JP2000330006A - Photographing device and accessory for photographing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a photographic optical system from being driven unnecessarily even when it is impossible to follow up a subject which moves at random and the subject moves temporarily out of a focus detection area. SOLUTION: When it is decided (step S105) that the subject which moves at random is followed up after a photographic lens 1 is driven and put in focus or almost in focus (step S108), decision conditions are so changed (step S106) so that the probability that it is decided that a focus detection result is not reliable is increased even if large defocusing is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photographing device and a photographing device accessory in which the focus detecting operation of the focus detecting device is improved.

[0002]

2. Description of the Related Art Conventionally, as one of focus detection methods in an automatic focus detection device of a camera, two images having parallax of a subject are led to a pair of photoelectric conversion element arrays, and an image output from each photoelectric conversion element array is obtained. There is known a phase difference detection method for calculating a relative shift amount between the two images to determine an in-focus state.

FIG. 5 is a diagram for explaining a phase difference detection method of the automatic focus detection device. After the light beam passing through the area 1A of the taking lens 1 is focused on the film equivalent surface 6,
The light passes through the band-pass filter 7, the field mask 2, the field lens 3, the aperture opening 4A and the re-imaging lens 5A of the focus detection optical system 8 in order, and forms an image on the sensor array 9A of the image sensor 9. Similarly, the area 1B of the photographing lens 1
After passing through the light beam, the beam is focused on the film equivalent surface 6, and then passes through the band-pass filter 7, the field mask 2, the field lens 3, the aperture opening 4B and the re-imaging lens 5B of the focus detection optical system 8 in this order. Then, an image is formed on the sensor array 9B of the image sensor 9.

The size of the area 1A of the taking lens 1 is equal to the back projection image of the aperture opening 4A by the field lens 3, and similarly, the size of the area 1B is the back projection of the aperture opening 4B by the field lens 3. Equal to the image. The secondary image of the pair of subject images formed on the sensor rows 9A and 9B of the image sensor 9 by the focus detection optical system 8 is such that the sharp image of the subject formed by the photographing lens 1 is located before the scheduled focal plane. In the so-called front focus state, they move away from each other,
Conversely, they approach each other in a so-called back focus state in which an image is formed after the planned focal plane. When a sharp image of a subject formed by the photographing lens 1 forms an image on a predetermined focal plane, that is, at the time of so-called focusing, the subject images on the sensor arrays 9A and 9B of the image sensor 9 relatively match. Therefore, the secondary image of the pair of subject images formed by the focus detection optical system 8 is photoelectrically converted by the sensor arrays 9A and 9B of the image sensor 9 to be converted into electric signals, and these pair of subject image signals are subjected to arithmetic processing. Then, by calculating the relative position of the secondary image of the pair of subject images, the focus adjustment state of the photographing lens 1, here, the amount away from the in-focus state and its direction (hereinafter, referred to as defocus amount) Is determined. The focus detection area is a portion where the sensor rows 9A and 9B of the image sensor 9 are back-projected by the focus detection optical system 8 and overlapped near the planned focal plane.

Next, an arithmetic processing method for obtaining the defocus amount will be described. Sensor row 9 of image sensor 9
Reference numerals A and 9B respectively denote a plurality of photoelectric conversion elements connected in one direction. As shown in FIGS. 6A and 6B,
From each of the sensor rows 9A, 9B, a plurality of photoelectric conversion outputs a1. . . an, b
1. . . bn is output. The correlation calculation is performed while relatively shifting these data strings by a predetermined data amount L. Specifically, the correlation amount C (L) is calculated by the following equation.

[0006]

(Equation 1)

Here, as described above, L is an integer corresponding to the shift amount of the data string, and the first term k and the last term r are:
It may be changed depending on the shift amount L. Among the correlation amounts C (L) thus obtained, a value obtained by multiplying the shift amount giving the minimum correlation amount by a constant determined by the pitch width of the photoelectric conversion elements of the optical system and the image sensor shown in FIG. Defocus amount.

However, as shown in FIG. 6C, the correlation amount C (L) is a discrete value, and the minimum unit of the detectable defocus amount is the sensor array 9A,
9B is limited by the pitch width of the photoelectric conversion elements. In view of this, a method has been proposed in which a minimum value Cex is newly calculated by performing an interpolation operation from the discrete correlation amount C (L), and a detailed focus detection is performed (Japanese Patent Laid-Open No. 60-37).
No. 513). This is a method of calculating the correlation value C (0) which is the minimum value and the correlation amounts C (1) and C (-1) of the shift amounts on both sides as shown in FIG. Shift amount Fm and defocus amount DF that give
Is obtained by the following equation.

DF = Kf × Fm Fm = L + DL / E DL = {C (−1) −C (1)} / 2 Cex = C (0) − | DL | E = MAX [ΔC (1) −C (0)｝, {C (−1) −C (0)}] (2)

Here, MAX {Ca, Cb} means that the larger of Ca and Cb is selected, and Kf is
It is a constant determined by the pitch width of the photoelectric conversion elements of the optical system and the image sensor shown in FIG. It is necessary to determine whether the defocus amount obtained in this way truly indicates the defocus amount or whether it is due to fluctuation of the correlation amount due to noise or the like. When the following condition is satisfied, the defocus amount is determined. Shall be reliable.

E> E1 and Cex / E <G1 (3)

Here, E1 and G1 are certain predetermined values.
E is a value that depends on the contrast of the subject. The larger the value, the higher the contrast and the higher the reliability. Cex / E mainly depends on the degree of coincidence of the images, and the closer to 0, the higher the reliability. Will be higher. Then, when it is determined that there is reliability, the photographing lens 1 is driven based on the defocus amount DF.

The above is the description of the phase difference detection method. By repeatedly performing the focus detection operation by the above-described focus detection method, the defocus amount of the photographing lens is repeatedly detected. When it is determined that the detected defocus amount is reliable, the driving of the photographing lens is performed based on the detected defocus amount, and the focus state of the photographing lens is in focus or in focus. It is driven until the defocus amount can be regarded as a state.

Further, even after it is determined that the focus state of the photographing lens is in focus or a defocus amount that can be regarded as being in focus, the focus state of the photographing lens is kept in focus by repeatedly performing the focus detection operation. When it is determined that the defocus amount exceeds the defocus amount that can be considered to be in the state, the driving of the photographing lens is resumed to the in-focus state or the defocus amount that can be considered to be in the focused state. As described above, by repeatedly performing the focus detection operation, the photographing lens is always in focus.

[0015]

By the way, in the focus detection operation as described above, the follow-up of the focus of the photographing lens with respect to the subject becomes quick, but the following problem occurs. In sports such as soccer and rugby, in order to capture the subject in the shooting screen, the camera must be swung right and left in accordance with the movement of the target player.
In addition, a camera with an automatic focusing device must keep capturing the subject in the focus detection area in the shooting screen.

However, it is difficult to shake the camera in accordance with the intense movement of the subject, and the subject to be focused is out of the focus detection area. The photographing lens was driven to focus on
In some cases, the subject to be refocused was re-captured in the focus detection area, and then the photographing lens was driven again to focus on the subject to be focused. In particular, this is likely to occur with telephoto lenses. When the focus detection area deviates from the subject,
A behavior in which the photographing lens is not driven and focuses on another unintended subject is not preferable in that the photographer does not miss a photo opportunity intended for the intended subject.

If the focus detection area deviates from the subject to be focused and the defocus amount detected by the photographing lens is large and the contrast is low, the reliability of the defocus amount is determined. Since the threshold value is not satisfied, detection becomes impossible, and immediately the scanning lens starts to be driven to drive the taking lens to increase the contrast of the subject. It may be driven one round trip,
It is not preferable for performing automatic focusing of the taking lens.

In Japanese Patent Application Laid-Open No. 8-76007, after a photographic lens is driven to an allowable range (focusing range) with respect to a focus position, information indicating the occurrence of a large defocus amount exceeding a predetermined range is obtained by a focus detection unit. There has been proposed an apparatus that detects and suppresses useless movement of a photographing lens.

An object of the present invention is to provide a method for driving a photographing optical system which is useless even after the photographing optical system has been driven to near the in-focus state, even for a moving subject which is difficult to keep in the focus detection area. An object of the present invention is to provide a photographing device and a photographing device accessory that can prevent the photographing from being performed.

[0020]

According to another aspect of the present invention, there is provided a focus detecting unit for detecting a focus adjustment state of a photographing optical system, and the photographing optical system detected by the focus detecting unit. A photographing apparatus comprising: a reliability determination unit that determines the reliability of a focus adjustment state of a system according to a predetermined determination condition; and a movement state detection unit that detects a movement state of a device including the photographing optical system. When the detecting section detects that the imaging optical system is in focus, and when the moving state detecting section detects that the moving state of the device is random, the reliability determining section When making the determination, the focus adjustment state detected by the focus detection unit so that the probability of determining that there is no reliability is high,
A photographing apparatus, comprising: a judgment condition changing unit that changes the judgment condition.

According to a second aspect of the present invention, in the photographing apparatus according to the first aspect, the determination condition changing unit detects the focus detection result by the focus detection unit when the focus detection result of the focus detection unit exceeds a predetermined range. The photographing apparatus is characterized in that the condition for the determination is changed so that the probability that the determined focus adjustment state is determined to be unreliable is increased. According to a third aspect of the present invention, in the imaging device according to the first aspect, the determination condition changing unit returns the determination condition after a lapse of a predetermined time when the determination condition is changed. Device.

According to a fourth aspect of the present invention, there is provided the first to third aspects.
In the imaging device according to any one of the above, the movement state determination unit includes a shake detection unit that detects shake, and a shake of the entire apparatus including the shooting optical system based on an output signal of the shake detection unit. And a blur state determination unit that determines a state.

According to a fifth aspect of the present invention, in the photographic apparatus according to the fourth aspect, the blur state determination section determines whether or not the entire apparatus including the photographic optical system is substantially stationary. It is a photographing device characterized by the following.

The invention of claim 6 is the invention of claim 4 or claim 5.
In the imaging device described in, a blur correction optical system that corrects blur, a drive unit that drives the blur correction optical system, and a control unit that drives and controls the drive unit, the control unit,
When the blur state determination unit determines that the camera is not in a substantially stationary state, the driving unit is stopped.

In a preferred embodiment of the present invention, a blur detecting section for detecting a blur, a blur state determining section for determining a blur state of the entire apparatus including the photographing optical system based on an output signal of the blur detecting section, A focus detection unit that detects a focus adjustment state of the imaging optical system; and a reliability determination unit that determines reliability of the focus adjustment state of the imaging optical system detected by the focus detection unit according to a predetermined determination condition. In the imaging device, when the focus detection unit detects that the imaging optical system is in focus, and when the blur state determination unit detects that the movement state of the device is random, A determination condition changing unit that changes the determination condition so that the probability that the focus adjustment state detected by the focus detection unit is determined to be unreliable is increased when performing the determination by the reliability determination unit. Is an imaging apparatus characterized by comprising a.

According to an eighth aspect of the present invention, in a photographing device accessory detachable from the photographing device main body, a blur detecting section for detecting a blur and outputting a blur detecting signal, and judging a blur state based on the blur detecting signal. The image capturing apparatus includes a blur state determining unit that outputs a blur state determining signal, and a determination signal transmitting unit that transmits the blur state determining signal to the image capturing apparatus body.

According to a ninth aspect of the present invention, in the accessory of the photographing apparatus according to the eighth aspect, the blur state determination unit determines whether or not the camera is in a substantially stationary state. It is.

According to a tenth aspect of the present invention, in the accessory for the photographing apparatus according to the eighth or ninth aspect, a blur correcting optical system for correcting a blur, a driving unit for driving the blur correcting optical system, and the driving unit A control unit for driving and controlling the unit, wherein the control unit stops the driving unit when the blur state determination unit determines that the camera unit is not in a substantially stationary state. .

[0029]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a camera system according to an embodiment of the present invention.
This camera system includes a camera body 14 and an interchangeable lens 20.

The camera body 14 includes the focus detection optical system 8
, An image sensor 9, a focus detection operation circuit 10, a motor drive control circuit 11, a motor 12, and a main CPU
13 and an electrical contact group 15-1 and the like.

The focus detecting optical system 8 is an optical system for guiding a light beam passing through the photographing lens 1 to the image sensor 9. The focus detection optical system 8 is similar to the one shown in FIG.
Bandpass filter 7, field mask 2, field lens 3, aperture openings 4A and 4B, re-imaging lens 5
A, 5B.

The image sensor 9 has a sensor array 9A, 9B
This is a sensor that photoelectrically converts the secondary image of the subject image formed thereon. The image sensor 9 generates an electric subject image signal corresponding to the intensity distribution of the subject image, and outputs the subject image signal to the focus detection calculation circuit 10. Sensor rows 9A, 9
B has a plurality of photoelectric conversion elements continuously provided in one direction. Note that the focus detection optical system 8 and the image sensor 9 are configured to be able to perform focus detection in a focus detection area set on a shooting screen.

The focus detection arithmetic circuit 10 is a circuit for calculating a defocus amount between an image forming surface (not shown) of the photographing lens 1 and the film equivalent surface 6 and determining the reliability of the defocus amount. The focus detection arithmetic circuit 10 includes a microcomputer and peripheral components necessary for its operation.

The motor drive control circuit 11 is a circuit for controlling the drive direction and the drive amount of the motor 12 based on the defocus amount calculated by the focus detection calculation circuit 10. The motor 12 is a motor that drives the focusing lens 1c of the photographing lens 1 in the optical axis direction to perform focus adjustment.

The main CPU 13 is a central processing unit for performing various controls of the entire camera system. Main CPU1
3, an electrical contact group 15, a release switch (not shown), a power supply unit (not shown), and the like are connected.

On the other hand, the interchangeable lens 20 is
, An in-lens CPU 16, a camera shake vibration detector 17,
Correction lens drive section 18 and correction lens position detection section 19
And an electrical contact group 15-2 and the like. The interchangeable lens 20 is detachable from the camera body 14 and is interchangeable.

The photographing lens 1 includes a fixed lens 1a, a blur correction lens 1b, a focusing lens 1c, and the like.
The blur correction lens 1b is a lens that corrects a blur by changing a photographing optical path, and is, for example, a single lens or a plurality of lens groups that move in a plane substantially perpendicular to the optical axis I (in an XY plane). It is. The blur correction lens 1b is driven in a direction substantially perpendicular to the optical axis I so that when an image on an imaging surface (not shown) moves due to camera shake or the like, the image moves in a direction opposite to the moving direction. To counteract blur.

The camera shake vibration detector 17 includes an interchangeable lens 20
And a sensor for detecting vibrations caused by camera shake applied to the camera body 14. The camera shake vibration detector 17 is, for example, an angular velocity sensor that detects an angular velocity value by using a Coriolis force acting on a camera and outputs an electric signal (blurring detection signal) proportional to the magnitude. The camera shake vibration detector 17 includes an angular velocity sensor for detecting a pitch around the X axis and an angular velocity sensor for detecting a yaw around the Y axis.

The correction lens driving section 18 is an actuator that generates a driving force and drives the blur correction lens 1b. The correction lens driving unit 18 includes, for example, a voice coil motor that arranges a coil in a magnetic circuit formed by a yoke and a magnet and generates an electromagnetic force according to Fleming's left hand rule when a driving current flows through the coil. it can.

The correction lens position detector 19 is a position sensor that detects the actual position of the blur correction lens 1b and outputs a current position signal (position detection signal). The correction lens position detection unit 19 includes, for example, an infrared light emitting diode (IRE)
D), a slit that moves together with the blur correction lens 1b, and a position detection element (PSD) that detects the position of the center of gravity of the light passing through the slit. The correction lens position detecting unit 19 outputs the current position signal to the lens CPU.
Feedback to 16

The CPU 16 in the lens is a central processing unit for performing various controls on the interchangeable lens 20 side. C in this lens
The camera shake vibration detector 17, the correction lens drive unit 18, the correction lens position detection unit 19, the electrical contact group 15-2, and the like are connected to the PU 16. Lens side CPU 16
Is a shake detection signal output from the camera shake vibration detector 17,
Based on the position detection signal output by the correction lens position detection unit 19, a target position signal for driving the blur correction lens 1b to a target position is calculated. CPU 16 in the lens
Based on this target position signal, the driving of the correction lens driving unit 18 is controlled.

Further, the in-lens CPU 16 determines whether or not the displacement of the entire camera system is random based on the shake detection signal output by the camera shake vibration detector 17. The in-lens CPU 16 switches the shake correction function between an active state and a non-active state according to the determination result. The lens-side CPU 16 is electrically connected to the body-side CPU 25, and can perform known serial communication with the main CPU 13. The in-lens CPU 16 transmits a parameter (flag) according to the state of the shake correction function to the main CPU 13 via the electric contact groups 15-1 and 15-2.

The electrical contact groups 15-1 and 15-2 are contacts for communicating information between the main CPU 13 and the lens-side CPU 16. The group of electric contacts 15 includes the interchangeable lens 2
0 and a mount portion (not shown) of the camera body 14.

In this embodiment, only one axis is shown in FIG. 1 for ease of explanation, but two independent axes on a plane substantially perpendicular to the photographing optical axis are shown. On the other hand, it is assumed that a camera shake vibration detector 17, a correction lens driving unit 18, and a correction lens position detector 19 are arranged.

Next, the focus detection operation of the camera system according to the present embodiment will be described. FIG. 2 is a flowchart illustrating a focus detection calculation process executed in the focus detection calculation circuit 10 according to the present embodiment. In step S100, when the power of the camera is turned on by a power switch (not shown) or a half-press operation or the like is performed by a release button (not shown), the focus detection operation is started. First, in step S101, the F flag for identifying whether the photographing lens 1 is in focus or in the vicinity thereof is set to 0.
Reset to. In the next step S102, a subject image signal is read from the image sensor 9, and focus detection calculation [various calculations shown in Expressions (1) and (2)] is performed.
The defocus amount of the photographing lens 1 is calculated.

In the following step S103, it is determined whether or not the F flag has been reset to "0".
When the F flag is 0, the process proceeds to step S104, and the reliability threshold value is set to an initial value. The threshold values are E1 and G1 in the above-described equation (3). In the following description, these are referred to as a threshold value E1 and a threshold value G1. On the other hand, when the F flag is set to 1, the process proceeds to step S105.
Proceed to.

In step S105, R flag> 1
Is determined. If the R flag> 1, the process proceeds to step S104. When the R flag is greater than 1, this corresponds to a situation where the camera is moving at random, for example, following a subject that moves at random. On the other hand, when the R flag ≤ 1, the process proceeds to step S106. Here, when the R flag = 0, the camera corresponds to a stationary state (only camera shake), and when the R flag = 1, panning for changing the composition or the start of random movement of the camera starts. Corresponds to the state. In the above-described Japanese Patent Application Laid-Open No. H8-76007, when the composition is simply changed, the lens is not driven until a predetermined time has elapsed. However, in the present embodiment, the R flag =
Since it can be determined from the information of 1 that the composition of the camera has been changed by panning, the photographing lens 1 is driven without waiting for a predetermined time.

In step S106, FIG.
Resets the reliability threshold value according to the subroutine.

In step S107, step S1
Whether the defocus amount calculated by 02 is reliable or not is determined by the above equation (3). If it is determined that it is reliable, the process proceeds to step S108.

In step S108, the photographing lens 1
Is at step S10 to determine whether or not
The determination is made based on the magnitude of the defocus amount calculated in (2). If it is determined that the taking lens 1 is at or near the in-focus position, the process proceeds to step S109, where 1 is added to the F flag. Otherwise, step S11 is performed.
Go to 0 and reset the F flag to 0. Step S1
After 09 and S110, the process proceeds to step S111.

In step S111, step S1
The lens is driven by the motor 12 via the motor drive control circuit 11 based on the defocus amount calculated by 02. Thereafter, returning to step S102,
The focus detection calculation is repeated. Note that the determination result of step S107 is stored in a memory (not shown).

When it is determined in step S107 that the defocus amount is not reliable, step S112 is performed.
Proceed to. In step S112, it is determined whether or not the previously calculated defocus amount is determined to be reliable based on the stored contents of the memory. If the previous defocus amount has been determined to be reliable, the flow advances to step S113 to start the built-in timer of the focus detection calculation circuit 10. Thereafter, the process proceeds to step S114. If it is determined in step S112 that the previous defocus amount has no reliability, the process directly proceeds to step S114.

In step S114, it is determined whether the time counted by the built-in timer has reached a predetermined time. If the predetermined time has elapsed, the process proceeds to step S115, where F flag =
Reset to zero. If the predetermined time has not elapsed, the process returns to step S102.

FIG. 3 is a flow chart showing the determination of the shake mode executed in the camera shake vibration detector 17 according to the present embodiment. In step S200, when the power of the camera is turned on by a power switch (not shown) or a half-press operation or the like is performed by a release button (not shown), the shake mode determination routine is executed. In step S201, the system is initialized and variables and the like used for calculation are initialized.

In step S202, a threshold value is provided for the output of the camera shake vibration detector 17, and it is determined whether the output (vibration) is larger than the threshold value. This threshold value is determined by paying attention to the fact that the magnitude of the fluctuation of the shake amount differs between a case where a still subject is photographed and a case where a random moving body is photographed. It has been confirmed in advance by preliminary experiments that the degree of fluctuation of camera shake vibration is smaller when a still subject is photographed.
If the blur fluctuation amount is large, step S203
Otherwise, the process proceeds to step S204.

In step S203, 1 is added to the R counter. This step is executed when it is determined that the fluctuation fluctuation amount is large. In this case, the camera system is determined to be following a subject with random movement,
Add 1 to the R counter. The R counter is provided to determine the state of camera movement.

In step S204, the R flag is reset to 0. The R flag is prepared as a flag indicating a shooting state. This step is executed when it is determined that the still subject is in a shooting state. In this case, the R flag is reset to a value of 0 indicating that the subject is not following a randomly moving subject.

In step S205, R flag = 0
Check whether or not. When the R flag is 0, it is determined that the still subject is in the shooting state, and the process proceeds to step S206. If the R flag is not 0, it is determined that the subject is following a subject with a composition change, a panning shot, or a random motion, and the process proceeds to step S214. In step S206, an anti-shake operation is performed. In this step, as the processing of the shooting state at rest, the image blur correction function is activated or, if already activated, the activation state is continued.

In step S207, it is determined whether or not the evaluation time for performing the random determination has elapsed.
This is due to the fact that R
This is a process for checking the value of the flag. Here, the evaluation time is, for example, a relatively short time of about 0.6 seconds. If it is within the evaluation time, step S2
08, otherwise, to step S215.

In step S208, it is determined whether or not the time is within the evaluation time of the random determination. Judgment time is a time for determining whether or not a subject with a random motion is being tracked a plurality of times within the evaluation time for random determination, and is a time shorter than the evaluation time (for example, every 0.2 seconds). ). In the present embodiment, the evaluation time is 0.6 seconds, and three determinations are made with a determination time every 0.2 seconds. If it is within the determination time, the process proceeds to step S209; otherwise, the process proceeds to step S213.

In step S209, it is determined whether the R counter is large. That is, since the judgment time is within the evaluation time of the random judgment, the value of the R counter accumulated at that time is referred to. If the value of the R counter is larger than a predetermined number of times, the process proceeds to step S210,
Otherwise, the process proceeds to step S211. In this embodiment, for each determination time (0.2 seconds), if a predetermined number of controls (for example, 70% or more) and an R counter are added within the determination time, a random number in the section of the determination time is obtained. It is determined that the subject is following a moving subject.

In step S210, the R flag is set to 1
Add. In this case, since the R counter is larger than the specified value at the judgment time within the evaluation time for the random judgment, at this time, it is in the process of following a composition change or a randomly moving subject. It is determined that. In step S211, R
Reset the flag to 0. This step S211 is
Contrary to step S210, the process is executed when the R counter is small, and it can be determined that the operation state of the camera is almost stationary.

In step S212, the value of the R counter accumulated for each judgment time within the evaluation time of the random judgment is reset to zero.

In step S214, it is checked whether the value of the timer counter is outside the evaluation time. If this value exceeds the evaluation time, the process proceeds to step S215; otherwise, the process proceeds to step S216. Step S21
5 is a case where the timer counter has exceeded the evaluation time, so that the value of the timer counter is cleared here. After the half-pressing operation is started by the processing of step S214 and step S215, a predetermined determination routine is repeatedly performed for each evaluation time.

In step S216, a vibration elimination stop process is performed. This step S216 is executed when the value of the R flag is 1 or more, that is, when it is determined that the subject is following a subject that is performing composition change, panning, or performing a random action. Stop the operation of the correction optical system. In this case, the image blur correction operation of the correction optical system is stopped, but the detection function of the shake vibration detection system is not stopped. Thereafter, the process proceeds to step S213.

In step S213, the interchangeable lens 2
Communication between the camera body 14 and the camera body 14 is performed regarding the image stabilization state. In this step, the value of the R flag corresponding to the shake state determined in each step described above is transmitted from the intra-lens CPU 16 of the interchangeable lens 20 to the main CPU 13 of the camera body 14 by serial communication.

FIG. 4 is a flowchart showing a subroutine for resetting a threshold value for determining reliability. This is a routine for driving the lens even if the subject moves in the front-rear direction with respect to the camera and goes out of the focusing range.

In step S301, it is determined whether a low frequency extraction operation has been performed. The low frequency extraction calculation is a focus detection calculation process performed using a signal obtained by extracting a low frequency component from a subject image signal. This is because, in the low-frequency extraction calculation, the range for detecting the defocus amount becomes narrow, so that when the defocus amount is large, the detection becomes impossible, and in the first place,
This is because it is not suitable for detecting a large defocus amount, such as when a subject goes out of the focus detection area. If the low-frequency extraction operation has been performed, the process proceeds to S302; otherwise, the process proceeds to S304.

In S302, it is determined whether or not the detected defocus amount is within a predetermined range. This is a case where the photographing lens 1 is not driven and the composition is changed to focus on another subject without increasing the defocus amount, such as when the subject is out of the focus detection area. As described above, when the defocus amount is not so large, the photographing lens 1 is immediately driven to focus. When the defocus amount is within the predetermined range, the process proceeds to S304, and when the defocus amount is out of the predetermined range, S303.
Proceed to.

In step S303, the threshold value E1 is set to a value (severe value) larger than the initial value, and the flow returns to the focus detection operation flowchart described with reference to FIG. Therefore, once the taking lens 1 is in or near the in-focus state, the threshold value for determining the reliability becomes strict, so that the detection cannot be easily performed. Even when the subject goes out of the focus detection area, the photographing lens 1 is not driven to immediately focus on the background. S30
At 4, the threshold values E1 and G1 are set to initial values.

As described above, according to the present embodiment, it is detected whether or not an object that performs a plurality of random movements is being tracked during a fixed evaluation time (S21).
4). As a result, if it is detected that the subject is following a randomly moving subject, the image blur correction control of the blur correction lens 1b with respect to the detected axis is stopped (S
215). This makes it possible to prevent the viewfinder from deteriorating due to a change in composition, panning, or a delay in image blur correction for a subject that performs a random operation.

On the other hand, if it is not determined that the camera is following a subject that moves randomly (S209),
The R flag remains at 0 (S211), that is, it is determined that the subject is to be photographed at rest.

When the R flag is 1 (S205: no), it is determined that the random detection operation is not performed for the subject performing the random operation but for changing the composition by the photographer. I do. Further, when the number of R flags is large (R flag> 1), it is determined that the random detection operation is following a subject that moves randomly. If the R flag is 1 or more, some random detection operation has been performed, and the image blur correction operation of the correction axis where the operation has been detected is stopped (S216).

Then, the CPU 16 in the lens determines in what state the image blur correction function has been stopped by the main CPU 13 of the camera body 14 based on the R flag.
To communicate. Thereby, the main CPU 13 can know the behavior state of the camera. This R flag is used for the determination in step S105 of the flowchart described above.

In the above processing, when the focus adjustment processing is started, first, the F flag is reset to 0 (S10).
1) In step S104, the threshold value E1 is set to an initial value. Thereafter, when the photographing lens 1 is driven to the in-focus state or a position near the in-focus state, the F flag is set to 1 in step S109, and thereafter, in step S105, it indicates that the subject is following a randomly moving subject. If the R flag is equal to or smaller than 1, the threshold value E1 is set in step S106.
Is changed to a large value. Thereby, step S10
7, the defocus amount is determined to be unreliable, and the probability of returning to step S102 without driving the lens is increased. Therefore, even when a large defocus amount occurs as in the case where the subject deviates from the focus detection area, the photographing lens 1 is not erroneously driven to focus on another subject such as the background.

If the state in which the defocus amount is determined to be unreliable continues for a predetermined time after the photographing lens 1 is driven to focus or near focus, step S114 is affirmed and the F flag is set to 0 in step S115. Therefore, the threshold value E1 is returned to the initial value in step S104. Therefore, even when the composition is intentionally changed for a still subject, there is no possibility that the defocus amount is continuously determined to be unreliable, and the photographing lens 1 is left standing still.

(Modification) In the present embodiment described above, the value of the threshold value E1 is increased when the reliability threshold value is increased. That is, the same effect can be obtained even if the threshold value G1 is reduced. Further, the threshold value E1 may be increased, and at the same time, the threshold value G1 may be decreased.

In this embodiment, the evaluation time is set to 0.6.
Seconds, judgment time 0.2 seconds, R counter for judgment,
Although 70% of the number of times of control is used, the value may be set to a different value because the size of the random tracking operation differs depending on the detection accuracy, the focal length of the imaging optical system, and the like.

Similarly, the relationship between the value of the random flag and the determination of composition change and random moving object tracking is not limited to the values shown here.

[0080]

According to the present invention, if it is determined that the photographing optical system is following a randomly moving subject after being driven to focus or near focus, the focus detection result is not reliable. Since the judgment conditions are changed so that the probability of judgment is high, it is not possible to follow a randomly moving subject, and even if the subject temporarily moves out of the focus detection area, useless driving of the imaging optical system Can be suppressed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a camera system according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating focus detection calculation processing of the camera system according to the present embodiment.

FIG. 3 is a flowchart illustrating a shake mode determination of the camera system according to the embodiment.

FIG. 4 is a flowchart illustrating resetting of a threshold for determining the reliability of the camera system according to the embodiment.

FIG. 5 is a diagram showing an optical system and an image sensor in a phase difference detection type focus detection device.

FIG. 6 is a diagram illustrating a correlation operation of the focus detection device of FIG. 5;

FIG. 7 is a diagram illustrating a correlation operation of the focus detection device in FIG. 5;

[Explanation of symbols]

 Reference Signs List 1 shooting lens 2 field mask 3 field lens 4A, 4B aperture opening 5A, 5B re-imaging lens 6 film equivalent surface 7 bandpass filter 8 focus detection optical system 9 image sensor 9A, 9B sensor array 10 focus detection arithmetic circuit 11 motor Drive control circuit 12 Motor 13 Main CPU 14 Camera body 15 Communication contact group 16 CPU in lens 17 Camera shake detector 18 Correction lens drive unit 19 Correction lens position detection unit 20 Interchangeable lens

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Tomita 3-2-3 Marunouchi, Chiyoda-ku, Tokyo Nikon Corporation (72) Inventor Kazutoshi Usui 3-2-2 Marunouchi, Chiyoda-ku, Tokyo F-term in Nikon (reference) 2H011 AA01 BA05 BB02 2H051 AA01 BA17 CE28 DA31 DA32 DA38 DB07 DC05 EA04 EB09 EC04 GB08 GB16

Claims (10)

[Claims] A focus detection unit that detects a focus adjustment state of a photographic optical system; and a reliability determination that determines reliability of the focus adjustment state of the photographic optical system detected by the focus detection unit according to a predetermined determination condition. And a moving state detecting unit that detects a moving state of the apparatus including the photographing optical system, wherein when the focus detecting unit detects that the photographing optical system is in a focused state, In the case where the movement state detection unit detects that the movement state of the device is random, when the reliability determination unit makes a determination, the focus adjustment state detected by the focus detection unit is reliable. A determination condition changing unit that changes a condition of the determination so as to increase a probability of determining that there is no sex. 2. The imaging apparatus according to claim 1, wherein the determination condition changing unit is configured to adjust a focus state detected by the focus detection unit when a focus detection result of the focus detection unit exceeds a predetermined range. Wherein the condition for the determination is changed so that the probability of determining that the image has no reliability is high. 3. The imaging device according to claim 1, wherein the determination condition changing unit returns the determination condition after a lapse of a predetermined time when the determination condition is changed. 4. One of claims 1 to 3
3. The image capturing apparatus according to claim 1, wherein the moving state determining unit includes: a blur detecting unit configured to detect a blur; A photographing apparatus comprising: a state determination unit; 5. The imaging apparatus according to claim 4, wherein the blur state determination unit determines whether or not the entire apparatus including the imaging optical system is in a substantially stationary state. . 6. The photographing apparatus according to claim 4, wherein a blur correcting optical system for correcting blur, a driving unit for driving the blur correcting optical system, and a control unit for driving and controlling the driving unit. An imaging device, wherein the control unit stops the driving unit when the blur state determination unit determines that the camera is not in a substantially stationary state. 7. A blur detecting section for detecting blur, a blur state determining section for determining a blur state of the entire apparatus including the photographing optical system based on an output signal of the blur detecting section, and a focus of the photographing optical system. A focus detection unit that detects an adjustment state; and a reliability determination unit that determines reliability of a focus adjustment state of the imaging optical system detected by the focus detection unit according to a predetermined determination condition. When the focus detection unit detects that the imaging optical system is in focus, and when the blur state determination unit detects that the movement state of the device is random, the reliability determination is performed. A determination condition changing unit that changes the determination condition so that the probability that the focus adjustment state detected by the focus detection unit is determined to be unreliable is increased when performing the determination by the unit. Imaging apparatus according to claim. 8. A blur detection unit for detecting a blur and outputting a blur detection signal, wherein the blur detection unit determines a blur state based on the blur detection signal. An imaging device accessory, comprising: a blur state determination unit that outputs a signal; and a determination signal transmission unit that transmits the blur state determination signal to the imaging device body. 9. The imaging device accessory according to claim 8, wherein the blur state determination unit determines whether or not the camera is in a substantially stationary state. 10. The camera accessory according to claim 8, wherein a shake correcting optical system for correcting shake, a driving unit for driving the shake correcting optical system, and drive control of the driving unit. And a control unit that stops the driving unit when the blur state determination unit determines that the camera is not in a substantially stationary state.