JP7013220B2 - Zoom lens and image pickup device with it - Google Patents

Description

The present invention relates to a zoom lens and an image pickup device having the same, and is suitable for, for example, a video camera, a digital still camera, a surveillance camera, a broadcasting camera, a smartphone, a tablet, a wearable device, and the like.

In recent years, as an imaging optical system used in an imaging device, there has been a demand for a zoom lens using a focusing method that has a short overall lens length, a small size, a high zoom ratio, and high-speed focusing. .. Further, it is required to have an anti-vibration function for correcting blurring (image blurring) of a photographed image due to camera shake or the like and preventing deterioration of optical performance. Conventionally, there is known a zoom lens that uses an inner focus method and performs image blur correction on a part of the lens groups constituting the zoom lens (Patent Document 1).

Patent Document 1 is composed of a first lens group to a fifth lens group having positive, negative, positive, positive, and negative refractive powers in order from the object side to the image side, and the distance between adjacent lens groups changes during zooming. The zoom lens is disclosed. In Patent Document 1, image blur correction is performed by a partial lens group having a negative refractive power on the object side of the fifth lens group or a partial lens group of a part of the fifth lens group. Focusing is performed with the 4th lens group.

In addition, there is a demand for a zoom lens that can reduce the thickness (thickness in the front-rear direction) when used in an image pickup device (camera). In order to reduce the thickness of the image pickup device, a so-called bending type zoom lens in which a reflecting member that bends the optical axis (optical path) of the photographing optical system by 90 °, for example, a prism member utilizing internal reflection is arranged in the optical path is known. (Patent Document 2).

In Patent Document 2, in a 5-group zoom lens composed of a first lens group to a fifth lens group having positive, negative, positive, positive, and negative refractive powers in order from the object side to the image side, the first lens group is included. A zoom lens in which a reflective member for bending an optical path is arranged is disclosed.

International Publication No. 2012/063711 Japanese Unexamined Patent Publication No. 2011-237832

Zoom lenses are required to obtain high optical performance over the entire zoom range and object distance at a high zoom ratio while reducing the size of the entire system, and to maintain high optical performance when correcting image blur. ..

For example, in an image pickup device mounted on a wearable device, it is important to reduce the volume of the optical unit constituting the zoom lens. Here, in order to reduce the size of the optical unit, it is important to configure a zoom lens that is optimal for reducing the size of each mechanical mechanism such as the vibration isolation function for image blur correction and the focus function for focusing. .. For example, it is important to select a zoom type (number of lens groups, refractive power of each lens group, etc.) and a lens group for image blur correction, and to appropriately set a lens configuration such as the refractive power.

In Patent Document 1, a partial lens group having a negative refractive power in a fifth lens group that is immobile during zooming is defined as an anti-vibration lens group, and a fourth lens group is configured as a focus lens group. Further, by immobilizing the third lens group during zooming, the number of moving lens groups during zooming is reduced.

Here, since the fourth lens group is the focus lens group, it is difficult to arrange the third lens group and the fourth lens group, which are immovable during zooming, in close proximity in order to secure a large movement interval for focusing at the telephoto end. , The total length of the lens tended to increase.

Here, if the positive refractive power of the fourth lens group is strengthened in order to shorten the total lens length, it becomes difficult to correct the spherical aberration. In addition, the number of constituent lenses in the fourth lens group increases due to achromaticity. For this reason, the weight of the fourth lens group has increased, the actuator for driving the focus has become large, and it has tended to be difficult to reduce the size of the optical unit.

The present invention is a zoom lens having a small size, a high zoom ratio, high optical performance for image blur correction, and easy miniaturization of both anti-vibration function and focus function. It is an object of the present invention to provide an image pickup apparatus having.

The zoom lens of the present invention has a positive refractive power first lens group, a negative refractive power second lens group, a positive refractive power third lens group, and a positive lens group arranged in order from the object side to the image side. In a zoom lens composed of a fourth lens group of refractive power and a rear group including one or more lens groups, the distance between adjacent lens groups changes during zooming or focusing.
The rear lens group is immovable during zooming and focusing, which is arranged in order from the object side, and moves in the direction including the component in the direction perpendicular to the optical axis during image blur correction. It is composed of a partial lens group on the image side of the positive refractive power that moves to the object side when focusing to a short distance, and from the lens surface apex on the image side of the third lens group at the telephoto end to the object side of the fourth lens group. When the distance to the lens surface apex is D3t and the focal length of the entire system at the telephoto end is ft,
0.1 <100 × (D3t / ft) <6.5
It is characterized by satisfying the conditional expression .
Further, the zoom lens of the present invention includes a first lens group having a positive refractive force, a second lens group having a negative refractive force, and a third lens group having a positive refractive force arranged in order from the object side to the image side. In a zoom lens consisting of a fourth lens group with a positive refractive force and a rear group including one or more lens groups, and the distance between adjacent lens groups changes during zooming or focusing, the rear groups are arranged in order from the object side. Partial lens group on the object side of the negative refractive force that is immobile during zooming and focusing and moves in the direction including the component in the direction perpendicular to the optical axis during image blur correction, to the object side when focusing from infinity to a short distance It is composed of a partial lens group on the image side of a moving positive refractive force, has an aperture aperture between the third lens group and the fourth lens group, and is an object of the fourth lens group from the aperture aperture at the telephoto end. When the distance to the apex of the lens surface on the side is D3tx and the focal distance of the entire system at the telephoto end is ft,
0.1 <100 × (D3tx / ft) <6.5
It is characterized by satisfying the conditional expression.

According to the present invention, there is a zoom lens in which the entire system is compact, has a high zoom ratio, can maintain high optical performance when correcting image blur, and is easy to miniaturize both the anti-vibration function and the focus function. can get.

Cross-sectional view of the lens at the wide-angle end when the optical path of the zoom lens of Example 1 is expanded. (A), (B), (C) Longitudinal aberration diagram at the wide-angle end, intermediate zoom position, and telephoto end when the zoom lens of Example 1 is in focus at infinity. (A), (B) Horizontal aberration diagram at the wide-angle end and the telephoto end when the image blur correction of 0.3 degrees at infinity of the zoom lens of Example 1 is performed. Cross-sectional view of the lens at the wide-angle end when the optical path of the zoom lens of Example 2 is expanded. (A), (B), (C) Longitudinal aberration diagram at the wide-angle end, intermediate zoom position, and telephoto end when the zoom lens of Example 2 is in focus at infinity. (A), (B) Horizontal aberration diagram at the wide-angle end and the telephoto end when the image blur correction of 0.3 degrees at infinity of the zoom lens of Example 2 is performed. Cross-sectional view of the lens at the wide-angle end when the optical path of the zoom lens of Example 3 is expanded. (A), (B), (C) Longitudinal aberration diagram at the wide-angle end, intermediate zoom position, and telephoto end when the zoom lens of Example 3 is in focus at infinity. (A), (B) Horizontal aberration diagram at the wide-angle end and the telephoto end when the image blur correction of 0.3 degrees at infinity of the zoom lens of Example 3 is performed. Cross-sectional view of the lens at the wide-angle end when the optical path of the zoom lens of Example 4 is expanded. (A), (B), (C) Longitudinal aberration diagram at the wide-angle end, intermediate zoom position, and telephoto end when the zoom lens of Example 4 is in focus at infinity. (A), (B) Horizontal aberration diagram at the wide-angle end and the telephoto end when the image blur correction of 0.3 degrees at infinity of the zoom lens of Example 4 is performed. Cross-sectional view of the zoom lens of Example 5 (A), (B), (C) Longitudinal aberration diagram at the wide-angle end, intermediate zoom position, and telephoto end when the zoom lens of Example 5 is in focus at infinity. (A), (B) Horizontal aberration diagram at the wide-angle end and the telephoto end when the image blur correction of 0.3 degrees at infinity of the zoom lens of Example 5 is performed. Cross-sectional view of the lens at the wide-angle end of the zoom lens of Example 1 Cross-sectional view of the lens at the wide-angle end of the zoom lens of Example 2 Schematic diagram of the main part of the image pickup apparatus having the zoom lens of Example 1.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The zoom lens of the present invention has a positive refractive power first lens group, a negative refractive power second lens group, a positive refractive power third lens group, and a positive lens group arranged in order from the object side to the image side. It is composed of a fourth lens group of optical power and a rear group including one or more lens groups. The distance between adjacent lens groups changes during zooming or focusing.

The rear group is a group of partial lenses on the object side (fifth lens) that are arranged in order from the object side and move in the direction including the component in the direction perpendicular to the optical axis during image blur correction, which is immovable during zooming and focusing. Group). Further, it is composed of a partial lens group (sixth lens group) on the image side of a positive refractive power that moves to the object side when focusing from infinity to a short distance.

FIG. 1 is a cross-sectional view of a lens at a wide-angle end (short focal length end) when the optical path of the zoom lens according to the first embodiment of the present invention is expanded. 2A, 2B, and 2C are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end (long focal length end) when the zoom lens of Example 1 is in focus at infinity, respectively. .. 3 (A) and 3 (B) are lateral aberration diagrams at the wide-angle end and the telephoto end when the image blur correction of 0.3 degrees at infinity is performed on the zoom lens of the first embodiment of the present invention. .. The first embodiment is a zoom lens having a zoom ratio of 4.73 and an F number of 2.88 to 6.70.

FIG. 4 is a cross-sectional view of the lens at the wide-angle end (short focal length end) when the optical path of the zoom lens according to the second embodiment of the present invention is expanded. 5 (A), (B), and (C) are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end (long focal length end) when the zoom lens of Example 2 is in focus at infinity, respectively. .. 6 (A) and 6 (B) are lateral aberration diagrams at the wide-angle end and the telephoto end when the image blur correction of 0.3 degrees at infinity is performed at the infinity of the zoom lens of the second embodiment of the present invention. .. The second embodiment is a zoom lens having a zoom ratio of 3.78 and an F number of 2.88 to 4.00.

FIG. 7 is a cross-sectional view of the lens at the wide-angle end (short focal length end) when the optical path of the zoom lens according to the third embodiment of the present invention is expanded. 8 (A), (B), and (C) are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end (long focal length end) when the zoom lens of Example 3 is in focus at infinity, respectively. .. 9 (A) and 9 (B) are lateral aberration diagrams at the wide-angle end and the telephoto end when the image blur correction of 0.3 degrees at infinity is performed at the infinity of the zoom lens of the third embodiment of the present invention. .. Example 3 is a zoom lens having a zoom ratio of 4.73 and an F number of 2.88 to 6.47.

FIG. 10 is a cross-sectional view of the lens at the wide-angle end (short focal length end) when the optical path of the zoom lens according to the fourth embodiment of the present invention is expanded. 11 (A), (B), and (C) are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end (long focal length end) when the zoom lens of Example 4 is in focus at infinity, respectively. .. 12 (A) and 12 (B) are lateral aberration diagrams at the wide-angle end and the telephoto end when the image blur correction of 0.3 degrees at infinity is performed at the infinity of the zoom lens of the fourth embodiment of the present invention. .. Example 4 is a zoom lens having a zoom ratio of 3.77 and an F number of 3.60 to 6.59.

FIG. 13 is a cross-sectional view of the lens at the wide-angle end of the zoom lens according to the fifth embodiment of the present invention. 14 (A), (B), and (C) are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end (long focal length end) when the zoom lens of Example 5 is in focus at infinity, respectively. .. 15 (A) and 15 (B) are lateral aberration diagrams at the wide-angle end and the telephoto end when the image blur correction of 0.3 degrees at infinity is performed at the infinity of the zoom lens of the fifth embodiment of the present invention. .. Example 5 is a zoom lens having a zoom ratio of 4.73 and an F number of 2.88 to 5.59.

FIG. 16 is a cross-sectional view of the lens when the optical path is bent by the reflecting member at the wide-angle end of the zoom lens according to the first embodiment of the present invention. FIG. 17 is a cross-sectional view of the lens when the optical path is bent by the reflecting member at the wide-angle end of the zoom lens according to the second embodiment of the present invention. FIG. 18 is a schematic view of a main part of the image pickup apparatus of the present invention.

The zoom lens of each embodiment is an image pickup optical system used in an image pickup device such as a video camera or a digital camera. In the cross-sectional view of the lens, the left side is the subject side (object side) (front) and the right side is the image side (rear). In the lens cross-sectional view, L0 is a zoom lens. i indicates the order of the lens group from the object side, and Li is the i-th lens group.

LR is a posterior group having one or more lens groups. LRa is an object-side partial lens group (partial lens group) (fifth lens group) that constitutes a part of the rear group LR. LRb is an image-side partial lens group (partial lens group) (sixth lens group) that constitutes a part of the rear group LR.

SP is an aperture stop that limits the F-number luminous flux. PR1 is a first reflecting member having a reflecting surface that bends an optical path (optical axis), and is made of a prism. PR2 is a second reflecting member having a reflecting surface that bends an optical path, and is made of a prism. The first reflective member PR1 and the second reflective member PR2 bend the optical path by 90 degrees or about 90 degrees (within 90 ° ± 10 °), respectively. G is an optical block corresponding to an optical filter, a face plate, a crystal low-pass filter, an infrared cut filter, or the like.

The IP is an image plane, and when used as an image pickup optical system for a video camera or a digital still camera, it is a solid-state image pickup element (photoelectric conversion element) such as a CCD sensor or CMOS sensor that receives an image formed by the image pickup optical system. Corresponds to the imaging surface. The arrow shows the movement trajectory of each lens group in zooming from the wide-angle end to the telephoto end. In the cross-sectional view of the lens, y is the short side direction of the image pickup device, x is the long side direction of the image pickup device, and z is the optical axis direction.

In the aberration diagram, in the spherical aberration diagram, the solid line d is the d line (wavelength 587.6 nm), and the broken line g is the g line (wavelength 435.8 nm). In the astigmatism diagram, the dotted line ΔM is the d-line meridional image plane, and the solid line ΔS is the d-line sagittal image plane. The g of the chromatic aberration of magnification is the g line. ω is a half angle of view (half the value of the imaged angle of view) (degrees), and Fno is an F number. In each of the following embodiments, the wide-angle end and the telephoto end refer to the zoom positions when the variable magnification lens group is located at both ends of the movable range on the optical axis due to the mechanism.

The zoom lens of the present invention has a positive refractive power first lens group L1, a negative refractive power second lens group L2, and a positive refractive power third lens group L3 arranged in order from the object side to the image side. , A fourth lens group L4 with positive power, a rear group LR containing one or more lens groups. Here, the rear group LR is a partial lens group having a negative refractive power (partial lens group on the object side) LRa and a partial lens group having a positive refractive power (partial lens group on the image side) LRb in order from the object side to the image side. It is composed.

The partial lens group LRa is immovable during zooming. That is, it is fixed to the image plane. Further, the partial lens group LRb has a focus function of moving to the object side on the optical axis when focusing from infinity to a short distance. Further, during image blur correction, the partial lens group LRa moves in a direction including a component in the direction perpendicular to the optical axis. That is, the partial lens group LRa has an anti-vibration function.

Here, in order from the object side, a configuration consisting of a first lens group L1 to a fourth lens group L having positive, negative, positive, and positive refractive powers and a rear group LR having two partial lens groups LRa and LRb is adopted. Therefore, while achieving a high zoom ratio, the entire system has been downsized. In particular, by forming the third lens group L3 and the fourth lens group L4 with a lens group having a positive refractive power, the effective diameter of the fourth lens group L4 can be reduced.

According to this configuration, in particular, in a bent arrangement in which the first reflecting member PR1 including a reflecting surface that bends the optical path (optical axis) by about 90 degrees is arranged in the first lens group L1, the thinning of the image pickup apparatus becomes easy. .. Further, the rear group LR is divided into two partial lens groups having a negative refractive power and a positive refractive power, and the partial lens group LRa having a negative refractive power has an anti-vibration function and is a partial lens group having a positive refractive power. The LRb is configured to have a focus function. As a result, anti-vibration sensitivity and focus sensitivity are set in a well-balanced manner.

Further, by adopting a configuration in which the partial lens group LRa is immovable during zooming, the entire system of the image pickup apparatus including the mechanical mechanism for vibration isolation is downsized. In addition, by adopting the rear focus method in the lightweight rear group LR, the optical performance at the time of focusing at a close distance is maintained well, and the focus mechanism is downsized.

Next, in each embodiment, it is preferable to satisfy one or more of the following conditional expressions. The distance from the lens surface apex on the image side of the partial lens group LRa at the telephoto end to the lens surface apex on the object side of the partial lens group LRb is D5t, and the focal length of the entire system at the wide-angle end is fw. And.

The distance from the apex of the lens surface on the image side of the third lens group L3 at the telephoto end to the apex of the lens surface on the object side of the fourth lens group L4 is D3t, and the focal length of the entire system at the telephoto end is ft. An aperture diaphragm SP is provided between the third lens group L3 and the fourth lens group L4, and the distance from the aperture diaphragm SP to the lens surface apex on the object side of the fourth lens group L4 at the telephoto end is defined as D3tx.

The lateral magnification of the partial lens group LRa at the telephoto end is β5at, and the lateral magnification of the partial lens group LRb at the time of focusing at infinity at the telephoto end is β5bt. The lateral magnification of the partial lens group LRb at the time of focusing at infinity at the telephoto end is β5bt. The focal length of the partial lens group LRa is f5a, and the focal length of the partial lens group LRb is f5b.

Let f2 be the focal length of the second lens group L2. The focal length of the fourth lens group L4 is f4. The focal length of the third lens group L3 is f3. Let f1 be the focal length of the first lens group L1. The first reflective member PR1 is made of a prism, and the refractive index of the material of the prism on the d line is Nd_PR. At this time, it is good to satisfy one or more of the following conditional expressions.

0.35 <D5t / fw <1.20 ... (1)
0.1 <100 × (D3t / ft) <6.5 ... (2)
0.1 <100 × (D3tx / ft) <6.5 ... (2x)
-1.3 <(1-β5at) x β5bt <-0.5 ... (3)
0.3 <(1-β5bt ² ) <1.2 ... (4)
0.2 << f5a | / f5b <1.3 ... (5)
0.1 << f2 | / ft <0.5 ... (6)
0.2 <f4 / ft <1.0 ... (7)
0.6 <f3 / f4 <3.0 ... (8)
0.3 <f1 / ft <1.2 ... (9)
1.8 <Nd_PR <2.5 ... (10)

Next, the technical meaning of each conditional expression will be described. Conditional expression (1) defines the lens group spacing at infinity at the telephoto end of the two partial lens groups arranged in the rear group LR. By satisfying the conditional expression (1), the length of the moving space of the partial lens group LRb for focusing is appropriately arranged, and the miniaturization of the optical unit is facilitated.

If the distance between the lens groups of the two partial lens groups arranged in the rear group LR becomes too small beyond the lower limit of the conditional expression (1), the partial lens group LRb becomes large, especially when focusing on a close object at the telephoto end. It interferes with the vibration-proof partial lens group LRa. On the other hand, if the distance between the lens groups of the two partial lens groups arranged in the rear group LR exceeds the upper limit and becomes too large, the total lens length becomes long, which is not good.

The conditional expression (2) is the third lens group L3 (the conditional expression (2x) is the aperture stop SS position when the aperture stop SP is arranged on the image side of the third lens group L3) and the telephoto of the fourth lens group L4. Defines the lens group spacing at the edges. By satisfying the conditional expression (2) or the conditional expression (2x), the arrangement of the third lens group L3 (or the aperture stop SS position) and the fourth lens group L4 at the telephoto end is optimized, and the total lens length is shortened. It's easy.

If the distance between the third lens group L3 (or aperture aperture SS) and the fourth lens group L4 becomes too small beyond the lower limit of the conditional expression (2) or the conditional expression (2x), the distance between the lens groups at the telephoto end is too small. A mechanical mechanism such as a holding lens barrel interferes. On the other hand, if the upper limit value is exceeded, the group spacing between the third lens group L3 (or the aperture stop SS) and the fourth lens group L4 becomes too large, and the total lens length becomes long, which is not good.

The conditional expression (3) defines the vibration isolation sensitivity of the partial lens group LRa of the rear group LR having the vibration isolation function. By satisfying the conditional expression (3), the sensitivity of the partial lens group LRa in vibration isolation is optimized. If the vibration isolation sensitivity becomes too high beyond the lower limit of the conditional expression (3), the refractive power of the partial lens group LRa becomes too strong, and it becomes difficult to correct the eccentric aberration at the time of vibration isolation. On the other hand, since the vibration isolation sensitivity is too low beyond the upper limit, the amount of movement of the object-side partial lens group LRa at the time of vibration isolation increases too much. At this time, the anti-vibration mechanism including the mechanical member becomes large, which is not good.

The conditional expression (4) defines the position sensitivity of the partial lens group LRb of the rear group LR having the focus function. By satisfying the conditional expression (4), the sensitivity of the partial lens group LRb in focus is optimized.

If the position sensitivity becomes too small beyond the lower limit of the conditional expression (4), the amount of movement of the partial lens group LRb at the time of focusing at a short distance increases too much. At this time, the focus mechanism including the mechanical member becomes large, which is not good. On the other hand, if the position sensitivity becomes too large beyond the upper limit, the refractive power of the partial lens group LRb becomes too strong, and the fluctuation of each aberration increases when focusing at a short distance. Correction becomes difficult.

Conditional expression (5) defines the ratio of the focal lengths of the partial lens group LRa and the partial lens group LRb arranged in the rear group LR. By satisfying the conditional equation (5), the ratio of the refractive powers of the partial lens group LRa and the partial lens group LRb is optimized, and the entire system of the image pickup apparatus including the mechanical mechanism is downsized.

If the focal length of the partial lens group LRb having the focus function becomes too long compared to the absolute value of the negative focal length of the partial lens group LRa having the anti-vibration function beyond the lower limit of the conditional expression (5), The negative refractive power of the partial lens group LRa becomes too strong. Then, it becomes difficult to correct the eccentric aberration generated at the time of vibration isolation.

Here, it is required that the partial lens group LRa, which is a lens group for vibration isolation, is achromatic for correcting eccentric magnification chromatic aberration while reducing the weight of the lens. In particular, when a partial lens group LRa is composed of a single lens, it is important to select a material having a high refractive index and low dispersion in order to achieve achromaticity while reducing the thickness of the lens. If the negative refractive power of the partial lens group LRa becomes too strong, it becomes difficult to select a material that can be achromatic while reducing the thickness of the lens.

Alternatively, the positive refractive power of the partial lens group LRb, which is a lens group for focusing, is too weak, and the amount of movement of the partial lens group LRb increases when focusing on a short distance, and the total length of the lens increases.

On the other hand, when the upper limit is exceeded, the positive focal length of the partial lens group LRb, which is the lens group for focusing, becomes larger than the absolute value of the negative focal length of the partial lens group LRa, which is the lens group for vibration isolation. It gets too long. At this time, the positive refractive power of the partial lens group LRb becomes too strong, and it becomes difficult to correct the fluctuation of each aberration at the time of focusing at a short distance. Alternatively, the refractive power of the partial lens group LRa is too weak, and the anti-vibration sensitivity is lowered, so that the movement including the component in the direction perpendicular to the optical axis at the time of anti-vibration is excessively increased. At this time, the anti-vibration mechanism including the mechanical member becomes large, which is not good.

The conditional expression (6) defines the focal length of the second lens group L2. By satisfying the conditional expression (6), a high zoom ratio is achieved while maintaining high optical performance. If the absolute value of the negative focal length of the second lens group L2 becomes too small beyond the lower limit of the conditional expression (6), the negative refractive power of the second lens group L2 becomes too strong, and the image in the entire zoom range is formed. It becomes difficult to correct the fluctuation of the curvature of field.

On the other hand, if the negative refractive power of the second lens group L2 becomes too weak beyond the upper limit, the amount of movement of the second lens group L2 for obtaining a desired zoom ratio such as 4 times or more increases, and the lens It is not good because the total length increases.

The conditional expression (7) defines the focal length of the fourth lens group L4. By satisfying the conditional expression (7), a high zoom ratio is achieved while maintaining high optical performance. If the focal length of the fourth lens group L4 becomes too short beyond the lower limit of the conditional equation (7), the positive refractive power of the fourth lens group L4 becomes too strong, resulting in spherical aberration and coma aberration over the entire zoom range. Correction becomes difficult.

On the other hand, if the positive refractive power of the fourth lens group L4 is too weak beyond the upper limit, the amount of movement of the fourth lens group L4 for obtaining a desired zoom ratio such as 4 times or more increases, and the lens It is not good because the total length increases.

The conditional expression (8) defines the ratio of the focal lengths of the third lens group L3 and the fourth lens group L4. By satisfying the conditional equation (8), the optical effective diameter of the 4th lens group L4 can be reduced and the overall lens length can be shortened to reduce the size of the zoom lens when aiming for a high zoom ratio and a large aperture ratio. It's easy.

If the focal length of the fourth lens group L4 becomes too long compared to the focal length of the third lens group L3 beyond the lower limit of the conditional equation (8), the positive of the fourth lens group which is the variable magnification lens group The refractive power of the lens is too weak. Then, the amount of movement of the fourth lens group L4 for securing a desired zoom ratio such as 4 times or more increases, and the total lens length increases.

On the other hand, if the upper limit is exceeded, the focal length of the fourth lens group L4 becomes too short as compared with the focal length of the third lens group L3. In this refractive power arrangement, as the refractive power of the third lens group L3 weakens, the light astringent action of the third lens group L3 becomes too weak. Then, it becomes difficult to reduce the effective diameter of the light beam of the fourth lens group L4, and in particular, the first lens group L1 is not good because the thickness direction of the optical unit increases in the optical path bending configuration in which the reflection member is arranged.

At the time of zooming, the first lens group L1 should be immovable. According to this configuration, the entire system can be a sealed lens barrel structure, and for example, it can be made to be waterproof and drip-proof, and to be strong against disturbance, impact, and the like.

The conditional expression (9) defines the focal length of the first lens group L1 when the first lens group L1 is immobile during zooming. By satisfying the conditional expression (9), it becomes easy to miniaturize the entire system while having high optical performance.

If the positive refractive power of the first lens group L1 becomes too strong beyond the lower limit of the conditional expression (9), it becomes difficult to correct the curvature of field and the fluctuation of the chromatic aberration of magnification during zooming. On the other hand, if the positive refractive power of the first lens group L1 is too weak beyond the upper limit, the effective diameter of the front lens increases, and it becomes difficult to reduce the size of the entire system.

In order to shorten the zoom lens in the front-rear direction, it is preferable to provide a first reflection member PR1 composed of a total reflection prism for bending the optical path in the first lens group L1. If the first reflective member PR1 is provided in the first lens group L1 and the optical path is bent by approximately 90 degrees, it becomes easy to reduce the thickness of the optical unit in the thickness direction when applied to an image pickup apparatus.

At this time, the conditional expression (10) defines the refractive index of the material of the first reflection member PR1 composed of the total reflection prism arranged in the first lens group L1 on the d line. By satisfying the conditional expression (10), the size of the first reflective member PR1 is reduced and the transmittance of the entire system is maintained satisfactorily. If the refractive index of the material becomes too small beyond the lower limit of the conditional expression (10), the air equivalent length of the first reflective member PR1 becomes long, and the distance between the prism incident surface and the aperture stop SP increases. As a result, the prism size becomes large and the thickness of the optical unit increases in order to capture a desired angle of view light flux at the wide-angle end.

Further, when the angle of view is widened, the incident angle of the off-axis luminous flux on the total reflection surface becomes too small, and the total reflection condition may not be satisfied. On the other hand, if the refractive index of the material exceeds the upper limit and becomes too high, the transmittance on the short wavelength side tends to be extremely low in many materials, and it is difficult to maintain a good color balance as an image pickup device. become.

More preferably, the numerical range of the conditional expressions (1), (2), (2x) to (10) is preferably the following range.

0.4 <D5t / fw <1.1 ... (1a)
0.5 <100 × (D3t / ft) <6.0 ... (2a)
0.5 <100 × (D3tx / ft) <6.0 ... (2xa)
-1.2 <(1-β5at) x β5bt <-0.6 ... (3a)
0.4 <(1-β5bt ² ) <1.1 ... (4a)
0.3 << f5a | / f5b <1.2 ... (5a)
0.13 << f2 | / ft <0.40 ... (6a)
0.3 <f4 / ft <0.9 ... (7a)
0.7 <f3 / f4 <2.8 ... (8a)
0.4 <f1 / ft <1.0 ... (9a)
1.90 <Nd_PR <2.35 ... (10a)

More preferably, the numerical range of the conditional expressions (1a), (2a), (2xa) to (10a) is preferably the following range.

0.5 <D5t / fw <1.0 ... (1b)
1.0 <100 × (D3t / ft) <5.5 ... (2b)
1.0 <100 x (D3tx / ft) <5.5 ... (2xb)
-1.1 <(1-β5at) x β5bt <-0.7 ... (3b)
0.45 <(1-β5bt ² ) <1.00 ... (4b)
0.4 << f5a | / f5b <1.1 ... (5b)
0.16 << f2 | / ft <0.30 ... (6b)
0.4 <f4 / ft <0.8 ... (7b)
0.8 <f3 / f4 <2.6 ... (8b)
0.5 <f1 / ft <0.9 ... (9b)
1.95 <Nd_PR <2.20 ... (10b)

The partial lens group LRb preferably has a positive lens on the image side most, and the outer shape of the positive lens is preferably non-circular.

Specifically, as shown in FIG. 16, in each embodiment, it is preferable that the positive lens included in the partial lens group LRb for focusing has a non-circular outer diameter. In general, the effective pixel imaging area (image plane size) of an electronic image pickup element is generally a rectangular shape with an aspect ratio of 4: 3, 16: 9, so the footprint (light ray effective region) of the image pickup flux on each lens surface is from the aperture. The farther the lens is, the more non-circular it becomes.

Therefore, in the positive lens of the partial lens group LRb arranged at a position away from the aperture stop SP, there is no problem even if the outer shape is cut in the region other than the light flux passing region. Here, by cutting the outer shape of the lens into a non-circular shape, it becomes easy to reduce the weight of the partial lens group LRb and to reduce the size of the mechanical mechanism related to the focus.

Next, the lens configuration of the zoom lens of each embodiment will be described.
[Example 1]
Hereinafter, the zoom lens according to the first embodiment of the present invention will be described. In the first embodiment, the first lens group L1 having a positive refractive power, the second lens group L2 having a negative refractive power, the third lens group L3 having a positive refractive power, and the positive ones are arranged in order from the object side to the image side. It is composed of a fourth lens group L4 and a rear group LR of refractive power.

Here, the rear group LR includes a negative refractive power partial lens group LRa (fifth lens group) and a positive refractive power partial lens group LRb (sixth lens group) arranged in order from the object side to the image side. It is composed of. Further, the partial lens group LRa is immovable during zooming and focusing.

Here, in the image blur correction, the partial lens group LRa moves in a direction including a component in the direction perpendicular to the optical axis. Further, the partial lens group LRb moves during focusing. As described above, the partial lens group LRa that is immovable during zooming and focusing is used as the anti-vibration lens group. Further, the partial lens group LRb is used as a focus lens group to reduce the size of the optical unit including the anti-vibration and focus mechanical configurations.

During zooming, the first lens group L1 and the rear group LR are immovable. Further, when zooming from the wide-angle end to the telephoto end, the second lens group L2 moves to the image side as a variable magnification lens group. Further, the third lens group L3 moves in a non-linear trajectory, suppresses an increase in the effective diameter of the front lens, and is responsible for image plane compensation due to scaling. Further, the fourth lens group L4 moves to the object side and shares the scaling of the entire system. This constitutes a zoom lens in which the entire system is compact and has a high zoom ratio.

Here, the first lens group L1 is a first reflection member composed of a (large) meniscus-shaped negative lens having a strong (large) curvature (inverse of the radius of curvature) of the lens surface on the image side and a total reflection prism in order from the object side to the image side. It is composed of PR1 and a biconvex aspherical lens. By arranging the first reflective member PR1 in the first lens group L1 and bending the optical path, the thickness of the optical unit is reduced in the thickness direction.

Further, the second lens group L2 is a bonded lens in which a bilateral concave aspherical lens, a negative lens having a meniscus shape with a convex surface on the object side, and a positive lens having a meniscus shape with a convex surface on the object side are joined in this order from the object side to the image side. It is composed. Further, the third lens group L3 is composed of a biconvex aspherical lens. Further, the fourth lens group L4 is composed of a biconvex aspherical lens, a biconvex positive lens, and a bonded lens in which a meniscus-shaped negative lens having a convex image side is joined in this order from the object side to the image side. There is. Further, the partial lens group LRa is composed of a bonded lens in which a negative lens having a concave shape and a positive lens having a meniscus shape having a convex surface on the object side are joined.

Further, the partial lens group LRb is composed of a biconvex aspherical lens. The weight of each lens group is reduced by configuring the anti-vibration lens group and the focus lens group with a bonded lens or a single lens, respectively.

By optimizing the refractive power arrangement of each lens group, the lens configuration within the lens group, and the movement conditions during zooming and focusing, a high zoom ratio is achieved while reducing the size of the entire system.

[Example 2]
Hereinafter, the zoom lens according to the second embodiment of the present invention will be described. The basic configuration such as the number of lenses of the zoom lens of the second embodiment and the equal sign of the refractive power of each lens group is the same as that of the first embodiment. In Example 2, as compared with Example 1, the refractive power arrangement of each lens group, the movement trajectory during zooming, the lens shape in each lens group are changed, the zoom ratio is changed, and the image side of the rear group LR is changed. The difference is that the second reflective member PR2 for bending the optical path, which is composed of a total internal reflection prism, is arranged.

Here, the first reflective member PR1 is arranged in the first lens group L1, the second reflective member PR2 is arranged on the image side of the rear group LR, and the optical path is bent twice. As a result, the image plane IP is arranged coaxially with the first optical axis (the optical axis before being bent by the first reflective member PR1 arranged in the first lens group L1). At this time, even if the package size of the image pickup element arranged at the position of the image plane IP is increased, if the thickness direction of the image pickup element is thin, there is an advantage that the thickness direction of the optical unit is not affected.

During zooming, the first lens group L1, the third lens group L3, and the partial lens group LRa are immovable. When zooming from the wide-angle end to the telephoto end, the second lens group L2 moves to the object side as a lens group for scaling. Further, the fourth lens group L4 moves to the object side and shares the scaling of the entire system. Further, the partial lens group LRb of the rear group LR moves to the image side, bears image plane compensation due to scaling, and secures a movement interval of the partial lens group LRb for focusing at the telephoto end.

Here, the lens configurations of the first lens group L1, the third lens group L3, the fourth lens group L4, the partial lens group LRa, and the partial lens group LRb are the same as those in the first embodiment. Further, the second lens group L2 is composed of a biconcave aspherical lens, a biconcave negative lens and a biconvex positive lens joined in this order from the object side to the image side.

[Example 3]
Hereinafter, the zoom lens according to the third embodiment of the present invention will be described. The basic configuration of the zoom lens of the third embodiment is the same as that of the first embodiment. The third embodiment is different from the first embodiment in that the refractive power arrangement of each lens group, each lens group, the lens shape, and the movement locus at the time of zooming are changed to increase the zoom ratio.

During zooming, the first lens group L1 and the partial lens group LRa are immovable. When zooming from the wide-angle end to the telephoto end, the second lens group L2 moves to the image side. The third lens group L3 moves toward the image side with a non-linear trajectory, suppresses an increase in the effective diameter of the front lens, and is responsible for image plane compensation due to scaling. The fourth lens group L4 moves toward the object. The partial lens group LRb moves to the image side. The lens configurations of the first lens group L1, the second lens group L2, the third lens group L3, and the partial lens group LRb are the same as those in the first embodiment.

Further, the fourth lens group L4 is composed of a biconvex aspherical lens, a biconvex positive lens and a biconcave negative lens joined in this order from the object side to the image side. Further, the partial lens group LRa is composed of a negative lens having a biconcave shape.

[Example 4]
Hereinafter, the zoom lens according to the fourth embodiment of the present invention will be described. The basic configuration of the zoom lens of the fourth embodiment is the same as that of the first embodiment. The fourth embodiment is different from the first embodiment in that the image plane size, the zoom ratio, the arrangement of the refractive power of each lens group, and the lens shape in each lens group are changed.

Here, when zooming from the wide-angle end to the telephoto end, an aperture stop SS that is immovable during zooming is arranged on the image side of the third lens group L3. By immobilizing the position of the aperture diaphragm SP during zooming, the optical unit is downsized while being equipped with an iris diaphragm mechanism. The lens configurations of the first lens group L1, the third lens group L3, and the partial lens group LRb are the same as those in the first embodiment.

Here, the second lens group L2 is composed of a biconcave aspherical lens, a biconcave negative lens, and a junction lens in which a biconvex positive lens is joined in this order from the object side to the image side. Further, the fourth lens group L4 is composed of a biconvex aspherical lens, a meniscus-shaped negative lens having a convex surface on the object side, and a bonded lens in which a biconvex positive lens is joined in this order from the object side to the image side. There is. Further, the partial lens group LRa is composed of a bonded lens in which a biconvex positive lens and a biconcave negative lens are joined.

[Example 5]
Hereinafter, the zoom lens according to the fifth embodiment of the present invention will be described. The basic configuration of the zoom lens of the fifth embodiment is the same as that of the first embodiment. Example 5 does not have the first reflective member PR1 as compared with Example 1. In addition, the refractive power arrangement of each lens group, the movement locus of each lens group due to zooming, and the lens shape in each lens group are changed. In particular, the difference is that the first lens group L1 and the partial lens group LRb are movable during zooming. During zooming, the third lens group L3 and the partial lens group LRa are immovable.

When zooming from the wide-angle end to the telephoto end, the first lens group L1 moves in a convex locus toward the image side and shares the scaling while suppressing the increase in the effective diameter of the front lens. Further, the second lens group L2 is moved to the image side as a lens group for scaling. Further, the fourth lens group L4 moves to the object side and shares the scaling of the entire system.

Further, the partial lens group LRb moves in a convex locus toward the image side, and is responsible for image plane compensation due to scaling. By making the first lens group L1 a movable zoom type, the total length of the lens at the wide-angle end is shortened, and the degree of freedom of aberration correction in the zoom intermediate region is secured. The lens configurations of the third lens group L3 and the partial lens group LRb are the same as those in the first embodiment.

Here, the first lens group L1 is composed of a meniscus-shaped negative lens having a convex surface on the object side and a positive lens having a biconvex shape in order from the object side to the image side. Further, the second lens group L2 is composed of a biconcave aspherical lens, a biconcave negative lens and a biconvex positive lens joined in this order from the object side to the image side. Further, the fourth lens group L4 is composed of a biconvex aspherical lens, a biconvex positive lens and a biconcave negative lens joined in this order from the object side to the image side. Further, the partial lens group LRa is composed of a negative lens having a meniscus shape with a convex surface on the object side.

In each embodiment, when correcting camera shake, it may be used in combination with a known method of displacing the image sensor. Further, it is preferable to apply various known methods to electronically correct the distortion aberration.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and modifications can be made within the scope of the gist thereof.

FIG. 16 shows a state in which the optical path is bent 90 degrees by the first reflecting member PR1 at the wide-angle end of the zoom lenses of Examples 1 and 4. The numbering assigned to each member is the same as in FIGS. 1 and 10.

FIG. 17 shows a state in which the optical path is bent 90 degrees by the first reflective member PR1 and the second reflective member PR2 at the wide-angle end of the zoom lenses of Examples 2 and 3, and the reference numerals attached to the respective members and the movement during zooming. Etc. are the same as those in FIGS. 4 and 7. The first reflecting member PR1 reflects the incident light flux by 90 degrees, and the second reflecting member PR2 reflects the incident light flux toward the object side.

In the image pickup apparatus having the zoom lens of the present invention, the effective range of the image pickup element is generally rectangular such as 4: 3 or 16: 9. Since the effective portion in the long side direction and the effective portion in the short side direction are different, the zoom lens of the present invention bends the optical path in the short side direction in which the effective portion becomes smaller to reduce the size of the first reflective member PR1 and the second reflective member PR2. ..

Next, an embodiment of a digital still camera using the zoom lens shown in Examples 1 and 4 as a photographing optical system will be described with reference to FIG. In FIG. 18, 20 is a camera body, and 21 is an imaging optical system composed of any of the zoom lenses described in Examples 1 to 4.

PR is a reflective member for bending an optical path. Reference numeral 22 denotes a solid-state image pickup element (photoelectric conversion element) such as a CCD sensor or a CMOS sensor, which is built in the camera body and receives a subject image formed by the image pickup optical system 21. Reference numeral 23 is a memory for recording information corresponding to the subject image photoelectrically converted by the solid-state image sensor 22. Reference numeral 24 denotes a finder composed of a liquid crystal display panel or the like for observing a subject image formed on the solid-state image sensor 22. As described above, by applying the zoom lens of the present invention to an image pickup device such as a digital still camera, a compact image pickup device having high optical performance is realized.

Next, numerical data 1 to 5 corresponding to Examples 1 to 5 of the present invention are shown. In each numerical data, i indicates the order of the optical planes from the object side. ri is the radius of curvature of the i-th optical plane (i-plane), di is the distance between the i-th plane and the i + 1 plane, and ndi and νdi are the refraction of the material of the i-th optical member with respect to the d line, respectively. Shows the rate and Abbe number.

Further, when k is the eccentricity factor, A4, A6, and A8 are the aspherical coefficient, and the displacement in the optical axis direction at the position of the height h from the optical axis is x with respect to the surface apex, the aspherical shape is
x = (h ² / R) / [1 + [1- (1 + k) (h / R) ² ] ^1/2 ] + A4h ⁴ + A6h ⁶ + A8h ⁸
It is displayed in. However, R is the radius of curvature of the paraxial axis. Further, for example, the display of "eZ" means "10 ^-Z ".

In the numerical data 1, the surface numbers 3 and 4 correspond to the first reflective member PR1. In the numerical data 2, the surface numbers 3 and 4 correspond to the first reflective member PR1, and the surface numbers 24 and 25 correspond to the second reflective member PR2. In the numerical data 3, the surface numbers 3 and 4 correspond to the first reflective member PR1, and the surface numbers 23 and 24 correspond to the second reflective member PR2. In the numerical data 4, the surface numbers 3 and 4 correspond to the first reflective member PR1.

The last four surfaces in each numerical data are the surfaces of optical blocks such as filters and faceplates. In each numerical data, the back focus (BF) represents the distance from the final lens plane to the paraxial image plane by the air conversion length. The total length of the lens is the distance from the lens surface on the object side to the final lens surface plus the back focus of the air equivalent length. Table 1 shows the correspondence between the above-mentioned conditional expressions in each numerical data.

(Numerical data 1)
LRa group movement amount at 0.3 degree vibration isolation Wide angle end 0.024mm
Telephoto end 0.113mm

Unit mm

Surface data Surface number rd nd νd Effective diameter
1 133.919 0.40 2.00100 29.1 6.97
2 7.062 0.90 6.26
3 ∞ 4.40 2.10420 17.0 6.20
4 ∞ 0.10 6.24
5 * 7.311 1.95 1.69680 55.5 6.26
6 * -10.528 (variable) 5.98
7 * -6.845 0.50 1.77250 49.5 3.60
8 * 5.093 0.31 3.17
9 43.735 0.30 1.88300 40.8 3.14
10 5.487 0.96 1.95906 17.5 3.05
11 22.735 (variable) 2.88
12 * 9.554 1.11 1.49700 81.5 4.46
13 -14.091 (variable) 4.54
14 * 14.382 1.60 1.55332 71.7 5.95
15 -10.580 0.30 6.09
16 10.326 1.85 1.49700 81.5 5.98
17 -14.081 0.30 1.89286 20.4 5.69
18 -315.045 (variable) 5.63
19 -19.798 0.30 1.92119 24.0 5.17
20 4.604 1.29 1.95906 17.5 5.18
21 12.000 (variable) 5.17
22 * 7.305 1.80 1.53110 55.9 6.79
23 -36.407 (variable) 6.74
24 ∞ 0.30 1.51633 64.1 10.00
25 ∞ 1.30 10.00
26 ∞ 0.50 1.51633 64.1 10.00
27 ∞ 0.53 10.00
Image plane ∞

Aspherical data surface 5
K = 0.00000e + 000 A 4 = -4.78087e-004 A 6 = 1.73987e-006 A 8 = -4.23290e-008

Side 6
K = 0.00000e + 000 A 4 = 1.98686e-004 A 6 = 4.85599e-006

Page 7
K = 0.00000e + 000 A 4 = 1.59798e-003

8th page
K = 0.00000e + 000 A 4 = -1.58612e-003 A 6 = 1.30864e-004 A 8 = -1.08661e-005

12th page
K = 0.00000e + 000 A 4 = -6.66340e-004 A 6 = 2.74256e-005 A 8 = -3.12498e-006

Page 14
K = 0.00000e + 000 A 4 = -2.28464e-004 A 6 = 5.82672e-007 A 8 = -5.72399e-008

22nd page
K = 0.00000e + 000 A 4 = -4.74076e-004 A 6 = -2.92189e-006 A 8 = -3.69545e-007

Various data Zoom ratio 4.73
Wide-angle medium telephoto focal length 4.01 6.93 18.95
F number 2.88 3.19 6.70
Half angle of view (degrees) 36.80 23.42 9.00
Image height 3.00 3.00 3.00
Lens total length 40.00 40.00 40.00
BF (in air) 4.01 4.01 4.01

d 6 0.30 2.90 5.49
d11 4.99 2.64 0.30
d13 7.02 5.03 0.30
d18 1.47 3.22 7.69
d21 3.56 3.56 3.56
d23 1.65 1.65 1.65

Entrance pupil position 4.67 6.65 8.99
Exit pupil position 516.94 -105.83 -43.87
Front principal point position 8.71 13.12 19.85
Rear principal point position -3.48 -6.40 -18.42

Lens group data group Start surface Focal length Lens configuration length Front principal point position Posterior principal point position
L1 1 10.63 7.75 6.07 4.38
L2 7 -3.52 2.07 0.26 -0.94
L3 12 11.64 1.11 0.30 -0.45
L4 14 8.76 4.05 0.50 -2.18
LRa 19 -8.28 1.59 0.53 -0.27
LRb 22 11.62 1.80 0.20 -0.99
G 24 ∞ 2.10 0.91 -0.91

Single lens data lens Start surface focal length
1 1 -7.46
PR 3 0.00
3 5 6.48
4 7 -3.71
5 9 -7.13
6 10 7.34
7 12 11.64
8 14 11.27
9 16 12.30
10 17 -16.52
11 19 -4.03
12 20 7.18
13 22 11.62

(Numerical data 2)
LRa group movement amount at 0.3 degree vibration isolation Wide angle end 0.026mm
Telephoto end 0.103mm

Unit mm

Surface data Surface number rd nd νd Effective diameter
1 56.547 0.40 2.00100 29.1 7.01
2 7.096 0.90 6.25
3 ∞ 4.40 2.10420 17.0 6.20
4 ∞ 0.10 6.10
5 * 6.938 1.91 1.69680 55.5 6.07
6 * -10.615 (variable) 5.74
7 * -7.126 0.50 1.77250 49.5 3.53
8 * 4.915 0.60 3.42
9 -14.890 0.30 1.88300 40.8 3.52
10 9.100 1.06 1.95906 17.5 3.74
11 -46.396 (variable) 4.03
12 * 8.337 1.25 1.49700 81.5 4.41
13 -10.838 (variable) 4.57
14 * 17.332 1.34 1.55332 71.7 4.90
15 -11.171 0.30 5.02
16 18.791 1.41 1.49700 81.5 5.00
17 -10.691 0.30 1.89286 20.4 4.90
18 -34.822 (variable) 4.90
19 -29.000 0.30 2.00069 25.5 4.80
20 6.941 0.88 1.95906 17.5 4.82
21 15.653 (variable) 4.85
22 * 12.138 1.64 1.53110 55.9 7.00
23 -13.399 (variable) 7.00
24 ∞ 5.00 1.83481 42.7 10.00
25 ∞ 0.65 10.00
26 ∞ 0.50 1.51633 64.1 10.00
27 ∞ 0.53 10.00
Image plane ∞

Aspherical data surface 5
K = 0.00000e + 000 A 4 = -5.17374e-004 A 6 = 6.02714e-007 A 8 = -2.34858e-008

Side 6
K = 0.00000e + 000 A 4 = 2.41029e-004 A 6 = 5.27969e-006

Page 7
K = 0.00000e + 000 A 4 = 1.49695e-003

8th page
K = 0.00000e + 000 A 4 = -1.42634e-003 A 6 = 2.42741e-006 A 8 = 8.69125e-006

12th page
K = 0.00000e + 000 A 4 = -8.34481e-004 A 6 = -2.55281e-006 A 8 = 1.09741e-006

Page 14
K = 0.00000e + 000 A 4 = -3.03256e-004 A 6 = 3.11063e-006 A 8 = 2.59915e-008

22nd page
K = 0.00000e + 000 A 4 = -4.37352e-004 A 6 = 2.07724e-006 A 8 = -7.39137e-007

Various data Zoom ratio 3.78

Focal length 4.01 6.85 15.15
F number 2.88 3.14 4.00
Half angle of view (degrees) 36.80 23.64 11.20
Image height 3.00 3.00 3.00
Lens total length 40.00 40.00 40.00
BF (in air) 6.15 5.60 5.23

d 6 0.30 2.46 4.62
d11 4.62 2.46 0.30
d13 6.43 4.20 0.81
d18 1.01 3.24 6.64
d21 1.47 2.02 2.39
d23 1.91 1.37 1.00

Entrance pupil position 4.83 6.69 8.95
Exit pupil position -54.39 -39.39 -31.95
Front principal point position 8.55 12.37 17.04
Rear principal point position -3.48 -6.32 -14.62

Lens group data group Start surface Focal length Lens configuration length Front principal point position Posterior principal point position
L1 1 9.57 7.70 5.58 3.43
L2 7 -3.32 2.45 0.18 -1.41
L3 12 9.69 1.25 0.37 -0.48
L4 14 10.50 3.35 0.57 -1.71
LRa 19 -9.69 1.18 0.36 -0.23
LRb 22 12.26 1.64 0.52 -0.57
G 24 ∞ 6.15 1.85 -1.85

Single lens data lens Start surface focal length
1 1 -8.14
PR 3 0.00
3 5 6.30
4 7 -3.70
5 9 -6.36
6 10 8.01
7 12 9.69
8 14 12.49
9 16 13.93
10 17 -17.38
11 19 -5.57
12 20 12.39
13 22 12.26
PR2 24 0.00

(Numerical data 3)
LRa group movement amount at 0.3 degree vibration isolation Wide angle end 0.024mm
Telephoto end 0.123mm

Unit mm

Surface data Surface number rd nd νd Effective diameter
1 158.516 0.40 2.00100 29.1 7.27
2 7.224 0.96 6.66
3 ∞ 4.80 2.10420 17.0 6.66
4 ∞ 0.10 6.79
5 * 7.956 2.15 1.69680 55.5 6.88
6 * -9.953 (variable) 6.64
7 * -7.219 0.50 1.77250 49.5 3.73
8 * 5.468 0.28 3.30
9 98.741 0.30 1.88300 40.8 3.28
10 6.310 1.20 1.94595 18.0 3.19
11 42.435 (variable) 2.99
12 * 9.594 1.07 1.49700 81.5 4.42
13 -15.210 (variable) 4.49
14 * 14.661 1.61 1.55332 71.7 6.21
15 -10.320 0.30 6.33
16 12.872 1.68 1.49700 81.5 6.20
17 -13.967 0.30 1.85478 24.8 5.97
18 75.329 (variable) 5.90
19 -27.445 0.50 1.83481 42.7 5.48
20 11.540 (variable) 5.50
21 * 9.634 1.79 1.53110 55.9 6.56
22 -17.019 (variable) 6.64
23 ∞ 5.00 1.71999 50.2 10.00
24 ∞ 0.65 10.00
25 ∞ 0.50 1.51633 64.1 10.00
26 ∞ 0.40 10.00
Image plane ∞

Aspherical data surface 5
K = 0.00000e + 000 A 4 = -3.63587e-004 A 6 = -4.09676e-007 A 8 = -3.41436e-008

Side 6
K = 0.00000e + 000 A 4 = 2.78576e-004 A 6 = 9.22617e-007

Page 7
K = 0.00000e + 000 A 4 = 1.51364e-003

8th page
K = 0.00000e + 000 A 4 = -1.277 78e-003 A 6 = 1.37263e-004 A 8 = -1.07320e-005

12th page
K = 0.00000e + 000 A 4 = -6.13650e-004 A 6 = 1.55714e-005 A 8 = -1.84658e-006

Page 14
K = 0.00000e + 000 A 4 = -2.81478e-004 A 6 = 4.18661e-006 A 8 = -2.32927e-007

21st page
K = 0.00000e + 000 A 4 = -4.06792e-004 A 6 = 1.33928e-006 A 8 = -2.19843e-007

Various data Zoom ratio 4.73

Focal length 4.01 7.15 18.95
F number 2.88 3.23 6.47
Half angle of view (degrees) 36.80 22.76 9.00
Image height 3.00 3.00 3.00
Lens total length 43.00 43.00 43.00
BF (in air) 6.87 6.26 5.29

d 6 0.30 3.02 5.75
d11 5.22 2.79 0.30
d13 7.78 5.13 0.30
d18 1.19 3.55 8.15
d20 1.42 2.03 3.01
d22 2.58 1.97 1.00

Entrance pupil position 4.85 6.88 9.31
Exit pupil position -80.93 -46.24 -41.13
Front principal point position 8.67 12.94 19.62
Rear principal point position -3.61 -6.75 -18.55

Lens group data group Start surface Focal length Lens configuration length Front principal point position Posterior principal point position
L1 1 10.48 8.42 6.37 4.69
L2 7 -3.85 2.28 0.22 -1.09
L3 12 12.01 1.07 0.28 -0.44
L4 14 10.40 3.89 0.20 -2.32
LRa 19 -9.68 0.50 0.19 -0.08
LRb 21 11.86 1.79 0.43 -0.76
G 23 ∞ 6.15 1.94 -1.94

Single lens data lens Start surface focal length
1 1 -7.57
PR 3 0.00
3 5 6.68
4 7 -3.96
5 9 -7.65
6 10 7.71
7 12 12.01
8 14 11.20
9 16 13.76
10 17 -13.76
11 19 -9.68
12 21 11.86
PR2 23 0.00

(Numerical data 4)
LRa group movement amount at 0.3 degree vibration isolation Wide-angle end 0.056 mm
Telephoto end 0.210mm

Unit mm

Surface data Surface number rd nd νd Effective diameter
1 67.501 1.00 1.91082 35.3 22.70
2 20.210 2.90 20.01
3 ∞ 12.00 2.00100 29.1 19.97
4 ∞ 0.15 18.98
5 * 18.566 5.00 1.55332 71.7 18.57
6 * -31.339 (variable) 17.92
7 * -14.930 1.00 1.77250 49.5 9.67
8 * 14.600 1.07 8.70
9 -28.172 0.80 1.71300 53.9 8.68
10 31.087 2.50 1.85896 22.7 8.64
11 -39.715 (variable) 8.55
12 * 26.972 1.85 1.49700 81.5 9.10
13 -32.851 (variable) 9.20
14 (Aperture) ∞ (Variable) 9.13
15 * 17.286 2.60 1.55332 71.7 9.44
16 -58.095 0.30 9.52
17 24.310 0.80 1.91650 31.6 9.50
18 11.136 2.50 1.49700 81.5 9.24
19 -45.401 (variable) 9.23
20 88.960 2.40 1.92286 18.9 8.77
21 -10.412 1.00 2.00069 25.5 8.69
22 12.755 (variable) 8.62
23 * 16.061 4.20 1.55332 71.7 16.13
24-160.518 (variable) 16.16
25 ∞ 0.50 1.51633 64.1 25.00
26 ∞ 2.50 25.00
27 ∞ 1.00 1.51633 64.1 25.00
28 ∞ 0.50 25.00
Image plane ∞

Aspherical data surface 5
K = 0.00000e + 000 A 4 = -1.72042e-005 A 6 = -2.72993e-008 A 8 = -5.60342e-011

Side 6
K = 0.00000e + 000 A 4 = 1.09170e-005

Page 7
K = 0.00000e + 000 A 4 = 1.14666e-004

8th page
K = 0.00000e + 000 A 4 = -7.01272e-005 A 6 = 9.64566e-007 A 8 = -1.26939e-008

12th page
K = 0.00000e + 000 A 4 = -4.00627e-005

Page 15
K = 0.00000e + 000 A 4 = -3.89752e-005 A 6 = 1.64125e-007 A 8 = -3.30332e-009

Page 23
K = 0.00000e + 000 A 4 = -1.91895e-005 A 6 = 4.09950e-007 A 8 = -1.53814e-009

Various data Zoom ratio 3.77
Wide-angle medium telephoto focal length 10.60 18.79 40.00
F number 3.60 5.10 6.59
Half angle of view (degrees) 37.04 23.06 11.31
Image height 8.00 8.00 8.00
Lens total length 90.00 90.00 90.00
BF (in air) 5.31 5.31 5.31

d 6 0.71 7.98 15.26
d11 15.27 6.91 0.30
d13 2.95 4.03 3.36
d14 9.91 6.37 1.04
d19 5.34 8.87 14.20
d22 7.95 7.95 7.95
d24 1.32 1.32 1.32

Entrance pupil position 15.54 22.99 33.16
Exit pupil position -60.20 -53.10 -49.30
Front principal point position 24.29 35.19 41.03
Rear principal point position -10.10 -18.29 -39.50

Lens group data group Start surface Focal length Lens configuration length Front principal point position Posterior principal point position
L1 1 34.60 21.05 16.69 8.78
L2 7 -10.04 5.37 -0.16 -3.82
L3 12 30.11 1.85 0.56 -0.69
SS 14 ∞ 0.00 0.00 -0.00
L4 15 19.47 6.20 0.89 -3.28
LRa 20 -13.45 3.40 1.98 0.19
LRb 23 26.61 4.20 0.25 -2.48
G 25 ∞ 4.00 1.74 -1.74

Single lens data lens Start surface focal length
1 1 -31.99
PR 3 0.00
3 5 21.85
4 7 -9.42
5 9 -20.61
6 10 20.64
7 12 30.11
8 15 24.38
9 17 -23.09
10 18 18.26
11 20 10.22
12 21 -5.61
13 23 26.61

(Numerical data 5)
LRa group movement amount at 0.3 degree vibration isolation Wide angle end 0.027mm
Telephoto end 0.133mm


Unit mm

Surface data Surface number rd nd νd Effective diameter
1 23.296 0.40 1.89286 20.4 10.00
2 15.711 0.10 9.33
3 16.832 1.19 1.77250 49.6 9.25
4-1065.358 (variable) 8.70
5 * -17.462 0.50 1.77250 49.5 6.62
6 * 7.722 1.50 5.34
7 -5.178 0.30 1.69680 55.5 4.92
8 12.081 1.07 2.00100 29.1 4.56
9 -19.366 (variable) 4.48
10 * 29.826 0.80 1.49700 81.5 3.03
11 -15.961 (variable) 3.12
12 * 10.657 1.95 1.61881 63.9 5.14
13 -8.844 0.22 5.37
14 11.762 1.39 1.49700 81.5 5.28
15 -10.995 0.30 1.72825 28.5 5.12
16 22.112 (variable) 5.03
17 21.811 0.50 1.88300 40.8 5.00
18 5.687 (variable) 4.88
19 * 5.606 2.30 1.59201 67.0 7.38
20 -57.700 (variable) 7.26
21 ∞ 0.30 1.51633 64.1 10.00
22 ∞ 1.30 10.00
23 ∞ 0.50 1.51633 64.1 10.00
24 ∞ 0.53 10.00
Image plane ∞

Aspherical data surface 5
K = 0.00000e + 000 A 4 = 1.57624e-003

Side 6
K = 0.00000e + 000 A 4 = 8.56075e-004 A 6 = 3.18894e-005 A 8 = 4.38363e-006

Page 10
K = 0.00000e + 000 A 4 = -1.01635e-003 A 6 = 1.02915e-006 A 8 = 1.25167e-007

12th page
K = 0.00000e + 000 A 4 = -3.64509e-004 A 6 = -4.47337e-006 A 8 = 1.52685e-007

Page 19
K = 0.00000e + 000 A 4 = -5.99924e-004 A 6 = -1.24393e-006 A 8 = -5.38239e-007

Various data Zoom ratio 4.73
Wide-angle medium telephoto focal length 4.01 8.19 18.95
F number 2.88 3.89 5.59
Half angle of view (degrees) 36.80 20.11 9.00
Image height 3.00 3.00 3.00
Lens total length 33.86 34.07 40.00
BF (in air) 4.91 3.72 4.33

d 4 0.72 4.37 11.87
d 9 5.34 1.91 0.34
d11 6.99 3.65 0.30
d16 1.00 4.35 7.69
d18 2.10 3.28 2.67
d20 2.55 1.36 1.97

Entrance pupil position 5.87 10.21 25.52
Exit pupil position 50.03 271.63 -69.07
Front principal point position 10.21 18.66 39.31
Rear principal point position -3.48 -7.66 -18.42

Lens group data group Start surface Focal length Lens configuration length Front principal point position Posterior principal point position
L1 1 35.38 1.69 0.11 -0.88
L2 5 -4.89 3.37 0.40 -2.13
L3 10 21.04 0.80 0.35 -0.19
L4 12 8.23 3.86 0.16 -2.24
LRa 17 -8.84 0.50 0.36 0.10
LRb 19 8.75 2.30 0.13 -1.33
G 21 ∞ 2.10 0.91 -0.91

Single lens data lens Start surface focal length
1 1 -55.42
2 3 21.46
3 5 -6.87
4 7 -5.17
5 8 7.56
6 10 21.04
7 12 8.12
8 14 11.67
9 15 -10.05
10 17 -8.84
11 19 8.75

L1 1st lens group L2 2nd lens group L3 3rd lens group L4 4th lens group LR rear group LR object side partial lens group LRb image side partial lens group PR1 1st reflection member PR2 2nd reflection member

Claims (16)

The first lens group of positive refractive power, the second lens group of negative refractive power, the third lens group of positive refractive power, and the fourth lens group of positive refractive power arranged in order from the object side to the image side. In a zoom lens that consists of a rear group containing one or more lens groups and whose spacing between adjacent lens groups changes during zooming or focusing.
The rear group is an object-side partial lens group with a negative refractive power that is immovable during zooming and focusing and moves in a direction including a component in the direction perpendicular to the optical axis during image blur correction, which is arranged in order from the object side, from infinity. It is composed of a group of partial lenses on the image side of the positive refractive power that move to the object side when focusing to a short distance .
When the distance from the apex of the lens surface on the image side of the third lens group to the apex of the lens surface on the object side of the fourth lens group at the telephoto end is D3t, and the focal length of the entire system at the telephoto end is ft.
0.1 <100 × (D3t / ft) <6.5
A zoom lens characterized by satisfying the conditional expression . The distance from the image-side lens surface apex of the object-side partial lens group to the object-side lens surface apex of the image-side partial lens group at in-focus at the telephoto end is D5t, and the entire system at the wide-angle end. When the focal length is fw,
0.35 <D5t / fw <1.20
The zoom lens according to claim 1, wherein the zoom lens satisfies the conditional expression. When the lateral magnification of the object-side partial lens group at the telephoto end is β5at and the lateral magnification of the image-side partial lens group at the telephoto end is β5bt.
-1.3 <(1-β5at) x β5bt <-0.5
The zoom lens according to claim 1 or 2 , wherein the zoom lens satisfies the conditional expression. When the lateral magnification of the image-side partial lens group at the time of focusing at infinity at the telephoto end is β5bt,
0.3 <(1-β5bt ² ) <1.2
The zoom lens according to any one of claims 1 to 3 , wherein the zoom lens satisfies the conditional expression. When the focal length of the object-side partial lens group is f5a and the focal length of the image-side partial lens group is f5b,
0.2 << f5a | / f5b <1.3
The zoom lens according to any one of claims 1 to 4 , wherein the zoom lens satisfies the conditional expression. When the focal length of the second lens group is f2,
0.1 << f2 | / ft <0.5
The zoom lens according to any one of claims 1 to 5 , wherein the zoom lens satisfies the conditional expression. When the focal length of the fourth lens group is f4,
0.2 <f4 / ft <1.0
The zoom lens according to any one of claims 1 to 6 , wherein the zoom lens satisfies the conditional expression. When the focal length of the third lens group is f3 and the focal length of the fourth lens group is f4,
0.6 <f3 / f4 <3.0
The zoom lens according to any one of claims 1 to 7 , wherein the zoom lens satisfies the conditional expression. The zoom lens according to any one of claims 1 to 8 , wherein the first lens group is immovable during zooming. When the focal length of the first lens group is f1 and the focal length of the entire system at the telephoto end is ft,
0.3 <f1 / ft <1.2
The zoom lens according to any one of claims 1 to 9 , wherein the zoom lens satisfies the conditional expression. The zoom lens according to any one of claims 1 to 10 , wherein the first lens group includes a first reflective member that bends an optical path. The first reflective member is made of a prism, and when the refractive index of the material of the prism in the d line is Nd_PR,
1.8 <Nd_PR <2.5
The zoom lens according to claim 11 , wherein the zoom lens satisfies the conditional expression. The zoom lens according to any one of claims 1 to 12 , wherein the image side partial lens group has a positive lens on the image side most, and the outer shape of the positive lens is a non-circular shape. The zoom lens according to any one of claims 1 to 13 , further comprising a second reflective member that bends an optical path on the image side of the rear group. The first lens group of positive refractive power, the second lens group of negative refractive power, the third lens group of positive refractive power, and the fourth lens group of positive refractive power arranged in order from the object side to the image side. In a zoom lens that consists of a rear group containing one or more lens groups and whose spacing between adjacent lens groups changes during zooming or focusing.
The rear lens group is immovable during zooming and focusing, which is arranged in order from the object side, and moves in the direction including the component in the direction perpendicular to the optical axis during image blur correction. It is composed of a group of partial lenses on the image side of the positive refractive power that move to the object side when focusing to a short distance.
An aperture diaphragm is provided between the third lens group and the fourth lens group, and the distance from the aperture diaphragm to the lens surface apex on the object side of the fourth lens group at the telephoto end is D3tx, and the entire system at the telephoto end. When the focal length of is ft,
0.1 <100 × (D3tx / ft) <6.5
A zoom lens characterized by satisfying the conditional expression. An image pickup apparatus comprising the zoom lens according to any one of claims 1 to 15 and an image pickup element that receives an image formed by the zoom lens.

Images