JP2017181577A - Zoom lens and imaging apparatus having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zoom lens capable of favorably correcting a variation of a focal position due to changes in a zoom position or temperature changes, while achieving a high-speed zooming operation and good optical performance, and an imaging apparatus having the zoom lens.SOLUTION: The zoom lens includes, successively from an object side, a focus lens group, a variable power lens group constituted by two or more lens groups which move on the optical axis upon zooming, an aperture stop, and a relay lens group which includes an extender lens group detachably attached in an optical path and which does not move for zooming, and further has a correction lens group which is disposed on an object side of the extender lens group and which moves in the optical axis direction so as to correct a variation of a focal position. A maximum moving amount of the correction lens group, a maximum moving amount to correct the variation of the focal position, a maximum change amount of an imaging position with respect to the moving amount of the correction lens group while the extender lens group is retracted, and a maximum moving amount of lens groups constituting the variable power lens group satisfy predetermined relations.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a zoom lens and an image pickup apparatus having the same, and is suitable for a broadcast television camera, a video camera, or the like in which a variation in focus position due to a manufacturing error or environmental change is favorably corrected.

In general, a TV camera lens, in order from the object side, includes a focus lens group for focusing, a variator for zooming, and a zooming lens group including a compensator for correcting image plane variation accompanying zooming, and imaging. It is comprised by the imaging lens group for.
Then, when focusing on the subject, manual focus for driving the focus lens group in the optical axis direction is performed by mechanical transmission of manual operation or electrical drive according to the manual operation.
This is because, in television shooting and movie shooting, not only focusing on the subject but also focusing on the intention of the photographer is often used as a video effect. is there.

Also, since a high-speed zooming operation is required in sports broadcasting or studio photography, a zoom cam mechanism in which the variable power lens group moves in the optical axis direction by the rotation of a cam cylinder is generally used.
In sports broadcasts and the like, a built-in extender is generally employed in order to obtain more powerful video. The built-in extender is a system that displaces the focal length range of the zoom lens toward the long focal point side by inserting and removing the extender lens group in a reserved space in the relay lens group or a space where some lenses are retracted. .

In the zoom lens driven by the manual focus and zoom cam mechanism as described above, there is a problem that the focus position fluctuates in the intermediate zoom range due to manufacturing variations such as the refractive index and interval of the variable power lens group and temperature changes.
Further, there is a problem that the focus position varies due to changes in spherical aberration when the diaphragm is opened and when it is stopped, changes in spherical aberration due to the position of the focus lens, switching of the extender lens group, changes in posture, and the like.

  In order to solve the above-described problems, it is necessary to suppress manufacturing variations and perform precise assembly adjustment. Further, in order to suppress a change in the focus position when the temperature changes, it is necessary to appropriately select a glass having a different refractive index change (dn / dt) with respect to the temperature change or a member having a different linear expansion coefficient. However, with the recent widespread use of UHD and 4K cameras, the resolution is higher than conventional HD cameras and the depth of focus has become shallower, making it difficult to keep the above-described variation in focus position within the range of depth of focus. ing.

  In order to cope with such a problem, Patent Document 1 discloses the following technique. At the time of assembling the lens, fluctuations in the focus position due to changes in zoom position, aperture value, and extender lens group switching state are obtained in advance. When the zoom position, aperture value, and extender lens group switching state change when the lens is used, the amount of focus position deviation is obtained from the lookup table and calculation formula based on the change, and the fluctuation amount is canceled out. In addition, a method for driving a master lens unit (imaging lens group) has been proposed.

JP-A-10-186209

  However, Patent Document 1 does not disclose any specific lens arrangement and configuration for realizing high-speed zooming operation and good optical performance while correcting the variation of the focus position.

  In the embodiment disclosed in Patent Document 1, a master lens unit for correcting the amount of focus position deviation is arranged on the image side with respect to the extender lens group. In general, the change in the focus position caused by the lens group on the object side of the extender lens group is magnified by the square of the magnification of the extender lens group, which causes a problem that the amount of movement of the correction lens group becomes large.

Accordingly, the present invention provides a zoom lens having a manual focus, a zoom cam mechanism and an extender lens group, while realizing high-speed zooming operation and good optical performance,
An object of the present invention is to provide a zoom lens capable of satisfactorily correcting a change in focus position due to a change in zoom position, a temperature change, and the like, and an image pickup apparatus having the same.

In order to achieve the above object, the zoom lens according to the present invention includes a focus lens group that moves in order from the object side to the image side, and two or more lens groups that move on the optical axis during zooming. Variation in focus position in a zoom lens including a variable magnification lens group, an aperture stop, and a relay lens group that includes an extender lens group that is detachably mounted in the optical path and does not move for zooming The correction lens group is arranged closer to the object side than the extender lens group, and the maximum movement amount of the correction lens group is Mc, and the focus position is changed. The maximum movement amount for correction is Mb, and the correction lens group is moved by the movement amount Mb when the extender lens group is retracted from the optical axis. ΔSk the maximum change amount of the imaging position when the when the maximum moving amount of the lens groups constituting the zoom lens set to Mm,
0.001 <Mc / Mm <0.3
0.3 <| ΔSk | / Mb <3.0
It is characterized by satisfying.

  According to the present invention, a zoom lens capable of satisfactorily correcting a zoom position change, a change of an extender lens group, a focus position change due to a temperature change, etc. while realizing a high-speed zooming operation and good optical performance, and a zoom lens therefor An imaging device having the same is obtained.

FIG. 3 is a cross-sectional view of the zoom lens according to Example 1 when focused at infinity and at infinity. FIG. 6A is an aberration diagram at the wide-angle end, (B) the focal length of 65.53 mm, and (C) the telephoto end when the zoom lens according to Example 1 is focused at infinity. (A) Wide-angle end, (B) Focal length 131.07 mm, (C) Telephoto end at the time of focusing on the object distance at infinity when the extender lens group displaced to the long focal length side of the zoom lens according to Example 1 is inserted It is an aberration diagram. 1 is a main part schematic diagram of an imaging apparatus according to Embodiment 1. FIG. FIG. 6 is a cross-sectional view of the zoom lens according to Example 2 at the wide-angle end and when focusing on infinity. FIG. 7A is an aberration diagram at the wide-angle end, (B) a focal length of 84.98 mm, and (C) a telephoto end when the zoom lens according to Example 2 is in focus at infinity. (A) Wide-angle end, (B) Focal length 169.96 mm, (C) Telephoto end at the time of focusing on the object distance at infinity when the extender lens group displaced to the long focal length side of the zoom lens according to Example 2 is inserted It is an aberration diagram. FIG. 6 is a schematic diagram of a main part of an imaging apparatus according to a second embodiment. FIG. 6 is a cross-sectional view of a zoom lens according to Example 3 at the wide-angle end and when focusing on infinity. FIG. 7A is an aberration diagram at the wide-angle end, (B) a focal length of 20.67 mm, and (C) a telephoto end when the zoom lens according to Example 3 is in focus at an object distance of 13 m. (A) Wide-angle end, (B) Focal length 41.35 mm, (C) Telephoto end at the time of focusing on the object distance at infinity when the extender lens group displaced to the long focal length side of the zoom lens according to Example 3 is inserted It is an aberration diagram. FIG. 6 is a schematic diagram of a main part of an imaging apparatus according to a third embodiment. It is the schematic of a zoom cam mechanism.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a lens cross-sectional view at the time of focusing on an object at infinity at the wide angle end according to Numerical Embodiment 1 as Embodiment 1 of the present invention. FIG. 2 is a longitudinal aberration diagram of the first numerical example at the time of focusing on an object at infinity at (A) the wide-angle end, (B) the focal length of 65.53 mm, and (C) the telephoto end. FIG. 3 shows (A) a wide-angle end, (B) a focal length of 131.07 mm, and (C) a telephoto end at the time of focusing on an object distance at infinity when an extender lens group that is displaced toward the long focal length side in Example 1 is inserted. It is an aberration diagram.

  In the longitudinal aberration diagram, spherical aberration indicates e-line (solid line) and g-line (dotted line). Astigmatism indicates the e-line meridional image plane (dotted line) and the sagittal image plane (solid line). The lateral chromatic aberration is represented by the g-line (dotted line). Fno represents an F number, and ω represents a shooting half angle of view. In the longitudinal aberration diagram, spherical aberration is 0.4 mm, astigmatism is 0.4 mm, distortion is 5%, and chromatic aberration of magnification is 0.05 mm. In the longitudinal aberration diagram when the extender lens group displaced to the long focal length side is inserted, the spherical aberration is 1.0 mm, the astigmatism is 1.0 mm, the distortion is 5%, and the chromatic aberration of magnification is 0.05 mm. Yes.

The zoom lens shown in Embodiment 1 will be specifically described with reference to FIG.
In FIG. 1, the first lens unit U1 is a lens unit having a positive refractive power that does not move for zooming. The second lens unit U2 is a variator having a negative refractive power for zooming, and zooming from the wide-angle end to the telephoto end by monotonically moving on the optical axis side to the image plane side. The third lens unit U3 is a compensator having a positive refractive power, and moves on the optical axis from the image side to the object side in order to correct image plane fluctuations accompanying zooming. SP is a stop, and the fourth lens unit U4 is a front relay lens unit. The fifth lens unit U5a is a unity lens unit, and one of the extender lens unit U5b and the extender lens unit U5b is disposed on the optical axis. The sixth lens group U6 is a rear relay lens group, and adjusts the flange back by moving in the optical axis direction. P is a color separation optical system, and I is an imaging surface. The first lens group U1 further includes a first sub lens group U11 having negative refractive power, a second sub lens group U12 having positive refractive power, and a third sub lens group U13 having positive refractive power, The second sub-lens group U12 and the third sub-lens group U13 are fed out from the image side to the object side at different ratios, thereby focusing on a short-distance object.

  In Example 1, the correction lens group is the same as the fourth lens group U4, which is the front relay lens group, and moves on the optical axis in order to correct the variation in the focus position.

  FIG. 3 shows the configuration of an imaging system that is Embodiment 1 of the present invention. In the figure, reference numeral 1 denotes a focus lens group. Reference numeral 2 denotes a zoom lens group, which includes a lens group (variator) 2a that moves on the optical axis and performs zooming, and a lens group (compensator) 2b that corrects an image plane that varies with zooming. Yes. Reference numeral 3 denotes an aperture stop. Reference numeral 4 denotes a front relay lens group. 5a is an equal-magnification lens group, and 5b is an extender lens group that shifts the focal length variable range of the entire system to the telephoto side, and either one of the lens groups is arranged on the optical axis. Reference numeral 6 denotes a rear relay lens. In the first exemplary embodiment, the correction lens group is the same as the front relay lens group 4 and moves on the optical axis in order to correct the variation in the focus position. As described above, in this embodiment, each element 1 to 6 constitutes a zoom lens. Reference numeral 7 denotes an image sensor that receives a subject image formed by a zoom lens, and 8 denotes a video signal processing circuit, which obtains a video signal based on a signal from the image sensor 7. Reference numeral 9 denotes a drive unit for the focus lens group 1, which drives the focus lens group 1 in the optical axis direction by a mechanism such as a helicoid or a cam. Reference numeral 10 denotes a drive unit for the variable power lens group 2, which drives the variable power lens group 2 (2a, 2b) in the optical axis direction by a cam mechanism as shown in FIG. Reference numeral 11 denotes a drive unit that adjusts the aperture diameter of the aperture stop 3. Reference numeral 12 denotes a driving unit for the correction lens group. Reference numeral 13 denotes switching means for the extender lens groups 5a and 5b. Reference numeral 14 denotes zoom position detecting means for detecting the zoom position of the variable magnification lens group 2. Reference numeral 15 denotes temperature detection means for detecting the temperature. Reference numeral 22 denotes correction lens group position detection means. Reference numeral 16 denotes a calculation unit, which performs calculations for controlling various types of driving of the entire zoom lens. Reference numeral 17 denotes a storage unit that stores (holds) a change amount of the focus position due to a change in zoom position, switching of the extender lens group, and a change in temperature.

  When the manufacturing error or temperature changes, the focus position changes as the curvature, refractive index, or interval of each lens changes. The change in the focus position has a characteristic that becomes larger from the wide-angle end toward the telephoto end. Since the change in the focus position on the telephoto side is mainly caused by the change in the first lens group U1 and the second lens group U2, the focus position can be corrected by performing focusing.

  On the wide-angle side, the change in the focus position due to focusing is very small mainly due to the change in the third lens group U3 to the sixth lens group U6. Therefore, the focus position change cannot be corrected by focusing. Therefore, the change in the focus position is corrected by the flange back adjustment by the sixth lens unit U6 in the relay unit. By adjusting the focus position at the telephoto end and wide-angle end by focusing and flange-back adjustment, the imaging surface is in focus at the wide-angle end and telephoto end, but the focus position changes at the intermediate zoom position. Remains.

  Further, when the magnification is changed by the extender lens group, the change in the focus position generated by the lens group closer to the object side than the extender lens group is enlarged by the square of the magnification of the extender lens group. Therefore, it is necessary to perform focusing and flange back adjustment again. Further, the fluctuation of the focus position at the intermediate zoom position remains enlarged by the square of the magnification of the extender lens group.

  On the other hand, in the first embodiment, changes in the zoom position, temperature changes, and changes in the focus position due to switching of the extender lens group during assembly adjustment are stored in the storage unit 17. The calculation unit 16 selects the amount of focus position variation stored in the storage unit 17 based on signals from the zoom position detection unit 14, the temperature detection unit 15, and the extender lens group switching detection unit 20, and drives the correction lens group. 12 is input. Then, the drive unit 12 of the correction lens group (front relay lens group 4) moves the correction lens group on the optical axis based on the signal from the calculation unit 16 to correct the variation in focus position.

The zoom lens according to the present invention includes a focus lens group that moves for manual focusing, and at least two or more lenses that are disposed on the image side of the focus lens group and move on the optical axis by a cam mechanism for zooming. The zoom lens unit includes a unit, a relay lens group including an aperture stop for adjusting the amount of light that does not move during zooming, and an extender lens group that is detachably mounted in the optical path. In order to correct at least one focus position change among a change in zoom position, a change in position of the focus lens group, a change in temperature, a change in aperture value, a change in posture, and a change in focus position due to switching of the extender lens group The correction lens group moves in the optical axis direction, and the correction lens group is disposed closer to the object side than the extender lens group. The maximum movement amount of the correction lens group is Mc, the maximum movement amount for correcting the focus position fluctuation is Mb, and the correction lens group is moved to the maximum movement amount in a state where the extender lens group is retracted from the optical axis. When the maximum change amount of the imaging position when moving by Mb is ΔSk and the maximum movement amount of the lens unit in the zoom lens unit is Mm, the following conditional expression is satisfied.
0.001 <Mc / Mm <0.3 (1)
0.3 <| ΔSk | / Mb <3.0 (2)
Conditional expression (1) defines the range of the ratio of the maximum movement amount of the correction lens group to the maximum movement amount of the lens unit in the variable magnification lens group, thereby enabling high-speed zoom operation while satisfactorily correcting the fluctuation of the focus position. Stipulates conditions for achieving high optical performance.

  In order to realize a high-speed zoom operation as described above, the variable power lens group is driven in the optical axis direction at high speed by the rotation of the cam barrel. If the driving of the correction lens group does not follow the driving of the variable power lens group at high speed, an image with a sense of incongruity that is in focus while being delayed at the time of shooting will be obtained. The correction lens group includes, for example, a stepping motor and a rack engaged with a feed screw that is an output shaft of the motor, and is driven in the optical axis direction. Therefore, if the movement amount of the correction lens group becomes too large, It takes time to reach the drive position.

  In addition, if the amount of movement of the correction lens group becomes too large, variations in spherical aberration, astigmatism, and chromatic aberration become large, and high optical performance cannot be achieved. On the other hand, if the movement amount of the correction lens becomes too small, it becomes impossible to correct the focus position deviation due to the zoom position, temperature change, etc. as described above.

  From the above, in order to achieve high-speed zoom operation and high optical performance while satisfactorily correcting the variation in focus position, the ratio of the maximum movement amount of the correction lens group to the maximum movement amount of the lens unit in the variable magnification lens group Must be set to an appropriate range.

  In addition, when an extender lens group is inserted to shift the focal length variable range of the entire system to the long focal length side, the variation in the focus position due to the change of the lens group closer to the object side than the extender lens group is the extender lens. Enlarged by the square of the group magnification. At this time, if the correction lens group is arranged on the object side of the extender lens group, the change in the focus position due to the correction lens group is also enlarged by the square of the magnification of the extender lens group. Therefore, the correction amount of the focus position can be increased and the movement amount can be reduced as compared with the case where it is arranged on the image side.

If the upper limit of conditional expression (1) is exceeded, the movement amount Mc of the correction lens group with respect to the maximum movement amount Mm of the lens unit in the variable magnification lens group becomes too large, and it is difficult to follow the driving speed of the variable magnification lens group. It becomes. In addition, the aberration fluctuation due to the movement of the correction lens group becomes too large, and it becomes difficult to maintain high optical performance.
If the lower limit of conditional expression (1) is exceeded, the movement amount Mc of the correction lens group with respect to the maximum movement amount Mm of the unit in the variable magnification lens group becomes too small, and fluctuations in focus position cannot be corrected sufficiently.

More preferably, conditional expression (1) is preferably set as follows.
0.001 <Mc / Mm <0.26 (1a)

  Conditional expression (2) defines the range of the ratio of the maximum displacement amount of the imaging position to the maximum movement amount for correcting the fluctuation of the focus position of the correction lens group, thereby favorably correcting the fluctuation of the focus position. It defines the conditions for achieving high-speed zoom operation and high optical performance.

If the upper limit of the conditional expression (2) is exceeded, the change amount ΔSk of the imaging position with respect to the movement amount Mb for correcting the variation of the focus position of the correction lens group becomes too large, and due to the minute change of the correction lens group, Variations in focus position will occur. Further, in order to suppress a minute change of the correction lens group, the stopping accuracy of the stepping motor becomes too high.
If the lower limit of conditional expression (2) is exceeded, the change amount ΔSk of the imaging position with respect to the movement amount Mb for correcting the variation in the focus position of the correction lens group becomes too small, and the movement amount of the correction lens group becomes large. Therefore, it becomes difficult to follow the driving speed of the variable power lens group. In addition, the aberration fluctuation due to the movement of the correction lens group becomes too large, and it becomes difficult to maintain high optical performance.

More preferably, conditional expression (2) is preferably set as follows.
0.45 <| ΔSk | / Mb <2.0 (2a)

Further, in the present invention, the maximum moving amount for correcting the change in the focus position due to the change in the zoom position of the variable power lens group, the change in the position of the focus lens group, and the change in the aperture value is Mex1, and the focal length of the entire system is the long focus. The maximum movement amount for correcting the change in the zoom position when the extender lens group to be displaced to the distance side is inserted into the optical path, the position change of the focus lens group, and the focus position due to the change in the aperture value is Mex2. It is preferable to satisfy the following condition: 0.8 <Mex1 / Mex2 <1.2 (3)

Conditional expression (3) defines the range of the ratio of the movement amounts of the correction lens group before and after the switching of the extender lens group. As a result, the movement of the correction lens group before and after switching of the extender lens group can be kept substantially the same, and high-speed zoom operation and high optical performance can be achieved while satisfactorily correcting fluctuations in the focus position. It becomes.
If the upper limit and lower limit of conditional expression (3) are exceeded, the amount of movement of the correction lens group becomes large, and the stationary accuracy of the stepping motor for driving the correction lens group becomes too high.

More preferably, conditional expression (3) is preferably set as follows.
0.9 <Mex1 / Mex2 <1.1 (3a)

Further, in the present invention, it is preferable that the following condition is satisfied, where Fno is the open F number of the zoom lens, δ is the allowable circle of confusion of the imaging apparatus, and D is the depth of focus.
D = Fno × δ
1.0 <Mb / D <300.0 (4)
Conditional expression (4) defines a range of movement of the correction group for correcting the focus position fluctuation, thereby achieving high-speed zoom operation and high optical performance while properly correcting the focus position fluctuation. The conditions are specified.

If the upper limit of conditional expression (4) is exceeded, the maximum movement amount Mb for correcting the variation in the focus position of the correction lens group with respect to the focal depth D becomes too large, and it is difficult to follow the driving speed of the variable power lens group. It becomes. In addition, the aberration fluctuation due to the movement of the correction lens group becomes too large, and it becomes difficult to maintain high optical performance.
When the lower limit of conditional expression (4) is exceeded, the maximum movement amount Mb for correcting the fluctuation of the focus position of the correction lens group with respect to the focal depth D becomes too small, and the effect of correcting the focus position deviation with respect to the movement of the correction lens group. Will disappear.

More preferably, conditional expression (4) is preferably set as follows.
1.0 <Mb / D <100.0 (4a)

Further, in the present invention, it is preferable that the correction lens group is disposed adjacent to the aperture stop.
By disposing the correction lens group adjacent to the aperture stop, the position of the off-axis principal ray passing through the correction lens group can be close to the optical axis, and the position of the peripheral image plane accompanying the movement of the correction lens group can be adjusted. Changes and coma aberration changes can be reduced.

Further, in the present invention, it is preferable that the correction lens group is disposed in the variable power lens group or on the image side of the variable power lens group.
When the correction lens group is arranged on the object side of the variable power lens group, the displacement of the image formation position relative to the movement of the correction lens group is proportional to the square of the image magnification due to the change in the image magnification of the variable power lens group. Increase. For this reason, the focus position fluctuates due to a minute change of the correction lens group on the telephoto side, or the driving amount becomes too large on the wide angle side, making it difficult to follow the driving speed of the variable power lens group. In addition, the aberration fluctuation due to the movement of the correction lens group becomes too large, and it becomes difficult to maintain high optical performance.

More preferably, the correction lens group is preferably disposed in the relay lens group.
When the correction lens group is arranged in the variable power lens group and the variable power lens group moves with acceleration, the torque required to drive the stepping motor becomes too large, and the driving speed of the variable power lens group can be followed. It becomes difficult.

Furthermore, in the present invention, it is desirable that the correction lens group is composed of 1 to 3 lenses.
When the number of correction lens groups is four or more, the mass of the correction lens group increases, and high-speed drive control using a stepping motor becomes difficult.

The zoom lens shown in Embodiment 1 will be specifically described with reference to FIG.
In FIG. 1, a first lens unit U1 is a lens unit having a positive refractive power that is fixed during zooming. The second lens unit U2 is a variator having a negative refractive power for zooming, and zooming from the wide-angle end to the telephoto end by monotonically moving on the optical axis side to the image plane side. The third lens unit U3 is a compensator having a positive refractive power, and moves on the optical axis from the image side to the object side in order to correct image plane fluctuations accompanying zooming. SP is an aperture stop, and the fourth lens unit U4 is a front relay lens unit. The fifth lens group U5 is an equal-magnification lens group, and U5ex is an extender lens group that displaces the focal length variable magnification range of the entire system to the long focal length side, and one of them is arranged on the optical axis. The sixth lens group U6 is a rear relay lens group. P is a color separation optical system, and I is an imaging surface. The first lens unit U1 further includes a first sub lens unit U11 having a negative refractive power, a second sub lens unit U12 having a positive refractive power, and a third sub lens group U13 having a positive refractive power. . The second sub-lens group U12 and the third sub-lens group U13 are fed out from the image side to the object side at different ratios, thereby focusing on a short-distance object.

  In Example 1, the correction lens group is the same as the fourth lens group U4, which is the front relay lens group, and moves on the optical axis in order to correct the variation in the focus position.

  The first lens unit U1 corresponds to the first surface to the tenth surface. The first sub lens unit U11 corresponds to the first surface to the fourth surface, and is composed of one negative lens and one positive lens. The second sub lens unit U12 corresponds to the fifth surface to the eighth surface and includes two positive lenses. The third sub lens unit U13 corresponds to the ninth surface to the tenth surface, and includes a single positive lens. The second lens unit U2 corresponds to the eleventh to seventeenth surfaces, and is composed of three negative lenses and one positive lens.

  The third lens unit U3 corresponds to the 18th to 26th surfaces, and is composed of one negative lens and four positive lenses. The fourth lens unit U4 corresponds to the 28th to 33rd surfaces, and is composed of two negative lenses and one positive lens. The fifth lens unit U5 corresponds to the 34th to 38th surfaces and includes two negative lenses and one positive lens.

  The extender lens unit U5ex corresponds to the 34th to 44th surfaces, and includes three negative lenses and three positive lenses.

The sixth lens unit U6 corresponds to the 39th to 48th surfaces and includes two negative lenses and four positive lenses.
The correction lens group is composed of three negative lenses and two positive lenses.
Aspheric surfaces are used for the 11th, 19th and 25th surfaces. It mainly corrects zoom fluctuations such as distortion and astigmatism.

The open F number Fno of the zoom lens in Example 1 is 1.8.
The allowable circle of confusion circle δ is 0.005 mm. Therefore, the focal depth D is 0.009 mm.

  In this embodiment, the maximum fluctuation amount of the focal position in the change of the zoom position is 5D. That is, it is set to 0.045 mm. The maximum fluctuation amount of the focal position in the temperature change is 20D. That is, it is 0.180 mm. The maximum amount of change in the focal position due to switching of the extender lens group is 1D. That is, it is set to 0.009 mm. As a result, a change in focus position of 0.234 mm occurs. Therefore, the change amount ΔSk of the imaging position due to the movement of the correction lens group may be 0.234 mm. The change amount of the imaging position per 1 mm of the movement amount of the correction lens group is 0.910 mm. Therefore, the maximum movement amount Mb for correcting the variation of the focus position of the correction lens group is 0.257 mm. The maximum movement amount Ma for zooming of the correction lens group is 0 mm. Therefore, the maximum movement amount Mc of the correction lens group is 0.257 mm. The moving amount of the second lens unit U2 having the largest moving amount in the variable power lens group is 191.209 mm.

  Table 1 shows values corresponding to the conditional expressions of Example 1. Numerical Example 1 satisfies all of the conditional expressions, and achieves high-speed zooming operation and good optical performance, and corrects the focus position deviation due to zoom position change, temperature change, and extender lens group switching well. A possible zoom lens is realized.

The zoom lens shown in Embodiment 2 will be specifically described with reference to FIG.
In FIG. 4, the first lens unit U1 is a lens unit having a positive refractive power that is fixed during zooming. The second lens unit U2 is a variator having a negative refractive power for zooming, and zooming from the wide-angle end to the telephoto end by monotonically moving on the optical axis side to the image plane side. The third lens unit U3 is a second variator having a positive refractive power, and performs zooming from the wide-angle end to the telephoto end by moving the optical axis from the image side to the object side. The fourth lens unit U4 is a compensator having a positive refractive power, and moves non-linearly on the optical axis toward the object side in order to correct image plane fluctuations accompanying zooming. SP is an aperture stop, and the fifth lens unit U5 is a front relay lens unit. The sixth lens group U6 is an equal-magnification lens group, U6ex is an extender lens group that displaces the focal length variable magnification range of the entire system to the long focal length side, and either one is arranged on the optical axis. The seventh lens group U7 is a rear relay lens group. P is a color separation prism optical system, and I is an imaging surface. The first lens unit U1 further includes a first sub lens unit U11 having a negative refractive power, a second sub lens unit U12 having a positive refractive power, and a third sub lens group U13 having a positive refractive power. . The second sub-lens group U12 and the third sub-lens group U13 are fed out from the image side to the object side at different ratios, thereby focusing on a short-distance object.

  In the second exemplary embodiment, the correction lens unit is the same as the fourth lens unit U4 that is a compensator, and moves on the optical axis in order to correct a variation in focus position.

  The first lens unit U1 corresponds to the first surface to the tenth surface. The first sub lens unit U11 corresponds to the first surface to the fourth surface, and is composed of one negative lens and one positive lens. The second sub lens unit U12 corresponds to the fifth surface to the eighth surface and includes two positive lenses. The third sub lens unit U13 corresponds to the ninth surface to the tenth surface, and includes a single positive lens. The second lens unit U2 corresponds to the eleventh to seventeenth surfaces, and is composed of three negative lenses and one positive lens.

  The third lens unit U3 corresponds to the 18th to 24th surfaces, and is composed of one negative lens and three positive lenses. The fourth lens unit U4 corresponds to the 25th to 26th surfaces and is composed of one positive lens. The fifth lens unit U5 corresponds to the 28th to 32nd surfaces, and is composed of two negative lenses and one positive lens. The sixth lens unit U6 corresponds to the 33rd to 39th surfaces and includes two negative lenses and two positive lenses.

  The extender lens unit U6ex corresponds to the 33rd to 42nd surfaces, and includes three negative lenses and three positive lenses.

The seventh lens unit U7 corresponds to the 40th to 49th surfaces and is composed of two negative lenses and four positive lenses.
The correction lens group is composed of one positive lens.
Aspheric surfaces are used for the 11th, 19th and 25th surfaces. It mainly corrects zoom fluctuations such as distortion and astigmatism.

FIG. 8 shows the configuration of an imaging system according to the second embodiment of the present invention.
Example 2 is compared to Example 1,
(A1) The variable power lens group is composed of three groups.
(A2) It has focus lens position detection means 18 for detecting the position of the focus lens group 1.
(A3) It has aperture value detection means 19 for detecting the aperture value of the aperture stop 3.
(A4) The change amount of the focus position due to the change of the position of the focus lens and the change of the aperture value is stored in the storage unit 17.
(A5) The first variator and the second variator are driven by a cam mechanism, and the compensator is driven by a stepping motor as a correction lens group.
Are different, and the other configurations are the same.
In addition, as a different form of the present embodiment,
(A5-2) The first variator, the second variator, and the compensator may be driven by a cam mechanism, and the correction lens group may be driven by a stepping motor inside the cylindrical cam.

  In the second embodiment, it is assumed that the focus position fluctuates due to a change in zoom position, a change in focus lens position, a change in temperature, a change in aperture value, and switching of the extender lens group. In the second embodiment, a change in the focus position due to a change in zoom position, a change in focus lens position, a change in temperature, and a change in aperture value is stored in the storage unit 17 during assembly adjustment. Therefore, the calculation unit 16 obtains signals from the zoom position detection unit 14, the focus lens position detection unit 18, the temperature detection unit 15, the aperture value detection unit 19, and the extender lens group switching detection unit 20. Thereafter, the calculation unit 16 selects the variation amount of the focus position stored in the storage unit 17 and inputs it to the drive unit 12 of the correction lens group. Then, the drive unit 12 of the correction lens group (compensator 2c) corrects the fluctuation amount of the focus position by moving the correction lens group on the optical axis based on the signal from the calculation unit 16.

The open F number Fno of the zoom lens in Example 2 is 1.8.
As in Example 1, the allowable circle of confusion circle δ is 0.005 mm. Therefore, the focal depth D is 0.009 mm. The maximum fluctuation amount of the focal position in the change of the zoom position in the second embodiment is 5D. That is, it is set to 0.045 mm. The maximum fluctuation amount of the focal position in the temperature change is 20D. That is, it is 0.180 mm. The maximum fluctuation amount of the focal position when the aperture value changes is 2D. That is, 0.018 mm. The maximum variation of the focal position at the position of the focusing lens is 2D. That is, 0.018 mm. The maximum variation of the focal position due to the switching of the extender lens group is 1D. That is, it is set to 0.009 mm. As a result, a focus position change of 0.270 mm occurs. Therefore, the change amount ΔSk of the imaging position due to the movement of the correction lens group may be 0.270 mm.

  The amount of change of the imaging position per 1 mm of the movement amount of the correction lens group is 0.583 (wide angle end) to 0.970 mm (telephoto end). Therefore, the maximum movement amount Mb for correcting the fluctuation of the focus position of the correction lens group is 0.463 mm. The maximum movement amount Ma for zooming of the correction lens group is 44.488 mm. Therefore, the movement amount Mc of the correction lens group is 44.951 mm. The moving amount of the second lens unit U2 having the largest moving amount in the variable power lens group is 195.390 mm.

  Table 1 shows values corresponding to the conditional expressions of Example 2. Numerical Example 2 satisfies all the conditional expressions, and realizes a zoom lens that can correct a variation in focus position while realizing a high-speed zooming operation and good optical performance. Variation factors in Numerical Example 2 are a change in zoom position, a change in focus lens position, a temperature change, a change in aperture value, and switching of the extender lens group.

The zoom lens shown in Embodiment 3 will be specifically described with reference to FIG.
In FIG. 9, the first lens unit U1 is a lens unit having a positive refractive power that does not move for zooming. The second lens unit U2 is a variator having a negative refractive power for zooming, and zooming from the wide-angle end to the telephoto end by monotonically moving on the optical axis side to the image plane side. The third lens unit U3 is a second variator having negative refractive power, and moves non-linearly on the optical axis toward the object side. The fourth lens unit U4 is a compensator having a positive refractive power, and moves non-linearly on the optical axis toward the object side in order to correct image plane fluctuations accompanying zooming. SP is an aperture stop, and the fifth lens unit U5 is a front relay lens unit. The sixth lens group U6 is a rear relay lens group. The extender lens group Uex may be detachably disposed in the space between the fifth lens group U5 that is the front relay lens group and the sixth lens group U6 that is the rear relay lens group. P is a color separation prism optical system, and I is an imaging surface. The first lens unit U1 further includes a first sub lens unit U11 having a negative refractive power and a second sub lens unit U12 having a positive refractive power, and the second sub lens unit U12 is moved from the image side to the object side. Focusing on a short-distance object is performed by feeding it out.

  In the third exemplary embodiment, the correction lens unit is the same as the fourth lens unit U4 that is a compensator, and moves on the optical axis in order to correct variations in focus position.

  The first lens unit U1 corresponds to the first surface to the eleventh surface. The first sub lens unit U11 corresponds to the first surface to the seventh surface, and includes two negative lenses and two positive lenses. The second sub lens unit U12 corresponds to the eighth surface to the eleventh surface, and includes two positive lenses. The second lens unit U2 corresponds to the 12th to 18th surfaces, and is composed of two negative lenses and two positive lenses. The third lens unit U3 corresponds to the 19th to 21st surfaces, and is composed of one negative lens and one positive lens. The fourth lens unit U4 corresponds to the 22nd to 25th surfaces and is composed of two positive lenses. The fifth lens unit U5 corresponds to the 27th to 29th surfaces, and is composed of one negative lens and one positive lens. The sixth lens unit U6 corresponds to the 30th to 39th surfaces and is composed of two negative lenses and four positive lenses.

The extender lens group Uex corresponds to the 30th to 37th surfaces and is composed of two negative lenses and three positive lenses.
The correction lens group corresponds to the 22nd to 25th surfaces and is composed of two positive lenses.

FIG. 12 shows the configuration of an imaging system according to the third embodiment of the present invention.
Example 3 is compared to Example 1,
(B1) The variable power lens group is composed of three groups.
(B2) The first variator and the second variator are driven by a cam mechanism, and the compensator is driven by a stepping motor as a correction lens group.
(B3) It has posture detecting means 21 for detecting the posture change of the zoom lens.
(B4) The variation amount of the focus position due to the posture change is stored in the storage unit 17.
Are different, and the other configurations are the same.

  In the third embodiment, it is assumed that the focus position fluctuates due to a change in zoom position and a temperature change. In the third embodiment, the change in the zoom position, the temperature change, the posture change, and the change in the focus position due to the switching of the extender lens group during assembly adjustment are stored in the storage unit 17. Then, the calculation unit 16 selects the amount of focus position variation stored in the storage unit 17 based on signals from the zoom position detection unit 14, the temperature detection unit 15, and the posture detection unit 21, and sends it to the drive unit 12 of the correction lens group. input. Then, the drive unit 12 of the correction lens group (compensator 2c) moves the correction lens group on the optical axis based on the signal from the calculation unit 16 to correct the fluctuation amount of the focus position.

The open F number Fno of the zoom lens in Example 3 is 1.8.
The allowable circle of confusion circle δ is set to 0.005 mm as in the first embodiment. Therefore, the focal depth D is 0.009 mm.

  The maximum fluctuation amount of the focal position in the change of the zoom position in the third embodiment is 5D. That is, it is set to 0.045 mm. The maximum fluctuation amount of the focal position in the temperature change is 20D. That is, it is 0.180 mm. The maximum fluctuation amount of the focal position in the posture change is 10D. That is, it is set to 0.090 mm. The maximum variation of the focal position due to the switching of the extender lens group is 1D. That is, it is set to 0.009 mm. As a result, a focus position change of 0.324 mm occurs. Accordingly, the change amount ΔSk of the imaging position due to the movement of the correction lens group may be 0.324 mm. The change amount of the imaging position per 1 mm of the movement amount of the correction lens group is 1.298 mm. Therefore, the maximum movement amount Mb for correcting the variation of the focus position of the correction lens group is 0.250 mm. The maximum movement amount Ma for zooming of the correction lens group is 8.136 mm. Therefore, the maximum movement amount Mc of the correction lens group is 8.386 mm. The moving amount of the second lens unit U2 having the largest moving amount in the variable power lens group is 54.763 mm.

  Table 1 shows values corresponding to the conditional expressions of Example 3. Numerical Example 3 satisfies all the conditional expressions. While realizing high-speed zooming operation and good optical performance, the zoom position change, temperature change, posture change, and focus position change by changing the extender lens group A zoom lens that can correct fluctuations well is realized.

  Next, numerical examples 1 to 3 corresponding to the first to third embodiments of the present invention will be described. In each numerical example, i indicates the order of the surfaces from the object side, ri is the radius of curvature of the i-th surface from the object side, di is the i-th distance from the i-th surface from the object side, and ndi and νdi are The refractive index and Abbe number of the i-th optical member. The focal length, F number, and angle of view represent values when focusing on an object at infinity. BF is the distance from the final surface of the lens to the image plane.

The aspherical shape is expressed by the following formula, where x is the coordinate in the optical axis direction, y is the coordinate in the direction perpendicular to the optical axis, R is the reference radius of curvature, k is the conic constant, and An is the nth-order aspherical coefficient. It is represented by However, “ex” means “× 10 ^−x ”. A lens surface having an aspherical surface is marked with an asterisk (*) on the right side of the surface number in each table.
^{x = (y 2 / r)} / {1+ (1-k × y 2 / r 2) 0.5} + A3 × y 3 + A4 × y 4 + A5 × y 5 + A6 × y 6 + A7 × y 7 + A8 × y 8 + A9 × y ⁹ + A10 × y ¹⁰ + A11 × y ¹¹ + A12 × y ¹² + A13 × y ¹³ + A14 × y ¹⁴ + A15 × y ¹⁵ + A16 × y ¹⁶

Numerical example 1

Unit mm

Surface data surface number i ri di ndi vdi Effective diameter
1 1571.411 5.91 1.90366 31.3 212.83
2 361.491 3.13 205.43
3 389.831 20.85 1.43387 95.1 204.88
4 -1519.134 25.29 203.52
5 379.388 19.40 1.43387 95.1 198.91
6 -1690.060 0.25 198.64
7 270.376 20.46 1.43387 95.1 194.91
8 5840.434 1.18 193.83
9 190.778 14.41 1.59240 68.3 182.16
10 365.545 (variable) 180.35
11 * 11015.733 2.20 2.00330 28.3 48.62
12 41.065 10.49 41.92
13 -62.377 1.40 1.88300 40.8 41.20
14 65.176 9.88 1.95906 17.5 42.38
15 -89.087 2.72 43.74
16 -51.909 1.60 1.83400 37.2 43.88
17 -103.320 (variable) 46.02
18 115.185 11.58 1.59201 67.0 78.48
19 * -2087.691 0.50 78.91
20 142.758 13.08 1.59201 67.0 80.06
21 -231.655 0.20 79.67
22 122.793 2.50 1.80518 25.4 76.01
23 57.717 18.11 1.43387 95.1 71.57
24 -564.234 0.50 70.45
25 * 364.246 6.50 1.49700 81.5 69.33
26 -414.835 (variable) 68.15
27 (Aperture) ∞ 5.89 31.81
28 -147.172 1.40 1.81600 46.6 32.30
29 46.924 1.05 31.20
30 37.303 4.69 1.80809 22.8 31.30
31 420.501 3.37 30.90
32 -76.047 1.40 1.88300 40.8 30.60
33 191.170 11.30 30.40
34 -41.223 1.78 1.65160 58.5 26.67
35 580.472 3.52 1.80518 25.4 27.78
36 -156.414 6.46 28.43
37 -103.332 5.71 1.70154 41.2 30.13
38 -53.979 10.53 31.42
39 -216.194 4.49 1.50137 56.4 32.25
40 -43.973 0.74 32.44
41 -72.585 1.30 1.88300 40.8 31.89
42 61.011 9.51 1.50137 56.4 32.28
43 -35.679 0.20 33.06
44 96.272 8.69 1.49700 81.5 32.15
45 -31.822 1.70 1.88300 40.8 31.45
46 -176.143 2.14 31.79
47 50.459 8.14 1.48749 70.2 31.95
48 -79.751 5.00 31.49
49 ∞ 33.00 1.60859 46.4 60.00
50 ∞ 13.20 1.51633 64.2 60.00
51 ∞ 60.00
Image plane

Aspheric data 11th surface
K = -2.61129e + 006 A 4 = 1.14924e-006 A 6 = -4.20242e-010 A 8 = 7.06050e-012 A10 = 1.71748e-014 A12 = -3.95143e-018 A14 = -2.50492e-020 A16 = 2.74832e-023
A 3 = -7.41007e-007 A 5 = -2.86209e-008 A 7 = 4.68402e-011 A 9 = -6.67517e-013 A11 = -2.87644e-016 A13 = 1.44174e-018 A15 = -1.26241e- 021

19th page
K = -8.09196e + 003 A 4 = 2.70610e-007 A 6 = 1.07566e-009 A 8 = -3.82716e-014 A10 = -1.89869e-016 A12 = 1.74435e-020 A14 = -2.31461e-023 A16 = 5.87253e-027
A 3 = -1.02923e-007 A 5 = -2.58308e-008 A 7 = -1.15844e-011 A 9 = 3.14187e-015 A11 = 2.64931e-018 A13 = 8.56747e-022 A15 = -2.81713e-025

25th page
K = 6.92275e + 001 A 4 = -4.53959e-007 A 6 = -6.59771e-011 A 8 = -3.55842e-013 A10 = -1.48669e-016 A12 = 8.98957e-020 A14 = 6.50522e-022 A16 = 1.24233e-026
A 3 = 7.06566e-007 A 5 = -1.77804e-008 A 7 = 3.13155e-011 A 9 = 8.81552e-016 A11 = -1.46851e-017 A13 = 1.62371e-021 A15 = -1.37737e-023

Various data Zoom ratio 90.00
Wide angle Medium telephoto focal length 8.60 65.53 774.03
F number 1.80 1.79 4.00
Angle of view 32.60 4.80 0.41
Image height 5.50 5.50 5.50
Total lens length 641.10 641.10 641.10
BF 18.00 18.00 18.00

d10 3.03 140.03 186.75
d17 279.71 118.33 3.07
d26 3.00 27.38 95.93

Entrance pupil position 126.14 812.29 9423.65
Exit pupil position 141.46 141.46 141.46
Front principal point position 135.34 912.61 15050.41
Rear principal point position 9.40 -47.53 -756.02

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 248.14 110.88 64.60 -17.20
2 11 -27.25 28.28 3.76 -16.43
3 18 70.50 52.98 12.00 -25.30
4 27 -50.95 17.80 11.51 -2.55
5 34 -411.92 17.46 -49.56 -70.97
6 39 52.26 88.11 20.24 -38.64

Extender surface number i ri di ndi vdi Effective diameter
33 191.170 6.00 30.40
34 46.021 4.74 1.43875 94.9 26.68
35 -68.081 0.70 26.40
36 18.600 7.70 1.60342 38.0 23.57
37 47.941 0.90 1.84666 23.8 19.70
38 14.526 7.25 17.47
39 92.503 0.80 1.77250 49.6 16.20
40 18.601 2.85 1.80809 22.8 15.70
41 55.271 1.56 15.30
42 -40.799 0.80 1.77250 49.6 15.24
43 -205.710 6.00 15.30
Group Start surface Focal length Lens construction length Front principal point position Rear principal point position
5ex 34 -467.87 27.30 350.71 187.20
Various data when inserting / removing extender

Wide angle Medium telephoto focal length 17.20 131.07 1548.04
F number 3.60 3.59 8.00
Angle of view 17.73 2.40 0.20
Image height 5.50 5.50 5.50
Total lens length 641.10 641.10 641.10
BF 18.00 18.00 18.00

Numerical example 2

Unit mm

Surface data surface number i ri di ndi vdi Effective diameter
1 8000.000 6.00 1.83400 37.2 203.23
2 373.691 1.54 196.39
3 361.776 26.52 1.43387 95.1 195.96
4 -518.880 25.95 194.72
5 370.520 17.79 1.43387 95.1 195.79
6 -3369.467 0.25 195.31
7 241.028 17.39 1.43387 95.1 190.20
8 861.689 1.20 188.93
9 203.790 14.06 1.49700 81.5 180.22
10 421.379 (variable) 178.48
11 * 3657.872 2.20 2.00330 28.3 43.69
12 40.621 10.00 38.07
13 -45.369 1.40 1.88300 40.8 37.29
14 98.142 5.97 1.95906 17.5 38.23
15 -67.097 0.69 38.36
16 -64.854 1.60 1.75500 52.3 38.12
17 -212.532 (variable) 38.80
18 140.986 10.25 1.56907 71.3 73.92
19 * -186.006 0.50 74.42
20 102.215 13.53 1.56907 71.3 76.51
21 -162.778 0.20 76.24
22 159.988 2.50 1.84666 23.8 71.21
23 60.722 13.35 1.43875 94.9 66.79
24 -6797.000 (variable) 65.77
25 * 254.766 5.14 1.60311 60.6 64.42
26 -369.734 (variable) 63.74
27 (Aperture) ∞ 2.93 33.76
28 -155.154 1.40 1.83481 42.7 32.24
29 24.535 6.89 1.76182 26.5 30.20
30 2780.241 3.70 29.80
31 -96.909 1.85 1.83481 42.7 28.78
32 71.731 0.15 28.46
33 33.014 4.69 1.84666 23.8 28.89
34 155.745 5.42 28.23
35 -122.347 1.58 1.83481 42.7 26.36
36 58.258 7.24 25.83
37 -72.547 1.91 1.71736 29.5 26.38
38 34.123 15.00 1.65160 58.5 27.73
39 -50.824 3.00 30.40
40 -403.126 4.32 1.54814 45.8 30.64
41 -47.125 3.12 30.76
42 -68.761 3.07 1.88300 40.8 29.52
43 37.681 9.19 1.51742 52.4 29.92
44 -49.851 0.20 30.96
45 164.690 7.05 1.49700 81.5 31.29
46 -34.793 2.50 1.83481 42.7 31.30
47 -98.072 1.18 32.20
48 68.401 7.25 1.54814 45.8 32.48
49 -56.118 14.45 32.28
50 ∞ 33.00 1.60859 46.4 60.00
51 ∞ 13.20 1.51633 64.2 60.00
52 ∞ 60.00
Image plane

Aspheric data 11th surface
K = -9.90196e + 004 A 4 = 1.00187e-006 A 6 = -7.44468e-010 A 8 = 5.01326e-013

19th page
K = -1.87503e + 001 A 4 = 2.45550e-007 A 6 = 7.82502e-011 A 8 = -3.75504e-015

25th page
K = 1.36886e + 001 A 4 = -1.59307e-007 A 6 = -1.02866e-010 A 8 = 3.28743e-015

Various data Zoom ratio 99.96
Wide angle Medium Telephoto focal length 8.90 84.98 889.65
F number 1.80 1.80 4.60
Angle of View 31.72 3.70 0.35
Image height 5.50 5.50 5.50
Total lens length 615.79 615.79 615.79
BF 10.17 10.17 10.17

d10 2.71 151.20 198.10
d17 269.28 96.90 1.99
d24 0.45 5.41 27.78
d26 0.86 19.79 45.44

Entrance pupil position 124.84 917.43 9513.22
Exit pupil position 149.25 149.25 149.25
Front principal point position 134.31 1054.33 16093.81
Rear principal point position 1.27 -74.81 -879.48

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 259.25 110.70 62.07 -20.39
2 11 -25.74 21.85 3.58 -12.51
3 18 69.30 40.33 5.79 -20.84
4 25 249.89 5.14 1.31 -1.90
5 27 -32.72 16.78 9.04 -2.82
6 33 203.64 35.82 -0.15 -32.05
7 40 51.58 98.55 24.94 -43.66

Extender surface number i ri di ndi vdi Effective diameter
32 71.731 1.87 28.60
33 41.701 6.24 1.43875 94.9 29.11
34 -50.965 0.70 28.98
35 20.811 9.32 1.61293 37.0 26.02
36 -335.253 0.90 1.84666 23.8 22.30
37 34.907 3.00 20.51
38 46.906 0.80 1.77250 49.6 18.71
39 15.321 2.02 1.80809 22.8 17.22
40 18.517 6.04 16.43
41 335.860 0.80 1.77250 49.6 15.08
42 31.875 7.28 14.77

Extender lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
6ex 33 91.24 29.82 -89.99 -57.39

Various data when inserting / removing extender
Wide angle Medium telephoto focal length 17.80 169.96 1779.31
F number 3.60 3.60 9.20
Angle of View 17.17 1.85 0.18
Image height 5.50 5.50 5.50
Total lens length 615.79 615.79 615.79
BF 10.17 10.17 10.17

Numerical Example 3

Unit mm

Surface data surface number i ri di ndi vdi Effective diameter
1 -210.024 2.30 1.72047 34.7 82.63
2 145.102 4.91 77.63
3 491.656 2.20 1.84666 23.8 77.24
4 236.100 8.88 1.43875 94.9 76.67
5 -196.805 0.40 76.63
6 152.079 11.02 1.43387 95.1 75.76
7 -147.909 6.94 75.65
8 136.777 7.72 1.59240 68.3 73.35
9 -441.404 0.15 73.09
10 62.631 6.49 1.72916 54.7 67.82
11 131.204 (variable) 67.13
12 72.053 1.00 1.88300 40.8 26.69
13 14.820 6.20 21.30
14 -45.643 6.88 1.80809 22.8 20.98
15 -12.496 0.75 1.88300 40.8 20.60
16 94.745 0.18 20.49
17 30.451 2.41 1.66680 33.0 20.72
18 82.062 (variable) 20.48
19 -38.647 0.75 1.75700 47.8 21.65
20 60.193 2.42 1.84649 23.9 22.99
21 -1560.081 (variable) 23.43
22 -172.490 3.22 1.64000 60.1 27.72
23 -44.456 0.15 28.38
24 84.388 3.66 1.51633 64.1 29.60
25 -130.776 (variable) 29.73
26 (Aperture) ∞ 2.00 29.78
27 63.114 6.26 1.51742 52.4 29.82
28 -38.329 1.00 1.83400 37.2 29.58
29 -187.721 36.00 29.64
30 -56.536 2.41 1.51633 64.1 26.08
31 -35.722 0.10 26.22
32 -503.242 0.80 1.80 100 35.0 25.72
33 30.789 5.54 1.50127 56.5 25.72
34 -125.107 0.15 26.12
35 61.177 5.93 1.48749 70.2 26.53
36 -36.075 0.85 1.88300 40.8 26.48
37 -84.336 0.23 26.82
38 53.704 3.66 1.51633 64.1 26.78
39 -144.281 4.50 26.54
40 ∞ 33.00 1.60859 46.4 40.00
41 ∞ 13.20 1.51633 64.1 40.00
42 ∞ 40.00
Image plane

Various data Zoom ratio 21.88
Wide angle Medium Telephoto focal length 7.80 20.67 170.68
F number 1.80 1.80 2.63
Angle of view 35.19 14.90 1.85
Image height 5.50 5.50 5.50
Total lens length 272.06 272.06 272.06
BF 7.01 7.01 7.01

d11 0.41 27.98 55.17
d18 61.23 18.97 11.88
d21 6.98 15.28 1.94
d25 2.17 8.56 1.79

Entrance pupil position 48.98 120.60 765.75
Exit pupil position 1826.32 1826.32 1826.32
Front principal point position 56.82 141.51 952.44
Rear principal point position -0.79 -13.66 -163.67

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 71.50 51.01 33.46 1.92
2 12 -13.80 17.42 2.44 -9.45
3 19 -57.00 3.17 -0.09 -1.82
4 22 48.00 7.03 2.82 -1.69
5 26 222.22 9.26 -0.98 -7.56
6 30 52.28 70.37 11.20 -35.11

Extender surface number i ri di ndi vdi Effective diameter
29 -187.721 2.96 29.64
30 25.634 7.45 1.61800 63.3 28.81
31 -196.746 1.39 27.40
32 34.380 8.89 1.58913 61.1 23.16
33 -33.742 3.00 2.00069 25.5 17.76
34 19.738 4.99 14.61
35 634.440 0.55 1.88300 40.8 13.37
36 10.422 3.80 1.80809 22.8 12.85
37 52.998 2.96 12.58

Extender lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
ex 30 -157.93 30.07 182.07 73.03

Various data when inserting / removing extender

Wide angle Medium telephoto focal length 15.60 41.35 341.35
F number 3.60 3.60 5.25
Angle of view 19.42 7.58 0.92
Image height 5.50 5.50 5.50
Total lens length 272.06 272.06 272.06
BF 7.01 7.01 7.01

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

DESCRIPTION OF SYMBOLS 1 Focus lens group 2 Variable magnification lens group 3 Aperture stop 4 Front relay lens group 5a Extender lens group 5b Extender lens group 6 Rear relay lens group 12 Drive part of correction lens group

Claims (13)

In order from the object side to the image side, a focus lens group that moves during focusing, a zoom lens group that includes two or more lens groups that move on the optical axis during zooming, an aperture stop, and an optical path In a zoom lens including an extender lens group that is detachably mounted and a relay lens group that does not move for zooming,
A correction lens group that moves in the direction of the optical axis to correct fluctuations in focus position;
The correction lens group is disposed closer to the object side than the extender lens group, and the maximum movement amount of the correction lens group is Mc, the maximum movement amount for correcting fluctuations in focus position is Mb, and the extender lens group is separated from the optical axis. In the retracted state, when the maximum change amount of the imaging position when the correction lens group is moved by the movement amount Mb is ΔSk and the maximum movement amount of the lens group constituting the zoom lens group is Mm,
0.001 <Mc / Mm <0.3
0.3 <| ΔSk | / Mb <3.0
A zoom lens characterized by satisfying   The correction lens group moves in the optical axis direction, thereby changing the position of the zoom lens group, changing the position of the focus lens group, changing the temperature, changing the aperture value of the aperture stop, changing the attitude of the zoom lens, 2. The zoom lens according to claim 1, wherein a change in a focus position due to one or more factors is corrected among changes in a focus position due to switching of the extender lens group. In a state where the extender lens group is retracted from the optical axis, a change in focus position due to one or more of a change in position of the variable power lens group, a change in position of the focus lens group, and a change in aperture value of the aperture stop In the state where the maximum movement amount of the correction lens group for correcting the correction is Mex1 and the extender lens group is disposed on the optical axis, the position change of the zoom lens group, the position change of the focus lens group, the aperture When the maximum moving amount of the correction lens group for correcting the fluctuation of the focus position due to one or more factors among the change in value is Mex2.
0.8 <Mex1 / Mex2 <1.2
The zoom lens according to claim 1, wherein the zoom lens satisfies the following.   4. The zoom lens according to claim 1, wherein the correction lens group is disposed in the relay lens group. 5.   The zoom lens according to claim 1, wherein the correction lens group is disposed adjacent to the aperture stop.   The zoom lens according to claim 1, wherein the correction lens group includes one or more lenses and three or less lenses. Temperature detection means;
Storage means for holding a variation in focus position caused by temperature change;
Control means for moving the correction lens group so as to cancel out the focus position fluctuation amount based on the detected temperature and the focus position fluctuation amount caused by the temperature change stored in the storage means;
The zoom lens according to claim 1, comprising: Zoom position detecting means for detecting the position of the zoom lens group;
Storage means for holding a variation in focus position resulting from a change in position of the zoom lens group;
Based on the position of the variable power lens group and the amount of change in focus position caused by the change in position of the variable power lens group stored in the storage means, the correction lens group is adjusted so as to cancel the amount of change in focus position. Control means to move;
The zoom lens according to claim 1, comprising: Focus lens position detecting means for detecting the position of the focus lens group;
Storage means for holding a variation in focus position caused by a change in the position of the focus lens group;
Based on the position of the focus lens group and the amount of change in focus position caused by the change in position of the focus lens group stored in the storage unit, the correction lens group is moved so as to cancel out the amount of change in focus position. Control means;
The zoom lens according to claim 1, comprising: Aperture value detection means for detecting the aperture diameter of the aperture stop,
Storage means for holding a variation amount of a focus position caused by a change in an aperture diameter of the aperture stop;
Based on the aperture diameter of the aperture stop and the variation amount of the focus position caused by the change of the aperture diameter of the aperture diaphragm stored in the storage means, the correction lens group is moved so as to cancel the variation amount of the focus position. Control means;
The zoom lens according to claim 1, comprising: Attitude detection means for detecting the attitude of the zoom lens;
Storage means for holding a variation amount of a focus position caused by a change in posture of the zoom lens;
Control means for moving the correction lens group based on the attitude of the zoom lens and the fluctuation amount of the focus position caused by the change in the attitude of the zoom lens stored in the storage means so as to cancel the fluctuation amount of the focus position. When,
The zoom lens according to claim 1, comprising: Switching detection means for detecting switching of the extender lens group;
Storage means for holding a variation in focus position resulting from switching of the extender lens group;
Control means for moving the correction lens group so as to cancel out the fluctuation amount of the focus position based on the fluctuation amount of the focus position resulting from the switching of the extender lens group and the switching of the extender lens group stored in the storage means. When,
The zoom lens according to claim 1, comprising: An image pickup apparatus comprising: the zoom lens according to any one of claims 1 to 12; and an image pickup element that picks up a subject image formed by the zoom lens.
When the open F number of the zoom lens is Fno, the allowable circle of confusion of the imaging device is δ, and the depth of focus is D,
D = Fno × δ
0.3 <Mb / D <300.0
An imaging apparatus characterized by satisfying

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