Lens unit and camera system

Abstract

The present invention provides a lens unit and camera system that can reduce the change in brightness of captured images during magnification while suppressing an increase in the burden on the control system compared to conventional methods. [Solution] The lens unit comprises a variable magnification optical system equipped with an aperture for adjusting the amount of light, and a processor that controls the aperture size based on information regarding the magnification of the variable magnification optical system. If the maximum and minimum F values ​​over the entire magnification range of the variable magnification optical system are defined as Fmax and Fmin, respectively, and the average value of the F value at the wide-angle end and the F value at the telephoto end of the variable magnification optical system is defined as Fave, the processor controls the aperture size within a range that satisfies 3 < {(Fmax-Fmin) / Fave} × 100 < 10.

Description

[Technical Field]

[0001] The technology disclosed herein relates to a lens unit and a camera system. [Background technology]

[0002] In variable magnification optical systems such as zoom lenses, the F-number may change even if the aperture size remains constant during magnification. A change in the F-number alters the brightness of the captured image. Patent documents 1 and 2 below describe lens devices that control the aperture size based on the position of the zoom lens group. Patent document 3 below describes an optical device that controls the aperture position of the aperture unit according to the zoom state. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2019-207334 [Patent Document 2] Japanese Patent Publication No. 2021-043260 [Patent Document 3] Japanese Patent Publication No. 2020-034779 [Overview of the project] [Problems that the invention aims to solve]

[0004] This disclosure aims to provide a lens unit and camera system that can reduce changes in the brightness of captured images during magnification while suppressing an increase in the burden on the control system compared to conventional methods. [Means for solving the problem]

[0005] The lens unit relating to the technology disclosed herein comprises a variable magnification optical system equipped with an aperture for adjusting the amount of light, and a processor that controls the aperture size based on information regarding the magnification of the variable magnification optical system, wherein when Fmax is the maximum F value over the entire magnification range of the variable magnification optical system, Fmin is the minimum F value over the entire magnification range of the variable magnification optical system, and Fave is the average value of the F value at the wide-angle end and the F value at the telephoto end of the variable magnification optical system, 3<{(Fmax-Fmin) / Fave}×100<10 (1) The system includes a processor that controls the aperture amount within a range that satisfies the conditional expression (1) represented by .

[0006] When changing the aperture, if the processor considers the F-number of the variable magnification optical system before the change in aperture to be F0 and the F-number of the variable magnification optical system after the change in aperture to be F1, 0.05 < |F1-F0| < 1 (2) It is preferable to change the opening amount within the range that satisfies the conditional expression (2) represented by . In that case, it is more preferable to satisfy the following conditional expression (2-1) instead of conditional expression (2), and even more preferable to satisfy the following conditional expression (2-2). 0.05 < |F1 - F0| < 0.75 (2-1) 0.05 < |F1 - F0| < 0.5 (2-2)

[0007] When changing the aperture, the processor considers the peripheral illumination ratio at the maximum image height of the variable magnification optical system before the change in aperture to be V0, and the peripheral illumination ratio at the maximum image height of the variable magnification optical system after the change in aperture to be V1. |(V1-V0) / V0|×100<20 (3) It is preferable to change the aperture amount within the range that satisfies the conditional expression (3) represented by . In that case, it is more preferable to satisfy the following conditional expression (3-1) instead of conditional expression (3). |(V1-V0) / V0|×100<15 (3-1)

[0008] When the maximum value and the minimum value of the peripheral light quantity ratio at the maximum image height of the zoom optical system in each zoom range with a constant aperture amount are Vmax and Vmin respectively, the processor is in a plurality of zoom ranges with a constant aperture amount Vmax / Vmin < 3.5 (4) It is preferable to change the aperture amount within a range that satisfies the conditional expression (4) represented by. In that case, it is more preferable to satisfy the following conditional expression (4-1), and it is even more preferable to satisfy the following conditional expression (4-2). Vmax / Vmin < 3 (4-1) Vmax / Vmin < 2 (4-2) Also, the processor is in all of the zoom ranges with a constant aperture amount Vmax / Vmin < 3.5 (4) It is preferable to change the aperture amount within a range that satisfies the conditional expression (4) represented by.

[0009] When the maximum zoom ratio of the zoom optical system is ZRmax and the zoom ratio of the zoom optical system is ZR, 0.15 < {log 10 (ZR) / log 10 (ZRmax)} < 0.85 in the zoom range The F value of the zoom optical system preferably takes Fmax and Fmin.

[0010] When the maximum zoom ratio of the zoom optical system is ZRmax and the zoom ratio of the zoom optical system is ZR, 0 < {log 10 (ZR) / log 10 (ZRmax)} < 0.15, and 0.85 < {log 10 (ZR) / log 10 (ZRmax)} < 1 in the zoom range It is preferable that the aperture amount is constant.

[0011] When the maximum zoom ratio of the zoom optical system is ZRmax and the zoom ratio of the zoom optical system is ZR, the zoom range in which the aperture amount can change is 0.15 < {log 10 (ZR) / log 10(ZRmax)} < 0.85, It is preferable.

[0012] The variable magnification optical system may be configured such that the minimum value of the peripheral illumination ratio at the maximum image height of the variable magnification optical system across the entire magnification range is less than 40%, or it may be configured to be less than 35%.

[0013] The variable magnification optical system may be configured such that the peripheral illumination ratio at the wide-angle end of the variable magnification optical system at the maximum image height is less than 50%, or it may be configured to be less than 45%.

[0014] The variable magnification optical system consists of, in order from the object side to the image side, a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with negative refractive power, and a fifth lens group with positive refractive power. When magnification is applied, the spacing between all adjacent lens groups changes, and the aperture may be positioned between the object-side surface of the second lens group and the image-side surface of the fourth lens group.

[0015] The camera system relating to the technology disclosed herein includes a variable magnification optical system equipped with an aperture for adjusting the amount of light, a detection unit for detecting the magnification state of the variable magnification optical system, and a processor for controlling the aperture amount based on the detection result of the detection unit, wherein when Fmax is the maximum value of the F-number over the entire magnification range of the variable magnification optical system, Fmin is the minimum value of the F-number over the entire magnification range of the variable magnification optical system, and Fave is the average value of the F-number at the wide-angle end and the F-number at the telephoto end of the variable magnification optical system, 3<{(Fmax-Fmin) / Fave}×100<10 (1) The system includes a processor that controls the aperture amount within a range that satisfies the conditional expression (1) represented by . [Effects of the Invention]

[0016] According to this disclosure, it is possible to provide a lens unit and camera system that can reduce the change in brightness of the captured image during magnification while suppressing an increase in the burden on the control system compared to conventional methods. [Brief explanation of the drawing]

[0017] [Figure 1] This is a functional configuration diagram of an example camera system. [Figure 2] This figure shows an example of table data. [Figure 3] This figure shows an example of the relationship between the scaling ratio and the aperture diameter. [Figure 4] This figure shows an example of the relationship between the scaling ratio and the F-number. [Figure 5] This figure shows an example of the relationship between the scaling ratio and the ambient light ratio. [Figure 6] This is a flowchart explaining the process of controlling the aperture diameter. [Figure 7] This is a functional configuration diagram of a modified camera system. [Figure 8] This is a cross-sectional view showing the configuration of an example of a variable magnification optical system. [Modes for carrying out the invention]

[0018] Embodiments of this disclosure will be described below with reference to the drawings. In the following description, a lens-interchangeable digital camera will be used as an example of one embodiment of this disclosure.

[0019] [Camera system configuration] Figure 1 shows a functional configuration diagram of a camera system 100 according to one embodiment of the present disclosure. The camera system 100 comprises a lens unit 10 and a camera body 50. The camera body 50 is provided with a mount 30 to which the lens unit 10 is detachably attached. By attaching the lens unit 10 to the mount 30, the lens unit 10 and the camera body 50 are electrically connected. Through this electrical connection, the lens processor 8 in the lens unit 10 and the body processor 58 in the camera body 50 become able to communicate with each other. The lens processor 8 is a processor that controls the lens unit 10, and the body processor 58 is a processor that controls the camera body 50. The lens processor 8 and the body processor 58 communicate with each other to comprehensively control the camera system 100.

[0020] The lens unit 10 includes a zoom lens 1, a lens processor 8, a variable magnification lens drive unit 12, a variable magnification state detection unit 13, an aperture drive unit 14, an aperture diameter detection unit 15, a focus lens drive unit 16, a focus detection unit 17, a memory 20, and a storage 22.

[0021] The zoom lens 1 is an example of a "variable magnification optical system" related to the technology of this disclosure. The zoom lens 1 functions as a photographic lens for photographing a subject (not shown) and forms an image of it. The zoom lens 1 comprises a variable magnification lens 2, an aperture 4, and a focus lens 6.

[0022] The variable magnification lens 2 magnifies the zoom lens 1 by moving along the optical axis AX. Although the variable magnification lens 2 actually contains multiple lenses, Figure 1 shows it conceptually. The position of each lens in the optical axis direction of the variable magnification lens 2 is determined according to the magnification state.

[0023] The focusing lens 6 focuses the zoom lens 1 by moving along the optical axis AX. The focusing lens 6 may include multiple lenses, but Figure 1 shows the focusing lens 6 conceptually.

[0024] Note that Figure 1 is a conceptual diagram and shows the variable magnification lens 2 and the focusing lens 6 separately, but a portion of the variable magnification lens 2 may be configured as the focusing lens 6. Also, the zoom lens 1 may include lenses that are not included in either the variable magnification lens 2 or the focusing lens 6.

[0025] Aperture 4 has a variable aperture, and by changing its aperture, it adjusts the amount of light passing through the zoom lens 1. In other words, by changing the aperture of aperture 4, the F-number of the zoom lens 1 can be adjusted.

[0026] In this example, aperture 4 has multiple aperture blades (not shown) spaced apart on a circumference centered on the optical axis AX, forming an annular light-shielding section as a whole. The portion radially inward from this light-shielding section is the opening, the part through which light passes. By moving the multiple aperture blades in the opening and closing direction, the amount of opening of the opening changes. The shape of the opening in a plane perpendicular to the optical axis AX can be a circle centered on the optical axis AX, or a polygon centered on the optical axis AX. If the opening is circular, the diameter of this circle is taken as the "aperture diameter" of aperture 4. If the opening is polygonal, this polygon is approximated to a circle, and the diameter of the approximated circle is taken as the "aperture diameter" of aperture 4. The amount of opening can be detected by detecting the aperture diameter, and the amount of opening can be controlled by controlling the aperture diameter.

[0027] The aperture drive unit 14 drives the aperture blades of the aperture 4 based on a control signal from the lens processor 8. The driving of the aperture blades changes the aperture diameter of the aperture 4, and therefore the aperture amount changes. The aperture drive unit 14 is configured to include an actuator, such as a stepping motor or a voice coil motor.

[0028] The aperture diameter detection unit 15 detects the position of the aperture blades in the opening and closing direction, detects the aperture diameter of the aperture 4 based on the detected position, and outputs the aperture diameter to the lens processor 8. The aperture diameter detection unit 15 is configured to include, for example, an encoder such as a photointerrupter or a magnetic sensor. Note that the aperture diameter may be detected by another method; for example, the lens processor 8 may indirectly detect the aperture diameter by counting the drive pulses of the stepping motor constituting the aperture drive unit 14. In this case, the lens processor 8 functions as the aperture diameter detection unit 15.

[0029] The variable magnification lens drive unit 12 drives each lens included in the variable magnification lens 2 based on control signals from the lens processor 8. The variable magnification lens drive unit 12 is configured to include actuators such as stepping motors.

[0030] The magnification state detection unit 13 detects the position in the optical axis direction of at least one lens included in the magnification lens 2, detects the magnification state based on the detected position, and outputs information regarding the magnification of the zoom lens 1 to the lens processor 8. The magnification state is, for example, the wide-angle end, the telephoto end, or a state expressed as a magnification ratio. As information regarding the magnification, for example, a magnification ratio or focal length can be used. If the focal length at the wide-angle end is fw, the magnification ratio at a certain focal length fx is expressed as fx / fw. The "magnification ratio" of the zoom lens 1 is also called the "zoom ratio" or "zoom magnification."

[0031] The magnification state detection unit 13 is an example of a "detection unit" related to the technology of this disclosure. The magnification state detection unit 13 may be configured to include, for example, a potentiometer or a linear encoder, or it may be configured to include a measuring instrument using a variable resistor and / or laser light. The magnification state may be detected by another method, for example, the magnification state may be detected based on the distance in the optical axis direction of two predetermined lenses. Alternatively, similar to the detection of the aperture diameter, the magnification state may be indirectly detected by the lens processor 8 counting the drive pulses of the stepping motor constituting the magnification lens drive unit 12. In this case, the lens processor 8 functions as the magnification state detection unit 13.

[0032] The focus lens drive unit 16 drives the focus lens 6 based on a control signal from the lens processor 8. The focus lens drive unit 16 is configured to include an actuator, such as a stepping motor.

[0033] The focus detection unit 17 detects the position of the focus lens 6 in the optical axis direction and outputs information regarding the detected position to the lens processor 8.

[0034] Memory 20 is work memory used for executing program 23 of the lens processor 8. Memory 20 is, for example, RAM (Random Access Memory). Examples of RAM include DRAM (Dynamic Random Access Memory) or SRAM (Static Random Access Memory).

[0035] Storage 22 is a non-volatile storage device. Examples of storage 22 include non-volatile memory such as flash memory, and data storage such as SSDs (Solid State Drives) and HDDs (Hard Disk Drives). Various data such as programs 23 and table data 24 are stored in storage 22.

[0036] Table data 24 includes data that associates the magnification state with the aperture amount. Table data 24 is the data that the lens processor 8 refers to when controlling the aperture amount of aperture 4. An example of table data 24 is shown in Figure 2. In this embodiment, the entire magnification range is divided into multiple magnification ranges, such as the first magnification range, the second magnification range, the third magnification range, etc., starting from the wide-angle side, and a target aperture diameter is associated with each magnification range as shown in Figure 2. In this specification, "entire magnification range" refers to the magnification range from the wide-angle end to the telephoto end. Note that the table data 24 shown in Figure 2 is just an example, and the target aperture diameter may be associated with each magnification ratio or each focal length.

[0037] The lens processor 8 is an example of a "processor" relating to the technology of this disclosure. The lens processor 8 controls the aperture amount of the aperture 4 based on information regarding the magnification of the zoom lens 1 from the magnification state detection unit 13. The lens processor 8 obtains a target aperture diameter according to the magnification state by referring to the table data 24. If the aperture diameter is different from the target aperture diameter, the lens processor 8 outputs a control signal to the aperture drive unit 14 so that the aperture diameter becomes the same as the target aperture diameter.

[0038] Furthermore, the lens processor 8 outputs signals to the variable magnification lens drive unit 12 and the focus lens drive unit 16 to control the driving of the variable magnification lens 2 and the focus lens 6. In addition, the lens processor 8 performs processing based on various control signals transmitted from the main unit processor 58. The lens processor 8 is, for example, a CPU (Central Processing Unit) and works in cooperation with the memory 20 to control each part of the lens unit 10 and execute various processes according to the program 23.

[0039] The camera body 50 comprises an image sensor 52, a main unit processor 58, a display unit 54, and an operation unit 56.

[0040] The image sensor 52 captures the image formed by the zoom lens 1. For example, the image sensor 52 can be a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). The image sensor 52 outputs the captured image, which is the image of the captured picture, to the main unit processor 58.

[0041] The main processor 58 performs image processing on the captured image and outputs the processed image data to the display unit 54. The main processor 58 also outputs image data related to various types of information to the display unit 54. The display unit 54 displays the image based on the signals from the main processor 58.

[0042] The camera system 100 offers two modes for focusing: autofocus mode and manual focus mode. When autofocus mode is selected, the main unit processor 58 performs autofocus processing based on the input captured image and outputs a signal to the lens processor 8 to control the focus lens drive unit 16. When manual focus mode is selected, the focus lens 6 is driven based on the user's operation of the focus ring (not shown) for adjusting the focus. The camera system 100 may also be configured to have only one of either autofocus mode or manual focus mode.

[0043] The control unit 56 receives user input. The control unit 56 includes, for example, a zoom button, a shutter release button, a dial, a cross-shaped or control wheel-type selection button, and a touch panel provided on the display. The zoom button is pressed when the user instructs a change in magnification, and includes, for example, a wide button for instructing zooming to the wide-angle side and a tele button for instructing zooming to the telephoto side. The shutter release button is pressed, for example, when the user instructs saving an captured image. The selection buttons and touch panel are operated, for example, when the user selects a mode or sets conditions. When the user operates the control unit 56, an operation signal is input to the main unit processor 58.

[0044] The main unit processor 58 controls each part based on the operation signal. Depending on the content of the operation signal, the main unit processor 58 outputs a control signal to the lens processor 8. Although not shown in the diagram, the main unit processor 58 is also connected to memory (not shown), similar to the lens processor 8. The main unit processor 58 works in cooperation with the memory (not shown) to control each part of the camera system 100 according to the control program and to execute various processes according to various application programs.

[0045] In this example, the lens processor 8 and the main unit processor 58 are shown as CPUs (Central Processing Units), which are general-purpose processors that execute programs and perform various processes. However, other processors may be used. Other processors include PLDs (Programmable Logic Devices) such as FPGAs (Field Programmable Gate Arrays) whose circuit configuration can be changed after manufacturing, and dedicated electrical circuits with circuit configurations specifically designed to perform particular processes, such as ASICs (Application Specific Integrated Circuits). Furthermore, one of these various processors may be used, or a combination of multiple processors may be used. More specifically, the hardware structure of these various processors is an electrical circuit (Circuitry) made up of circuit elements such as semiconductor elements.

[0046] [Method for controlling aperture size] Next, the control of the aperture in the camera system 100 will be explained. The zoom lens 1 is configured such that the F-number changes when the zoom is changed from the wide-angle end to the telephoto end without changing the aperture of the aperture 4. When the F-number changes, the brightness of the captured image changes. For example, when zooming is performed during video recording and the F-number changes, the brightness of the image changes in the middle of shooting, and if the change is large, the exposure will be outside the correct exposure, which may cause discomfort to the user. In addition, since the depth of field also changes when the F-number changes, there are effects other than brightness. Therefore, the camera system 100 controls it as follows.

[0047] Regarding the F-number, the lens processor 8 controls the aperture within the range that satisfies the following condition (1). 3<{(Fmax-Fmin) / Fave}×100<10 (1) The definitions of each symbol used in conditional expression (1) are as follows. Fmax is the maximum value of the F-number in the entire zoom range of the zoom lens 1. Fmin is the minimum value of the F-number in the entire zoom range of the zoom lens 1. Fave is the average value of the F-number at the wide-angle end and the F-number at the telephoto end of the zoom lens 1. The specific values of the table data 24 shown in FIG. 2 are set to satisfy the conditional expression (1).

[0048] By ensuring that the corresponding value of the conditional expression (1) does not exceed the upper limit, compared with the conventional case where control based on the conditional expression (1) is not performed, the change in the F-number during zooming can be suppressed, and thus the change in the brightness of the photographed image during zooming can be reduced. As an example of the control of the aperture amount, as shown in the table data 24, the entire zoom range is divided into a plurality of zoom ranges, and control is performed so that the target aperture diameter is obtained in each zoom range. In this case, when the number of divisions of the zoom range increases, the control becomes complicated, and the data capacity used for control also becomes enormous. Therefore, by ensuring that the corresponding value of the conditional expression (1) does not fall below the lower limit, compared with the conventional case where control based on the conditional expression (1) is not performed, the complication of the control of the aperture amount and the increase in the data capacity used for control can be suppressed, and thereby the increase in the burden on the control system can be suppressed.

[0049] FIG. 3 shows an example of the relationship between the zoom ratio and the aperture diameter when the aperture diameter is controlled so that the entire zoom range is divided into a plurality of zoom ranges and the target aperture diameter is associated with each divided zoom range. The example shown in FIG. 3 is based on the embodiment of the zoom lens 1 shown in FIG. 8. In FIG. 3, the zoom ratio is denoted as ZR, and log 10 (ZR) is taken on the horizontal axis. log 10 (ZR) is the logarithm of ZR with a base of 10. The maximum zoom ratio (zoom ratio at the telephoto end) of the embodiment in FIG. 8 is 6.3, and FIG. 3 shows the data in the entire zoom range of this embodiment. The point 0 on the horizontal axis of FIG. 3 corresponds to the wide-angle end, and the point 0.799 on the horizontal axis corresponds to the telephoto end. The vertical axis of FIG. 3 is the aperture diameter in units of mm (millimeters).

[0050] Figure 3 shows three examples, A, B, and C, which differ in how the multiplication range is divided, represented by solid, dashed, and dotted lines, respectively. Example A is an example where the entire multiplication range is divided into three multiplication ranges for control. If the divided multiplication ranges are designated as the 1st multiplication range, 2nd multiplication range, 3rd multiplication range, etc., starting from the wide-angle side, then in Example A, the point where the value on the horizontal axis is 0.225 corresponds to the boundary between the 1st and 2nd multiplication ranges, and the point where the value on the horizontal axis is 0.553 corresponds to the boundary between the 2nd and 3rd multiplication ranges.

[0051] Example B, like Example A, is an example of controlling by dividing the entire multiplication range into three multiplication ranges, but the boundary points of each divided multiplication range, i.e., the multiplication ratios at the boundaries of each divided multiplication range, are different from those in Example A. Example C is an example of controlling by dividing the entire multiplication range into five multiplication ranges. In Examples A, B, and C, the aperture diameter remains constant within each divided multiplication range, and is controlled to change in steps at the boundaries of each multiplication range.

[0052] Figure 4 shows the relationship between the magnification ratio and the F-number when the zoom lens 1, as shown in Figure 8, is controlled as shown in Figure 3. The horizontal axis in Figure 4 is the same as the horizontal axis in Figure 3. The vertical axis in Figure 4 is the F-number. In Figure 4, the data for Example A, Example B, and Example C are shown as solid, dashed, and dotted lines, respectively.

[0053] As shown in Figure 4, in Examples A, B, and C, in the magnification range where the aperture diameter remains constant, the F-number increases as the magnification ratio increases, and the F-number decreases when the aperture diameter is increased at the magnification ratio corresponding to the boundary. When magnifying from the wide-angle end to the telephoto end, this increase and decrease in the F-number is repeated according to the number of divided magnification ranges, thereby suppressing the overall change in the F-number.

[0054] Table 1 shows the values ​​for conditional equation (1) in Examples A, B, and C in Figure 4. Note that Table 1 shows values ​​rounded to a predetermined number of decimal places, and this is also the case in the following tables. Although the number of divisions in the multiplication range and the target aperture diameter are the same for Examples A and B, the multiplication ratio corresponding to the boundary of the divided multiplication range is different, so the amount of change in the F value across the entire multiplication range, i.e., (Fmax-Fmin), is significantly different.

[0055] [Table 1]

[0056] The zoom range in which the f-number of zoom lens 1 takes its maximum and minimum values ​​is as follows: 0.15 < {log 10 (ZR) / log 10 (ZRmax) {<0.85} It is preferable to take Fmax and Fmin in the zoom range. Note that ZR is the zoom ratio of zoom lens 1, and ZRmax is the maximum zoom ratio of zoom lens 1, and the definitions of these symbols are the same in the following explanation.

[0057] When using camera system 100, it is common to set zoom lens 1 to the wide-angle setting to search for a subject over a wide area, and after confirming that the subject is within the captured image, increase the magnification ratio to zoom in on the subject and take a picture. From this, it can be inferred that two magnification ranges are frequently used: the wide-angle end and its vicinity, and the telephoto end and its vicinity. 0.15 < {log 10 (ZR) / log 10 (ZRmax) {<0.85} The zoom range can be roughly considered to be the range obtained by subtracting the two frequently used zoom ranges mentioned above from the entire zoom range. By configuring the lens so that the F-number does not take its maximum or minimum value within this range, abrupt changes in brightness do not occur within this range, thus improving the user experience compared to when the lens is not configured in this way.

[0058] Furthermore, for the same reasons as above, 0 < {log 10 (ZR) / log 10 (ZRmax)}<0.15, and, 0.85 < {log 10 (ZR) / log 10 (ZRmax) {<1} It is preferable that the aperture amount remains constant in the two magnification ranges. However, it is sufficient that the aperture amount remains constant in each of the two magnification ranges, and the aperture amounts in the two magnification ranges do not have to be the same. Furthermore, "constant" includes errors that are practically permissible in the art to which the technology of this disclosure belongs. By configuring the aperture amount to remain constant in the two frequently used magnification ranges described above, abrupt changes in brightness do not occur in these two magnification ranges, and thus the user experience can be improved compared to when this configuration is not used.

[0059] In Figures 3 and 4, the range indicated by Wc, which is near the wide-angle end, is 0 < {log 10 (ZR) / log 10 (ZRmax) corresponds to < 0.15, The range indicated by Tc, which is near the telephoto end, is 0.85 < {log 10 (ZR) / log 10 (ZRmax) corresponds to {ZRmax} < 1.

[0060] Similarly, for the same reasons as above, the magnification range in which the aperture can be changed is, 0.15 < {log 10 (ZR) / log 10 (ZRmax) {<0.85} It is preferable to configure it in this manner. By configuring it to limit the variable magnification range in which the aperture amount can be changed to the above range, abrupt changes in brightness do not occur in the two frequently used variable magnification ranges, thus improving the user experience compared to when it is not configured in this way.

[0061] When changing the aperture, it is preferable that the lens processor 8 controls the aperture within a range that satisfies the following condition (2). 0.05 < |F1-F0| < 1 (2) The definitions of each symbol used in conditional equation (2) are as follows: F0 is the F-number of zoom lens 1 before the change in aperture. F1 is the F-number of zoom lens 1 after the change in aperture. For example, when the aperture is changed while having a predetermined magnification ratio, F0 and F1 are the values ​​in that predetermined magnification ratio state.

[0062] By ensuring that the corresponding value in condition (2) does not exceed the upper limit, the change in the F-number before and after the change in aperture can be suppressed, thereby reducing the change in brightness of the captured image before and after the change in aperture. By ensuring that the corresponding value in condition (2) does not fall below the lower limit, the same effect as when the corresponding value in condition (1) does not fall below the lower limit can be obtained.

[0063] A more preferable embodiment is to satisfy the following condition (2-1) instead of condition (2), and an even more preferable embodiment is to satisfy the following condition (2-2) instead of condition (2). 0.05 < |F1 - F0| < 0.75 (2-1) 0.05 < |F1 - F0| < 0.5 (2-2)

[0064] Table 2 shows the values ​​for conditional equation (2) in Examples A, B, and C in Figure 4. Table 2 shows the logarithm during changes in aperture diameter. 10 The value of (ZR) is also shown.

[0065] [Table 2]

[0066] Incidentally, in images captured with a typical photographic lens, the edges of the image are darker than the center, so it is preferable to consider the brightness of the edges of the image when determining the brightness of the captured image. For this reason, when changing the aperture, it is preferable for the lens processor 8 to control the aperture within a range that satisfies the following condition (3). |(V1-V0) / V0|×100<20 (3) The definitions of each symbol used in conditional equation (3) are as follows: V0 is the peripheral illumination ratio at the maximum image height of zoom lens 1 before the change in aperture. V1 is the peripheral illumination ratio at the maximum image height of zoom lens 1 after the change in aperture. For example, when the aperture is changed while having a predetermined magnification ratio, V0 and V1 are the values ​​in that predetermined magnification ratio state. By satisfying conditional equation (3), changes in brightness at the edges of the image can be suppressed during magnification.

[0067] A more preferable embodiment is to satisfy the following condition (3-1) instead of condition (3). |(V1-V0) / V0|×100<15 (3-1)

[0068] Figure 5 shows the relationship between the magnification ratio and the peripheral illumination ratio when the aperture diameter is controlled as shown in Figure 3, in the embodiment of zoom lens 1 shown in Figure 8. The horizontal axis in Figure 5 is the same as the horizontal axis in Figure 3. The vertical axis in Figure 5 is the peripheral illumination ratio at the maximum image height of this embodiment, with the unit being % (percent). In Figure 5, the data for Example A, Example B, and Example C are shown as solid, dashed, and dotted lines, respectively.

[0069] Table 3 shows the values ​​for conditional equation (3) in Examples A, B, and C in Figure 5. Table 3 shows the logarithm during changes in aperture diameter. 10 The value of (ZR) is also shown.

[0070] [Table 3]

[0071] In this embodiment, the aperture amount remains constant in the magnification range where the aperture diameter remains constant. As shown in the example in Figure 3, when there is a magnification range where the aperture amount remains constant, it is preferable for the lens processor 8 to control the aperture amount within a range that satisfies the following condition (4) in multiple magnification ranges where the aperture amount remains constant. Vmax / Vmin<3.5 (4) The definitions of the symbols used in conditional equation (4) are as follows: Vmax and Vmin are the maximum and minimum values ​​of the peripheral illumination ratio at the maximum image height of zoom lens 1 in each magnification range where the aperture is constant, respectively. By satisfying conditional equation (4), changes in brightness at the edges of the image can be suppressed during magnification.

[0072] In order to better suppress changes in brightness at the edges of the image during magnification, it is preferable that the lens processor 8 controls the aperture within a range that satisfies condition (4) in the entire magnification range where the aperture remains constant.

[0073] A more preferable embodiment is to satisfy the following condition (4-1) instead of condition (4), and an even more preferable embodiment is to satisfy the following condition (4-2) instead of condition (4). Vmax / Vmin < 3 (4-1) Vmax / Vmin < 2 (4-2)

[0074] Table 4 shows the values ​​for conditional equation (4) in Examples A, B, and C in Figure 5. In Table 4, in each example, the magnification ranges in which the aperture amount remains constant are designated as the 1st magnification range, 2nd magnification range, 3rd magnification range, and so on, starting from the wide-angle side.

[0075] [Table 4]

[0076] In all three examples A, B, and C shown in Figure 5, the peripheral illumination ratio at maximum image height corresponds to the logarithmic end. 10 At the point where (ZR)=0, the minimum value across the entire multiplication range is 27.3%.

[0077] As shown in the example in Figure 5, the zoom lens 1 may be configured such that the minimum value of the peripheral illumination ratio at the maximum image height across the entire zoom range is less than 40%. This configuration is advantageous for reducing the diameter of the zoom lens 1. To further reduce the diameter of the zoom lens 1, it is preferable to configure it so that the minimum value of the peripheral illumination ratio at the maximum image height across the entire zoom range is less than 35%.

[0078] Furthermore, the zoom lens 1 may be configured such that the peripheral illumination ratio at the maximum image height at the wide-angle end is less than 50%. This configuration is also advantageous for reducing the diameter of the zoom lens 1. To further reduce the diameter of the zoom lens 1, it is preferable to configure it so that the peripheral illumination ratio at the maximum image height at the wide-angle end is less than 45%.

[0079] Next, the process of controlling the aperture diameter will be explained with reference to the flowchart in Figure 6. In step S10, the lens processor 8 monitors the magnification state based on the signal output from the magnification state detection unit 13 as the result of detecting the magnification state. For example, the lens processor 8 reads the signal from the magnification state detection unit 13 at predetermined time intervals and monitors whether the current magnification state has changed from the magnification state at the time of the previous readout.

[0080] In step S11, the lens processor 8 determines whether the current magnification state has changed from the magnification state at the time of the last readout. If the lens processor 8 determines that the magnification state has not changed (step S11: NO), it continues to monitor the magnification state.

[0081] If the lens processor 8 determines that the magnification state has changed (step S11: YES), it proceeds to step S12. In step S12, the lens processor 8 refers to the table data 24 and obtains the target aperture diameter corresponding to the current magnification state. For example, if the magnification ratio is used as the information for the magnification state, the lens processor 8 determines which of the first, second, third, ... magnification ranges of the table data 24 the current magnification ratio corresponds to, and obtains the target aperture diameter associated with the corresponding magnification range.

[0082] In the control example shown in Figure 3, if the current scaling ratio corresponds to the boundary value of the divided scaling range, the target aperture diameter may be determined according to the direction of scaling. The direction of scaling refers to the direction from wide-angle to telephoto, or from telephoto to wide-angle. For example, if the current scaling ratio corresponds to the boundary value between the first and second scaling ranges, the target aperture diameter associated with the second scaling range may be obtained when scaling from wide-angle to telephoto, and the target aperture diameter associated with the first scaling range may be obtained when scaling from telephoto to wide-angle.

[0083] In step S13, the lens processor 8 detects the current aperture diameter based on the signal output from the aperture diameter detection unit 15.

[0084] In step S14, the lens processor 8 determines whether the target aperture diameter obtained from the table data 24 is the same as the detected current aperture diameter.

[0085] If the lens processor 8 determines that the target aperture diameter and the detected current aperture diameter are the same (step S14: YES), it proceeds to step S16. If the lens processor 8 determines that the target aperture diameter and the detected current aperture diameter are different (step S14: NO), in step S15, it outputs a control signal to the aperture drive unit 14 to drive the aperture 4 to the same aperture diameter as the target aperture diameter.

[0086] In step S16, the lens processor 8 determines whether the power is off or not. If it determines that the power is off (step S16: YES), the process ends. If it determines that the power is not off (step S16: NO), the process proceeds to step S10.

[0087] [Differences in camera systems] Next, a modified version of the camera system will be described. In the above embodiment, an example was described in which the lens processor 8 performs the processing shown in Figure 6, but other configurations are also possible. For example, the camera body 50 may be equipped with table data 24, the main body processor 58 may perform the processing shown in Figure 6, the main body processor 58 may send a signal to the lens processor 8 to drive the aperture 4, and the lens processor 8 may output a control signal to the aperture drive unit 14 to drive the aperture 4 based on this signal. In other words, the "processor" that controls the aperture amount of the aperture 4 according to the technology of this disclosure may be realized by a combination of the lens processor 8 and the main body processor 58.

[0088] Alternatively, the camera body 50 may be equipped with table data 24, and the main unit processor 58 may perform the processing shown in Figure 6 and output a control signal to the aperture drive unit 14 to drive the aperture 4 without going through the lens processor 8. In this case, the main unit processor 58 may output control signals to the variable magnification lens drive unit 12 and the focus lens drive unit 16 without going through the lens processor 8. In other words, the "processor" that controls the aperture amount of the aperture 4 according to the technology of this disclosure may be realized in the main unit processor 58. Figure 7 shows a functional configuration diagram of a modified camera system 200 configured in this way.

[0089] The camera system 200 in Figure 7 comprises a lens unit 210 and a camera body 250 to which the lens unit 210 is detachably and communicatively mounted. The camera body 250 is provided with a mount 30 to which the lens unit 210 is detachably mounted. By mounting the lens unit 210 to the mount 30, the lens unit 210 and the camera body 250 are electrically connected.

[0090] The camera system 200 in Figure 7 differs from the camera system 100 in Figure 1 mainly in the following respects. The camera body 250 is equipped with memory 20 and storage 22. In the camera system 200, the magnification state detection unit 13, the aperture diameter detection unit 15, and the focus detection unit 17 each output their detection results to the main unit processor 58 included in the camera body 250 via the mount 30. In the camera system 200, the magnification lens drive unit 12, the aperture drive unit 14, and the focus lens drive unit 16 receive control signals from the main unit processor 58 via the mount 30. When the main unit processor 58 receives information about the magnification state from the magnification state detection unit 13, it obtains the target aperture diameter corresponding to the magnification state by referring to the table data 24 in the storage 22, and if the aperture diameter is different from the target aperture diameter, it outputs a control signal to the aperture drive unit 14 so that the aperture diameter becomes the same as the target aperture diameter. Alternatively, a lens driver IC (Integrated circuit) may be provided in the lens unit 210 that receives control signals from the main processor 58 and outputs control signals to the variable magnification lens drive unit 12, the aperture drive unit 14, and / or the focus lens drive unit 16.

[0091] [Examples of zoom lenses] Next, an embodiment of the zoom lens 1 will be described. Figure 8 shows the configuration of a cross-section including the optical axis AX of one embodiment of the zoom lens 1. In Figure 8, the left side is the object side and the right side is the image side. The zoom lens 1 in Figure 8 consists of five lens groups in which the distance between adjacent lens groups changes when the magnification is changed. More specifically, the zoom lens 1 in Figure 8 consists of, in order from the object side to the image side along the optical axis AX, a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with negative refractive power, and a fifth lens group G5 with positive refractive power. Between the fifth lens group G5 and the image plane Sim, a parallel plate-shaped optical element PP, which is assumed to be various filters and / or cover glass, is arranged.

[0092] The configuration consisting of five lens groups is advantageous for achieving a high magnification ratio. Furthermore, by making the first lens group G1 a lens group with positive refractive power, the overall length of the lens system can be easily shortened, which is advantageous for achieving both miniaturization and a high magnification ratio. By making the first lens group G1 a lens group with positive refractive power, the height of the light rays incident on the second lens group G2 from the optical axis AX becomes lower, which is advantageous for suppressing aberration fluctuations during magnification.

[0093] The first lens group G1 consists of three lenses, L11 to L13, arranged from the object side to the image side. The second lens group G2 consists of four lenses, L21 to L24, arranged from the object side to the image side. The third lens group G3 consists of an aperture diaphragm St and three lenses, L31 to L33, arranged from the object side to the image side. The fourth lens group G4 consists of two lenses, L41 to L42, arranged from the object side to the image side. The fifth lens group G5 consists of three lenses, L51 to L53, arranged from the object side to the image side.

[0094] The third lens group G3 includes an aperture diaphragm St. The aperture diaphragm St is an example of the "aperture" in the technology of this disclosure. In such a five-group zoom lens 1, it is preferable that the aperture diaphragm St is positioned between the object-side surface of the second lens group G2 and the image-side surface of the fourth lens group G4. Positioning the aperture diaphragm St in this range is advantageous for miniaturization compared to positioning the aperture diaphragm St in the first lens group G1 or the fifth lens group G5.

[0095] During magnification, the spacing between all adjacent lens groups changes. More specifically, in the example in Figure 8, during magnification, the first lens group G1, the third lens group G3, and the fifth lens group G5 are fixed relative to the image plane Sim, while the second lens group G2 and the fourth lens group G4 move along the optical axis AX by changing the spacing between adjacent lens groups. The grounding symbols below the first lens group G1, the third lens group G3, and the fifth lens group G5 in Figure 8 indicate that they are fixed relative to the image plane Sim during magnification. The curved arrows below the second lens group G2 and the fourth lens group G4 in Figure 8 show the approximate movement trajectories of these lens groups during magnification from the wide-angle end to the telephoto end. During focusing, the fourth lens group G4 moves along the optical axis AX. In the example in Figure 8, the lenses of the second lens group G2 and the fourth lens group G4 function as magnification lenses, and the lens of the fourth lens group G4 also functions as a focusing lens.

[0096] For zoom lens 1 in Figure 8, the basic lens data is shown in Table 5, the specifications and variable interplanar spacing in Table 6, and the aspherical coefficient in Table 7. The table of basic lens data is written as follows: The Sn column shows the surface number, with the surface closest to the object being the first surface and the number increasing by one as you move toward the image side. The R column shows the radius of curvature of each surface. The D column shows the interplanar spacing on the optical axis between each surface and the surface adjacent to it on the image side. The Nd column shows the refractive index of each component with respect to the d line. The νd column shows the Abbe number of each component with respect to the d line. In this specification, the wavelength of the d line is assumed to be 587.56 nm (nanometers).

[0097] In the basic lens data table, the sign of the radius of curvature of a surface with a convex shape facing the object is positive, and the sign of the radius of curvature of a surface with a convex shape facing the image is negative. In the column for the surface number of the surface corresponding to the aperture diaphragm St, the surface number and the phrase (St) are entered. The basic lens data table also shows the optical component PP. The value in the bottom column of column D of the table is the distance between the image-side surface in the table and the image plane Sim. For variable surface spacing, the symbol DD[ ] is used, and the object-side surface number for this spacing is written in column D with the [ ] inside.

[0098] Table 6 shows the magnification ratio ZR, focal length f, back focus Bf in air equivalent distance, F-number FNo. at wide open aperture, maximum angle of view 2ω, maximum image height IH, and variable plane spacing relative to the d line. The [°] in the 2ω column indicates that the unit is degrees. In Table 6, the columns labeled "Wide-angle end_Infinity" show the values ​​when the lens is in focus on an object at infinity at the wide-angle end, the columns labeled "Telephoto end_Infinity" show the values ​​when the lens is in focus on an object at infinity at the telephoto end, and the columns labeled "Telephoto end_Closest" show the values ​​when the lens is in focus on a close object at the telephoto end. However, f and Bf are shown only when the lens is in focus on an object at infinity. In this embodiment, the distance on the optical axis from the lens surface closest to the object to the closest object is 1.1 m (meters).

[0099] In the basic lens data, the aspherical surface number is marked with an asterisk (*), and the column for the radius of curvature of the aspherical surface lists the value of the paraxial radius of curvature. In Table 7, the row for Sn shows the aspherical surface number, and the rows for KA and Am show the aspherical coefficient values ​​for each aspherical surface. Note that m in Am is an integer greater than or equal to 3 and varies depending on the surface. For example, for surface 6, m = 4, 6, 8, ..., 20. The value of the aspherical coefficient in Table 7, "E±n" (n: integer), is "×10 ±n This means "[...]. KA and Am are the aspheric coefficients in the aspheric equation expressed by the following formula. Zd = C × h 2 / {1+(1-KA×C 2 ×h 2 ) 1 / 2}+ΣAm×h m however, Zd: Aspherical depth (length of the perpendicular line drawn from a point on the aspherical surface at height h to a plane perpendicular to the optical axis AX to which the aspherical surface vertex is tangent). h: Height (distance from optical axis AX to lens surface) C: Reciprocal of the radius of paraxial curvature KA, Am: Aspherical coefficients Therefore, the Σ in aspherical formulas represents the summation with respect to m.

[0100] In the data in the following tables, degrees are used as the unit for angles and millimeters (mm) as the unit for lengths. However, since optical systems can be used with proportional magnification or reduction, other appropriate units can also be used. Furthermore, the values ​​in the following tables are rounded to a predetermined number of decimal places.

[0101] [Table 5]

[0102] [Table 6]

[0103] [Table 7]

[0104] The above embodiments are merely examples, and the variable magnification optical system of this disclosure can be modified in various ways. For example, the radius of curvature, interplanar spacing, refractive index, Abbe number, and aspherical coefficient of each lens are not limited to the values ​​shown in the above embodiments, but can take other values. The number of lens groups constituting the variable magnification optical system of this disclosure, and the number of lenses included in each lens group, may be different from the example in Figure 8. In the example in Figure 8, the lens group including the aperture diaphragm St is fixed during magnification, but the lens group including the aperture diaphragm St may be configured to move during magnification. Furthermore, the variable magnification optical system of this disclosure is not limited to zoom lenses, but may also be a varifocal lens.

[0105] The technology disclosed herein is applicable not only to interchangeable-lens digital cameras but also to fixed-lens digital cameras. Furthermore, the technology disclosed herein is applicable to various optical devices other than digital cameras, such as video cameras, cinema cameras, and security cameras.

[0106] In the above embodiment, an example was given in which the entire multiplication range is divided into three or five multiplication ranges for control. However, in the technology of this disclosure, the number of divisions in the multiplication range can be arbitrarily changed. Furthermore, the method for determining the target aperture amount according to the multiplication state is not limited to the above example and can be arbitrarily changed. In the above, an example was described in which control is performed using table data that associates the multiplication state with the aperture amount. However, instead of table data, a function that associates the multiplication state with the aperture amount, or a relational expression that associates the multiplication state with the aperture amount may be used. The above-described preferred control, preferred configuration, and possible configuration can be arbitrarily selected and combined according to the required specifications, in addition to control within the range that satisfies condition (1).

[0107] The descriptions and illustrations presented above are detailed explanations of the technical aspects of this disclosure and are merely examples of the technical aspects. For example, the above descriptions of the structure, function, operation, and effect are examples of the structure, function, operation, and effect of the technical aspects of this disclosure. Therefore, it goes without saying that you may delete unnecessary parts, add new elements, or replace elements in the descriptions and illustrations presented above, as long as you do not deviate from the essence of the technical aspects of this disclosure. Furthermore, in order to avoid confusion and facilitate understanding of the technical aspects of this disclosure, explanations of common technical knowledge and the like that do not require special explanation to enable the implementation of the technical aspects of this disclosure have been omitted from the descriptions and illustrations presented above.

[0108] In this specification, "A and / or B" is synonymous with "at least one of A and B." That is, "A and / or B" means that it may be A alone, or B alone, or a combination of A and B. Furthermore, in this specification, the same concept as "A and / or B" applies when expressing three or more things linked by "and / or."

[0109] All documents, patent applications, and technical standards described herein are incorporated by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted to be incorporated by reference. [Explanation of Symbols]

[0110] 1 Zoom lens 2x variable lens 4 aperture 6 Focus Lenses 8 Lens Processors 10 Lens Units 12. Variable magnification lens drive unit 13. Variable Distortion Detection Unit 14 Aperture drive unit 15 Aperture diameter detection unit 16 Focus lens drive unit 17 Focus detection unit 20 memory 22 storage 23 Programs 24 Table Data 30 Mount 50 Camera body 52 Image sensors 54 Display section 56 Operation section 58 Main Processor 100 Camera System 200 Camera System 210 Lens Unit 250 Camera Body AX optical axis G1 First Lens Group G2 Second Lens Group G3 3rd lens group G4 4th lens group G5 5th lens group L11~L53 Lenses PP optical components Sim image plane St aperture diaphragm

Claims

1. A variable magnification optical system equipped with an aperture to adjust the amount of light, A processor that controls the aperture amount of the aperture based on information regarding the magnification of the magnification optical system, The maximum value of the F-number across the entire magnification range of the aforementioned variable magnification optical system is Fmax. The minimum value of the F-number over the entire magnification range of the aforementioned variable magnification optical system is Fmin. If the average value of the F-number at the wide-angle end and the F-number at the telephoto end of the variable magnification optical system is defined as Fave, 3<{(Fmax-Fmin) / Fave}×100<10 (1) The system includes a processor that controls the aperture amount within a range that satisfies the conditional expression (1) represented by, When changing the aperture amount while having a predetermined multiplication ratio, The maximum magnification ratio of the aforementioned magnification optical system is ZRmax, When the magnification ratio of the aforementioned magnification optical system is ZR, 0.15 < {log} １０ (ZR) / log １０ (ZRmax) { < 0.85} A lens unit in which the F-number of the variable magnification optical system takes Fmax and Fmin.

2. A variable magnification optical system equipped with an aperture to adjust the amount of light, A processor that controls the aperture amount of the aperture based on information regarding the magnification of the magnification optical system, The maximum value of the F-number across the entire magnification range of the aforementioned variable magnification optical system is Fmax. The minimum value of the F-number over the entire magnification range of the aforementioned variable magnification optical system is Fmin. If the average value of the F-number at the wide-angle end and the F-number at the telephoto end of the variable magnification optical system is defined as Fave, 3<{(Fmax-Fmin) / Fave}×100<10 (1) The system includes a processor that controls the aperture amount within a range that satisfies the conditional expression (1) represented by, When changing the aperture amount while having a predetermined multiplication ratio, The maximum magnification ratio of the aforementioned magnification optical system is ZRmax, When the magnification ratio of the aforementioned magnification optical system is ZR, 0 < {log} １０ (ZR) / log １０ (ZRmax)} < 0.15, and 0.85 < {log} １０ (ZR) / log １０ (ZRmax) {< 1} in the multiplication range A lens unit in which the aforementioned aperture size remains constant.

3. A variable magnification optical system equipped with an aperture to adjust the amount of light, A processor that controls the aperture amount of the aperture based on information regarding the magnification of the magnification optical system, The maximum value of the F-number across the entire magnification range of the aforementioned variable magnification optical system is Fmax. The minimum value of the F-number over the entire magnification range of the aforementioned variable magnification optical system is Fmin. If the average value of the F-number at the wide-angle end and the F-number at the telephoto end of the variable magnification optical system is defined as Fave, 3<{(Fmax-Fmin) / Fave}×100<10 (1) The system includes a processor that controls the aperture amount within a range that satisfies the conditional expression (1) represented by, When changing the aperture amount while having a predetermined multiplication ratio, The maximum magnification ratio of the aforementioned magnification optical system is ZRmax, When the magnification ratio of the aforementioned magnification optical system is ZR, The variable magnification range in which the aperture can be changed is 0.15 < {log} １０ (ZR) / log １０ A lens unit where (ZRmax) < 0.

85.

4. When Vmax and Vmin are the maximum and minimum values ​​of the peripheral light intensity ratio at the maximum image height of the magnification optical system in each magnification region where the aperture amount remains constant, The aforementioned processor, In multiple multiplication regions where the aperture amount remains constant Vmax / Vmin<3.5 (4) The lens unit according to any one of claims 1 to 3, wherein the aperture amount is changed within a range that satisfies the conditional expression (4) represented by .

5. The aforementioned processor, In the entire range of the magnification region in which the aperture amount remains constant Vmax / Vmin<3.5 (4) The lens unit according to claim 4, wherein the aperture amount is changed within a range that satisfies the conditional expression (4) represented by .

6. The lens unit according to any one of claims 1 to 5, wherein the minimum value of the peripheral light intensity ratio at the maximum image height of the variable magnification optical system over the entire magnification range of the variable magnification optical system is less than 40%.

7. The lens unit according to any one of claims 1 to 5, wherein the minimum value of the peripheral light intensity ratio at the maximum image height of the variable magnification optical system over the entire magnification range of the variable magnification optical system is less than 35%.

8. The lens unit according to any one of claims 1 to 7, wherein the peripheral illumination ratio at the wide-angle end of the variable magnification optical system is less than 50% at the maximum image height of the variable magnification optical system.

9. The lens unit according to any one of claims 1 to 7, wherein the peripheral illumination ratio at the wide-angle end of the variable magnification optical system is less than 45% at the maximum image height of the variable magnification optical system.

10. The aforementioned variable magnification optical system is From the object side to the image side, it consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with negative refractive power, and a fifth lens group with positive refractive power. When magnification is applied, the spacing between all adjacent lens groups changes. The lens unit according to any one of claims 1 to 8, wherein the aperture is positioned between the object-side surface of the second lens group and the image-side surface of the fourth lens group.

11. The aforementioned processor, In multiple multiplication regions where the aperture amount remains constant Vmax / Vmin<3 (4-1) The lens unit according to claim 4, wherein the aperture amount is changed within a range that satisfies the conditional expression (4-1) represented by .

12. The aforementioned processor, In multiple multiplication regions where the aperture amount remains constant Vmax / Vmin<2 (4-2) The lens unit according to claim 4, wherein the aperture amount is changed within a range that satisfies the conditional expression (4-2) represented by .

13. A variable magnification optical system equipped with an aperture to adjust the amount of light, A detection unit for detecting the magnification state of the magnification optical system, A processor that controls the aperture amount of the aperture based on the detection result of the detection unit, The maximum value of the F-number across the entire magnification range of the aforementioned variable magnification optical system is Fmax. The minimum value of the F-number over the entire magnification range of the aforementioned variable magnification optical system is Fmin. If the average value of the F-number at the wide-angle end and the F-number at the telephoto end of the variable magnification optical system is defined as Fave, 3<{(Fmax-Fmin) / Fave}×100<10 (1) The system includes a processor that controls the aperture amount within a range that satisfies the conditional expression (1) represented by, When changing the aperture amount while having a predetermined multiplication ratio, The maximum magnification ratio of the aforementioned magnification optical system is ZRmax, When the magnification ratio of the aforementioned magnification optical system is ZR, 0.15 < {log １０ (ZR) / log １０ (ZRmax)} < 0.85 in the zoom range A camera system in which the F-number of the variable magnification optical system takes Fmax and Fmin.

14. A variable magnification optical system equipped with an aperture to adjust the amount of light, A detection unit for detecting the magnification state of the magnification optical system, A processor that controls the aperture amount of the aperture based on the detection result of the detection unit, The maximum value of the F-number across the entire magnification range of the aforementioned variable magnification optical system is Fmax. The minimum value of the F-number over the entire magnification range of the aforementioned variable magnification optical system is Fmin. If the average value of the F-number at the wide-angle end and the F-number at the telephoto end of the variable magnification optical system is defined as Fave, 3<{(Fmax-Fmin) / Fave}×100<10 (1) The system includes a processor that controls the aperture amount within a range that satisfies the conditional expression (1) represented by, When changing the aperture amount while having a predetermined multiplication ratio, The maximum magnification ratio of the aforementioned magnification optical system is ZRmax, When the magnification ratio of the aforementioned magnification optical system is ZR, 0 < {log} １０ (ZR) / log １０ (ZRmax)} < 0.15, and 0.85 < {log} １０ (ZR) / log １０ (ZRmax) {< 1} in the multiplication range A camera system in which the aperture size remains constant.

15. A variable magnification optical system equipped with an aperture to adjust the amount of light, A detection unit for detecting the magnification state of the magnification optical system, A processor that controls the aperture amount of the aperture based on the detection result of the detection unit, The maximum value of the F-number across the entire magnification range of the aforementioned variable magnification optical system is Fmax. The minimum value of the F-number over the entire magnification range of the aforementioned variable magnification optical system is Fmin. If the average value of the F-number at the wide-angle end and the F-number at the telephoto end of the variable magnification optical system is defined as Fave, 3<{(Fmax-Fmin) / Fave}×100<10 (1) The system includes a processor that controls the aperture amount within a range that satisfies the conditional expression (1) represented by, When changing the aperture amount while having a predetermined multiplication ratio, The maximum magnification ratio of the aforementioned magnification optical system is ZRmax, When the magnification ratio of the aforementioned magnification optical system is ZR, The variable magnification range in which the aperture can be changed is 0.15 < {log} １０ (ZR) / log １０ A camera system where (ZRmax) < 0.85.

Images