JP4489398B2 - Zoom lens and electronic imaging apparatus using the same - Google Patents

Description

  The present invention relates to a zoom lens and an electronic image pickup apparatus using the same, and more particularly to a zoom lens suitable for a video camera and a digital camera and an electronic image pickup apparatus using the same.

In recent years, digital cameras (electronic cameras) have attracted attention as next-generation cameras that replace silver salt 35 mm film (commonly known as Leica version) cameras. In particular, a so-called positive leading zoom lens in which the most object-side lens group has a positive refractive power, which is advantageous for setting high specifications such as a zoom ratio and an F value, has a thickness of each lens element. The dead space is large and the thickness when retracted tends to increase (Patent Document 1). A zoom lens having a negative leading type and particularly having three or less groups is advantageous in that respect. In order to achieve a high zoom ratio and a wide angle, it is necessary to appropriately set the refractive power arrangement of each lens group and the lens configuration in the lens group. The F-number at the same time tends to be large, the imaging performance deterioration due to the influence of diffraction becomes remarkable, and it is difficult to improve the image quality. In addition, with the increase in the number of pixels of the image sensor, the optical system needs to maintain sufficient brightness even at the telephoto end in order to compensate for the lack of sensitivity due to the miniaturization of the pixels. In the prior art, for example, Patent Document 2 has a zoom ratio of 3.5 times or more.
Japanese Patent Laid-Open No. 11-258507 JP 2002-267930 A

  However, in the negative leading high-magnification zoom lens in the prior art, the F-number at the wide-angle end is too small with respect to the F-number at the telephoto end. It must be large. As described above, in the prior art, it has been difficult to achieve both high zooming and downsizing when retracted while sufficiently correcting aberrations.

  The present invention has been made in view of such a problem of the prior art, and an object of the present invention is to make it easier to correct aberrations and reduce the size by reducing the fluctuation of the open F-number due to zooming compared to the prior art. It is an object of the present invention to provide a zoom lens suitable for a video camera and a digital camera, and an electronic imaging device using the same, which can achieve a high zoom ratio and a wide angle.

  The first zoom lens of the present invention that achieves the above object has, in order from the object side, a first lens group having a negative refractive power, an aperture stop having a variable aperture area, and a second lens group having a positive refractive power. When zooming from the wide-angle end to the telephoto end, zooming is performed by changing the distance between the lens groups, and the zooming ratio is 3.4 or more. The two lens groups are moved in the same direction as the moving direction, and the maximum area of the aperture when photographing the aperture stop is configured to be smaller at the wide-angle end than at the telephoto end, and the following conditional expression (1): (2) is satisfied.

-2 <f ₁ / √ (f _T · f _W ) <− 1 (1)
1.05 <S _T / S _W <4 (2)
Where f _{1 is} the focal length of the first lens group,
f _W : focal length of the entire zoom lens system at the wide-angle end,
f _T : the focal length of the entire zoom lens system at the telephoto end,
S _W : Maximum area of the aperture of the aperture stop when shooting at the wide-angle end,
S _T : Maximum area of the aperture of the aperture stop at the time of photographing at the telephoto end,
It is.

  Hereinafter, the reason and action of the first zoom lens according to the present invention having the above-described configuration will be described.

  The first lens group having a negative refractive power, an aperture stop having a variable aperture area, and a second lens group having a positive refractive power that moves in the same direction as the movement of the stop during zooming are arranged in this order, thereby retrofitting the portion. Since it is configured as a focus type, it is easy to widen the angle of view, and the diameter of the first lens group can be made smaller than a zoom lens of the front-preceding type, it is possible to make a compact zoom lens without increasing the size of the lens barrel It becomes easy.

  In addition, since the aperture stop image viewed from the incident side is enlarged toward the telephoto side, it is easy to suppress changes in the F number.

  At this time, if the zoom lens is configured as a zoom lens having a zoom ratio exceeding 3.4, the F number change becomes too large as described above, so that it is difficult to correct aberrations with a small lens configuration.

  Therefore, in the present invention, in order to further reduce the size and increase the performance of the high-magnification negative leading zoom lens having a zoom ratio exceeding 3.4, the maximum area of the aperture at the time of shooting the aperture stop. However, it is configured to be smaller at the wide-angle end than at the telephoto end. Thereby, the change of F number is suppressed small.

  If this zoom ratio is less than the lower limit zoom ratio of 3.4, even if the maximum aperture area of the variable aperture is kept constant, the effect on the optical performance is reduced, and the aperture area of the aperture is at the wide angle end. The merit of making it smaller becomes smaller.

  Further, as an incidental effect, the diameter of the group located in front of the stop is greatly influenced by the effective light beam near the wide-angle end, but when the aperture area of the stop at the wide-angle end becomes small, the lens diameter before the stop is reduced. There is also an effect that can be reduced. In particular, the effect of miniaturizing the diameter is significant when there is only one lens unit having a negative refractive power before the stop.

  In addition, the present invention is configured to satisfy the conditional expressions (1) and (2).

  Conditional expression (1) defines the focal length of the first lens group by the average focal length of the zoom lens in order to make the entire zoom lens compact.

  If the focal length of the first lens unit becomes shorter than the upper limit of -1 in conditional expression (1), the magnification of the second lens unit at the telephoto end becomes too large, and performance degradation due to manufacturing errors tends to increase. Become. Also, the diameter of the second lens group is likely to increase. On the other hand, if the focal length of the first lens unit is increased beyond the lower limit of −2, the total length of the lens system at the wide-angle end increases, the diameter of the first lens unit tends to increase, the entire body increases, and the design increases. The restrictions on are increased. Further, when an aspherical surface is used for the first lens group, processing of the aspherical lens becomes expensive.

Condition (2) defines the ratio of the maximum area S _T of the aperture of the aperture stop at the time of shooting in the maximum area S _W and the telephoto end of the opening of the aperture stop at the time of shooting at the wide-angle end is there.

  When attempting to achieve a high zoom ratio with the negative leading zoom configuration as described above, if the open aperture area (maximum area of the aperture stop aperture during shooting) is small on the telephoto side, the resolving power will be affected by diffraction. Since it tends to decrease, it is better to increase the area of the open aperture. When the lower limit of 1.05 in conditional expression (2) is exceeded and the ratio of the area of the aperture stop becomes small, the area of the aperture stop at the telephoto end becomes small and the influence of diffraction tends to occur, or at the wide angle end. The open aperture area becomes large and correction of coma aberration becomes difficult. On the other hand, when the upper limit of 4 is exceeded, the wide aperture end becomes too small and the restriction on the light amount adjustment becomes large.

  In addition, regarding conditional expression (1), the lower limit value may be set to −1.7, and further to −1.6.

  In conditional expression (1), the upper limit value may be set to -1.2, and further to -1.35.

  In conditional expression (2), the lower limit value may be 1.2, or 1.3.

  In addition, regarding conditional expression (2), the upper limit may be set to 3, and further to 2.

  Further, an upper limit value may be provided for the zoom ratio so that the zoom ratio does not exceed 5.5. When a zoom lens having a zoom ratio exceeding 5.5 times is used, it is easier to achieve a higher zoom ratio if the zoom lens is preceded by a positive lens group.

  According to a second zoom lens of the present invention, in the first zoom lens, the first lens group includes a negative lens including at least one aspherical surface and a positive lens, and the second lens group includes at least one non-surface. It has a spherical surface, has a third lens group on the image side of the second lens group, and performs focusing on a short-distance object point by moving the third lens group. .

  Hereinafter, the reason and operation of the second zoom lens according to the present invention having the above-described configuration will be described.

  In order to widen the angle of view at the wide-angle end, it is preferable to dispose a negative lens provided with an aspheric surface in the first lens group having negative refractive power. Further, correction of chromatic aberration and the like can be easily performed with the positive lens of the first lens group. In addition, the second lens group has a main refractive power, but by providing an aspheric surface, it becomes easy to correct on-axis or off-axis aberrations. In addition, by adopting the rear focus method using the third lens group, the lens barrel can be configured simply and compactly.

  According to a third zoom lens of the present invention, in the first and second zoom lenses, the aperture shape of the aperture stop has a substantially circular maximum aperture shape at the time of photographing at the telephoto end, and photographing at the wide angle end. The maximum opening shape at the time is a shape formed by seven or less aperture blades.

  Hereinafter, the reason and action of the third zoom lens of the present invention having the above-described configuration will be described.

  Since the depth of field is shallow at the telephoto end, it is preferable that the shape of the wide aperture is as close to a circle as possible in order to make the blur beautiful. Specifically, it is preferably a substantially circular shape having a minimum length of the diameter of the opening including the optical axis divided by a maximum length of 0.95 or more. On the wide-angle side, in order to make the open stop smaller than the telephoto end, it is preferable to arrange the stop blades so as to overlap the circular opening that becomes the open stop at the telephoto end and form a small opening. A larger number of aperture blades is preferable in terms of blur because it is closer to a circular aperture at the wide-angle end, but if the aperture member between the first lens group and the second lens group is thick, the thickness when retracted is increased. The number of blades is preferably 7 or less because the distance between the first lens group and the second lens group cannot be reduced on the telephoto side, which is disadvantageous for a high zoom ratio.

  According to a fourth zoom lens of the present invention, in the third zoom lens, the aperture shape of the aperture stop is a shape formed by two aperture blades at the wide angle end.

  Hereinafter, the reason and operation of the fourth zoom lens according to the present invention having the above-described configuration will be described.

  By configuring the diaphragm blades with two, the diaphragm member can be simplified, and the distance between the first lens group and the second lens group at the telephoto end can be easily reduced, which is advantageous for achieving a high zoom ratio.

  The fifth zoom lens of the present invention is characterized in that, in the first to fourth zoom lenses, the following conditional expressions (3) and (4) are satisfied.

−0.01 <M _W / f _W <−0.002 (3)
−0.006 <M _T / f _W <0.015 (4)
However, M _W : Spherical aberration at the d-line at a position 0.7 times the aperture ratio of a circle around the optical axis having the same area as the maximum area of the aperture of the aperture stop at the time of photographing at the wide angle end amount,
M _T : spherical aberration at the d-line at a position 0.7 times the aperture ratio of a circle centered on the optical axis having the same area as the maximum area of the aperture of the aperture stop at the time of photographing at the telephoto end,
f _W : focal length of the entire zoom lens system at the wide-angle end,
It is.

  Hereinafter, the reason and action of the fifth zoom lens according to the present invention having the above-described configuration will be described.

  In order to suppress the aberration in a balanced manner from the wide-angle end to the telephoto end, the spherical aberration at the wide-angle end is slightly undercorrected so that the conditional expressions (3) and (4) are satisfied at the same time. It is better to make it near 0 or overcorrected.

  When the negative spherical aberration at the wide-angle end increases beyond the lower limit value −0.01 of conditional expression (3), the resolution at the wide-angle end becomes noticeable.

  If the upper limit of −0.002 of conditional expression (3) is exceeded, the number of lenses tends to increase in order to satisfy conditional expression (4).

  If the spherical aberration at the telephoto end is insufficiently corrected beyond the lower limit of −0.006 in conditional expression (4), the number of lenses tends to increase in order to perform aberration correction that satisfies conditional expression (3). Become.

  If the spherical aberration at the telephoto end is excessively corrected beyond the upper limit of 0.015 in conditional expression (4), the resolution at the telephoto end becomes noticeable.

  Furthermore, the lower limit value of conditional expression (3) may be set to -0.008, and further to -0.007.

  Or it is good also considering the upper limit of conditional expression (3) as -0.003.

  Or it is good also considering the lower limit of conditional expression (4) as -0.002, and also 0. Furthermore, it may be 0.003.

  The upper limit value of conditional expression (4) is preferably 0.01, and more preferably 0.008.

  According to a sixth zoom lens of the present invention, in the first to fifth zoom lenses, the first lens group includes, in order from the object side, two or less negative meniscus lenses having a convex surface facing the object side, and an object side. And a single positive meniscus lens having a convex surface facing the surface.

  Hereinafter, the reason and action of the sixth zoom lens according to the present invention having the above-described configuration will be described.

  With this configuration, the most off-axis light beam is gently refracted, and the configuration having a negative lens and a positive lens facilitates correction of chromatic aberration and the like, and a wide-angle zoom lens can be configured. .

  According to a seventh zoom lens of the present invention, in the first to sixth zoom lenses, the first lens group includes a negative meniscus lens having a convex surface on the object side, and all of the negative lenses are on the object side. The surface is a multi-coat, and the image-side surface is a single-layer coat.

  Hereinafter, the reason and action of the seventh zoom lens according to the present invention having the above-described configuration will be described.

  The effect of ghost light can be reduced by applying multi-coating to the object side surface of the meniscus lens having a large curvature radius to reduce the reflectance. It is easier to stabilize the reflectance at the periphery of the lens when the surface on the image surface side with a small radius of curvature is a single layer coat.

  According to an eighth zoom lens of the present invention, in the first to seventh zoom lenses, the second lens group includes, in order from the object side, a positive lens having a convex surface directed toward the object side, and a positive lens having a convex surface directed toward the object side. It consists of four lenses, a lens, a negative lens, and a positive lens.

  Hereinafter, the reason and operation of the eighth zoom lens according to the present invention having the above-described configuration will be described.

  Since the second lens group moves to perform main magnification, in order to suppress aberration fluctuation, the second group is configured as a positive lens component, a negative lens component, and a positive lens component to facilitate correction of various aberrations. It is preferable.

  Further, in order to make the principal point closer to the object side and to facilitate high zoom ratio, it is preferable that the positive lens component is a positive lens having a convex surface facing the object side.

  Therefore, the second lens group includes four lenses, a positive lens having a convex surface facing the object side, a positive lens having a convex surface facing the object side, a negative lens, and a positive lens in order from the object side. Aberration fluctuation due to high zoom ratio can be suppressed.

  According to a ninth zoom lens of the present invention, in the eighth zoom lens, the negative lens of the second lens group is cemented with any adjacent positive lens.

  Hereinafter, the reason and action of the ninth zoom lens according to the present invention having the above-described configuration will be described. Further, chromatic aberration can be corrected satisfactorily.

  According to a tenth zoom lens of the present invention, in the ninth zoom lens, the negative lens of the second lens group is cemented with an adjacent positive lens on the object side, and the image surface side is a concave surface that is in contact with the space. It is characterized by this.

  The reason and action of the tenth zoom lens according to the present invention will be described below. The principal point of the second lens group can be easily located closer to the object side while ensuring the chromatic aberration correction function. Become.

  According to an eleventh zoom lens of the present invention, in the first to tenth zoom lenses, a third lens group having a positive refractive power including two or less lenses is disposed on the image side of the second lens group. The zoom lens is configured as a group zoom lens.

  Hereinafter, the reason and action of the eleventh zoom lens according to the present invention will be described.

  If comprised in this way, it will become easy to collimate the emitted light beam to an image side, suppressing the increase in the thickness at the time of collapsing. In particular, it is suitable for a zoom lens used in an electronic imaging apparatus having an electronic imaging element. Even if the third lens group is a single lens, it is preferable in terms of miniaturization.

  A twelfth zoom lens according to the present invention is configured as a three-group zoom lens having a third lens group having a positive refractive power on the image side of the second lens group in the first to eleventh zoom lenses, The zoom lens according to any one of claims 1 to 11, wherein focusing on a short-distance object point is performed by moving the third lens group, and the following conditional expression is satisfied.

1.0 <f ₂ / √ (f _T · f _W ) <2.0 (5)
1.6 <f ₃ / √ (f _T · f _W ) <3.6 (6)
Where f _{2 is} the focal length of the second lens group,
f ₃ : focal length of the third lens group,
It is.

  Hereinafter, the reason and action of the twelfth zoom lens according to the present invention having the above-described configuration will be described.

  In particular, when the present invention is constituted by a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a third lens group having a positive refractive power, the size reduction and the high zoom ratio can be achieved. Since the telecentric state can be easily maintained, it is preferable to give an appropriate refractive power so as to satisfy the above-described conditions.

  If the lower limit value 1.0 of the conditional expression (5) for the focal length of the second lens group is exceeded, the focal length of the second lens group becomes too short and aberrations tend to occur, and if the upper limit value of 2.0 is exceeded. The amount of movement of the second lens group becomes large and it is difficult to reduce the size.

  Furthermore, the lower limit value of conditional expression (5) may be 1.1, further 1.3, or 1.5.

  The upper limit value may be 1.8, or 1.7.

  If the lower limit value 1.6 of the conditional expression (6) of the focal length of the third lens group is exceeded, the angle change of the emitted light beam becomes large when the zoom ratio is increased, and it becomes difficult to ensure telecentricity. When the value of 3.6 is exceeded, the amount of movement when focusing is performed by the movement of the third lens group, and it becomes difficult to reduce the size including the moving mechanism.

  Furthermore, the lower limit value of conditional expression (6) may be 1.8, further 2.0, or 2.5.

  Further, the upper limit value may be set to 3.2, or even 3.0.

  According to a thirteenth zoom lens of the present invention, in the first to tenth zoom lenses, the zoom lens is configured as a zoom lens having a configuration of three groups or less.

  Hereinafter, the reason and action of the thirteenth zoom lens according to the present invention having the above-described configuration will be described.

  If comprised in this way, a moving mechanism can be simplified and the thickness at the time of retraction can be made small. Particularly, a negative, positive, and positive three-group zoom lens is basically a negative / positive type two-group zoom lens, and the pupil can be moved away from the final positive lens group, which is suitable for a small electronic imaging device. It will be a thing.

  In a fourteenth zoom lens according to the present invention, in the first to thirteenth zoom lenses, an interval between the most image side surface of the first lens unit at the wide angle end and the aperture stop satisfies the following conditional expression. It is a feature.

−3.0 <D _1S / f ₁ <−0.8 (7)
Where D _1S is the distance between the most image side surface of the first lens unit and the aperture stop at the wide-angle end,
It is.

  The reason and action of the above-described configuration in the fourteenth zoom lens of the present invention will be described below.

  Conditional expression (7) is a condition for suppressing an increase in the total length and facilitating a high zoom ratio. If the lower limit of −3.0 is exceeded, the total length at the wide-angle end becomes long, or the focal length of the first lens group becomes short, and aberration tends to occur. If the upper limit of −0.8 is exceeded, the surface spacing at the wide-angle end becomes short, and it becomes difficult to achieve a high zoom ratio.

  Furthermore, when the lower limit value of the conditional expression (5) is −2.5, and further −2, the total length at the wide angle end can be shortened.

  Alternatively, if the upper limit value of the conditional expression (5) is set to −1.2, and further −1.6, it becomes easier to achieve a higher zoom ratio.

  A fifteenth electronic imaging apparatus of the present invention is characterized by including the first to fourteenth zoom lenses and an electronic imaging device arranged on the image side thereof.

  Hereinafter, the reason and action of the fifteenth electronic image pickup apparatus of the present invention having the above configuration will be described. The zoom lens of the present invention described above is suitable for use in a small electronic image pickup apparatus.

  According to a sixteenth electronic imaging device of the present invention, in the fifteenth electronic imaging device, a photographing field angle at a wide angle end is 70 ° or more.

  Hereinafter, the reason and action of the above-described configuration in the sixteenth electronic imaging device of the present invention will be described. A zoom lens having a large zoom ratio and a wide field end shooting field angle of 70 ° or more. In a lens, since the effect by satisfying conditional expression (1) and conditional expression (2) increases, it is preferable.

  According to a seventeenth electronic imaging device of the present invention, there are provided second, eleventh and twelfth zoom lenses satisfying the following conditional expression (8), and an electronic imaging device arranged on the image side thereof: It is characterized by having.

_{D 11> D 12> D 31} > D 22> D 21 ··· (8)
Where D ₁₁ is the maximum effective diameter in the entire zoom range on the most object side surface of the first lens group,
D ₁₂ : the maximum effective diameter in the entire zoom range on the most image side surface of the first lens unit,
D ₃₁ : the maximum effective diameter in the entire variable magnification region on the most object side surface of the third lens group,
D ₂₂ : the maximum effective diameter in the entire zoom range on the most image side surface of the second lens group,
D ₂₁ : the maximum effective diameter in the entire zoom range on the most object side surface of the second lens group,
It is.

  The reason and action of the above-described configuration in the seventeenth zoom lens of the present invention will be described below.

  When the first lens group has a larger diameter on the object side, it can pass light rays with a wide angle of view while keeping the entire group small. In the second and subsequent lens groups, coma aberration caused by lens eccentricity due to manufacturing errors between the inner diameter of the frame and the outer diameter of the lens is larger when the diameter is larger on the image surface side and is in contact with the frame on the object side of the lens. The curvature of field can be reduced. In addition, when the outer diameter of the lens far from the stop is increased, the decrease in the amount of peripheral light of the captured image can be reduced.

  Further, if the maximum effective diameter of the second lens group is large on the most image side, the reflection of the light beam incident on the second lens group at the lens edge in the second lens group can be reduced, thereby generating ghost. It is also easy to reduce the amount.

  According to an eighteenth electronic imaging device of the present invention, in the fifteenth to seventeenth electronic imaging devices, storage means having information corresponding to a maximum aperture area corresponding to a zoom state, information from the storage means, and the zoom state And a control means for controlling the maximum aperture area at the time of photographing the aperture stop from information.

  Hereinafter, the reason and action of the above-described configuration in the eighteenth electronic imaging device of the present invention will be described. The maximum opening area at the time of photographing based on the zoom state and information in the storage unit is controlled by the control unit. Is controlled.

  According to the present invention described above, aberration correction can be easily performed by reducing the fluctuation of the open F-number due to zooming as compared with the prior art, and also miniaturization, high zooming, and widening of the angle can be achieved. A zoom lens suitable for a camera and an electronic imaging device using the zoom lens can be provided.

  Examples 1 to 7 of the zoom lens according to the present invention will be described below. FIGS. 1 to 7 show lens cross-sectional views at the wide-angle end (a), the intermediate state (b), and the telephoto end (c) when focusing on an object point at infinity in Examples 1 to 7, respectively. In the figure, the first lens group is G1, the aperture stop is S, the second lens group is G2, the third lens group is G3, the parallel plate constituting the low-pass filter with IR cut coating is LF, and the electronic imaging device cover The parallel plate of glass is indicated by CG and the image plane is indicated by I. In addition, you may give the multilayer film for wavelength range limitation to the surface of the cover glass CG. Further, the cover glass CG may have a low-pass filter function.

  As shown in FIG. 1, the imaging optical system of Embodiment 1 includes, in order from the object side, a first lens group G1 having a negative refractive power, an aperture stop S, a second lens group G2 having a positive refractive power, and a positive refractive power. Consists of the third lens group G3, and when zooming from the wide-angle end to the telephoto end, the first lens group G1 moves along a locus convex toward the image side, and at the telephoto end, the position of the wide-angle end Located closer to the image side. The aperture stop S and the second lens group G2 integrally move monotonically toward the object side, and the third lens group G3 moves along a locus convex toward the object side, and is located closer to the image side than the wide-angle end position at the telephoto end. To do.

  In order from the object side, the first lens group G1 includes two negative meniscus lenses having a convex surface facing the object side, and a positive meniscus lens having a convex surface facing the object side. The second lens group G2 has a convex surface facing the object side. A positive meniscus lens having a convex surface facing the object side, a cemented lens having a positive meniscus lens having a convex surface facing the object side, and a negative meniscus lens having a convex surface facing the object side, and a biconvex positive lens. The third lens group G3 is a biconvex positive lens. Consists of a single lens.

  The aspheric surfaces are used for the three surfaces of the second negative meniscus lens in the first lens group G1, the image side surface, and the most object side surface and the image side surface of the second lens group G2.

  As shown in FIG. 2, the imaging optical system according to the second embodiment includes, in order from the object side, a first lens group G1 having a negative refractive power, an aperture stop S, a second lens group G2 having a positive refractive power, and a positive refractive power. Consists of the third lens group G3, and when zooming from the wide-angle end to the telephoto end, the first lens group G1 moves along a locus convex toward the image side, and at the telephoto end, the position of the wide-angle end Located closer to the image side. The aperture stop S and the second lens group G2 integrally move monotonically toward the object side, and the third lens group G3 moves toward the image side.

  In order from the object side, the first lens group G1 includes two negative meniscus lenses having a convex surface facing the object side, and a positive meniscus lens having a convex surface facing the object side. The second lens group G2 has a convex surface facing the object side. A positive meniscus lens having a convex surface facing the object side, a cemented lens having a positive meniscus lens having a convex surface facing the object side, and a negative meniscus lens having a convex surface facing the object side, and a biconvex positive lens. The third lens group G3 is a biconvex positive lens. Consists of a single lens.

  The aspherical surfaces are three surfaces: the image side surface of the second negative meniscus lens of the first lens group G1, the most object side surface of the second lens group G2, and the object side surface of the third lens group G3. Used for.

  As shown in FIG. 3, the imaging optical system of Example 3 includes, in order from the object side, a first lens group G1 having a negative refractive power, an aperture stop S, a second lens group G2 having a positive refractive power, and a positive refractive power. Consists of the third lens group G3, and when zooming from the wide-angle end to the telephoto end, the first lens group G1 moves along a locus convex toward the image side, and at the telephoto end, the position of the wide-angle end Located closer to the image side. The aperture stop S and the second lens group G2 integrally move monotonically toward the object side, and the third lens group G3 moves along a locus convex toward the object side, and is located closer to the image side than the wide-angle end position at the telephoto end. To do.

  In order from the object side, the first lens group G1 includes two negative meniscus lenses having a convex surface facing the object side, and a positive meniscus lens having a convex surface facing the object side. The second lens group G2 has a convex surface facing the object side. A positive meniscus lens having a convex surface facing the object side, a cemented lens having a positive meniscus lens having a convex surface facing the object side, and a negative meniscus lens having a convex surface facing the object side, and a biconvex positive lens. The third lens group G3 is a biconvex positive lens. Consists of a single lens.

  The aspheric surfaces are used for the two surfaces, the image side surface of the second negative meniscus lens of the first lens group G1 and the most object side surface of the second lens group G2.

  As shown in FIG. 4, the imaging optical system of Example 4 includes, in order from the object side, a first lens group G1 having a negative refractive power, an aperture stop S, a second lens group G2 having a positive refractive power, and a positive refractive power. Consists of the third lens group G3, and when zooming from the wide-angle end to the telephoto end, the first lens group G1 moves along a locus convex toward the image side, and at the telephoto end, the position of the wide-angle end Located closer to the image side. The aperture stop S and the second lens group G2 integrally move monotonically toward the object side, and the third lens group G3 moves along a locus convex toward the object side, and is located closer to the image side than the wide-angle end position at the telephoto end. To do.

  In order from the object side, the first lens group G1 includes two negative meniscus lenses having a convex surface facing the object side, and a positive meniscus lens having a convex surface facing the object side. The second lens group G2 has a convex surface facing the object side. A positive meniscus lens having a convex surface facing the object side, a cemented lens having a positive meniscus lens having a convex surface facing the object side, and a negative meniscus lens having a convex surface facing the object side, and a biconvex positive lens. The third lens group G3 is a biconvex positive lens. Consists of a single lens.

  The aspherical surfaces are the image side surface of the second negative meniscus lens in the first lens group G1, the object side surface of the most meniscus positive meniscus lens in the second lens group G2, and the second lens group G2. It is used for three surfaces on the object side of the biconvex positive lens closest to the image side.

  As shown in FIG. 5, the imaging optical system of Example 5 includes, in order from the object side, a first lens group G1 having a negative refractive power, an aperture stop S, a second lens group G2 having a positive refractive power, and a positive refractive power. Consists of the third lens group G3, and when zooming from the wide-angle end to the telephoto end, the first lens group G1 moves along a locus convex toward the image side, and at the telephoto end, the position of the wide-angle end Located closer to the image side. The aperture stop S and the second lens group G2 integrally move monotonically toward the object side, and the third lens group G3 moves along a locus convex toward the object side, and is located closer to the image side than the wide-angle end position at the telephoto end. To do.

  In order from the object side, the first lens group G1 includes two negative meniscus lenses having a convex surface facing the object side, and a positive meniscus lens having a convex surface facing the object side. The second lens group G2 has a convex surface facing the object side. A positive meniscus lens having a convex surface facing the object side, a cemented lens having a positive meniscus lens having a convex surface facing the object side, and a negative meniscus lens having a convex surface facing the object side, and a biconvex positive lens. The third lens group G3 is a biconvex positive lens. Consists of a single lens.

  The aspherical surfaces are the image side surface of the second negative meniscus lens in the first lens group G1, the object side surface of the most meniscus positive meniscus lens in the second lens group G2, and the second lens group G2. It is used on the object side surface of the biconvex positive lens closest to the image side and the image side surface of the third lens group G3.

  As shown in FIG. 6, the imaging optical system of Example 6 includes, in order from the object side, a first lens group G1 having a negative refractive power, an aperture stop S, a second lens group G2 having a positive refractive power, and a positive refractive power. Consists of the third lens group G3, and when zooming from the wide-angle end to the telephoto end, the first lens group G1 moves along a locus convex toward the image side, and at the telephoto end, the position of the wide-angle end Located slightly closer to the object side. The aperture stop S and the second lens group G2 integrally move monotonically toward the object side, and the third lens group G3 moves toward the image side.

  In order from the object side, the first lens group G1 includes a negative meniscus lens having a convex surface facing the object side and a positive meniscus lens having a convex surface facing the object side. The second lens group G2 includes a biconvex positive lens, A cemented lens of a positive meniscus lens having a convex surface facing the object side and a negative meniscus lens having a convex surface facing the object side, and a biconvex positive lens. The third lens group G3 is composed of one biconvex positive lens.

  The aspheric surfaces are used for the three surfaces of the negative meniscus lens image-side surface of the first lens group G1 and both surfaces of the biconvex positive lens closest to the object side of the second lens group G2.

  As shown in FIG. 7, the imaging optical system of Example 7 includes, in order from the object side, a first lens group G1 having a negative refractive power, an aperture stop S, a second lens group G2 having a positive refractive power, and a positive refractive power. Consists of the third lens group G3, and when zooming from the wide-angle end to the telephoto end, the first lens group G1 moves along a locus convex toward the image side, and at the telephoto end, the position of the wide-angle end Located slightly closer to the image side. The aperture stop S and the second lens group G2 integrally move monotonically toward the object side, and the third lens group G3 moves along a locus convex toward the image side, and is positioned closer to the image side than the wide-angle end position at the telephoto end. To do.

  In order from the object side, the first lens group G1 includes a negative meniscus lens having a convex surface facing the object side and a positive meniscus lens having a convex surface facing the object side. The second lens group G2 includes a biconvex positive lens, A positive meniscus lens having a positive meniscus lens having a convex surface facing the object side and a negative meniscus lens having a convex surface facing the object side, and a positive meniscus lens having a convex surface facing the object side, and the third lens group G3 is a biconvex positive lens 1. It consists of sheets.

  The aspheric surfaces are used for the two surfaces, the image side surface of the negative meniscus lens of the first lens group G1 and the object side surface of the biconvex positive lens closest to the object side of the second lens group G2.

  In each embodiment, the negative meniscus lens in the first lens group G1 has a multi-coat on the object side and a single-layer coat on the image side.

Hereinafter, numerical data of each embodiment described above, but the symbols are outside the above, f is the focal length, F _NO is the F-number, 2 [omega is field angle, WE denotes a wide angle end, ST intermediate state, TE is Telephoto end, φ _S / 2 is the aperture diameter, r ₁ , r ₂ ... Is the radius of curvature of each lens surface, d ₁ , d ₂ ... _Are the distances between the lens surfaces, n _d1 , n _d2 . The refractive index of the line, ν _d1 , ν _d2 ... Is the Abbe number of each lens. The aspherical shape is represented by the following expression, where x is an optical axis with the light traveling direction being positive, and y is a direction orthogonal to the optical axis.

x = (y ² / r) / [1+ {1- (K + 1) (y / r) ² } ^1/2 ]
_{^{+ A 4 y 4 + A 6}} y 6 + A 8 y 8 + A 10 y 10
Here, r is a paraxial radius of curvature, K is a conical coefficient, and A ₄ , A ₆ , A ₈ , and A ₁₀ are fourth-order, sixth-order, eighth-order, and tenth-order aspherical coefficients, respectively.

Example 1
r ₁ = 36.860 d ₁ = 1.20 n _d1 = 1.74100 ν _d1 = 52.64
r ₂ = 11.241 d ₂ = 3.12
r ₃ = 20.005 d ₃ = 1.30 n _d2 = 1.74330 ν _d2 = 49.33
r ₄ = 8.091 (aspherical surface) d ₄ = 3.98
r ₅ = 15.491 d ₅ = 3.01 n _d3 = 1.84666 ν _d3 = 23.78
r ₆ = 33.328 d ₆ = (variable)
r ₇ = ∞ (aperture) d ₇ = 0.80
r ₈ = 16.975 (aspherical surface) d ₈ = 1.58 n _d4 = 1.69350 ν _d4 = 53.21
r ₉ = 38.888 d ₉ = 0.28
r ₁₀ = 9.759 d ₁₀ = 4.61 n _d5 = 1.72000 ν _d5 = 43.69
r ₁₁ = 47.955 d ₁₁ = 0.89 n _d6 = 1.84666 ν _d6 = 23.78
r ₁₂ = 7.899 d ₁₂ = 1.51
r ₁₃ = 22.430 d ₁₃ = 2.80 n _d7 = 1.48749 ν _d7 = 70.23
r ₁₄ = -19.802 (aspherical surface) d ₁₄ = (variable)
r ₁₅ = 20.122 d ₁₅ = 2.85 n _d8 = 1.49700 ν _d8 = 81.54
r ₁₆ = -152.133 d ₁₆ = (variable)
r ₁₇ = ∞ d ₁₇ = 1.30 n _d9 = 1.54771 ν _d9 = 62.84
r ₁₈ = ∞ d ₁₈ = 0.80
r ₁₉ = ∞ d ₁₉ = 0.50 n _d10 = 1.51633 ν _d10 = 64.14
r ₂₀ = ∞
Aspheric coefficient 4th surface K = -0.842
A ₄ = -6.74445 × 10 ^-7
A ₆ = -2.55662 × 10 ^-7
A ₈ = -4.63462 × 10 ^-10
A ₁₀ = -3.76434 × 10 ^-11
8th surface K = -0.850
A ₄ = -1.89434 × 10 ^-5
A ₆ = -7.45889 × 10 ^-8
A ₈ = 0
A ₁₀ = 0
14th face K = -0.429
A ₄ = 6.19289 × 10 ^-5
A ₆ = 6.31162 × 10 ^-8
A ₈ = 4.88137 × 10 ^-8
A ₁₀ = 0
Zoom data (∞)
WE ST TE
f (mm) 5.780 11.400 22.500
F _NO 2.85 3.41 4.86
2ω (°) 78.5 43.8 22.6
d ₆ 31.27 11.71 3.43
d ₁₄ 5.77 13.82 33.94
d ₁₆ 5.27 6.22 3.79
φ _S / 2 3.60 3.90 4.25.

Example 2
r ₁ = 35.867 d ₁ = 1.24 n _d1 = 1.78590 ν _d1 = 44.20
r ₂ = 11.136 d ₂ = 3.38
r ₃ = 23.278 d ₃ = 1.30 n _d2 = 1.74330 ν _d2 = 49.33
r ₄ = 8.404 (aspherical surface) d ₄ = 3.03
r ₅ = 15.998 d ₅ = 3.11 n _d3 = 1.84666 ν _d3 = 23.78
r ₆ = 51.708 d ₆ = (variable)
r ₇ = ∞ (aperture) d ₇ = 0.80
r ₈ = 18.343 _{(aspherical) d 8 = 2.11 n d4 =} 1.69350 ν d4 = 53.21
r ₉ = 39.619 d ₉ = 0.05
r ₁₀ = 9.929 d ₁₀ = 4.62 n _d5 = 1.72000 ν _d5 = 43.69
r ₁₁ = 41.025 d ₁₁ = 1.04 n _d6 = 1.84666 ν _d6 = 23.78
r ₁₂ = 8.029 d ₁₂ = 1.18
r ₁₃ = 26.936 d ₁₃ = 2.19 n _d7 = 1.49700 ν _d7 = 81.54
r ₁₄ = -15.731 d ₁₄ = (variable)
r ₁₅ = 19.932 (aspherical surface) d ₁₅ = 3.34 n _d8 = 1.48749 ν _d8 = 70.23
r ₁₆ = -135.370 d ₁₆ = (variable)
r ₁₇ = ∞ d ₁₇ = 1.30 n _d9 = 1.54771 ν _d9 = 62.84
r ₁₈ = ∞ d ₁₈ = 0.80
r ₁₉ = ∞ d ₁₉ = 0.50 n _d10 = 1.51633 ν _d10 = 64.14
r ₂₀ = ∞
Aspheric coefficient 4th surface K = -0.841
A ₄ = -3.18836 × 10 ^-5
A ₆ = -2.83895 × 10 ^-7
A ₈ = 3.42260 × 10 ^-11
A ₁₀ = -3.52479 × 10 ^-11
The eighth side K = -6.573
A ₄ = 7.72043 × 10 ^-5
A ₆ = -8.85647 × 10 ^-7
A ₈ = 0
A ₁₀ = 0
15th page K = -17.194
A ₄ = 2.23176 × 10 ^-4
A ₆ = -2.70882 × 10 ^-6
A ₈ = 1.96635 × 10 ^-8
A ₁₀ = 0
Zoom data (∞)
WE ST TE
f (mm) 5.800 11.514 22.500
F _NO 2.84 3.42 4.80
2ω (°) 77.9 43.2 22.5
d ₆ 30.62 11.65 3.20
d ₁₄ 4.56 13.89 32.82
d ₁₆ 5.79 5.36 2.99
φ _S / 2 3.45 3.8 4.15.

Example 3
r ₁ = 38.881 d ₁ = 1.21 n _d1 = 1.72916 ν _d1 = 54.68
r ₂ = 12.531 d ₂ = 3.50
r ₃ = 21.795 d ₃ = 1.30 n _d2 = 1.74330 ν _d2 = 49.33
r ₄ = 8.298 (aspherical surface) d ₄ = 4.02
r ₅ = 16.122 d ₅ = 3.39 n _d3 = 1.84666 ν _d3 = 23.78
r ₆ = 36.855 d ₆ = (variable)
r ₇ = ∞ (aperture) d ₇ = 0.80
r ₈ = 15.694 (aspherical surface) d ₈ = 2.25 n _d4 = 1.74330 ν _d4 = 49.33
r ₉ = 34.961 d ₉ = 0.24
r ₁₀ = 9.281 d ₁₀ = 2.99 n _d5 = 1.75700 ν _d5 = 47.82
r ₁₁ = 28.352 d ₁₁ = 1.46 n _d6 = 1.84666 ν _d6 = 23.78
r ₁₂ = 7.211 d ₁₂ = 1.27
r ₁₃ = 45.498 d ₁₃ = 2.83 n _d7 = 1.48749 ν _d7 = 70.23
r ₁₄ = -16.301 d ₁₄ = (variable)
r ₁₅ = 19.658 d ₁₅ = 2.70 n _d8 = 1.49700 ν _d8 = 81.54
r ₁₆ = -120.480 d ₁₆ = (variable)
r ₁₇ = ∞ d ₁₇ = 1.30 n _d9 = 1.54771 ν _d9 = 62.84
r ₁₈ = ∞ d ₁₈ = 0.80
r ₁₉ = ∞ d ₁₉ = 0.50 n _d10 = 1.51633 ν _d10 = 64.14
r ₂₀ = ∞
Aspheric coefficient 4th surface K = -0.869
A ₄ = 7.72245 × 10 ^-6
A ₆ = 2.93661 × 10 ^-8
A ₈ = -1.62810 × 10 ^-9
A ₁₀ = -1.46177 × 10 ^-11
Surface 8 K = -2.394
A ₄ = 2.73461 × 10 ^-5
A ₆ = -1.11350 × 10 ^-7
A ₈ = 0
A ₁₀ = 0
Zoom data (∞)
WE ST TE
f (mm) 5.840 11.501 22.504
F _NO 2.84 3.37 4.82
2ω (°) 77.8 43.6 22.7
d ₆ 31.46 11.93 3.64
d ₁₄ 3.53 12.82 33.10
d ₁₆ 6.99 7.12 3.66
φ _S / 2 3.45 3.85 4.20.

Example 4
r ₁ = 23.444 d ₁ = 1.20 n _d1 = 1.63930 ν _d1 = 44.87
r ₂ = 15.500 d ₂ = 3.60
r ₃ = 35.523 d ₃ = 1.30 n _d2 = 1.74320 ν _d2 = 49.34
r ₄ = 8.249 (aspherical surface) d ₄ = 3.89
r ₅ = 13.662 d ₅ = 2.80 n _d3 = 1.84666 ν _d3 = 23.78
r ₆ = 22.847 d ₆ = (variable)
r ₇ = ∞ (aperture) d ₇ = 0.80
r ₈ = 14.631 (aspherical surface) d ₈ = 1.40 n _d4 = 1.77250 ν _d4 = 49.60
r ₉ = 34.012 d ₉ = 0.10
r ₁₀ = 10.239 d ₁₀ = 3.19 n _d5 = 1.77250 ν _d5 = 49.60
r ₁₁ = 26.955 d ₁₁ = 1.83 n _d6 = 1.84666 ν _d6 = 23.78
r ₁₂ = 7.358 d ₁₂ = 1.71
r ₁₃ = 36.600 (aspherical surface) d ₁₃ = 3.14 n _d7 = 1.58313 ν _d7 = 59.38
r ₁₄ = -21.350 d ₁₄ = (variable)
r ₁₅ = 16.805 d ₁₅ = 2.70 n _d8 = 1.49700 ν _d8 = 81.54
r ₁₆ = -153.231 d ₁₆ = (variable)
r ₁₇ = ∞ d ₁₇ = 1.30 n _d9 = 1.54771 ν _d9 = 62.84
r ₁₈ = ∞ d ₁₈ = 0.80
r ₁₉ = ∞ d ₁₉ = 0.50 n _d10 = 1.51633 ν _d10 = 64.14
r ₂₀ = ∞
Aspheric coefficient 4th surface K = -0.595
A ₄ = 8.57632 × 10 ^-6
A ₆ = 2.89918 × 10 ^-8
A ₈ = 1.20170 × 10 ^-9
A ₁₀ = -2.23755 × 10 ^-11
8th surface K = -2.293
A ₄ = 5.18474 × 10 ^-5
A ₆ = -3.33636 × 10 ^-7
A ₈ = -1.97514 × 10 ^-9
A ₁₀ = 0
Surface 13 K = -0.059
A ₄ = 9.11545 × 10 ^-8
A ₆ = 8.13085 × 10 ^-7
A ₈ = -1.60810 × 10 ^-10
A ₁₀ = 0
Zoom data (∞)
WE ST TE
f (mm) 5.900 12.897 28.525
F _NO 2.80 3.60 4.90
2ω (°) 77.1 39.4 17.8
d ₆ 34.95 9.91 2.60
d ₁₄ 3.84 11.20 36.06
d ₁₆ 5.12 6.76 0.52
φ _S / 2 3.27 3.32 4.37.

Example 5
r ₁ = 26.139 d ₁ = 1.20 n _d1 = 1.74320 ν _d1 = 49.34
r ₂ = 14.200 d ₂ = 3.30
r ₃ = 26.285 d ₃ = 1.30 n _d2 = 1.74320 ν _d2 = 49.34
r ₄ = 8.448 (aspherical surface) d ₄ = 3.66
r ₅ = 13.750 d ₅ = 3.39 n _d3 = 1.84666 ν _d3 = 23.78
r ₆ = 23.170 d ₆ = (variable)
r ₇ = ∞ (aperture) d ₇ = 0.80
r ₈ = 15.165 (aspherical surface) d ₈ = 1.72 n _d4 = 1.78800 ν _d4 = 47.37
r ₉ = 33.388 d ₉ = 0.10
r ₁₀ = 9.515 d ₁₀ = 2.96 n _d5 = 1.74320 ν _d5 = 49.34
r ₁₁ = 26.822 d ₁₁ = 1.58 n _d6 = 1.84666 ν _d6 = 23.78
r ₁₂ = 7.283 d ₁₂ = 1.63
r ₁₃ = 35.704 (aspherical surface) d ₁₃ = 3.10 n _d7 = 1.58313 ν _d7 = 59.38
r ₁₄ = -19.396 d ₁₄ = (variable)
r ₁₅ = 18.643 d ₁₅ = 2.70 n _d8 = 1.49700 ν _d8 = 81.54
r ₁₆ = -371.719 (aspherical surface) d ₁₆ = (variable)
r ₁₇ = ∞ d ₁₇ = 1.30 n _d9 = 1.54771 ν _d9 = 62.84
r ₁₈ = ∞ d ₁₈ = 0.80
r ₁₉ = ∞ d ₁₉ = 0.50 n _d10 = 1.51633 ν _d10 = 64.14
r ₂₀ = ∞
Aspheric coefficient 4th surface K = -0.606
A ₄ = 5.96675 × 10 ^-6
A ₆ = -5.12154 × 10 ^-10
A ₈ = 1.15133 × 10 ^-9
A ₁₀ = -2.21290 × 10 ^-11
8th surface K = -2.476
A ₄ = 4.45482 × 10 ^-5
A ₆ = -4.22739 × 10 ^-7
A ₈ = -1.96055 × 10 ^-9
A ₁₀ = 0
Surface 13 K = -0.199
A ₄ = 8.95360 × 10 ^-6
A ₆ = 7.49249 × 10 ^-7
A ₈ = 3.59024 × 10 ^-10
A ₁₀ = 0
16th surface K = 0.000
A ₄ = 1.54951 × 10 ^-5
A ₆ = -4.91310 × 10 ^-7
A ₈ = 1.39082 × 10 ^-11
A ₁₀ = 0
Zoom data (∞)
WE ST TE
f (mm) 5.845 12.902 28.549
F _NO 2.80 3.50 4.90
2ω (°) 77.8 39.1 17.9
d ₆ 33.92 10.03 0.76
d ₁₄ 3.21 12.00 34.73
d ₁₆ 5.73 6.16 2.60
φ _S / 2 3.26 3.49 4.16.

Example 6
r ₁ = 21714.389 d ₁ = 1.30 n _d1 = 1.80610 ν _d1 = 40.92
r ₂ = 8.162 (aspherical surface) d ₂ = 2.87
r ₃ = 14.791 d ₃ = 2.40 n _d2 = 1.84666 ν _d2 = 23.78
r ₄ = 50.672 d ₄ = (variable)
r ₅ = ∞ (aperture) d ₅ = 0.80
r ₆ = 13.330 (aspherical surface) d ₆ = 1.90 n _d3 = 1.69350 ν _d3 = 53.21
r ₇ = -272.159 (aspherical surface) d ₇ = 0.10
r ₈ = 7.488 d ₈ = 2.10 n _d4 = 1.61800 ν _d4 = 63.33
r ₉ = 17.487 d ₉ = 2.27 n _d5 = 1.84666 ν _d5 = 23.78
r ₁₀ = 5.383 d ₁₀ = 1.50
r ₁₁ = 12241145.775 d ₁₁ = 1.15 n _d6 = 1.61800 ν _d6 = 63.33
r ₁₂ = -25.461 d ₁₂ = (variable)
r ₁₃ = 33.000 d ₁₃ = 2.00 n _d7 = 1.61800 ν _d7 = 63.33
r ₁₄ = -33.000 d ₁₄ = (variable)
r ₁₅ = ∞ d ₁₅ = 0.96 n _d8 = 1.54771 ν _d8 = 62.84
r ₁₆ = ∞ d ₁₆ = 0.60
r ₁₇ = ∞ d ₁₇ = 0.50 n _d9 = 1.51633 ν _d9 = 64.14
r ₁₈ = ∞
Aspheric coefficient 2nd surface K = -0.744
A ₄ = 1.01099 × 10 ^-11
A ₆ = 2.55746 × 10 ^-7
A ₈ = -4.50803 × 10 ^-9
A ₁₀ = 0
6th surface K = 0.000
A ₄ = -1.07809 × 10 ^-5
A ₆ = -3.65463 × 10 ^-7
A ₈ = 0
A ₁₀ = 0
Surface 7 K = 0.000
A ₄ = 5.59162 × 10 ^-5
A ₆ = -1.63843 × 10 ^-7
A ₈ = 0
A ₁₀ = 0
Zoom data (∞)
WE ST TE
f (mm) 7.952 14.692 27.270
F _NO 2.80 3.90 4.90
2ω (°) 60.8 33.9 18.5
d ₄ 22.28 9.82 2.20
d ₁₂ 4.16 13.63 27.21
d ₁₄ 5.64 4.00 2.80
φ _S / 2 3.37 3.37 4.01.

Example 7
r ₁ = 110.048 d ₁ = 2.00 n _d1 = 1.80400 ν _d1 = 46.57
r ₂ = 8.847 (aspherical surface) d ₂ = 3.52
r ₃ = 15.019 d ₃ = 2.60 n _d2 = 1.80518 ν _d2 = 25.42
r ₄ = 34.932 d ₄ = (variable)
r ₅ = ∞ (aperture) d ₅ = 0.30
r ₆ = 17.789 (aspherical surface) d ₆ = 1.92 n _d3 = 1.69350 ν _d3 = 53.21
r ₇ = -62.142 d ₇ = 0.10
r ₈ = 7.284 d ₈ = 2.30 n _d4 = 1.61800 ν _d4 = 63.33
r ₉ = 15.673 d ₉ = 2.50 n _d5 = 1.84666 ν _d5 = 23.78
r ₁₀ = 5.221 d ₁₀ = 2.60
r ₁₁ = 29.011 5 d ₁₁ = 1.15 n _d6 = 1.51742 ν _d6 = 52.43
r ₁₂ = 482171.189 d ₁₂ = (variable)
r ₁₃ = 26.000 d ₁₃ = 2.47 n _d7 = 1.48749 ν _d7 = 70.23
r ₁₄ = -26.000 d ₁₄ = (variable)
r ₁₅ = ∞ d ₁₅ = 0.96 n _d8 = 1.54771 ν _d8 = 62.84
r ₁₆ = ∞ d ₁₆ = 0.60
r ₁₇ = ∞ d ₁₇ = 0.50 n _d9 = 1.51633 ν _d9 = 64.14
r ₁₈ = ∞
Aspheric coefficient 2nd surface K = -0.581
A ₄ = -9.74609 × 10 ^-11
A ₆ = 6.60366 × 10 ^-8
A ₈ = -1.64695 × 10 ^-9
A ₁₀ = 0
6th surface K = 0.000
A ₄ = -3.89622 × 10 ^-5
A ₆ = -2.55361 × 10 ^-7
A ₈ = 0
A ₁₀ = 0
Zoom data (∞)
WE ST TE
f (mm) 7.840 15.493 30.176
F _NO 2.80 3.85 4.90
2ω (°) 61.5 32.2 16.8
d ₄ 29.24 12.49 3.10
d ₁₂ 3.55 13.22 28.68
d ₁₄ 5.04 4.00 4.10
φ _S / 2 3.64 3.75 4.50.

  Aberration diagrams at the time of focusing on an object point at infinity in Examples 1 to 7 are shown in FIGS. In these aberration diagrams, (a) is a wide-angle end, (b) is an intermediate state, and (c) is spherical aberration, astigmatism, distortion, and lateral chromatic aberration at a telephoto end.

Next, the values of conditional expressions (1) to (7) and the values of D ₁₁ , D ₁₂ , D ₃₁ , D ₂₂ , and D ₂₁ related to conditional expression (8) in the above-described embodiments will be shown.

Conditional Example Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7
(1) -1.41 -1.48 -1.54 -1.54 -1.50 -1.44 -1.48
(2) 1.39 1.45 1.48 1.79 1.64 1.41 1.53
(3) -0.005 -0.004 -0.006 -0.006 -0.006 -0.005 -0.006
(4) 0.006 0.001 0.006 -0.005 0.010 0.000 0.007
(5) 1.67 1.65 1.71 1.45 1.42 1.12 1.15
(6) 3.15 3.14 2.99 2.35 2.76 1.83 1.76
(7) -1.95 -1.82 -1.78 -1.75 -1.74 -1.05 -1.29
D ₁₁ 27.7 27.3 29.0 31.7 31.7 19.1 22.6
D ₁₂ 17.9 18.1 18.4 20.1 19.9 14.2 16.5
D ₃₁ 14.6 14.3 14.7 13.5 13.7 12.9 13.3
D ₂₂ 13.0 13.1 12.8 13.5 13.5 12.1 12.1
D ₂₁ 10.5 10.5 10.4 10.8 10.5 10.2 10.9
.

  In Examples 1 to 7 above, focusing is performed by extending the third lens group G3 to the object side.

The aperture diameter φ _S / 2 in the numerical data is a radius value when the aperture diameter is circular.

  In each embodiment, for example, as shown in FIG. 15, the configuration of the diaphragm S is a hexagonal variable diaphragm S <b> 2 composed of a circular fixed aperture diaphragm S <b> 1 and six diaphragm blades arranged adjacent thereto. It is good also as composition which consists of. At that time, when the aperture shape at the wide-angle end is a regular hexagon as shown in FIG. 16A, if the diagonal length is set to the following values, the wide-angle end in Examples 1 to 7 above The area is approximately equal to the area.

Example No. wide angle end regular hexagon the diagonal length S _W telephoto end circle diameter S _T
1 7.92 40.7 8.50 56.7
2 7.59 37.4 8.30 54.1
3 7.59 37.4 8.40 55.4
4 7.19 33.6 8.74 60
5 7.16 33.3 8.32 54.5
6 7.41 35.7 8.02 50.5
7 8.00 41.6 9.00 63.6.

  Also in this case, at the telephoto end, as shown in FIG. 16C, the diaphragm blades are retracted, and only the circular fixed aperture stop S1 has the function of an aperture stop that determines the axial beam diameter. In this way, the regular hexagonal shape expands from the wide-angle end to the telephoto end side, and the regular hexagonal corner overlaps with the circular aperture stop in the middle, resulting in a shape close to a circle on the telephoto end side. 16A shows the wide-angle end open state, FIG. 16B shows the halfway open state, and FIG. 16C shows the telephoto end open state. The regular hexagonal opening in the figure is the opening of the hexagonal variable aperture S2. The circular portion indicates the opening of the fixed aperture stop S1 having a circular shape. And the shaded part in FIGS. 15A to 15C shows the part where both openings overlap.

  Thus, the variable diaphragm can be configured to move the six diaphragm blades arranged across the optical axis. The six diaphragm blades of the hexagonal variable diaphragm S2 are controlled by the power unit 14 (for example, the motor M and the gear G). In the state of being retracted to the maximum, the fixed diaphragm S1 having a circular opening is exposed. In this way, the opening area of the variable diaphragm can be changed.

  Further, the aperture position at the time of opening corresponding to the zoom state is stored in the storage means 11 such as a memory in advance, and the control means 12 performs zooming state information 13 (helicoid movement information for zoom movement not shown) and the like. The power unit 14 is controlled based on the information stored in the storage unit 11, and the open state of the variable aperture S2 is thereby controlled. By configuring in this way, an opening area suitable for the zoom state can be obtained.

  Further, a configuration may be adopted in which a fixed aperture member such as a turret in which a plurality of shape fixed apertures are arranged is inserted into and removed from the optical path of the zoom lens to control the maximum aperture area.

  Further, if the openings formed in the fixed aperture member such as the turret are all circular and have different areas, it is possible to form a beautiful blur at the time of photographing the minimum F number in all zoom states with a simple configuration. .

  In the case where control is performed by inserting and removing the opening, a stop having an opening area corresponding to the maximum area may be arranged on the optical axis in accordance with the zoom state.

  Further, when an aperture having a fixed aperture area is arranged in the optical path, a shutter may be separately provided in the optical path.

  The variable aperture can have various configurations. FIG. 17 shows an example in which the variable diaphragm is composed of five diaphragm blades. In addition, this variable aperture also serves as a shutter. In FIG. 17, the size of each diaphragm blade is illustrated to be short for the sake of explanation. However, in actuality, the edge portion forming the aperture of the diaphragm blade is configured to be longer than the drawing.

  Also, the aperture shape is not limited to the configuration formed by an even number of aperture blades. For example, when the aperture shape by the aperture is reduced with 5 aperture blades as in this example, an approximately pentagonal aperture shape is formed. It may be. Thus, in the present invention, the number of aperture blades may be an odd number (for example, 7).

  Further, as in the example of FIG. 17, the edge portion on the optical axis side of the diaphragm blade may be configured with a concave curve so that the opening shape is close to a circular shape. Thereby, the bokeh becomes clean.

  The aperture may also serve as a shutter during shooting. Thereby, the number of parts can be reduced.

  The specific description of FIG. 17 will be given below. In the figure, (a) shows a state in the shielding state, and (b) shows a diagram in the open state at the time of telephoto end photographing. The opaque diaphragm blades (shielding members) 15c, 15d, 15e, 15f, and 15g are rotatable about the fixing pins 22c, 22d, 22e, 22f, and 22g. When the connecting ring 23 is rotated by the power means 14 (for example, the motor M and the gear G), the protrusions 24c, 24d, 24e, 24f, and 24g fixed to the connecting ring 23 are shield members 15c, 15d, 15e, The base ends of 15f and 15g are pushed, whereby the shielding members 15c, 15d, 15e, 15f and 15g are retracted to the outside. In the state of being retracted to the maximum, a fixed diaphragm having a circular opening is exposed. In this way, the transmission / shielding operation of the shutter / variable aperture can be performed.

  Further, the aperture position at the time of opening corresponding to the zoom state is stored in the storage means 11 such as a memory in advance, and the control means 12 performs zooming state information 13 (helicoid movement information for zoom movement not shown) and the like. The power unit 14 is controlled based on the information stored in the storage unit 11, and the open state of the variable aperture S2 is thereby controlled. By configuring in this way, an opening area suitable for the zoom state can be obtained.

  The data stored in the storage means 11 may be configured to continuously determine the open area in all zoom states, or linearly controlled in three steps, near the wide-angle end, near the telephoto end, and near the intermediate state. Also, a three-stage open aperture may be used. Of course, control in two steps, five steps, etc. may be performed.

  Further, the variable diaphragm may have various conventionally known configurations. For example, as shown in FIG. 18A, the telephoto end is open, and in FIG. 18B, the wide-angle end is open, the two diaphragm blades 32a, 32b are moved in front of or behind the circular fixed opening 31. The configuration may be such that the opening shape is changed. At this time, as the edge shape of the diaphragm blades 32a and 32b, a concave shape on the optical axis side is preferable as shown in the figure. In this case, the shutter can also be used.

  18 will be further described. The two variable diaphragm blades 32a and 32b are provided with guide grooves (not shown) provided in the moving direction. The two variable aperture blades 32a and 32b are formed in an edge shape so as to have a square opening shape with the optical axis of the zoom lens as the center. Further, the two variable apertures 32a and 32b have sawtooth gears (not shown), which are connected to the motor M and the rotating gear G, and are configured to be moved and controlled by the operation of the motor M. Yes. A diaphragm substrate provided with a circular fixed opening 31 around the optical axis of the zoom lens is provided with a fixed pin (not shown), and the fixed pin is sandwiched between guide grooves of the variable diaphragm blades 32a and 32b. . Thereby, the shake at the time of movement of the variable aperture is reduced. Since the method for controlling the maximum area of the aperture of the diaphragm at the time of shooting is the same as in FIGS.

  Now, an imaging apparatus, particularly a digital camera, a video camera, and an information processing apparatus, which forms an object image with the zoom lens and imaging optical system of the present invention as described above, and receives the image with an image pickup device such as a CCD. It can be used for personal computers, telephones, especially mobile phones that are easy to carry. The embodiment is illustrated below.

  19 to 21 are conceptual diagrams of a configuration in which the zoom lens according to the present invention is incorporated in the photographing optical system 41 of the digital camera. 19 is a front perspective view showing the appearance of the digital camera 40, FIG. 20 is a rear perspective view thereof, and FIG. 21 is a cross-sectional view showing the configuration of the digital camera 40. In this example, the digital camera 40 includes a photographing optical system 41 having a photographing optical path 42, a finder optical system 43 having a finder optical path 44, a shutter 45, a flash 46, a liquid crystal display monitor 47, and the like. When the shutter 45 disposed in the position is pressed, photographing is performed through the photographing optical system 41, for example, the zoom lens of the first embodiment, in conjunction therewith. An object image formed by the photographing optical system 41 is formed on the imaging surface of the CCD 49 via a low-pass filter LF having an IR cut coat and a cover glass CG. The object image received by the CCD 49 is displayed as an electronic image on the liquid crystal display monitor 47 provided on the back of the camera via the processing means 51. Further, the processing means 51 is connected to a recording means 52 so that a photographed electronic image can be recorded. The recording means 52 may be provided separately from the processing means 51, or may be configured to perform recording / writing electronically using a floppy disk, memory card, MO, or the like. Further, it may be configured as a silver salt camera in which a silver salt film is arranged in place of the CCD 49.

  Further, a finder objective optical system 53 is disposed on the finder optical path 44. The object image formed by the finder objective optical system 53 is formed on the field frame 57 of the Porro prism 55 which is an image erecting member. Behind the Porro prism 55, an eyepiece optical system 59 for guiding the image formed into an erect image to the observer eyeball E is disposed. Note that cover members 50 are disposed on the incident side of the photographing optical system 41 and the finder objective optical system 53 and on the exit side of the eyepiece optical system 59, respectively.

  The digital camera 40 configured as described above can achieve high performance and downsizing since the photographing optical system 41 is high performance and small.

  In the example of FIG. 21, a parallel plane plate is disposed as the cover member 50, but a lens having power may be used.

  Next, a personal computer which is an example of an information processing apparatus in which the zoom lens of the present invention is incorporated as an objective optical system is shown in FIGS. 22 is a front perspective view with the cover of the personal computer 300 opened, FIG. 23 is a sectional view of the photographing optical system 303 of the personal computer 300, and FIG. 24 is a side view of the state of FIG. As shown in FIGS. 22 to 24, the personal computer 300 includes a keyboard 301 for inputting information from the outside by an author, information processing means and recording means not shown, and a monitor for displaying information to the operator. 302 and a photographing optical system 303 for photographing the operator himself and surrounding images. Here, the monitor 302 may be a transmissive liquid crystal display element that is illuminated from the back by a backlight (not shown), a reflective liquid crystal display element that reflects and displays light from the front, a CRT display, or the like. Further, in the drawing, the photographing optical system 303 is built in the upper right of the monitor 302. However, the imaging optical system 303 is not limited to the place, and may be anywhere around the monitor 302 or the keyboard 301.

  The photographic optical system 303 includes an objective lens 112 including a zoom lens (abbreviated in the drawing) according to the present invention and an image sensor chip 162 that receives an image on a photographic optical path 304. These are built in the personal computer 300.

  Here, an optical low-pass filter F is additionally attached on the image sensor chip 162 to be integrally formed as an image pickup unit 160, and can be fitted and attached to the rear end of the lens frame 113 of the objective lens 112 with one touch. Therefore, the center alignment of the objective lens 112 and the image sensor chip 162 and the adjustment of the surface interval are unnecessary, and the assembly is simple. A cover glass 114 for protecting the objective lens 112 is disposed at the tip of the lens frame 113. The zoom lens driving mechanism in the lens frame 113 is not shown.

  The object image received by the image pickup device chip 162 is input to the processing means of the personal computer 300 via the terminal 166 and displayed on the monitor 302 as an electronic image. FIG. A rendered image 305 is shown. The image 305 can also be displayed on the personal computer of the communication partner from a remote location via the processing means, the Internet, or the telephone.

  Next, FIG. 25 shows a telephone which is an example of an information processing apparatus in which the zoom lens of the present invention is incorporated as a photographing optical system, particularly a mobile telephone which is convenient to carry. 25A is a front view of the mobile phone 400, FIG. 25B is a side view, and FIG. 25C is a cross-sectional view of the photographing optical system 405. As shown in FIGS. 25A to 25C, the mobile phone 400 includes a microphone unit 401 that inputs an operator's voice as information, a speaker unit 402 that outputs the voice of the other party, and an operator who receives information. An input dial 403 for inputting information, a monitor 404 for displaying information such as a photographed image and a telephone number of the operator and the other party, a photographing optical system 405, an antenna 406 for transmitting and receiving communication radio waves, and an image And processing means (not shown) for processing information, communication information, input signals, and the like. Here, the monitor 404 is a liquid crystal display element. In the drawing, the arrangement positions of the respective components are not particularly limited to these. The photographing optical system 405 includes an objective lens 112 including a zoom lens (abbreviated in the drawing) according to the present invention disposed on a photographing optical path 407, and an image sensor chip 162 that receives an object image. These are built in the mobile phone 400.

  Here, an optical low-pass filter F is additionally attached on the image sensor chip 162 to be integrally formed as an image pickup unit 160, and can be fitted and attached to the rear end of the lens frame 113 of the objective lens 112 with one touch. Therefore, the center alignment of the objective lens 112 and the image sensor chip 162 and the adjustment of the surface interval are unnecessary, and the assembly is simple. A cover glass 114 for protecting the objective lens 112 is disposed at the tip of the lens frame 113. The zoom lens driving mechanism in the lens frame 113 is not shown.

  The object image received by the imaging element chip 162 is input to the processing means (not shown) via the terminal 166 and displayed as an electronic image on the monitor 404, the monitor of the communication partner, or both. . Further, when transmitting an image to a communication partner, the processing means includes a signal processing function for converting information of an object image received by the image sensor chip 162 into a signal that can be transmitted.

FIG. 2 is a lens cross-sectional view at the wide-angle end (a), the intermediate state (b), and the telephoto end (c) when focusing on an object point at infinity according to the first exemplary embodiment of the zoom lens of the present invention. FIG. 6 is a lens cross-sectional view similar to FIG. 1 of a zoom lens according to Embodiment 2. FIG. 6 is a lens cross-sectional view similar to FIG. 1 of a zoom lens according to Embodiment 3. FIG. 6 is a lens cross-sectional view similar to FIG. 1 illustrating a zoom lens according to a fourth exemplary embodiment. FIG. 6 is a lens cross-sectional view similar to FIG. 1 illustrating a zoom lens according to a fifth exemplary embodiment. FIG. 6 is a lens cross-sectional view similar to FIG. 1 illustrating a zoom lens according to Example 6; FIG. 10 is a lens cross-sectional view similar to FIG. 1 illustrating a zoom lens according to a seventh embodiment. FIG. 6 is an aberration diagram for Example 1 upon focusing on an object point at infinity. FIG. 6 is an aberration diagram for Example 2 upon focusing on an object point at infinity. FIG. 10 is an aberration diagram for Example 3 upon focusing on an object point at infinity. FIG. 10 is an aberration diagram for Example 4 upon focusing on an object point at infinity. FIG. 10 is an aberration diagram for Example 5 upon focusing on an object point at infinity. FIG. 10 is an aberration diagram for Example 6 upon focusing on an object point at infinity. FIG. 10 is an aberration diagram for Example 7 upon focusing on an object point at infinity. It is sectional drawing containing the optical axis which shows the example which comprised the variable aperture stop from the circular shaped fixed aperture stop and the hexagonal variable aperture. It is a figure which shows the wide-angle end open state (a), halfway open state (b), and telephoto end open state (c) of a variable stop in the structure of FIG. It is a figure which shows the time of the shielding state which shows the example which comprised the variable aperture_diaphragm | restriction blade with five sheets (a), and the open state (b). It is a figure which shows the telephoto end open state (a) and wide-angle end open state (b) of the example which comprised the variable aperture_diaphragm | restriction opening and two aperture blades. It is a front perspective view which shows the external appearance of the digital camera incorporating the zoom lens by this invention. FIG. 20 is a rear perspective view of the digital camera of FIG. 19. It is sectional drawing of the digital camera of FIG. It is the front perspective view which opened the cover of the personal computer incorporating the zoom lens by this invention as an objective optical system. It is sectional drawing of the imaging optical system of a personal computer. It is a side view of the state of FIG. FIG. 2 is a front view (a), a side view (b), and a sectional view (c) of the photographing optical system of a mobile phone in which the zoom lens according to the present invention is incorporated as an objective optical system.

Explanation of symbols

G1 ... 1st lens group G2 ... 2nd lens group G3 ... 3rd lens group S ... Aperture stop LF ... Low pass filter CG ... Cover glass I ... Image plane S1 ... Circular fixed aperture stop S2 ... Hexagonal variable stop M ... Motor G ... Gear E ... Observer eye F ... Optical low-pass filter 11 ... Storage means 12 ... Control means 13 ... Zooming state information 14 ... Power means 15c, 15d, 15e, 15f, 15g ... Aperture blade (shielding member)
22c, 22d, 22e, 22f, 22g... Fixing pin 23... Connection ring 24c, 24d, 24e, 24f, 24g... Projection 31. ... Photographing optical path 43 ... finder optical system 44 ... finder optical path 45 ... shutter 46 ... flash 47 ... liquid crystal display monitor 49 ... CCD
DESCRIPTION OF SYMBOLS 50 ... Cover member 51 ... Processing means 52 ... Recording means 53 ... Finder objective optical system 55 ... Porro prism 57 ... Field frame 59 ... Eyepiece optical system 112 ... Objective lens 113 ... Lens frame 114 ... Cover glass 160 ... Imaging unit 162 ... Image sensor chip 166 ... Terminal 300 ... Personal computer 301 ... Keyboard 302 ... Monitor 303 ... Shooting optical system 304 ... Shooting optical path 305 ... Image 400 ... Mobile phone 401 ... Microphone unit 402 ... Speaker unit 403 ... Input dial 404 ... Monitor 405 ... Shooting optics System 406 ... Antenna 407 ... Imaging optical path

Claims (20)

In order from the object side, a three-unit zoom lens including a first lens unit having a negative refractive power, an aperture stop having a variable aperture area, a second lens unit having a positive refractive power, and a third lens group having a positive refractive power. Thus, when zooming from the wide angle end to the telephoto end, zooming is performed by changing the distance between the lens groups, and the zooming ratio is 3.4 or more, and the aperture stop is used for zooming. It moves in the same direction as the movement direction of the second lens group, and the maximum area of the aperture when photographing the aperture stop is configured to be smaller at the wide-angle end than at the telephoto end. The following conditional expression (1) A zoom lens satisfying (2).
-2 <f ₁ / √ (f _T · f _W ) <− 1 (1)
1.2 <S _T / S _W < 3 (2)
Where f _{1 is} the focal length of the first lens group,
f _W : focal length of the entire zoom lens system at the wide-angle end,
f _T : the focal length of the entire zoom lens system at the telephoto end,
S _W : Maximum area of the aperture of the aperture stop when shooting at the wide-angle end,
S _T : Maximum area of the aperture of the aperture stop at the time of photographing at the telephoto end,
It is. The zoom lens according to claim 1, wherein the following conditional expression (2) ′ is satisfied.
1.2 <S _T / S _W <2 (2) ' The zoom lens according to claim 1, wherein the following conditional expression (2) '' is satisfied.
1.2 <S _T / S _W ≦ 1.79 (2) '' The zoom lens according to claim 1, wherein the following conditional expression (2) ′ ′ is satisfied.
1.3 <S _T / S _W <3 (2) "' The first lens group includes a negative lens and a positive lens including at least one aspherical surface, and the second lens group includes at least one aspherical surface, and is moved at a short distance by moving the third lens group. any one claim of the zoom lens of claims 1 4, characterized in that for focusing of the object point. As for the aperture shape of the aperture stop, the maximum aperture shape at the time of photographing at the telephoto end is substantially circular, and the maximum aperture shape at the time of photographing at the wide angle end is a shape formed by seven or less aperture blades. any one claim of the zoom lens of claims 1 to 5, characterized in that. 7. The zoom lens according to claim 6, wherein the aperture shape of the aperture stop is a shape formed by two aperture blades at the wide angle end. The zoom lens according to any one of claims 1 to 7 , wherein the following conditional expressions (3) and (4) are satisfied.
−0.01 <M _W / f _W <−0.002 (3)
−0.006 <M _T / f _W <0.015 (4)
However, M _W : Spherical aberration at the d-line at a position 0.7 times the aperture ratio of a circle around the optical axis having the same area as the maximum area of the aperture of the aperture stop at the time of photographing at the wide angle end amount,
M _T : spherical aberration at the d-line at a position 0.7 times the aperture ratio of a circle centered on the optical axis having the same area as the maximum area of the aperture of the aperture stop at the time of photographing at the telephoto end,
f _W : focal length of the entire zoom lens system at the wide-angle end,
It is. The first lens group includes, in order from the object side, two or less negative meniscus lenses having a convex surface directed toward the object side, and one positive meniscus lens having a convex surface directed toward the object side. Item 9. The zoom lens according to any one of Items 1 to 8 . The first lens group has a negative meniscus lens having a convex surface facing the object side, and all of the negative lenses have a multi-coat on the object side and a single-layer coat on the image side. any one claim of the zoom lens of claim 1, wherein 9. The second lens group includes four lenses in order from the object side: a positive lens having a convex surface facing the object side, a positive lens having a convex surface facing the object side, a negative lens, and a positive lens. Item 11. The zoom lens according to any one of Items 1 to 10 . The zoom lens according to claim 11 , wherein the negative lens of the second lens group is cemented with any adjacent positive lens. 13. The zoom lens according to claim 12 , wherein the negative lens of the second lens group is cemented with an adjacent positive lens on the object side, and the image surface side is a concave surface in contact with the space. The third lens group is any one of claims zoom lens according to claim 1 to 13, characterized in that it consists of two or less lenses. The performed focusing on a close object by moving the third lens group, any one of claims zoom lens according to claim 1 to 14, characterized by satisfying the following conditional expression.
1.0 <f ₂ / √ (f _T · f _W ) <2.0 (5)
1.6 <f ₃ / √ (f _T · f _W ) <3.6 (6)
Where f _{2 is} the focal length of the second lens group,
f ₃ : focal length of the third lens group,
It is. 16. The zoom lens according to claim 1, wherein a distance between the most image side surface of the first lens unit at the wide-angle end and the aperture stop satisfies the following conditional expression.
−3.0 <D _1S / f ₁ <−0.8 (7)
Where D _1S is the distance between the most image side surface of the first lens unit and the aperture stop at the wide-angle end,
It is. Any one claim of the zoom lens of claims 1 16, and an electronic image pickup apparatus characterized by comprising an electronic image sensor disposed on the image side. 18. The electronic imaging apparatus according to claim 17 , wherein a photographing field angle at a wide angle end is 70 ° or more. The following conditional expression (8) is satisfied: An electronic device comprising: the zoom lens according to any one of claims 1 to 16 ; and an electronic image pickup device disposed on an image side thereof. Imaging device.
_{D 11> D 12> D 31} > D 22> D 21 ··· (8)
Where D ₁₁ is the maximum effective diameter in the entire zoom range on the most object side surface of the first lens group,
D ₁₂ : the maximum effective diameter in the entire zoom range on the most image side surface of the first lens unit,
D ₃₁ : the maximum effective diameter in the entire variable magnification region on the most object side surface of the third lens group,
D ₂₂ : the maximum effective diameter in the entire zoom range on the most image side surface of the second lens group,
D ₂₁ : the maximum effective diameter in the entire zoom range on the most object side surface of the second lens group,
It is. Storage means having information corresponding to the maximum opening area corresponding to the zoom state, and control means for controlling the maximum opening area at the time of photographing the aperture stop from information from the storage means and information on the zoom state electronic imaging device according to any one of 19 claims 17, wherein.

Images