JP2013122565A - Lens device and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a variation in image magnification inconspicuous without communicating a large amount of information about the variation in image magnification accompanying a movement of a focus lens between a lens device and an imaging apparatus.SOLUTION: A lens device 2 comprises: an actuator 28 that moves a focus lens 22 and of which the driving speed is variable; and an image magnification memory 36 that stores image magnification variation information about the variation in image magnification accompanying driving of the actuator. A lens control section 26 receives a tolerance value of the variation in image magnification from an imaging apparatus 1, calculates an upper limit value of the driving speed of the actuator using the tolerance value and the image magnification variation information; transmits the upper limit value of the driving speed to the imaging apparatus to cause the imaging apparatus to determine the driving speed of the actuator which is equal to or less than the upper limit value of the driving speed; and drives the actuator at the driving speed received from the imaging apparatus.

Description

  The present invention relates to an interchangeable lens type imaging apparatus and a lens apparatus that is detachably attached to the imaging apparatus.

  In an image pickup apparatus such as a video camera, in autofocus (AF), the focus lens is reciprocated in the closest direction and the infinity direction to determine the direction of the in-focus position and whether or not it is in focus. In some cases, so-called wobbling is performed. However, in an imaging apparatus having an imaging optical system in which the image magnification changes due to the movement of the focus lens, it is desirable that the change in image magnification accompanying the wobbling is not noticeable in the image obtained by imaging.

  Patent Document 1 discloses the following interchangeable lens camera system. The interchangeable lens includes a memory that stores information on image magnification change (image magnification change information) caused by the wobbling of the focus lens for each position of the zoom lens that performs zooming. On the other hand, in the initial operation when the interchangeable lens is mounted, the camera body acquires image magnification change information from the interchangeable lens by communication and stores it in the flash memory. The camera body acquires the position information of the zoom lens at the time of shooting, and controls the driving of the focus lens so that the change in image magnification accompanying wobbling is not noticeable based on the position information and the image magnification change information. A focus control signal is generated for this purpose.

JP 2010-271696 A

  However, the camera system disclosed in Patent Document 1 has the following problems. First, it is necessary to mount a large-capacity flash memory in the camera body for storing large-capacity image magnification change information transmitted from the interchangeable lens. Second, as part of the initial operation when the interchangeable lens is mounted on the camera body, communication of image magnification change information from the interchangeable lens to the camera body and flashing of the image magnification change information on the camera body A storage process to the memory is performed. For this reason, it takes a long time until all of the initial operations including them are completed and photographing is possible.

  The present invention drives the focus lens so that the change in the image magnification is not noticeable without communicating large-capacity information regarding the change in the image magnification accompanying the movement of the focus lens between the lens device and the imaging device. A lens device and an imaging device are provided.

  A lens device according to an aspect of the present invention is detachably attached to an imaging device and can communicate with the imaging device. The lens apparatus includes an actuator that moves the focus lens and the drive speed is variable, a lens control unit that controls the drive of the actuator, and image magnification change information that is information regarding a change in image magnification accompanying the drive of the actuator. And a stored image magnification memory. The lens control unit receives an allowable value of the change amount of the image magnification from the imaging device, obtains an upper limit value of the actuator driving speed using the allowable value and the image magnification change information, and images the upper limit value of the driving speed. It is transmitted to the apparatus, and the imaging apparatus is caused to determine the driving speed of the actuator that is equal to or lower than the upper limit of the driving speed, and the actuator is driven at the determined driving speed received from the imaging apparatus.

  In an imaging apparatus according to another aspect of the present invention, a lens device is detachably mounted, and communication with the lens device is possible. The lens device stores an actuator that moves the focus lens and the driving speed is variable, a lens control unit that controls the driving of the actuator, and image magnification change information that is information regarding a change in image magnification caused by the driving of the actuator. Image magnification memory. The imaging apparatus has an imaging apparatus control unit that determines the drive speed of the actuator. The imaging apparatus control unit transmits an allowable value of the change amount of the image magnification to the lens control unit, and uses the allowable value and the image magnification change information for the lens control unit to drive the actuator. The driving speed upper limit value is received from the lens control unit, the driving speed of the actuator below the driving speed upper limit value is determined, and the determined driving speed is transmitted to the lens control unit, The actuator is driven at the determined driving speed.

  According to the present invention, the allowable value of the image magnification is transmitted from the imaging apparatus to the lens apparatus, and only the driving speed upper limit value is transmitted from the lens apparatus to the imaging apparatus. For this reason, the focus lens can be driven so that the change in the image magnification is not noticeable without communicating large capacity information between the lens apparatus and the imaging apparatus.

1 is a block diagram showing a configuration of a camera system that is an embodiment of the present invention. 6 is a flowchart showing an operation in the camera system of the embodiment. The figure which shows the relationship between the power supply voltage and drive speed in the camera system of an Example. The figure which shows the relationship between the temperature and drive speed in the camera system of an Example. The figure which shows the relationship between the attitude | position and drive speed in the camera system of an Example. The figure which shows the relationship between the historical information and drive speed in the camera system of an Example.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a configuration of a camera system including a camera body (imaging device) and an interchangeable lens (lens device) that is Embodiment 1 of the present invention. Reference numeral 1 denotes a camera body, and 2 denotes an interchangeable lens.

  An electric circuit unit 3 including the following components is provided in the camera body 1. Reference numeral 4 denotes an image sensor such as a CCD sensor or a CMOS sensor, which photoelectrically converts a subject image formed by light from the photographing optical system in the interchangeable lens 2 and outputs an electrical signal. An image processing unit 8 performs various processes on the electric signal from the image sensor 4 to generate an image signal that forms a moving image or a still image (hereinafter also referred to as an image).

  Reference numeral 5 denotes a photometric unit which detects subject brightness from the image signal. A focus detection unit 6 detects the focus state of the photographing optical system using the contrast information obtained from the image signal. Reference numeral 7 denotes a shutter control unit that controls the exposure time of the image sensor 4. Reference numeral 9 denotes a camera CPU as an imaging device control unit that controls the operations of the camera body 1 and the interchangeable lens 2.

  Reference numeral 10 denotes a lens mounting detection unit that detects that the interchangeable lens 2 is mounted, and includes, for example, a switch or a photodetector. Reference numeral 11 denotes a camera communication unit that communicates with the camera CPU 9 and the lens CPU 26 as a lens control unit provided in the interchangeable lens 2 together with the lens communication unit 25 provided in the interchangeable lens 2.

  Reference numeral 12 denotes a control system power supply that supplies power to control system circuits such as the image sensor 4, the photometry unit 5, the focus detection unit 6, and the image processing unit 8. A drive system power supply 13 supplies power to the drive system circuits such as the shutter control unit 7 and the interchangeable lens 2. Reference numeral 14 denotes an imaging switch (SW1) for starting an imaging operation. Reference numeral 15 denotes a recording unit composed of a nonvolatile memory or the like, which records the image generated by the image processing unit 8.

  In the interchangeable lens 2, a photographic optical system and an electric circuit unit 20 are provided. The photographic optical system moves in the optical axis direction and performs zooming, zoom lens 21 that moves in the optical axis direction and focus lens 22 that moves in the optical axis direction, and moves in a direction perpendicular to the optical axis to correct image blur. A correction lens 23 and a diaphragm 24 for adjusting the amount of light are included.

  The electric circuit unit 20 includes the following components in addition to the lens communication unit 25 described above and the lens CPU 26 that controls the operation of the interchangeable lens 2 together with the camera CPU 9. A zoom lens drive control unit 27 includes a zoom actuator that moves the zoom lens 21, and a focus lens drive control unit 28 includes a focus actuator that moves the focus lens 22. A correction lens drive control unit 29 includes a correction actuator that moves the correction lens 23. A diaphragm drive control unit 30 includes a diaphragm actuator that opens and closes the diaphragm 24 (moves diaphragm blades (not shown)).

  Each actuator used in the present embodiment is constituted by a stepping motor, a vibration type motor, or the like, and its drive speed is variable.

  Reference numeral 31 denotes a drive system power supply voltage detection unit that detects a power supply voltage supplied to the zoom lens drive control unit 27, the focus lens drive control unit 28, the correction lens drive control unit 29, and the aperture drive control unit 30. Reference numeral 32 denotes a temperature detection unit that detects the temperature in the interchangeable lens 2. Reference numeral 33 denotes an attitude detection unit that detects the attitude of the interchangeable lens 2 and includes an acceleration sensor and the like.

  Inside the lens CPU 26, a history memory 34 is configured by a non-volatile memory or the like, and stores a driving history such as a cumulative driving number and a cumulative driving time after the interchangeable lens 2 is manufactured.

  The power supply voltage, posture, temperature, and drive history correspond to actuator drive conditions (hereinafter referred to as actuator drive conditions). The drive system power supply voltage detection unit 31, the temperature detection unit 32, the attitude detection unit 33, and the history memory 34 correspond to an actuator drive condition acquisition unit.

  In the lens CPU 26, reference numeral 35 denotes a drive characteristic memory that stores information (drive characteristic information) regarding the drive characteristics of the focus actuator corresponding to the power supply voltage, temperature, posture, and drive history. The drive characteristic of the focus actuator here indicates an actual focus actuator drive speed at which the lens CPU 26 drives and controls the focus actuator at the same drive speed with respect to the focus drive control unit 28.

  Reference numeral 36 denotes an image magnification memory that stores information (hereinafter referred to as focus image magnification change information) regarding a change in image magnification of the photographing optical system accompanying the movement of the focus lens 22 (drive of the focus actuator). Specifically, the focus image magnification change information is information indicating the relationship between the drive amount of the focus actuator and the change amount of the image magnification. Note that the amount of change in image magnification accompanying the movement of the focus lens 22 varies depending on the position of the zoom lens 21, so that focus image magnification change information is also stored for each position of the zoom lens 21.

  Next, the operation of the camera body 1 and the interchangeable lens 2 will be described using the flowchart of FIG. The flowchart on the left side in FIG. 2 shows the operation of the camera body 1, and the flowchart on the right side shows the operation of the interchangeable lens 2. These operations are executed by the camera CPU 9 and the lens CPU 26 according to computer programs stored therein.

  First, when the operation of the camera CPU 9 starts in step (Step) 1, a signal indicating that the interchangeable lens 2 is mounted is input from the interchangeable lens mounting detection unit 10 in step 2 (the interchangeable lens 2 is mounted). Or not). When the interchangeable lens 2 is attached, the camera CPU 9 supplies power to the interchangeable lens 2 via the control system power supply 12 and the drive system power supply 13.

  Next, in step 3, the camera CPU 9 determines whether or not the imaging switch (SW1) 14 is turned on. If it is turned on, the process proceeds to step 4. In step 4, the camera CPU 9 sends a command for causing the camera CPU 9 to transmit information on the model and focal length of the interchangeable lens 2 and information on the positions of the lenses 21 to 23 and the aperture 24 to the lens CPU 26 as initial communication. To do. Further, the initial communication includes a drive command for each actuator from the camera CPU 9.

  The lens CPU 26 receives these instructions at step 22 and transmits corresponding information to the camera CPU 9. In step 23, the lens CPU 26 drives the zoom lens 21 via the zoom lens drive control unit 27 if the command from the camera CPU 9 is a drive command for the zoom lens 21. If the driving command is for the focus lens 22, the focus lens 22 is driven via the focus lens drive control unit 28. Further, if it is a correction lens drive command, the correction lens 23 is driven via the correction lens drive control unit 29. If the drive command is for the diaphragm 24, the diaphragm 24 is driven via the diaphragm drive control unit 30.

  The allowable value of the change amount of the image magnification appearing in the image obtained by imaging depends on the allowable image magnification change factors such as the spatial frequency and luminance of the image, the effect of the image processing in the image processing unit 8, and the time interval for acquiring the image. Change.

  Therefore, in step 5, the camera CPU 9 determines the image magnification change upper limit value, which is the allowable value of the change amount of the image magnification according to the above-described allowable image magnification change factor, and the drive time that is the length of time that the focus actuator can be driven. t1 is calculated and transmitted to the lens CPU. Note that the driving time t1 may be a time interval for acquiring an image by imaging, is set to a short driving time so that the change of the image during imaging is small, or the change amount of the image magnification per unit time is reduced. In order to make it inconspicuous, a long drive time may be used.

  In step 24, the lens CPU 26 receives the image magnification change upper limit value and the drive time t1 transmitted from the camera CPU 9. In step 25, the lens CPU 26 determines the power supply voltage, posture, temperature, and drive history as actuator drive conditions from the drive system power supply voltage detector 31, the temperature detector 32, the posture detector 33, and the history memory 34, respectively. To get.

  Next, in step 26, the lens CPU 26 compares the power supply voltage, posture, temperature, and drive history acquired in step 25 with the drive characteristic information of the focus actuator stored in the drive characteristic memory 35. Based on the comparison result, the driving speed, which is the driving amount capable of driving the focus actuator per unit time, with respect to the acquired power supply voltage, posture, temperature, and driving history is determined as the first driving speed (hereinafter referred to as driving speed 1). To be calculated).

  The actuator driving condition used for obtaining the driving speed 1 may be at least one of the power supply voltage, the attitude, the temperature, and the driving history.

  Subsequently, in step 27, the lens CPU 26 determines a second drive speed (hereinafter referred to as drive speed 2) corresponding to the upper limit value of the image magnification change acquired in step 24 from the focus image magnification change information stored in the image magnification memory 36. Is calculated). In this step, the lens CPU 26 compares the driving speed 1 with the driving speed 2 and sets the lower driving speed to a driving speed upper limit value (driving speed 3) that is an upper limit value (allowable value) of the driving speed. ) Is determined (selected).

  Hereinafter, a method for determining the drive speed upper limit value (drive speed 3) for each power supply voltage, attitude, temperature, and drive history will be described.

  FIG. 3 shows the relationship between the power supply voltage supplied to the focus drive controller 28 and the drive speed of the focus actuator. The horizontal axis indicates time, 0 is the focus drive start time, and t1 is the focus drive end time. The vertical axis represents the drive amount (position) of the focus actuator. The driving amount up to time t1 determined from the image magnification change upper limit value is x0, and the driving speed 2 is x0 / t1. As described above, the driving speed 1 is calculated by the lens CPU 26 from the output from the driving system power supply voltage detection unit 31 and the driving characteristic information of the focus actuator stored in the driving characteristic memory 35. When the power supply voltage is high, the driving speed 1 is x1 / t1 (> x0 / t1), and when the power supply voltage is low, the driving speed 1 is x2 / t1 (<x0 / t1).

  The lower drive speed 3 (drive speed upper limit) of the drive speed 1 and the drive speed 2 is x0 / t1 when the power supply voltage is high, and x2 / t1 when the power supply voltage is low. Each driving speed here corresponds to a driving speed at a constant speed when the focus actuator is accelerated and then driven at a constant speed and then decelerated toward a stop position. The same applies to the driving speed described below with reference to FIGS.

  FIG. 4 shows the relationship between the temperature and the driving speed of the focus actuator. The meanings of the horizontal axis, 0, t1, and the vertical axis, and the driving speed 2 (= x0 / t1) are the same as in FIG. The driving speed 1 is calculated by the lens CPU 26 from the output from the temperature detection unit 32 and the driving characteristic information of the focus actuator stored in the driving characteristic memory 35 as described above. When the temperature is high, the driving speed 1 is x3 / t1 (> x0 / t1), and when the temperature is low, the driving speed 1 is x4 / t1 (<x0 / t1).

  The lower drive speed 3 (drive speed upper limit value) of the drive speed 1 and the drive speed 2 is x0 / t1 when the temperature is high, and x4 / t1 when the temperature is low. .

  FIG. 5 shows the relationship between the posture and the driving speed of the focus actuator. The meanings of the horizontal axis, 0, t1, and the vertical axis, and the driving speed 2 (= x0 / t1) are the same as in FIG. As described above, the driving speed 1 is calculated by the lens CPU 26 from the output from the attitude detection unit 33 and the driving characteristic information of the focus actuator stored in the driving characteristic memory 35. The driving speed 1 is x5 / t1 (> x0 / t1) when the optical axis direction of the photographing optical system is a horizontal posture, and the driving speed when the posture is a vertical posture where the optical axis direction is upward. 1 becomes x6 / t1 (<x0 / t1).

  The lower drive speed 3 (drive speed upper limit value) of the drive speed 1 and the drive speed 2 is x0 / t1 in the normal posture and x6 / t1 in the vertical posture. .

  FIG. 6 shows the relationship between the drive history and the drive speed of the focus actuator. The meanings of the horizontal axis, 0, t1, and the vertical axis, and the driving speed 2 (= x0 / t1) are the same as in FIG. As described above, the driving speed 1 includes the driving history read from the history memory 34 by the lens CPU 26 (here, the cumulative driving time of the focus actuator) and the driving characteristic information of the focus actuator stored in the driving characteristic memory 35. And is calculated from When the cumulative drive time is short, the drive speed 1 is x7 / t1 (> x0 / t1), and when the cumulative drive time is long, the drive speed 1 is x8 / t1 (<x0 / t1).

  The lower drive speed 3 (drive speed upper limit) of the drive speed 1 and the drive speed 2 is x0 / t1 when the cumulative drive time is short, and x8 when the cumulative drive time is long. / T1.

  The drive speed upper limit value determined in this manner is transmitted from the lens CPU 26 to the camera CPU 9 in step 28. In step 6, the camera CPU 9 receives the driving speed upper limit value from the lens CPU 26 and stores it.

  Next, in step 7, the camera CPU 9 starts imaging (recording of an image). Then, the process proceeds to step 8, and the focus detection unit 6 is caused to generate contrast information from the image signal.

  Next, in step 9, the camera CPU 9 determines the drive direction of the focus lens 22 and the drive speed below the upper limit of the drive speed received in step 6 according to the contrast information generated in step 8. Then, a focus lens driving command including information on the driving direction and the driving speed is transmitted to the lens CPU 26.

  In step 29, the lens CPU 26 receives a focus lens drive command from the camera CPU 9. In step 30, the lens CPU 26 drives the focus lens 22 through the focus lens drive control unit 28 in the drive direction designated by the focus drive command at the designated drive speed.

  Next, in step 10, the camera CPU 9 determines whether or not the contrast information indicates an in-focus state. If the focus information does not indicate the in-focus state, the process returns to step 8 to continue the focus lens drive command. Is transmitted to the lens CPU 26. If the in-focus state is indicated, the process proceeds to step 12. When Steps 8 to 10 are repeated, the focus lens 22 is continuously driven (for example, wobbling that reciprocates in the closest direction and the infinity direction is performed), and the change in image magnification at that time is easily noticeable. . For this reason, by driving the focus actuator at a driving speed equal to or lower than the upper limit of the driving speed, it is possible to reduce a change in image magnification that occurs during driving of the focus lens 22.

  Note that when the focus lens 22 continuously moves in the same direction, the change in image magnification is less noticeable than when wobbling is performed. For this reason, as described above, the driving of the focus actuator at a driving speed equal to or lower than the upper limit of the driving speed may be limited only to the case where wobbling is performed.

  In step 11, the camera CPU 9 checks conditions for continuing imaging such as whether or not the imaging switch 14 is turned off and whether or not the storage capacity and power source of the recording unit 15 are sufficient. Return to 2 and continue imaging. When the imaging is finished, the process proceeds to step 12 and an actuator drive stop command is transmitted to the lens CPU 26.

  When the lens CPU 26 receives the actuator drive stop command in step 31, the lens CPU 26 stops the drive of each actuator.

  As described above, according to the present embodiment, the focus actuator can be driven so that the change in the image magnification is not noticeable without communicating large-capacity information between the interchangeable lens 2 and the camera body 1. it can.

  In this embodiment, the driving speed 1 calculated according to the actuator driving conditions (power supply voltage, temperature, posture, and driving history) is compared with the driving speed 2 corresponding to the image magnification change upper limit value. Was determined as a driving speed upper limit value (driving speed 3). However, it is not always necessary to compare the driving speed 1 and the driving speed 2, and the driving speed 2 corresponding to the image magnification change upper limit value is determined as the driving speed upper limit value (driving speed 3) without considering the actuator driving conditions. May be.

  Each embodiment described above is only a representative example, and various modifications and changes can be made to each embodiment in carrying out the present invention.

  It is possible to provide an imaging system capable of capturing high-quality images without noticeable change in image magnification due to focus lens driving.

1 Camera body 2 Interchangeable lens 9 Camera CPU
22 Focus lens 26 Lens CPU
28 Focus lens drive control unit 36 Image magnification memory

Claims (6)

A lens device that is detachably attached to an imaging device and capable of communicating with the imaging device,
An actuator that moves the focus lens and the drive speed is variable;
A lens control unit for controlling the driving of the actuator;
An image magnification memory storing image magnification change information, which is information relating to a change in image magnification accompanying driving of the actuator,
The lens control unit
Receiving an allowable value of the change amount of the image magnification from the imaging device;
Using the allowable value and the image magnification change information, an upper limit value of the driving speed of the actuator is obtained,
Transmitting the driving speed upper limit value to the imaging device, causing the imaging device to determine a driving speed of the actuator that is equal to or lower than the driving speed upper limit value;
A lens apparatus, wherein the actuator is driven at the determined driving speed received from the imaging apparatus. An actuator driving condition acquisition unit for acquiring the driving condition of the actuator;
A drive characteristic memory that stores drive characteristic information that is information related to the drive characteristic of the actuator according to the drive condition;
The lens control unit
Using the drive characteristic information, obtain a first drive speed of the actuator according to the drive condition acquired from the actuator drive condition acquisition unit,
A second driving speed of the actuator is obtained using the allowable value and the image magnification change information,
The lens apparatus according to claim 1, wherein the lower one of the first driving speed and the second driving speed is selected as the driving speed upper limit value.   The lens according to claim 2, wherein the driving condition includes at least one of a power supply voltage supplied to the actuator, an attitude of the lens device, a temperature of the lens device, and a driving history of the actuator. apparatus. An imaging apparatus in which a lens apparatus is detachably mounted and can communicate with the lens apparatus,
The lens device is
An actuator that moves the focus lens and the drive speed is variable;
A lens control unit for controlling the driving of the actuator;
An image magnification memory storing image magnification change information, which is information relating to a change in image magnification accompanying driving of the actuator,
The imaging apparatus has an imaging apparatus control unit that determines the driving speed of the actuator,
The imaging device control unit
An allowable value of the change amount of the image magnification is transmitted to the lens control unit, and the upper limit value of the driving speed of the actuator is set to the lens control unit using the allowable value and the image magnification change information. Let me ask
Receiving the driving speed upper limit value from the lens control unit, determining the driving speed of the actuator below the driving speed upper limit value;
An imaging apparatus, wherein the determined driving speed is transmitted to the lens control unit, and the actuator is driven at the determined driving speed. The lens device is
An actuator driving condition acquisition unit for acquiring the driving condition of the actuator;
A drive characteristic memory that stores drive characteristic information that is information related to the drive characteristic of the actuator according to the drive condition;
The lens control unit
Using the drive characteristic information, obtain a first drive speed of the actuator according to the drive condition acquired from the actuator drive condition acquisition unit,
The imaging device control unit
The allowable value of the change amount of the image magnification is transmitted to the lens control unit, and the second drive speed of the actuator is set to the lens control unit using the allowable value and the image magnification change information. 5. The imaging apparatus according to claim 4, wherein the imaging device is made to calculate and the lower one of the first driving speed and the second driving speed is selected as the driving speed upper limit value.   The imaging according to claim 5, wherein the driving condition includes at least one of a power supply voltage supplied to the actuator, an attitude of the lens device, a temperature of the lens device, and a driving history of the actuator. apparatus.

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