JP5845665B2 - Lens barrel and camera system - Google Patents

Description

  The present invention relates to a lens barrel and a camera system.

  Conventionally, in a camera having a focusing lens, it is known that the driving range of the focusing lens changes due to a change in environmental temperature. For example, Patent Document 1 describes a video camera that adjusts a correction amount according to a temperature change at the close end and the infinite end of cam trajectory data.

JP-A-11-142714

  Patent Document 1 does not disclose any specific configuration for temperature correction in an interchangeable lens camera system.

The lens barrel according to claim 1 is capable of transmitting and receiving signals between a camera body and a mounting portion to which a camera body can be attached, an imaging optical system having a focusing lens that can change a focal length, and the camera body. A transmission / reception unit, a drive unit that drives the focusing lens with a drive amount corresponding to a drive signal received from the camera body via the transmission / reception unit, a temperature detection unit that detects the temperature of the lens barrel and outputs a temperature signal, and a temperature A calculation unit that calculates the correction amount of the driving position of the focusing lens based on the signal, a determination unit that determines whether the correction amount needs to be transmitted to the camera body via the transmission / reception unit, and the determination unit And a control unit that controls the transmission / reception unit so that the transmission / reception unit transmits the correction amount to the camera body.
  The lens barrel according to claim 5 is detected by a focusing lens used for focus control, a transmission / reception unit capable of transmitting / receiving signals between the camera body, and a temperature detection unit provided in the lens barrel. A calculation unit that calculates the correction amount of the focusing lens position based on the temperature, a determination unit that determines whether to transmit the correction amount to the camera body via the transmission / reception unit, and a determination unit that determines that the correction amount is transmitted In this case, the transmission / reception unit includes a control unit that controls the transmission / reception unit so as to transmit the correction amount to the camera body.
  A camera system according to a seventeenth aspect includes the lens barrel according to any one of the first to sixteenth aspects, and a camera body that can be attached to the lens barrel.

  According to the present invention, suitable focus adjustment can be performed.

1 is a perspective view showing an interchangeable lens type camera system according to a first embodiment. It is sectional drawing which showed the lens-interchangeable camera system which concerns on 1st Embodiment. 2 is a cross-sectional view of a lens barrel 200 showing the arrangement of a temperature sensor 214. FIG. It is a schematic diagram which shows the detail of the connection parts 102 and 202. FIG. It is a schematic diagram which shows the drive range of the focusing lens 210b. It is a figure which shows the correction information table and soft limit table which are memorize | stored in ROM215. It is sectional drawing which showed the lens-interchangeable camera system which concerns on the 2nd Embodiment of this invention. It is a figure which shows the correction | amendment information table memorize | stored in ROM215 which concerns on 2nd Embodiment. It is a figure which shows the correction relevant data memorize | stored in ROM215 which concerns on 3rd Embodiment.

(First embodiment)
FIG. 1 is a perspective view showing an interchangeable lens type camera system to which the present invention is applied. FIG. 1 shows only devices and apparatuses according to the present invention, and illustration and description of other devices and apparatuses are omitted. The camera system 1 includes a camera body 100 and a lens barrel 200 that can be attached to and detached from the camera body 100.

  The camera body 100 is provided with a lens mount 101 to which a lens barrel 200 can be attached. The lens barrel 200 is provided with a lens mount 201 to which the camera body 100 can be attached, corresponding to the lens mount 101 on the camera body side. When the lens barrel 200 is attached, the connection portion 102 including a plurality of contacts provided on the lens mount 101 is changed to a connection portion 202 including a plurality of contacts provided on the lens mount 201 of the lens barrel 200. Connected. The connection units 102 and 202 are used for power supply from the camera body 100 to the lens barrel 200 and transmission / reception of various signals between the camera body 100 and the lens barrel 200.

  An imaging element 104 is provided behind the lens mount 101 (in the camera body 100). Above the housing of the camera body 100, buttons 17a and 17b serving as input devices are provided. The user uses these buttons 17a and 17b to instruct the camera body 100 to shoot, set shooting conditions, and the like.

  FIG. 2 is a cross-sectional view showing an interchangeable lens type camera system to which the present invention is applied. The lens barrel 200 includes a photographing optical system 210 that forms a subject image. The photographing optical system 210 includes a plurality of lenses such as a front lens 210a, a focusing lens 210b, and a shake correction lens 210c. The focusing lens 210b is a lens for controlling the focus position of the subject image, and the blur correction lens 210c is a lens for correcting the image blur of the subject image.

  Inside the lens barrel 200, a lens-side control circuit 203 that controls each part of the lens barrel 200 is provided. The lens side control circuit 203 includes a microcomputer (not shown) and its peripheral circuits. A lens driving unit 212, a lens position detection unit 213, a temperature sensor 214, a ROM 215, a RAM 216, and a lens side transmission / reception unit 217 are connected to the lens side control circuit 203.

  The lens driving unit 212 includes an actuator such as a stepping motor, for example, and drives the focusing lens 210b with a driving amount corresponding to a driving signal input to the lens driving unit 212. The lens side control circuit 203 outputs a drive signal to the lens drive unit 212 in accordance with a drive command received from the camera body 100 via the lens side transmission / reception unit 217. That is, the lens driving unit 212 drives the focusing lens 210b with a driving amount corresponding to the driving command received from the camera body 100 via the lens side transmitting / receiving unit 217.

  The lens position detector 213 detects the position of the focusing lens 210b and outputs a lens position signal. The lens position detection unit 213 detects the position of the focusing lens 210b by counting the number of pulses of the stepping motor included in the lens driving unit 212, for example. Alternatively, the position of the focusing lens 210b may be detected using a known distance encoder or the like provided in the lens barrel 200.

  The temperature sensor 214 is a sensor that detects the temperature of the lens barrel 200 and outputs a temperature signal. The ROM 215 is a non-volatile storage medium, and stores in advance a predetermined control program executed by the lens-side control circuit 203, a correction information table described later, and the like. The RAM 216 is a volatile temporary storage medium and is used as a temporary storage area for various data by the lens-side control circuit 203. The lens side transmission / reception unit 217 is an electronic circuit capable of transmitting / receiving a signal to / from the camera body 100. The lens side transmission / reception unit 217 transmits / receives a signal to / from the camera body 100 via the connection unit 202 in accordance with an instruction from the lens side control circuit 203.

  The lens side control circuit 203 includes a correction calculation unit 231 and a transmission determination unit 232. Each of these functional units is realized by software by the lens side control circuit 203 executing a predetermined control program stored in the ROM 215.

  The correction calculation unit 231 calculates the correction amount of the driving position of the focusing lens 210b based on the temperature signal output from the temperature sensor 214. The correction amount here will be described in detail later. The transmission determination unit 232 determines whether or not the correction amount calculated by the correction calculation unit 231 needs to be transmitted to the camera body 100 via the lens side transmission / reception unit 217. When the transmission determining unit 232 determines that the correction amount needs to be transmitted, the lens side control circuit 203 determines the correction amount, the closest limit position (described later), and the infinite limit position (described later). The lens side control circuit 203 is controlled to transmit to the camera body 100.

  Note that the transmission determination unit 232 according to the present embodiment needs to transmit the correction amount when a predetermined time (for example, 16 milliseconds) has elapsed since the last correction amount was transmitted by the lens-side transmission / reception unit 217. Judge that there is.

  A shutter 115 and a filter 116 are provided on the front surface of the image sensor 104. The subject light transmitted through the photographing optical system 210 enters the image sensor 104 through the shutter 115 and the filter 116. The shutter 115 controls the exposure state of the image sensor 104. The filter 116 is an optical filter that combines an optical low-pass filter and an infrared cut filter.

  Inside the camera body 100, a body-side control circuit 103 that controls each part of the camera body 100 is provided. The body side control circuit 103 is composed of a microcomputer, a RAM and its peripheral circuits (not shown). The body side control circuit 103 is connected to the body side transmitting / receiving unit 117. The body side transmission / reception unit 117 is configured to be able to transmit and receive signals to and from the lens barrel 200 via the connection unit 102.

  A display device 111 configured by an LCD panel or the like is disposed on the back surface of the camera body 100. The body-side control circuit 103 displays various menu screens for setting a subject image (so-called through image) based on the output of the image sensor 104, shooting conditions, and the like on the display device 111.

(Explanation of automatic focus adjustment)
The body side control circuit 103 is configured to execute a known automatic focus adjustment process. In this automatic focus adjustment process, the body side control circuit 103 is configured to be able to use two types of focus detection processes properly. Specifically, the body-side control circuit 103 can selectively use a so-called imaging surface phase difference detection type focus detection process and a so-called contrast detection type focus detection process. The body-side control circuit 103 uses these two types of focus detection processing properly depending on the shooting situation, the characteristics of the subject, and the like.

  The focus detection process of the imaging surface phase difference detection method by the body side control circuit 103 will be described. The image sensor 104 of the present embodiment has focus detection pixels (referred to as focus detection pixels). The focus detection pixels are the same as those described in Japanese Patent Application Laid-Open No. 2007-317951. The body side control circuit 103 performs a focus detection process by performing a known phase difference detection calculation using pixel output data from the focus detection pixels. The phase difference detection calculation is the same as that described in, for example, Japanese Patent Application Laid-Open No. 2007-317951, and thus the description thereof is omitted. The body side control circuit 103 performs automatic focus adjustment by driving the focusing lens 210b based on the defocus amount obtained by the focus detection process.

  The contrast detection focus detection processing by the body side control circuit 103 will be described. The body side control circuit 103 performs a well-known contrast detection calculation using pixel output data from the imaging pixels included in the imaging element 104. The body side control circuit 103 performs this contrast detection calculation while driving the focusing lens 210b between the closest drive limit position and the infinity drive limit position, and the focus evaluation value (contrast value) peaks. Automatic focus adjustment is performed by detecting the position of the focusing lens 210b.

(Description of temperature sensor 214)
FIG. 3 is a cross-sectional view of the lens barrel 200 showing the arrangement of the temperature sensor 214. The left side of FIG. 3 is the subject direction, and the right side of FIG. 3 is the camera body 100 direction. In the lens barrel 200, a main substrate 242 on which the lens side control circuit 203 and the like are arranged is provided. The shake correction lens 210c is fixed to the shake correction substrate 241 with a spring or the like. On the shake correction substrate 241, a voice coil motor (not shown) for driving the shake correction lens 210c, a sensor (not shown) for detecting the position of the shake correction lens 210c, and the like are arranged. The shake correction board 241 and the main board 242 are electrically connected by a flexible cable 243. In the present embodiment, the temperature sensor 214 is mounted on the surface of the main board 242 on the camera body 100 side.

  Note that the temperature sensor 214 may be mounted on the surface of the flexible cable 243 as indicated by a broken line in FIG. Further, the temperature sensor 214 may be arranged at a location different from these positions.

(Description of data communication)
FIG. 4 is a schematic diagram showing details of the connection units 102 and 202. As shown in FIG. 4, each of the connection units 102 and 202 has eight contacts for transmitting and receiving signals. That is, there are eight signal lines corresponding to the respective contacts between the lens barrel 200 and the camera body 100 attached to the lens mount 201. In addition to these contacts, for example, there are contacts for supplying power from the camera body 100 to the lens barrel 200, and the description thereof is omitted here. Hereinafter, these eight signal lines are referred to as HCLK, HREQ, HANS, HDAT, CLK, RDY, BDAT, and LDAT, as shown in FIG.

  Of the eight signal lines described above, HCLK, HREQ, HANS, and HDAT constitute the first transmission path 310. Similarly, CLK, RDY, BDAT, and LDAT constitute the second transmission path 320. Hereinafter, these two types of transmission lines will be described.

  The first transmission path 310 is used for the lens-side control circuit 203 to transmit lens position information indicating the position of the focusing lens 210b to the camera body 100. The body side control circuit 103 changes the signal level of the HREQ every predetermined cycle (for example, 1 millisecond). The lens side control circuit 203 starts a communication preparation process in response to a change in the HREQ signal level. Specifically, the communication preparation process is a process of causing the lens position detection unit 213 to detect the position of the focusing lens 210b and generating lens position information to be transmitted to the camera body 100.

  When the communication preparation process is completed, the lens-side control circuit 203 changes the signal level of HANS. The body side control circuit 103 outputs a clock signal to HCLK in accordance with a change in the signal level of HANS. The lens side control circuit 203 outputs lens position information to the HDAT in synchronization with this clock signal.

  The second transmission path 320 is used to transmit a control instruction from the camera body 100 to the lens barrel 200 and to transmit various information from the lens barrel 200 to the camera body 100. The second transmission line 320 is a full-duplex transmission line. In other words, data is transmitted from the lens barrel 200 to the camera body 100 simultaneously with transmission of data from the camera body 100 to the lens barrel 200.

  When it becomes necessary to perform communication using the second transmission path 320, the body side control circuit 103 outputs a clock signal to CLK. At this time, the body side control circuit 103 outputs data to be transmitted to the BDAT in synchronization with the clock signal. On the other hand, the transmission / reception unit 233 outputs data to be transmitted to the LDAT in synchronization with the clock signal. Note that the transmission / reception unit 233 changes the RDY signal level depending on whether data transmission / reception is possible or not. For example, the RDY signal level is set to H when the transmission / reception unit 233 cannot transmit / receive data, and is set to L when the data transmission / reception is possible. The body-side control circuit 103 checks the RDY signal level before starting communication, and does not perform communication if the transmission / reception unit 233 cannot transmit / receive data.

  The body side control circuit 103 transmits various control signals to the lens barrel 200 using the second transmission path 320 described above. Examples of the control signal include a control signal for moving the focusing lens 210b in a infinity direction by a specific number of pulses (for example, 10 pulses), and a stop (not shown) by a specific number of stages (for example, two stages). There are control signals.

  In addition to the signals transmitted by the body side control circuit 103 using the second transmission path 320, there are request signals for requesting various types of information of the lens barrel 200. Examples of the request signal include a request signal for information indicating the focal length of the photographing optical system 210 and a request signal for information indicating the current aperture value of an aperture (not shown). When the transmission / reception unit 233 receives the request signal, the transmission / reception unit 233 transmits the corresponding information to the body-side control circuit 103 via the second transmission path 320.

  Note that the time required for the body-side control circuit 103 to receive some information from the lens-side control circuit 203 using the second transmission path 320 is the first transmission path 310 using the focusing lens 210b. This is larger than the time required to receive the position information. This is because the first transmission line 310 is informed that the lens side control circuit 203 is requesting data only by changing the signal level of HREQ, whereas the second transmission line 320 first receives CLK and BDAT. This is because it is necessary to transmit a request for specific information to the lens-side control circuit 203 using.

(Description of driving range by lens driving unit 212)
FIG. 5 is a schematic diagram showing a driving range of the focusing lens 210b. The focusing lens 210b is configured to be movable in the infinity direction 410 and the closest direction 420 on the optical axis 400 indicated by a one-dot chain line in FIG. A stopper (not shown) is provided at the end 430 in the infinity direction 410 and the end 440 in the closest direction 420 to limit the movement of the focusing lens 210b. In other words, the focusing lens 210b is configured to be movable from the end 430 in the infinity direction 410 to the end 440 in the closest direction 420.

  However, the range in which the lens driving unit 212 actually drives the focusing lens 210b is smaller than the range from the end 430 to the end 440 described above. Specifically, the moving range of the lens driving unit 212 is from an infinite soft limit position 450 provided inside the end 430 in the infinity direction 410 to a close distance provided inside the end 440 in the close direction 420. The focusing lens 210b is driven in the range up to the soft limit position 460. That is, the lens driving unit 212 drives the focusing lens 210b between the closest soft limit position 460 corresponding to the closest drive limit position and the infinite soft limit position 450 corresponding to the infinity drive limit position.

  The infinite soft limit position 450 is provided outside the infinite focus position 470. The infinite focusing position 470 is the position of the focusing lens 210b corresponding to the position on the most infinite side where the photographing optical system 210 can focus. The reason why the infinite soft limit position 450 is provided at such a position is that a peak of the focus evaluation value may exist at the infinite focus position 470 when performing automatic focus adjustment by a so-called hill climbing method. If the infinite focus position 470 is made to coincide with the infinite soft limit position 450, it is not desirable because the peak of the focus evaluation value existing at the infinite focus position 470 cannot be recognized as a peak. Similarly, the closest soft limit position 460 is provided outside the closest focus position 480. Here, the closest focus position 480 is the position of the focusing lens 210b corresponding to the closest position where the photographing optical system 210 can focus.

  In the present embodiment, the position of the focusing lens 210b is represented by the number of pulses of the driving signal given to the lens driving unit 212. The number of pulses is set to the infinite focus position 470 as the origin (reference). For example, as shown in FIG. 4, the infinite soft limit position 450 is a position of -100 pulses, the closest focusing position 480 is a position of 9800 pulses, and the closest soft limit position 460 is a position of 9900 pulses. In this case, in order to move the focusing lens 210b from the infinite soft limit position 450 to the closest soft limit position 460, it is necessary to provide a drive signal for 10,000 pulses to the lens driving unit 212.

  Note that the infinite soft limit position 450, the closest soft limit position 460, and the closest focus position 480 may be different from the above numerical values, and may be different depending on the type or individual of the lens barrel.

(Explanation of correction information table)
For example, the body-side control circuit 103 needs to know the infinite soft limit position 450, the closest soft limit position 460, the infinite focus position 470, and the close focus position 480 when performing automatic focus adjustment. On the other hand, the amount of movement of the focusing lens 210b varies depending on the temperature change in the lens barrel 200. For example, in order to move the focusing lens 210b at the infinite focus position 470 to the closest focus position 480, the number of pulses of the drive signal input to the lens drive unit 212 varies.

  Therefore, in this embodiment, an infinite correction amount for correcting the infinite focus position 470 is stored in advance in the ROM 215 in association with the temperature detected by the temperature sensor 214 (that is, the temperature in the lens barrel 200). Then, an infinite correction amount corresponding to the current temperature is transmitted from the lens side control circuit 203 to the body side control circuit 103 via the second transmission path. The body-side control circuit 103 corrects the infinite focus position 470 and the closest focus position 480 by adjusting the received infinite correction amount to the infinite focus position 470 and the closest focus position 480.

  Strictly speaking, the fluctuation of the infinite focus position 470 with respect to the temperature change is different from the fluctuation of the closest focus position 480. Nevertheless, the reason why the infinite correction amount for correcting the infinite focus position 470 is also used to correct the closest focus position 480 is to reduce the amount of data stored in the ROM 215 and the communication amount of the second transmission path 320. is there.

  FIG. 6A shows a correction information table stored in the ROM 215. The correction information table 510 of this embodiment stores infinite correction amounts corresponding to every 10 degrees in a range from −10 degrees Celsius to +50 degrees Celsius. The correction calculation unit 231 calculates an infinite correction amount corresponding to the temperature by referring to the correction information table 510 with the temperature of the lens barrel represented by the temperature signal output from the temperature sensor 214.

  FIG. 6B shows a soft limit table stored in the ROM 215. The soft limit table 520 stores the closest soft limit position 460 and the infinite soft limit position 450 shown in FIG. The lens-side control circuit 203 includes the infinite soft limit position 460 and the infinite soft limit position stored in the soft limit table 520 together with the infinite correction amount calculated by the correction calculating unit 231 as described above. The lens-side transmitting / receiving unit 217 is controlled to transmit 450 to the camera body 100.

  Based on the received information, the body-side control circuit 103 determines the number of pulses for moving the focusing lens 210b to a target position, and determines the scan range of the focusing lens 210b in the contrast type focus detection processing. .

According to the camera system according to the first embodiment described above, the following operational effects can be obtained.
(1) The temperature sensor 214 detects the temperature of the lens barrel and outputs a temperature signal. The correction calculation unit 231 calculates the correction amount of the driving position of the focusing lens 210b based on the temperature signal output from the temperature sensor 214. When the transmission determination unit 232 determines that the correction amount needs to be transmitted to the camera body 100 via the lens side transmission / reception unit 217, the lens side control circuit 203 causes the lens side transmission / reception unit 217 to determine the correction amount. The lens-side transmitting / receiving unit 217 is controlled so as to transmit to. The camera body 100 transmits a drive signal for driving the focusing lens 210b based on the correction amount. The lens driving unit 212 drives the focusing lens 210b with a driving amount corresponding to the driving signal received from the camera body 100 via the lens side transmitting / receiving unit 217. Since it did in this way, in a camera system of an interchangeable lens type, appropriate temperature correction can be performed with the minimum communication amount.

(2) The transmission determination unit 232 determines that the correction amount needs to be transmitted when a predetermined time has elapsed since the last correction amount was transmitted by the lens side transmission / reception unit 217. Since it did in this way, the amount of corrections will not be transmitted more than necessary, and the amount of communication will be reduced.

(3) The lens driving unit 212 drives the focusing lens 210b between a close limit position corresponding to the close drive limit position and an infinite limit position corresponding to the infinite drive limit position. In the lens-side control circuit 203, the lens-side transmission / reception unit 217 transmits the closest limit position and the infinite limit position to the camera body 100 together with the correction amount. Since it did in this way, the camera body 100 can recognize easily that three data are data relevant to each other.

(4) The correction amount handled by the correction calculation unit 231 and the like is an infinite correction amount that corrects the infinite focus position corresponding to the position on the most infinite side where the photographing optical system 210 can focus. Since this is done, it is guaranteed that the subject positioned at least at infinity is accurately focused.

(Second Embodiment)
FIG. 7 is a cross-sectional view showing an interchangeable lens type camera system according to a second embodiment of the present invention. The description of the camera system 2 will be described below, but portions similar to those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and description thereof is omitted.

  The camera system 2 according to this embodiment includes a camera body 100 and a lens barrel 700. The lens barrel 700 is a so-called super telephoto lens. That is, the lens barrel 700 includes a photographing optical system 710 having a focal length that is equal to or longer than a predetermined length (for example, 200 mm).

  Since the focal length of the photographing optical system 710 is relatively large, the driving range of the focusing lens 210b and the total length of the lens barrel 700 are also relatively large. In this case, an appropriate temperature cannot be detected even if only one temperature sensor 214 is used as in the lens barrel 200 according to the first embodiment.

  Therefore, the lens barrel 700 of the present embodiment has two temperature sensors 214a and 214b. The temperature sensor 214a is disposed closer to the center of the driveable range of the focusing lens 210b. That is, the temperature sensor 214a can detect the temperature closer to the center of the driveable range of the focusing lens 210b. Similarly, the temperature sensor 214b is disposed on the infinity side from the center of the driveable range of the focusing lens 210b. That is, the temperature sensor 214b can detect the temperature at infinity from the center of the driveable range of the focusing lens 210b.

  The correction calculation unit 731 included in the lens-side control circuit 703 of the present embodiment is configured to focus either the closest correction amount or the infinite correction amount according to the lens position signal output from the lens position detection unit 213. Is calculated as a correction amount of the drive position. Specifically, when the focusing lens 210b is closer to the center of the drivable range, the correction calculator 731 calculates the closest correction amount. Conversely, when the focusing lens 210b is on the infinity side from the center of the drivable range, the correction calculator 731 calculates an infinite correction amount.

  The correction calculation unit 731 switches the temperature used for calculation of the correction amount among the two temperatures detected by the temperature sensors 214 a and 214 b according to the lens position signal output from the lens position detection unit 213. Specifically, when the focusing lens 210b is closer to the center of the drivable range, the correction calculation unit 731 corrects the correction amount (closest correction amount) based on the temperature detected by the temperature sensor 214a on the closest side. Is calculated. On the other hand, when the focusing lens 210b is on the infinity side from the center of the drivable range, the correction calculator 731 corrects the correction amount (infinite correction amount) based on the temperature detected by the temperature sensor 214b on the infinity side. Is calculated.

  FIG. 8 is a diagram illustrating a correction information table stored in the ROM 215 according to the second embodiment. In the correction information table 511 of the present embodiment, infinite correction amount and closest correction amount are stored. The correction calculation unit 731 calculates a correction amount using either the infinite correction amount or the closest correction amount in accordance with the lens position signal output from the lens position detection unit 213.

According to the camera system according to the second embodiment described above, the following operational effects can be obtained.
(1) The correction calculation unit 731 corresponds to the closest position where the photographing optical system 710 can be focused, according to the lens position signal output by the lens position detection unit 213 detecting the position of the focusing lens 210b. One of the closest correction amount for correcting the closest focus position and the infinite correction amount for correcting the infinite focus position corresponding to the most infinitely far position where the photographing optical system 710 can focus is used as a correction amount. Calculate. As a result, the accuracy of the correction amount is improved.

(2) The temperature sensors 214a and 214b can individually detect the temperature closer to the center of the driveable range of the focusing lens 210b and the temperature infinity from the center of the driveable range of the focusing lens 210b. is there. The correction calculation unit 731 switches the temperature used for calculation of the correction amount among the two temperatures detected by the temperature sensors 214 a and 214 b according to the lens position signal output from the lens position detection unit 213. Since it did in this way, it becomes possible to detect the temperature of the lens barrel 700 more accurately.

(Third embodiment)
The camera system according to the third embodiment includes a camera body 100 and a lens barrel 200 as in the camera system 1 according to the first embodiment described above. Hereinafter, the same parts as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and the description thereof is omitted.

  FIG. 9 is a diagram illustrating correction-related data stored in the ROM 215 according to the third embodiment. The correction information table 512 shown in FIG. 9A and the soft limit table 522 shown in FIG. 9B are both the same as in the first embodiment. As in the first embodiment, the correction calculation unit 231 calculates an infinite correction amount corresponding to the temperature by referring to the correction information table 512 with the temperature of the lens barrel represented by the temperature signal output from the temperature sensor 214. To do. The lens-side control circuit 203 uses the infinite correction amount calculated by the lens-side transmission / reception unit 217 by the correction calculation unit 231 and the closest soft limit position 460 and the infinite soft limit position 450 stored in the soft limit table 522 to the camera body. The lens side transmission / reception unit 217 is controlled so as to transmit to 100.

  The ROM 215 of this embodiment further stores a focus correction information table 532 shown in FIG. 9C and a focal length table 542 shown in FIG. Similar to the correction information table 512, the in-focus correction information table 532 stores a corresponding correction amount α every 10 degrees in a range from −10 degrees Celsius to +50 degrees Celsius. The focal length table 542 stores an expression for calculating the closest in-focus position for every predetermined interval (for example, 10 mm) for the entire focal length (for example, 20 mm to 200 mm) of the lens barrel 200. This equation includes the correction amount α described above.

  The correction calculation unit 231 of this embodiment calculates a correction amount α corresponding to the temperature by referring to the focus correction information table 532 with the temperature of the lens barrel represented by the temperature signal output from the temperature sensor 214. The correction calculation unit 231 further obtains an expression for calculating the closest focus position by referring to the focal length table 542 with the current focal length of the lens barrel 200. Then, the correction calculation unit 231 performs the temperature correction calculation of the closest in-focus position by applying the correction amount α to the acquired expression. The lens-side control circuit 203 controls the lens-side transmission / reception unit 217 so that the temperature-corrected closest focus position calculated by the lens-side transmission / reception unit 217 is transmitted to the camera body 100.

  The correction calculation unit 231 may perform the temperature correction calculation of the closest focus position instead of performing the temperature correction calculation of the closest focus position. For example, an equation for calculating the closest focus position and the correction amount α are transmitted to the camera body 100, and the body side control unit 103 uses these data to correct the closest focus position after temperature correction. May be calculated. Further, these calculations may be performed not on the closest focus position but on the infinite focus position, and the expression for calculating the closest focus position is more complicated than that shown in FIG. It may be.

According to the camera system of the third embodiment described above, the following operational effects can be obtained.
(1) The correction calculation unit 231 acquires an expression for calculating the closest focus position by referring to the focal length table 542 with the current focal length of the lens barrel 200. Since it did in this way, it becomes possible to correct | amend the close focus position after temperature correction to the more exact value according to a focal distance.

  The embodiment of the interchangeable lens camera system, which is a camera system including a detachable lens barrel and camera body, has been described above, but the present invention is not limited to such an embodiment. The following modifications are also within the scope of the present invention, and one or a plurality of modifications can be combined with the above-described embodiment.

(Modification 1)
In each of the above-described embodiments, the transmission determination unit 232 determines that the correction amount needs to be transmitted when a predetermined time has elapsed since the last correction amount was transmitted by the lens side transmission / reception unit 217. It was. The present invention can be applied even when the transmission determination unit 232 determines that the correction amount needs to be transmitted based on other criteria. For example, when the temperature signal output from the temperature sensor 214 changes, that is, when the temperature of the lens barrel 200 changes, the transmission determination unit 232 may determine that it is necessary to transmit the correction amount. By doing in this way, when the temperature is constant, the correction amount is not sent, and an effect that the communication amount between the body and the lens is reduced can be obtained.

(Modification 2)
In the first embodiment, the correction amount is the infinite correction amount, but this may be the closest correction amount. Further, the lens-side transmitting / receiving unit 217 may transmit positions representing the end 430 on the infinity side and the end 440 on the close side, respectively, instead of the infinite soft limit position and the closest soft limit position.

(Modification 3)
In each of the above-described embodiments, the lens-side transmission / reception unit 203 causes the lens-side transmission / reception unit 217 to transmit the closest focus position, the closest soft limit position, and the infinite soft limit position to the camera body 100. 217 was controlled. Of these three positions transmitted to the camera body 100, the lens-side control unit transmits a position closer to the inner side (infinity side) than the actual driving limit position instead of the closest soft limit position. 203 may be configured. However, this position must be closer to the closest soft limit position than the closest focusing position. In other words, an intermediate position between the closest soft limit position and the closest in-focus position may be transmitted instead of the closest soft limit position. In this case, the body-side control circuit 103 recognizes the intermediate position as the closest soft limit position, determines the number of pulses for moving the focusing lens 210d to the target position, and performs contrast-type focus detection processing. The scanning range of the focusing lens 210d is determined. Similarly, for the infinite soft limit position, a position closer to the inner side (closest side) than the actual limit position on the infinite side may be transmitted instead. That is, an intermediate position between the infinite soft limit position and the infinite focus position may be transmitted instead of the infinite soft limit position.

  The distance between the position (or the closest soft limit position itself) transmitted to the camera body 100 instead of the closest soft limit position and the closest focus position is transmitted to the camera body 100 instead of the infinite soft limit position. It is desirable that the distance is greater than the distance between the infinite focus position (or the infinite soft limit position itself) and the infinite focus position. This is based on the fact that focusing near the closest focusing position is more difficult than focusing near the infinite focusing position. With this configuration, false focusing in the vicinity of the closest focusing position can be suppressed.

(Modification 4)
In the first embodiment described above, the temperature sensor 214 detects the temperature of the lens barrel and outputs a temperature signal. Alternatively, the temperature outside the lens barrel may be detected. In this case, the correction calculation unit 231 operates with the temperature signal output from the temperature sensor 214 and the operating status of the heat generating member (for example, the lens driving unit 212) existing inside the lens barrel (for example, the focusing lens 210b by the lens driving unit 212). The correction amount of the driving position of the focusing lens 210b may be calculated based on the total driving time, total driving distance, energization time integration, and the like. This eliminates the need to install the temperature sensor 214 inside the lens barrel, thereby reducing the space required inside the lens barrel, reducing the size of the lens barrel, and manufacturing the lens barrel. Simplification can be performed.

  As long as the characteristics of the present invention are not impaired, the present invention is not limited to the above-described embodiments, and other forms conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention. .

DESCRIPTION OF SYMBOLS 1, 2 ... Camera system, 100 ... Camera body, 101, 201 ... Lens mount, 102, 202 ... Connection part, 103 ... Body side control circuit, 200, 700 ... Lens barrel, 203, 703 ... Lens side control circuit, 210, 710 ... Shooting optical system, 210b ... Focusing lens, 212 ... Lens drive unit, 213 ... Lens position detection unit, 214, 214a, 214b ... Temperature sensor, 215 ... ROM, 216 ... RAM, 217 ... Lens side transmission / reception unit, 231, 731 ... correction calculation unit, 232 ... transmission judgment unit, 310 ... first transmission path, 320 ... second transmission path

Claims (17)

A mounting part on which the camera body can be mounted;
An imaging optical system that has a focusing lens and can change the focal length;
A transceiver capable of transmitting and receiving signals to and from the camera body;
A drive unit that drives the focusing lens with a drive amount according to a drive signal received from the camera body via the transmission / reception unit;
A temperature detector that detects the temperature of the lens barrel and outputs a temperature signal;
A calculation unit that calculates a correction amount of the driving position of the focusing lens based on the temperature signal;
A determination unit that determines whether the correction amount needs to be transmitted to the camera body via the transmission / reception unit;
And a control unit that controls the transmission / reception unit so that the transmission / reception unit transmits the correction amount to the camera body when the determination unit determines that the correction amount needs to be transmitted. Lens barrel to be used. The lens barrel according to claim 1 ,
The determination unit determines the correction amount when a predetermined time has elapsed since the transmission / reception unit transmitted the correction amount to the camera body or when the temperature signal output from the temperature detection unit has changed. It is determined that it is necessary to transmit to the camera body. The lens barrel according to claim 1 or 2 ,
The drive unit moves the focusing lens between a close limit position corresponding to a drive limit position on the close side of the focusing lens and an infinite limit position corresponding to a drive limit position on the infinity side of the focusing lens. Can be driven,
The lens barrel, wherein the control unit controls the transmission / reception unit so that the transmission / reception unit transmits the close limit position and the infinite limit position together with the correction amount to the camera body. In the lens barrel according to any one of claims 1 to 3 ,
The correction amount includes a correction amount of a closest focusing position corresponding to a closest position where the imaging optical system can focus on the image plane, and a correction amount of the imaging optical system that can focus on the image plane. A lens barrel characterized by being at least one of correction amounts of an infinite focus position corresponding to a position on the infinity side. A focusing lens used for focus control;
  A transmission / reception unit capable of transmitting / receiving signals to / from the camera body;
  A calculation unit that calculates a correction amount of the position of the focusing lens based on a temperature detected by a temperature detection unit provided in the lens barrel;
  A determination unit that determines whether or not to transmit the correction amount to the camera body via the transmission / reception unit;
  And a control unit that controls the transmission / reception unit so that the transmission / reception unit transmits the correction amount to the camera body when the determination unit determines to transmit the correction amount. The lens barrel according to claim 5,
  The determination unit determines whether a predetermined time has elapsed since the correction amount was transmitted,
  The control unit is a lens barrel that controls the transmission / reception unit so that the transmission / reception unit transmits the correction amount to the camera body when the determination unit determines that the predetermined time has elapsed. The lens barrel according to claim 5,
  The determination unit determines whether the temperature output from the temperature detection unit is within a certain range,
  The control unit controls the transmission / reception unit so that the transmission / reception unit transmits the correction amount to the camera body when the determination unit does not determine that the temperature output from the temperature detection unit is within a certain range. The lens barrel to control. The lens barrel according to claim 5,
  The determination unit determines whether the temperature output from the temperature detection unit has changed,
  The control unit controls the transmission / reception unit so that the transmission / reception unit transmits the correction amount to the camera body when the determination unit determines that the temperature output from the temperature detection unit has changed. Lens barrel. A lens barrel according to any one of claims 5 to 8,
  A drive unit capable of driving the focusing lens between a close limit position corresponding to a drive limit position on the closest side of the focusing lens and an infinite limit position corresponding to a drive limit position on the infinity side of the focusing lens Have
  The control unit is a lens barrel that controls the transmission / reception unit so that the transmission / reception unit transmits the close limit position and the infinite limit position together with the correction amount to the camera body. A lens barrel according to any one of claims 5 to 9,
  The correction amount is the correction amount of the closest focusing position corresponding to the closest position at which the imaging optical system can focus on the image plane, and the infinite amount at which the imaging optical system can focus on the image plane. A lens barrel that is at least one of the correction amounts of the infinite focus position corresponding to the far side position. The lens barrel according to claim 10, wherein
  A lens position detector that detects the position of the focusing lens and outputs a lens position signal;
  The calculation unit is a lens barrel that calculates at least one of a correction amount of the closest focus position and a correction amount of the infinite focus position using the lens position signal. A lens barrel according to claim 11, wherein
  The temperature detection unit is capable of detecting a temperature closer to the center of the driving range of the focusing lens and a temperature of infinity from the center of the driving range of the focusing lens,
  The calculation unit selects at least one of the close-side temperature and the infinity-side temperature in accordance with the lens position signal output from the lens position detection unit, and is used for calculating the correction amount. . A lens barrel according to any one of claims 5 to 8,
  An imaging optical system having the focusing lens;
  The correction amount includes a correction amount for a close focus position that is a focus position on the closest side of the imaging optical system, and a correction for an infinite focus position that is a focus position on the infinity side of the imaging optical system. A lens barrel that is at least one of the quantities. The lens barrel according to claim 13,
  The imaging optical system is a lens barrel whose focal length can be changed. The lens barrel according to claim 13 or 14,
  The closest focusing position and the infinite focusing position are a first position that is the closest position that can be driven by the driving unit that drives the focusing lens, and a most infinite position that can be driven by the driving unit. A lens barrel provided between the second position and the second position. The lens barrel according to claim 15, wherein
  The first position and the second position are provided between a first stopper on the near side that restricts the movement of the focusing lens and a second stopper on the infinity side that restricts the movement of the focusing lens. Lens barrel. Camera system having a lens barrel according to any one of claims 1 to 16, and a camera body attachable to the lens barrel.

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