -11.02 -52.85

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 26.80 109.58 47.04 36.95
2 21 -16.80 15.91 0.43 -11.92
3 30 -43.80 3.20 -0.39 -2.18
4 33 55.14 131.20 60.51 -118.56

(Numerical Example 3)
Surface number rd nd vd θgF Effective diameter
1 * 227.195 2.50 1.77250 49.6 0.5521 87.70
2 33.736 19.76 61.84
3 311.589 1.85 1.75500 52.3 0.5476 61.28
4 80.391 13.54 58.97
5 -80.728 1.75 1.75500 52.3 0.5476 58.73
6 -17642.010 1.30 60.74
7 135.169 6.62 1.80518 25.4 0.6161 63.25
8 -339.711 1.16 63.31
9 328.904 9.40 1.51633 64.1 0.5352 62.99
10 * -74.094 11.86 62.84
11 1211.778 8.57 1.48749 70.2 0.5300 54.63
12 -67.682 1.65 1.88300 40.8 0.5667 54.19
13 -126.215 0.20 54.42
14 182.391 1.65 2.00330 28.3 0.5980 52.89
15 55.727 10.56 1.49700 81.5 0.5375 52.39
16 -405.898 0.20 53.25
17 130.732 9.01 1.49700 81.5 0.5375 54.61
18 -91.216 0.20 54.76
19 57.687 7.79 1.62041 60.3 0.5426 52.65
20 1234.500 (variable) 51.79
21 52.721 0.75 1.88300 40.8 0.5667 21.51
22 13.435 3.29 18.24
23 67.192 0.75 1.88300 40.8 0.5667 18.10
24 36.490 2.83 17.67
25 -48.656 4.75 1.80518 25.4 0.6161 17.46
26 -12.990 0.80 1.88300 40.8 0.5667 17.55
27 -1003.160 0.20 18.01
28 33.652 2.54 1.68893 31.1 0.6003 18.31
29 1299.417 (variable) 18.15
30 -26.243 0.75 1.75 500 52.3 0.5476 18.06
31 52.073 2.45 1.80810 22.8 0.6307 19.53
32 -173.421 (variable) 20.04
33 (Aperture) ∞ 1.40 26.40
34 74917.413 3.48 1.53172 48.8 0.5630 27.36
35 -43.582 0.20 27.87
36 120.353 3.49 1.53172 48.8 0.5630 28.90
37 -80.921 0.20 29.04
38 55.956 6.65 1.53172 48.8 0.5630 28.96
39 -38.300 1.20 1.84666 23.8 0.6205 28.56
40 657.884 34.00 28.47
41 84.421 4.17 1.84666 23.8 0.6205 28.30
42 -68.461 5.37 28.06
43 -84.755 1.20 1.88300 40.8 0.5667 23.78
44 24.694 5.66 1.48749 70.2 0.5300 22.73
45 -72.325 0.24 22.72
46 43.202 6.81 1.49700 81.5 0.5375 22.86
47 -21.609 1.20 1.90366 31.3 0.5947 22.63
48 -585.336 0.20 23.38
49 73.112 5.54 1.48749 70.2 0.5300 23.77
50 -29.309 4.00 23.94
51 ∞ 33.00 1.60859 46.4 0.5664 40.00
52 ∞ 13.20 1.51680 64.2 0.5347 40.00
53 ∞ (variable) 40.00
Image plane ∞


Aspheric data 1st surface
K = -5.42173e + 001 A 4 = 1.90661e-006 A 6 = 3.73103e-011 A 8 = -1.91524e-013 A10 = -6.77526e-019
A 3 = -4.12872e-006 A 5 = -1.32181e-008 A 7 = 2.42261e-012 A 9 = 2.44378e-015

10th page
K = -2.28238e + 000 A 4 = -2.08837e-007 A 6 = 2.96604e-011 A 8 = 3.48782e-013 A10 = -1.18721e-016
A 3 = -6.36724e-007 A 5 = 5.61037e-010 A 7 = -1.11164e-011 A 9 = -3.18271e-016

Various data zoom ratio 13.00
Wide angle Medium Telephoto focal length 4.45 16.02 57.85
F number 1.90 1.90 2.80
Angle of view 51.02 18.95 5.43
Image height 5.50 5.50 5.50
Total lens length 300.04 300.04 300.04
BF 38.17 38.17 38.17

d20 0.91 31.10 44.72
d29 42.27 8.63 6.22
d32 9.00 12.46 1.24
d53 5.00 5.00 5.00

Entrance pupil position 34.85 53.95 97.66
Exit pupil position 432.51 432.51 432.51
Front principal point position 39.35 70.57 163.34
Rear principal point position 0.55 -11.02 -52.85

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 26.80 109.58 47.04 36.95
2 21 -16.80 15.91 0.43 -11.92
3 30 -43.80 3.20 -0.39 -2.18
4 33 56.42 131.20 62.82 -121.43

(Numerical example 4)
Surface data surface number rd nd vd θgF Effective diameter
1 348.182 3.86 1.77250 49.6 0.5521 78.53
2 65.248 6.25 70.54
3 65.578 6.13 1.75520 27.5 0.6103 69.19
4 97.706 8.94 67.70
5 612.487 5.45 1.49700 81.5 0.5375 65.53
6 -416.776 20.81 64.14
7 373.686 2.97 1.69895 30.1 0.6029 59.10
8 58.828 11.20 1.43875 95.0 0.5342 57.56
9 -578.845 0.12 57.57
10 113.463 6.31 1.43875 95.0 0.5342 57.41
11 -693.179 0.12 57.04
12 81.228 7.09 1.77250 49.6 0.5521 56.42
13 -911.265 (variable) 55.84
14 47.769 1.19 1.77250 49.6 0.5521 23.96
15 19.993 5.13 21.26
16 -37.085 1.19 1.77250 49.6 0.5521 20.80
17 37.085 4.25 20.22
18 -44.595 3.54 1.72825 28.5 0.6077 20.54
19 -24.436 1.19 1.77250 49.6 0.5521 21.25
20 -72.930 0.12 22.15
21 74.058 4.17 1.67270 32.1 0.5988 22.78
22 -70.755 (variable) 22.94
23 -35.850 1.07 1.77250 49.6 0.5521 19.03
24 56.162 3.95 1.84666 23.8 0.6205 20.13
25 -516.532 (variable) 21.02
26 (Aperture) ∞ 1.86 23.29
27 -217.157 3.27 1.64000 60.1 0.5372 24.12
28 -41.752 0.12 24.76
29 281.173 4.80 1.53172 48.8 0.5630 25.25
30 -30.833 1.37 1.83400 37.2 0.5775 25.44
31 -91.060 0.12 26.18
32 63.027 4.81 1.72047 34.7 0.5834 26.66
33 -55.843 1.78 1.80518 25.4 0.6161 26.52
34 -11707.793 31.11 26.37
35 45.769 4.81 1.49700 81.5 0.5375 26.82
36 -87.359 0.12 26.57
37 357.305 1.37 1.88300 40.8 0.5667 26.06
38 29.004 5.19 1.49700 81.5 0.5375 25.14
39 -134.470 0.28 25.06
40 64.530 5.27 1.49700 81.5 0.5375 24.73
41 -33.681 1.37 1.88300 40.8 0.5667 24.30
42 -158.115 0.12 24.22
43 157.207 2.49 1.80518 25.4 0.6161 24.03
44 9233.957 2.97 23.69
45 ∞ 37.48 1.60859 46.4 0.5664 29.73
46 ∞ 5.17 1.51633 64.2 0.5352 29.73
47 ∞ (variable) 29.73
Image plane ∞


Various data zoom ratio 8.00
Wide angle Medium Telephoto focal length 10.70 30.29 85.62
F number 2.28 2.27 2.27
Angle of view 27.20 10.29 3.68
Image height 5.50 5.50 5.50
Total lens length 285.47 285.47 285.47
BF 41.53 41.53 41.53

d13 4.21 40.88 60.78
d22 60.35 19.59 3.47
d25 4.07 8.16 4.38
d47 11.89 11.89 11.89

Entrance pupil position 71.13 153.89 313.63
Exit pupil position -233.54 -233.54 -233.54
Front principal point position 81.36 180.44 369.38
Rear principal point position 1.19 -18.40 -73.73

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 77.30 79.25 62.50 14.52
2 14 -22.59 20.78 0.20 -19.02
3 23 -54.11 5.02 -0.29 -3.03
4 26 41.48 115.89 32.68 -79.41

(Numerical example 5)
Surface data surface number rd nd vd θgF Effective diameter
1 348.182 3.86 1.77250 49.6 0.5521 78.53
2 65.248 6.25 70.54
3 65.578 6.13 1.75520 27.5 0.6103 69.19
4 97.706 8.94 67.70
5 612.487 5.45 1.49700 81.5 0.5375 65.53
6 -416.776 20.81 64.14
7 373.686 2.97 1.69895 30.1 0.6029 59.10
8 58.828 11.20 1.43875 95.0 0.5342 57.56
9 -578.845 0.12 57.57
10 113.463 6.31 1.43875 95.0 0.5342 57.41
11 -693.179 0.12 57.04
12 81.228 7.09 1.77250 49.6 0.5521 56.42
1 -911.265 (variable) 55.84
14 47.769 1.19 1.77250 49.6 0.5521 23.96
15 19.993 5.13 21.26
16 -37.085 1.19 1.77250 49.6 0.5521 20.80
17 37.085 4.25 20.22
18 -44.595 3.54 1.72825 28.5 0.6077 20.54
19 -24.436 1.19 1.77250 49.6 0.5521 21.25
20 -72.930 0.12 22.15
21 74.058 4.17 1.67270 32.1 0.5988 22.78
22 -70.755 (variable) 22.94
23 -35.850 1.07 1.77250 49.6 0.5521 19.03
24 56.162 3.95 1.84666 23.8 0.6205 20.13
25 -516.532 (variable) 21.02
26 (Aperture) ∞ 1.65 23.29
27 -112.419 2.64 1.64000 60.1 0.5372 24.12
28 -41.910 0.12 24.76
29 2388.431 4.30 1.58144 40.8 0.5775 25.25
30 -30.493 1.37 1.90366 31.3 0.5947 25.44
31 -71.086 0.56 26.18
32 54.519 6.01 1.72047 34.7 0.5834 26.66
33 -67.745 1.78 1.80518 25.4 0.6161 26.52
34 321.099 (variable) 26.37
35 32.697 6.90 1.49700 81.5 0.5375 26.82
36 -173.413 2.00 26.57
37 197.167 1.37 1.88300 40.8 0.5667 26.06
38 23.856 5.61 1.49700 81.5 0.5375 25.14
39 -143.740 0.28 25.06
40 75.774 5.23 1.49700 81.5 0.5375 24.73
41 -29.046 1.37 1.88300 40.8 0.5667 24.30
42 -185.352 0.12 24.22
43 95.154 2.34 1.80518 25.4 0.6161 24.03
44 -905.404 2.95 23.69
45 ∞ 37.48 1.60859 46.4 0.5664 29.73
46 ∞ 5.17 1.51633 64.2 0.5352 29.73
47 ∞ (variable) 29.73
Image plane ∞


Various data zoom ratio 8.00
Wide angle Medium Telephoto focal length 10.70 30.29 85.62
F number 2.30 2.30 2.30
Angle of view 27.20 10.29 3.68
Image height 5.50 5.50 5.50
Total lens length 289.97 289.97 289.97
BF 41.50 41.50 41.50

d13 4.21 40.88 60.78
d22 60.35 19.59 3.47
d25 4.07 8.16 4.38
d34 31.14 31.14 31.14
d47 11.89 11.89 11.89

Entrance pupil position 71.13 153.89 313.63
Exit pupil position -274.21 -274.21 -274.21
Front principal point position 81.43 180.97 373.63
Rear principal point position 1.19 -18.40 -73.73

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 77.30 79.25 62.50 14.52
2 14 -22.59 20.78 0.20 -19.02
3 23 -54.11 5.02 -0.29 -3.03
4 26 46.01 18.43 5.48 -6.28
5 35 59.97 70.81 3.95 -43.72

(Numerical example 6)
Surface data surface number rd nd vd θgF Effective diameter
1 * 227.195 2.50 1.77250 49.6 0.5521 87.70
2 33.736 19.76 61.84
3 311.589 1.85 1.75500 52.3 0.5476 61.28
4 80.391 13.54 58.97
5 -80.728 1.75 1.75500 52.3 0.5476 58.73
6 -17642.010 1.30 60.74
7 135.169 6.62 1.80518 25.4 0.6161 63.25
8 -339.711 1.16 63.31
9 328.904 9.40 1.51633 64.1 0.5352 62.99
10 * -74.094 11.86 62.84
11 1211.778 8.57 1.48749 70.2 0.5300 54.63
12 -67.682 1.65 1.88300 40.8 0.5667 54.19
13 -126.215 0.20 54.42
14 182.391 1.65 2.00330 28.3 0.5980 52.89
15 55.727 10.56 1.49700 81.5 0.5375 52.39
16 -405.898 0.20 53.25
17 130.732 9.01 1.49700 81.5 0.5375 54.61
18 -91.216 0.20 54.76
19 57.687 7.79 1.62041 60.3 0.5426 52.65
20 1234.500 (variable) 51.79
21 52.721 0.75 1.88300 40.8 0.5667 21.51
22 13.435 3.29 18.24
23 67.192 0.75 1.88300 40.8 0.5667 18.10
24 36.490 2.83 17.67
25 -48.656 4.75 1.80518 25.4 0.6161 17.46
26 -12.990 0.80 1.88300 40.8 0.5667 17.55
27 -1003.160 0.20 18.01
28 33.652 2.54 1.68893 31.1 0.6003 18.31
29 1299.417 (variable) 18.15
30 -26.243 0.75 1.75 500 52.3 0.5476 18.06
31 52.073 2.45 1.80810 22.8 0.6307 19.53
32 -173.421 (variable) 20.04
33 (Aperture) ∞ 1.40 26.40
34 -2121.299 3.15 1.51742 52.4 0.5564 27.32
35 -49.227 0.20 27.85
36 417.806 2.64 1.51742 52.4 0.5564 28.75
37 -96.963 0.20 29.02
38 80.890 6.59 1.54072 47.2 0.5650 29.47
39 -34.094 1.20 1.92286 18.9 0.6495 29.42
40 -84.780 1.50 29.97
41 31.960 6.58 1.49700 81.5 0.5375 29.96
42 -129.452 0.24 29.27
43 38.837 5.28 1.49700 81.5 0.5375 26.96
44 -102.023 1.50 1.90366 31.3 0.5947 25.55
45 401349.727 9.05 24.48
46 -46.307 3.07 1.92286 18.9 0.6495 16.55
47 -23.607 1.50 1.77250 49.6 0.5521 15.93
48 19.071 5.28 14.42
49 50.710 4.80 1.80810 22.8 0.6307 29.92
50 -107.018 6.73 29.50
51 -121.364 1.20 1.88300 40.8 0.5667 23.81
52 21.943 5.75 1.48749 70.2 0.5300 22.38
53 -90.948 0.24 22.24
54 63.655 6.27 1.49700 81.5 0.5375 21.83
55 -19.511 1.20 2.00330 28.3 0.5980 21.66
56 -95.121 0.15 22.70
57 150.628 5.28 1.49700 81.5 0.5375 23.08
58 -25.533 4.00 23.38
59 ∞ 33.00 1.60859 46.4 0.5664 40.00
60 ∞ 13.20 1.51680 64.2 0.5347 40.00
61 ∞ (variable) 40.00
Image plane ∞

Aspheric data 1st surface
K = -5.42173e + 001 A 4 = 1.90661e-006 A 6 = 3.73103e-011 A 8 = -1.91524e-013 A10 = -6.77526e-019
A 3 = -4.12872e-006 A 5 = -1.32181e-008 A 7 = 2.42261e-012 A 9 = 2.44378e-015

10th page
K = -2.28238e + 000 A 4 = -2.08837e-007 A 6 = 2.96604e-011 A 8 = 3.48782e-013 A10 = -1.18721e-016
A 3 = -6.36724e-007 A 5 = 5.61037e-010 A 7 = -1.11164e-011 A 9 = -3.18271e-016

Various data zoom ratio 13.00
Wide angle Medium Telephoto focal length 8.90 32.04 115.70
F number 3.80 3.81 5.60
Angle of View 31.72 9.74 2.72
Image height 5.50 5.50 5.50
Total lens length 300.02 300.02 300.02
BF 38.14 38.14 38.14

d20 0.91 31.10 44.72
d29 42.27 8.63 6.22
d32 9.00 12.46 1.24
d61 4.97 4.97 4.97

Entrance pupil position 34.85 53.95 97.66
Exit pupil position -121.15 -121.15 -121.15
Front principal point position 43.12 77.85 107.22
Rear principal point position -3.93 -27.07 -110.73

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 26.80 109.58 47.04 36.95
2 21 -16.80 15.91 0.43 -11.92
3 30 -43.80 3.20 -0.39 -2.18
4 33 33.34 131.21 7.71 -111.12

  Table 1 shows the correspondence between each example and the conditional expression described above.

  According to the present embodiment, it is possible to obtain a zoom lens having high optical performance in the entire zoom range and an image pickup apparatus having the same.

Claims (8)

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 negative refractive power, an aperture stop, and a fourth lens group having a positive refractive power. A zoom lens comprising:
The fourth lens group includes, in order from the object side, a 41st lens group having a positive refractive power and a 42nd lens group having a positive refractive power, with the longest air gap in the fourth lens group. And
The Abbe number of the material of the first positive lens having the largest dispersion among the positive lenses included in the forty-second lens group is νm, and the average Abbe of the materials of the positive lenses other than the first positive lens in the forty-second lens group. When the number is νrp and the average Abbe number of the material of the negative lens in the forty-second lens group is νrn,
0.400 <νm / (νrp−νrn) <0.630
A zoom lens characterized by satisfying The average Abbe number and partial dispersion ratio of the positive lens material in the 41st lens group are respectively νfp and θfp, and the Abbe number and partial dispersion ratio of the negative lens material in the 41st lens group are respectively average values. When νfn and θfn,
2.1 × 10 ⁻³ <(θfn−θfp) / (νfp−νfn) <3.7 × 10 ⁻³
The zoom lens according to claim 1, wherein: When the refractive power of the 41st lens group is φf and the refractive power of the first positive lens is φm,
2 <φm / φf <1.1
The zoom lens according to claim 1, wherein the zoom lens satisfies the following. When the partial dispersion ratio of the first positive lens is θm,
−1.65 × 10 ⁻³ <(θm−0.652) / νm <0
15 <νm <30
The zoom lens according to claim 1, wherein the following condition is satisfied.   The zoom lens according to claim 1, wherein the first positive lens is disposed as a single lens.   6. The zoom lens according to claim 1, wherein the forty-first lens group includes at least one positive lens and a cemented lens in which a positive lens and a negative lens are cemented. 6.   The zoom lens according to claim 1, wherein an image is formed on the photoelectric conversion element.   An image pickup apparatus comprising: an image pickup element; and the zoom lens according to claim 1 that forms an image of a subject on the image pickup element.

Images