JP2002023046A - Automatic focusing device, optical equipment and camera system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow an objective lens to sufficiently exhibit its performance by reducing the load of processing on the objective lens side in the midst of overlap control. SOLUTION: This automatic focusing device equipped with an overlap control function for updating the lens driving amount by consecutively detecting the defocus amount not only in the midst of stopping a lens but also in the midst of driving the lens is provided with a lens position detection means for detecting the position of the objective lens, a time measuring means for measuring the time of detecting the lens position, and a lens position estimating means (#111) for measuring the lens position it the midst of the overlap control on the basis of the change of the lens position detected a plurality of times in the past and the detecting time of the lens position. By estimating the position of the objective lens by the lens position estimating means, the number of lens position detection in the midst of the overlap control is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic focus adjusting device for adjusting the focus of an objective lens, an optical apparatus having the device, and an improvement of a camera system.

[0002]

2. Description of the Related Art Conventionally, in an automatic focusing apparatus for a camera, a light beam from a subject passing through different exit pupil regions of a photographing lens is combined on a pair of line sensors, and the subject image is obtained by photoelectric conversion. An automatic focus adjustment method that detects a defocus amount of a subject by calculating an image shift amount that is a relative position displacement amount of a pair of image signals by a correlation operation and drives a photographing lens based on the detected defocus amount is widely known. ing.

In many cases, as shown in FIG. 7, an overlap control for continuously detecting the defocus amount and updating the lens drive amount not only during the stop of the lens drive but also during the lens drive is performed. Is going. First, as the amount of defocus increases, the obtained subject image itself becomes blurred, and sufficient detection accuracy cannot be obtained. Second, the larger the defocus amount is, the larger the image shift amount is. Therefore, the obtained subject image appears toward the end on the line sensor and further protrudes from the line sensor. Third, in order to actually drive the photographing lens, the amount of defocus must be converted into the amount of lens drive. However, as is well known, the two amounts have a non-linear relationship, so that the amount of defocus is The larger the value, the more difficult it is to obtain an accurate lens drive amount. In order to solve these problems, the photographing lens is accurately driven to the in-focus position by performing overlap control.

In order to reliably perform the overlap control, it is necessary to accurately obtain the position of the photographing lens during lens driving. As described above, since the subject image is photoelectrically converted (accumulation control) in the focus detection, an accumulation time corresponding to the subject brightness, contrast, and the like is required. Further, in order to obtain a lens drive amount required for focusing from the obtained subject image, calculation time such as a correlation calculation, a defocus amount calculation, and a lens drive amount calculation is required. Therefore, in updating the lens drive amount during the overlap control, the idle running amount of the photographing lens during this time must be considered.

[0005] Generally, it is as shown in FIG. First, from the start of focus detection to the update of the lens drive amount,
It is assumed that the taking lens is driven at a constant speed. The lens positions at the start and end of the focus detection are acquired, and the middle point is set as the lens position at the time of focus detection. After the correlation calculation, the defocus amount calculation, and the lens driving amount calculation, the lens position is acquired again. By subtracting the difference between the two lens positions as the lens idle amount from the lens drive amount obtained by the current focus detection, the lens drive amount necessary for focusing is obtained.

[0006]

The overlap control is performed as described above. Most interchangeable lens type single-lens reflex cameras have an MPU (micro processing unit) for each of the camera body and the interchangeable lens.
And perform specific operations by performing communication via the mount. That is, focus detection is performed by the MPU of the camera body, but acquisition of the lens position is requested by the MPU of the camera body to communicate with the MPU of the interchangeable lens, and actual acquisition processing is performed by the MPU of the interchangeable lens (hereinafter, referred to as lens MPU). ) Do. Normally, the lens position acquisition processing affects the overlap control if a delay occurs.
In general, the PU is preferentially processed by interrupt processing or the like. However, since the photographing lens is driven during the overlap control, the lens MP
U must also perform drive control in parallel. However, ultrasonic motors widely used in interchangeable lenses are
The drive control is complicated, and the processing load on the lens MPU is large. Further, in the case of an image stabilizing lens that prevents camera shake during photographing, in addition to these processes, more complicated image stabilizing control must be performed, and a very large load is applied to the lens MPU.

As described above, during the overlap control,
An extremely large load is concentrated on the lens MPU, and at this time, if the MPU of the camera body frequently requests the lens MPU to acquire the lens position, as described above, Since this process is performed with priority, the lens original process such as the lens driving process and the image stabilization control process is frequently interrupted, and sufficient performance cannot be exhibited. Specifically, if the lens driving process is frequently interrupted, the lens driving time is extended,
The accuracy of stopping at the lens position that is the drive target becomes poor. In addition, if the anti-shake control process is frequently interrupted, a sufficient anti-shake effect cannot be obtained.

(Object of the Invention) A first object of the present invention is to reduce the processing load on the objective lens or the photographic lens during the overlap control, and to make full use of the performance of the objective lens or the photographic lens. It is an object of the present invention to provide an automatic focusing device and an optical device that can perform the above-described operations.

A second object of the present invention is to provide an automatic focusing device and an optical apparatus which can accurately position an objective lens or a photographing lens at an in-focus position.

A third object of the present invention is to reduce the processing load on the objective lens or the photographic lens during the overlap control, to sufficiently exhibit the performance of the objective lens or the photographic lens, and to reduce the load on the in-focus position. An object of the present invention is to provide an automatic focusing device, an optical device, and a camera system that can accurately position an objective lens or a photographing lens.

A fourth object of the present invention is to provide a camera system capable of reducing the number of suspensions of image stabilization control during overlap control and preventing the image stabilization accuracy from deteriorating. It is.

[0012]

In order to achieve the first object, according to the first aspect of the present invention, a defocus amount which is a difference between an image forming position of an objective lens and an image plane position of the objective lens is provided. , A lens driving amount calculating unit for calculating a driving amount of the objective lens based on the defocus amount from the defocus amount detecting unit, and a lens driving amount from the lens driving amount calculating unit. Lens driving means for driving the objective lens in accordance with the following. The overlap control function of continuously detecting the defocus amount not only during the lens stop but also during the lens driving and updating the lens driving amount is provided. In the automatic focusing device provided, a lens position detecting means for detecting the position of the objective lens, a time measuring means for measuring the detection time of the lens position, a plurality of past lens positions and the like. Lens position estimating means for estimating the lens position during the overlap control from a change in the detection time, and estimating the position of the objective lens by the lens position estimating means to detect the lens position during the overlap control. This is an automatic focusing device that reduces the number of times.

In the above configuration, the number of lens position detections during the overlap control is reduced by estimating the position of the photographic lens in the future from changes in the lens position and its detection time in the past multiple times.

Further, in order to achieve the second object,
According to a second aspect of the present invention, there is provided a determining means for determining whether the lens drive is a constant-speed drive from a plurality of changes in the lens position in the past and a change in the detection time thereof. 2. The automatic focusing apparatus according to claim 1, wherein when it is determined that there is, the lens position estimating means is operated to reduce the number of lens position detections during the overlap control.

In the above configuration, when it is determined that the lens drive is the constant speed drive, the number of times of detecting the lens position during the overlap control is reduced.

In order to achieve the first object,
According to a third aspect of the present invention, there is provided a defocus amount detecting means for detecting a defocus amount which is a difference between an image forming position of the objective lens and an image plane position of the objective lens, and defocusing from the defocus amount detecting means. Lens driving amount calculating means for calculating the driving amount of the objective lens based on the amount; lens driving means for driving the objective lens according to the lens driving amount from the lens driving amount calculating means; and lens driving speed during the lens driving. A lens drive speed detecting means for detecting, and an overlap control function of continuously detecting the defocus amount not only during lens stop but also during lens drive and updating the lens drive amount. In the automatic focusing device, a lens position detecting means for detecting the position of the objective lens, and a clock means for measuring the detection time of the lens position,
Lens position estimating means for estimating the lens position during the overlap control from the lens position, the detection time thereof, and the lens driving speed from the lens driving speed detecting means; and The present invention is directed to an automatic focus adjustment device configured to reduce the number of times of detecting the lens position during the overlap control by estimating the position.

In the above arrangement, the number of lens position detections during the overlap control is reduced by estimating the position of the photographic lens in the future from the lens position, its detection time, and its driving speed.

Further, in order to achieve the second object,
According to a fourth aspect of the present invention, there is provided a control device for determining whether the lens drive is a constant-speed drive based on a plurality of changes in the lens drive speed in the past, and the determination unit may perform the constant-speed drive. 4. The automatic focusing apparatus according to claim 3, wherein the lens position estimating means is operated when the determination is made, and the number of lens position detections during the overlap control is reduced.

In the above configuration, when it is determined that the lens drive is the constant speed drive, the number of times of detecting the lens position during the overlap control is reduced.

In order to achieve the third object,
According to a fifth aspect of the present invention, there is provided a defocus amount detecting means for detecting a defocus amount which is a difference between an image forming position of an objective lens and an image plane position of the objective lens, and a defocus amount from the defocus amount detecting means. Lens driving amount calculating means for calculating a driving amount of the objective lens based on the amount, lens driving means for driving the objective lens according to the lens driving amount from the lens driving amount calculating means, and a lens acceleration / deceleration state during driving of the lens And a lens acceleration / deceleration state detecting means for detecting the amount of defocus. The overlap control function of continuously detecting the defocus amount not only during the stop of the lens but also during the driving of the lens and updating the lens driving amount is provided. In the automatic focusing device provided, a lens position detecting means for detecting the position of the objective lens, a time measuring means for measuring the detection time of the lens position, Lens position estimating means for estimating the lens position during the overlap control from the shift position and the detection time thereof, and when the lens acceleration / deceleration state is a constant velocity state, the lens position estimating means The automatic focus adjustment device is configured to reduce the number of times of detecting the lens position during the overlap control by estimating the position of the lens.

In the above configuration, when the lens acceleration / deceleration state is a constant speed state, the position of the future photographing lens is estimated from the lens position, the detection time thereof, and the driving speed, whereby the lens under overlap control is estimated. The number of position detections is reduced.

In order to achieve any of the first to third objects, the invention according to claim 6 is directed to claim 1 to claim 1.
5. An optical apparatus comprising the automatic focusing device according to any one of 5.

In order to achieve the third object,
According to a seventh aspect of the present invention, there is provided a defocus amount detecting means for detecting a defocus amount which is a difference between an image forming position of a photographing lens and an image plane position of the photographing lens, and a defocus amount from the defocus amount detecting means. Lens driving amount calculating means for calculating the driving amount of the photographing lens based on the amount, and lens driving means for driving the photographing lens according to the lens driving amount from the lens driving amount calculating means. In a camera system having an overlap control function of continuously detecting the defocus amount even during lens driving and updating the lens driving amount, a lens position detecting unit for detecting a position of a taking lens; A timing means for measuring the detection time of the lens position, and a lens position during the overlap control is estimated from a plurality of past lens positions and changes in the detection time. A lens position estimating means, from the change in the detection time and lens position of the previous several times, and determining means for determining lens driving is constant speed drive to,
A camera system in which the lens position estimating means functions when the determining means determines that the driving is at a constant speed, and the number of lens position detections during the overlap control is reduced.

Similarly, in order to achieve the third object,
According to a ninth aspect of the present invention, there is provided a defocus amount detecting means for detecting a defocus amount which is a difference between an image forming position of a photographing lens and an image plane position of the photographing lens, and a defocus amount from the defocus amount detecting means. A lens driving amount calculating unit that calculates a driving amount of the taking lens based on the amount, a lens driving unit that drives the taking lens according to the lens driving amount from the lens driving amount calculating unit, and a lens driving speed during driving the lens. A lens drive speed detecting means for detecting, and an overlap control function of continuously detecting the defocus amount not only during lens stop but also during lens drive and updating the lens drive amount. In the camera system, a lens position detecting means for detecting the position of the photographing lens, a clock means for measuring the detection time of the lens position,
Lens position estimating means for estimating the lens position during the overlap control from the lens position, the detection time thereof, and the lens driving speed from the lens driving speed detecting means;
Determining means for determining whether the lens drive is constant-speed drive from a plurality of changes in the lens drive speed in the past, and determining that the lens drive is constant-speed drive; A camera system in which the position estimating means functions so as to reduce the number of lens position detections during the overlap control.

Similarly, in order to achieve the third object,
According to an eleventh aspect of the present invention, there is provided a defocus amount detecting means for detecting a defocus amount which is a difference between an image forming position of a photographing lens and an image plane position of the photographing lens, and a defocus amount from the defocus amount detecting means. Lens driving amount calculating means for calculating the driving amount of the photographing lens based on the amount, lens driving means for driving the photographing lens according to the lens driving amount from the lens driving amount calculating means, and a lens acceleration / deceleration state during driving of the lens And a lens acceleration / deceleration state detecting means for detecting the amount of defocus. The overlap control function of continuously detecting the defocus amount not only during the stop of the lens but also during the driving of the lens and updating the lens driving amount is provided. In the camera system provided, a lens position detecting means for detecting the position of the taking lens, a time measuring means for measuring the detection time of the lens position, Lens position estimating means for estimating the lens position during the overlap control from the shift position and the detection time thereof, and when the lens acceleration / deceleration state is a constant speed state, the lens position estimating means The camera system is designed to reduce the number of lens position detections during overlap control by estimating the position of the camera.

In order to achieve the fourth object,
According to a thirteenth aspect of the present invention, the interchangeable photographic lens is a camera system according to the eighth, tenth, or twelfth aspect having an image stabilizing function.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on illustrated embodiments.

(First Embodiment) FIG. 1 is a block diagram showing a configuration of an interchangeable lens type single-lens reflex camera which is an example of an optical apparatus according to a first embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a lens MPU (micro-processing unit) for performing all calculations and controls relating to the photographing lens, 2 denotes a lens driving unit for driving the photographing lens, 3 denotes a lens position detecting unit, and 4 denotes a lens position detecting unit. The extension position detection unit 5 is an optical information table that differs for each interchangeable lens, such as the sensitivity described below, the extension amount of the lens per pulse, and the best focus correction value.

The taking lens according to the present embodiment is a fixed focal length lens having a fixed focal length, but the present embodiment can be similarly applied to a zoom lens having a variable focal length. In an actual photographing lens, an aperture drive unit for driving the aperture is required, but the description is omitted because it is not directly related to the present invention. The photographing lens has a circuit block including the lens MPU 1 to the optical information table 5.

The photographic lens having the above configuration is connected to the camera body via a mount indicated by a dotted line in the center of FIG.

Reference numeral 8 denotes a camera MPU (micro processing unit) that performs all calculations and controls related to the camera body.
The lens MPU1 is connected to the lens MPU1 via a signal line of the mount, and can acquire a lens position, drive a lens, and acquire optical information unique to each interchangeable lens. Reference numeral 9 denotes a defocus amount detection unit, 10 denotes a shutter drive unit, 11 denotes a film feed unit, and 12 denotes a dial unit for performing various settings (shutter speed, aperture value, shooting mode, etc.) of the camera. SW1 is a switch that is turned on by the first stroke operation (half press) of the release button, and SW2 is a switch that is turned on by the second stroke operation (full press) of the release button.

In this embodiment, when the switch SW1 is turned on, automatic focusing is performed, and the switch S1 is turned on.
When W2 is turned on, a release operation is performed.

Various photographing modes can be set by operating the dial unit 12. Here, the automatic focusing according to the present invention will be described with reference to the flowchart of FIG.

When switch SW1 is turned on, step #
From 101, automatic focusing is started. First, step # 10
In 2, the lens position is obtained from the lens position detection unit 3. This acquisition is performed by communicating from the camera MPU8 to the lens MPU1. At the same time, the acquisition time is obtained by a timer built in the camera MPU 8.

The defocus amount (difference between the image forming position of the photographing lens and the image plane position of the photographing lens for performing the photographing operation) required for the automatic focus adjustment passes through two different areas sandwiching the optical axis of the photographing lens. It is calculated from the image shift amount (prediction amount) between two images formed from the subject light flux. Specifically, the luminous flux of these two images passes through a main mirror which is a half mirror, is reflected by a sub-mirror located behind the half mirror, and is guided to a defocus amount detection unit 9 by a focus detection optical system (not shown). The defocus amount detection unit 9 has a photoelectric conversion element, and the camera M
In the next step # 103, the PU 8 reads out the signals of these two images from the photoelectric conversion element. Then, in the next step # 104, it is determined whether or not the acquisition of the lens position can be omitted. If the acquisition can be omitted, the process immediately proceeds to step # 106, but if not, the process proceeds to step # 105 to acquire the lens position. In step # 104, the time is obtained by a timer built in the MPU 8. Then, the process proceeds to step # 106.

In step # 106, the amount of image shift is calculated by performing a correlation operation, and the defocus amount is obtained. The defocus amount is obtained in this manner. There is a relationship of l = d / S between the defocus amount d (mm) and the actual driving amount l (mm) of the photographing lens. Call it sensitivity. As is well known, in a currently mainstream inner focus photographing lens, this sensitivity varies depending on the photographing lens and the extension position of the photographing lens. As described above, the defocus amount and the lens driving amount have a non-linear relationship, and the sensitivity S is a function corresponding to the defocus amount d. Also, the amount handled in the actual feeding is not the l itself, but the number of focus pulses P
(Pulse) is expressed as follows.

P = 1 / h = d / h / S where h (mm / pulse) is the amount of lens extension per pulse. Therefore, when the calculation of the defocus amount d is completed in step # 106, the camera MPU 8 proceeds to step # 107, and acquires h and S by communicating with the lens MPU1. Specifically, the distance ring of the photographing lens is electrically divided at equal intervals, and is connected to the extended position detecting unit 4. Lens MPU1
Obtains the current feed-out position from the feed-out position detecting unit 4, determines the sensitivity S by referring to the optical information table 5, and transmits this to the camera MPU8. Also,
h is always constant irrespective of the feeding position, and is transmitted to the camera MPU 8.

When the above h and S are obtained, the camera MPU 8
Goes to step # 108, and is converted into the number P of focus pulses. Then, in the next step # 109, it is determined whether the acquisition of the lens position can be omitted. If the acquisition can be omitted, the process immediately proceeds to step # 111, but if not, the process proceeds to step # 110 to acquire the lens position. Similarly to step # 104, the time is obtained by the timer built in the MPU 8 in step # 109. Then, the process proceeds to step # 111.

The lens drive amount necessary for focusing is obtained in this manner. In the next step # 111, the number of focus pulses of the lens idle travel amount is corrected. As described above with reference to FIG. 8, when calculating the lens drive amount during the overlap control, the idle running amount of the photographing lens during the focus detection must be considered. Step # 104 above
The determination as to whether the acquisition of the lens position can be omitted in step # 109 is always determined to be impossible in the focus detection up to the second time after the switch SW1 is turned on. If it is determined that the omission is not possible from the start of the automatic focus adjustment, the lens position is obtained in steps # 102, # 105 and # 110. At this time, the lens position obtained in step # 102 is the lens position at the start of focus detection, and the lens position obtained in step # 105 is the lens position at the end of focus detection. The lens position. Then, the above step # 1
The difference from the lens position obtained in step 10 is taken as the lens idling amount, and is subtracted from the number of focus pulses P obtained in the current focus detection, to obtain a lens driving amount necessary for focusing.

Then, the process proceeds to a step # 112, in which the lens is driven via the lens driving unit 2, and in a succeeding step # 113, it is determined whether or not the switch SW1 is turned on. If the switch SW1 is turned off, the process proceeds to a step # 115. Cancel auto focus. On the other hand, the switch SW1
If is turned on, the process proceeds to step # 114, and it is determined from the current lens drive amount whether focusing can be considered. Here, if it is determined that the focus is achieved, the process proceeds to step # 115 to end the automatic focus adjustment, and if it is not determined that the focus is achieved, the process returns to step # 102.
The automatic focus adjustment is continued until the in-focus state is determined or the switch SW1 is turned off.

After the third focus detection, the determination as to whether the acquisition of the lens position can be omitted in steps # 104 and # 109 is performed as follows.

The past 3 obtained in step # 102
From the number of lens positions and its acquisition time, it is assumed that the lens position is y and the acquisition time is t, and it is regarded as a uniform acceleration motion, and y = 0.5 at ² + vt + d is solved for a, v, and d. As is known, a represents acceleration in constant acceleration motion, v represents velocity, and d represents a position at t = 0. When a is sufficiently small, the lens drive can be regarded as constant-speed drive. Therefore, at this time, it is determined that the acquisition of the lens position can be omitted, and conversely, when a is large, it is determined that the omission cannot be performed.

If it is determined that the acquisition of the lens position can be omitted, the correction of the number of focus pulses of the lens idle amount in step # 111 is performed as follows. Since the time of determining whether the acquisition of the lens position can be omitted in Steps # 104 and # 109 has been obtained, this time is substituted into the above equation to obtain Steps # 104 and # 10.
The lens position at 9 is estimated. From the estimated lens position, the lens idle amount is obtained by the same method as in the case where acquisition of the lens position is not omitted, and the lens driving amount is corrected.

In the first embodiment, the number of lens position detections during the overlap control is reduced by estimating the position of the future photographing lens from a plurality of past changes in the lens position and changes in the detection time. It is configured as follows. Thereby, the lens MP during the overlap control is controlled.
The processing load on U can be reduced, and the performance of the interchangeable lens can be sufficiently exhibited. Specifically, the lens driving process is not interrupted frequently, so that the lens driving time can be shortened, and the stopping accuracy at the lens position serving as the driving target can be improved. In addition, in the case where the apparatus has the image stabilizing function, the image stabilizing control process is not interrupted frequently, so that a sufficient image stabilizing effect can be obtained.

Also, only when it is determined that the lens drive is the constant speed drive, the number of times of detecting the lens position during the overlap control is reduced, so that an automatic focus adjusting device for accurately driving the photographing lens to the in-focus position is provided. It becomes possible.

(Second Embodiment) Second embodiment of the present invention
This embodiment has substantially the same configuration as that of the first embodiment, and reduces the number of lens position detections during the overlap control for the lens capable of measuring the driving speed of the photographing lens, and sets the lens at the in-focus position. The present invention is configured to enable an automatic focusing device that accurately drives a photographing lens.

FIG. 3 is a block diagram showing a configuration of an interchangeable lens type single-lens reflex camera which is an example of an optical apparatus according to a second embodiment of the present invention.

Referring to FIG. 1, reference numeral 1 denotes a lens MPU (micro processing unit) for performing all calculations and controls related to the photographing lens, 2 denotes a lens driving unit for driving the photographing lens, 3 denotes a lens position detecting unit, and 4 denotes a lens position detecting unit. The extension position detection unit 5 is an optical information table that differs for each interchangeable lens, such as the sensitivity described below, the extension amount of the lens per pulse, and the best focus correction value. Reference numeral 6 denotes a lens drive speed detection unit that measures a photographing lens drive speed.

The taking lens according to the present embodiment is a fixed focal length lens having a fixed focal length. However, the present embodiment can be similarly applied to a zoom lens having a variable focal length. In an actual photographing lens, an aperture drive unit for driving the aperture is required, but the description is omitted because it is not directly related to the present invention. The taking lens has a circuit block from the lens MPU 1 to the lens driving speed detecting unit 6.

The taking lens is connected to the camera body via a mount indicated by a dotted line in the center of FIG. The configuration of the camera body is the same as that of the first embodiment, and a description thereof will be omitted.

The automatic focus adjustment according to the second embodiment of the present invention will be described with reference to the flowchart of FIG.

When the switch SW1 is turned on, step #
From 201, automatic focus adjustment is entered. First, step # 20
In step 2, the lens position is acquired, and the next step # 20
In 3, the lens drive speed is obtained. This acquisition is performed by communicating from the camera MPU8 to the lens MPU1. At the same time, the acquisition time is obtained by a timer built in the camera MPU 8.

Then, similarly to the first embodiment,
The camera MPU 8 reads out the image signal in step # 204, and in subsequent step # 205, determines whether or not acquisition of the lens position can be omitted.
07, but if not, the process proceeds to step # 206 to acquire the lens position. Step # 2
At 05, the time is obtained by a timer built in the MPU 8. Then, the process proceeds to step # 207.

In step # 207, the amount of image shift is calculated by performing a correlation operation, and the defocus amount is obtained. When the calculation of the defocus amount d is completed, the process proceeds to step # 208, where h and S are obtained by communicating with the lens MPU1, and in the following step # 209, the number of focus pulses is converted into the number P of focus pulses. Subsequently, in step # 210, it is determined whether the acquisition of the lens position can be omitted. If the acquisition can be omitted, the process proceeds to step # 212. If not, the process proceeds to step # 211 to acquire the lens position. Also, as in step # 205, in step # 210, the time is obtained by a timer built in the MPU 8. And step # 2
Proceed to 12.

When the flow proceeds to step # 212, the number of focus pulses of the lens idle travel amount is corrected here. The determination as to whether the acquisition of the lens position can be omitted in Steps # 205 and # 210 is always made impossible in the focus detection up to the first time after the switch SW1 is turned on. If it is determined that the omission cannot be omitted from the start of the automatic focus adjustment, steps # 202, # 206 and step # 21
At 1, the lens position is obtained. At this time,
The lens position obtained in step # 202 is the lens position at the start of focus detection, the lens position obtained in step # 206 is the lens position at the end of focus detection, and the middle point is the lens position at the time of focus detection. I do. The difference from the lens position obtained in step # 211 is subtracted from the number of focus pulses P obtained in the current focus detection as a lens idle travel amount, and is set as a lens drive amount necessary for focusing.

In the next step # 213, the lens is driven. In the following step # 214, it is determined whether or not the switch SW1 is turned on. If the switch SW1 is turned off, the process proceeds to step # 216 to stop the automatic focus adjustment. On the other hand, if the switch SW1 is turned on, step # 21
The process proceeds to step 5, and it is determined from the current lens driving amount whether focusing can be considered. Here, if it is determined that focus is achieved, step #
Proceeding to 216, the automatic focus adjustment is completed, and if it is not determined that the focus is achieved, the process returns to step # 202. Thereafter, the overlap control is performed until the automatic focus adjustment is determined to be in focus or the switch SW1 is turned off. to continue.

After the second focus detection, the determination as to whether the acquisition of the lens position can be omitted in step # 205 and step # 210 is performed as follows.

The past 2 obtained in step # 203
It is determined whether or not the current lens drive can be regarded as a constant speed drive based on the change in the lens drive speed. When it is determined that the driving can be regarded as the constant-speed driving, it is determined that the acquisition of the lens position can be omitted.

If it is determined that the acquisition of the lens position can be omitted, the correction of the number of focus pulses of the lens idling amount in step # 212 is performed as follows. Since the time at the time of determining whether the acquisition of the lens position can be omitted in Steps # 205 and # 210 has been obtained, this time t is substituted into the following equation to obtain Steps # 205 and # 2.
The lens position y at 10 is estimated.

Y = v (t−t0) + d0 where d0 is the lens position acquired in step # 202, t0 is the acquisition time at that time, and v is step # 203.
Is the driving speed of the lens obtained in step (1). From the estimated lens position, the lens idle amount is obtained by the same method as in the case where acquisition of the lens position is not omitted, and the lens driving amount is corrected.

In the second embodiment, the number of lens position detections during overlap control is reduced by estimating the position of the future photographic lens from the past lens position, its detection time, and its driving speed. It is configured as follows. Thereby, the lens M during the overlap control is
The processing load on the PU can be reduced, and the performance of the interchangeable lens can be sufficiently exhibited.

Also, only when it is determined that the lens drive is the constant speed drive, the number of times of detecting the lens position during the overlap control is reduced, so that an automatic focus adjusting device for accurately driving the photographing lens to the in-focus position is provided. It becomes possible.

(Third Embodiment) A third embodiment of the present invention.
This embodiment has almost the same configuration as that of the first embodiment. For the lens capable of detecting the acceleration / deceleration state of the photographing lens, the number of times of detecting the lens position during the overlap control is reduced, and Thus, an automatic focusing device for accurately driving the photographing lens can be realized.

FIG. 5 is a block diagram showing a configuration of an interchangeable lens type single-lens reflex camera which is an example of an optical apparatus according to a third embodiment of the present invention.

In the figure, reference numeral 1 denotes a lens MPU (micro processing unit) for performing all operations and control relating to the photographing lens, 2 denotes a lens driving unit for driving the photographing lens, 3 denotes a lens position detecting unit, and 4 denotes a lens position detecting unit. The extension position detection unit 5 is an optical information table that differs for each interchangeable lens, such as the sensitivity described below, the extension amount of the lens per pulse, and the best focus correction value. An acceleration / deceleration state detection unit 7 detects the acceleration / deceleration state of the photographing lens.

The photographic lens in the present embodiment is a fixed focal length lens having a fixed focal length. However, the present embodiment can be similarly applied to a zoom lens having a variable focal length. Further, an actual photographing lens requires an aperture driving unit for driving the aperture, but the description is omitted because it is not directly related to the present invention.
The photographing lens has a circuit block from 1 to the lens MPU 5 to the acceleration / deceleration state detection unit 7.

The taking lens is connected to the camera body via a mount indicated by a dotted line in the center of FIG. The configuration of the camera body is the same as that of the first embodiment, and a description thereof will be omitted.

The automatic focus adjustment according to the third embodiment of the present invention will be described with reference to the flowchart of FIG.

When switch SW1 is turned on, step #
From 301, automatic focus adjustment is entered. First, step # 30
In step 2, the lens position is acquired, and the next step # 3
At 03, a lens acceleration / deceleration state is obtained. This acquisition is performed by communicating from the camera MPU8 to the lens MPU1. At the same time, the acquisition time is obtained by a timer built in the camera MPU 8.

Then, similarly to the first embodiment,
In step # 304, the camera MPU 8 reads out the image signal, and in step # 305, determines whether the acquisition of the lens position can be omitted. If it can be omitted, the process immediately proceeds to step # 307; otherwise, the process proceeds to step # 3.
In step 06, the lens position is acquired. In step # 305, the time is obtained by a timer built in the MPU 8. And step # 3
Proceed to 07.

In step # 307, the amount of image shift is calculated by performing a correlation operation to determine the amount of defocus. When the calculation of the defocus amount d is completed, the process proceeds to step # 308, where h and S are obtained by communicating with the lens MPU1, and converted into the number of focus pulses P in step # 309. Then, step # 310
In, it is determined whether the acquisition of the lens position can be omitted. If the acquisition can be omitted, the process immediately proceeds to step # 312. If not, the process proceeds to step # 311 to acquire the lens position. Further, similarly to step # 305, step # 3
In 10, the time is obtained by a timer built in the MPU 8. Then, the process proceeds to step # 312.

In step # 312, the number of focus pulses of the lens idle travel amount is corrected. Step # 3 above
The determination as to whether the acquisition of the lens position can be omitted in step 05 and step # 310 is always determined to be impossible in the focus detection up to the second time after the switch SW1 is turned on. If it is determined that the omission cannot be performed from the start of the automatic focus adjustment, the lens position is obtained in steps # 302, # 306 and # 311. At this time, the lens position obtained at step # 302 is the lens position at the start of focus detection, the lens position obtained at step # 306 is the lens position at the end of focus detection, and the middle point is the lens position at the time of focus detection. And Then, the difference from the lens position obtained in step # 311 is subtracted from the number of focus pulses P obtained by the current focus detection as the lens idle distance,
The lens drive amount required for focusing is set.

In the next step # 313, the lens is driven. In the following step # 314, it is determined whether or not the switch SW1 is turned on. If the switch SW1 is turned off, the process proceeds to step # 316 to stop the automatic focus adjustment. On the other hand, if it is turned on, the process proceeds to step # 315, and it is determined whether focusing can be considered based on the current lens drive amount. Here, if it is determined that the focus is achieved, the process proceeds to step # 316, and the automatic focus adjustment is terminated. If it is not determined that the focus is achieved, the process returns to step # 302.
The automatic focus adjustment is continued until it is determined that the focus is achieved or the SW1 is turned off.

After the third focus detection, the determination as to whether the acquisition of the lens position can be omitted in steps # 305 and # 310 is performed as follows.

From the acceleration / deceleration state of the lens obtained in step # 303, it is determined whether the current lens drive is the constant speed drive. When it is determined that the driving is performed at the constant speed, it is determined that the acquisition of the lens position can be omitted.

If it is determined that the acquisition of the lens position can be omitted, the correction of the number of focus pulses of the lens idle amount in step # 312 is performed as follows. Based on the past three lens positions and the acquisition time obtained in step # 302, it is assumed that the lens position is y and the acquisition time is t, and the acceleration is constant, and y = 0.5at ² + vt + d is calculated as a, v, d Solve for Since the time for determining whether the acquisition of the lens position can be omitted in step # 305 and step # 310 has been obtained, this time is substituted into this equation, so that step # 305 and step # 31 are obtained.
Estimate the lens position at zero. From the estimated lens position, the lens idle amount is obtained by the same method as in the case where acquisition of the lens position is not omitted, and the lens driving amount is corrected.

In the third embodiment, when the lens acceleration / deceleration state is a constant speed state, the position of the photographic lens in the future is estimated from the lens position, its detection time, and its driving speed, thereby obtaining an over-range. The number of lens position detections during the lap control is reduced. As a result, the processing load on the lens MPU during the overlap control can be reduced, and the performance of the interchangeable lens can be sufficiently exhibited.

Also, only when it is determined that the lens drive is the constant speed drive, the number of times of detecting the lens position during the overlap control is reduced, so that an automatic focus adjusting device for accurately driving the photographing lens to the in-focus position is provided. It becomes possible.

(Modification) In the above embodiment, the case where the present invention is applied to a single-lens reflex camera has been described. However, the present invention is also applicable to other optical devices such as a video camera and an electronic still camera.

(Correspondence between the Invention and the Embodiment) In each of the above embodiments, the camera MPU 8 and the defocus amount detection unit 9 correspond to the defocus amount detection means of the present invention, and the lens MPU 1, the camera MPU 8 and the optical information table 5 corresponds to the lens driving amount calculating means of the present invention, the lens MPU1 and the lens driving unit 2 correspond to the lens driving means of the present invention, and the lens MPU1 and the lens position detecting unit 3 correspond to the lens position detecting means of the present invention. The lens MPU 1 and the lens driving speed detecting unit 6 correspond to a lens driving speed detecting unit of the present invention,
The lens MPU1 and the acceleration / deceleration detecting unit 7 correspond to the lens acceleration / deceleration state detecting means of the present invention, and the camera MPU8 corresponds to the time measuring means and the lens position estimating means of the present invention.

[0082]

As described above, according to the first, third, or sixth aspect of the present invention, the processing load on the objective lens or the photographic lens during the overlap control is reduced, and An object of the present invention is to provide an automatic focusing device or an optical device capable of sufficiently exhibiting the performance of a lens.

According to the second, fourth or sixth aspect of the present invention, it is possible to provide an automatic focusing device or an optical device capable of accurately positioning an objective lens or a photographing lens at a focus position. .

According to the fifth, sixth, seventh, ninth and eleventh aspects of the present invention, the processing load on the objective lens or the photographic lens during the overlap control is reduced, and the load on the objective lens or the photographic lens is reduced. An object of the present invention is to provide an automatic focusing device, an optical device, or a camera system capable of sufficiently exhibiting performance and accurately positioning an objective lens or a photographing lens at a focus position.

According to the thirteenth aspect of the present invention,
An object of the present invention is to provide a camera system capable of reducing the number of times the image stabilization control is interrupted during the overlap control and preventing the image stabilization accuracy from deteriorating.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a main part of an automatic focusing camera according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of a main part of the automatic focusing camera according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a main part of an automatic focusing camera according to a second embodiment of the present invention.

FIG. 4 is a flowchart showing an operation of a main part of an automatic focusing camera according to a second embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a main part of an automatic focusing camera according to a third embodiment of the present invention.

FIG. 6 is a flowchart showing an operation of a main part of an automatic focusing camera according to a third embodiment of the present invention.

FIG. 7 is a diagram for explaining overlap control.

FIG. 8 is a detailed diagram similarly illustrating overlap control.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 lens MPU 2 lens drive unit 3 lens position detection unit 4 extension position detection unit 5 optical information table 6 lens drive speed detection unit 7 acceleration / deceleration state detection unit 8 camera MPU 9 defocus amount detection unit 10 shutter drive unit 11 film feeding Unit 12 Dial unit

Claims (13)

[Claims] 1. A defocus amount detecting means for detecting a defocus amount, which is a difference between an image forming position of an objective lens and an image plane position of the objective lens, and a defocus amount based on the defocus amount from the defocus amount detecting means. Lens driving amount calculating means for calculating the driving amount of the objective lens; and lens driving means for driving the objective lens according to the lens driving amount from the lens driving amount calculating means. An automatic focus adjustment device having an overlap control function of continuously detecting the defocus amount and updating the lens drive amount, wherein: a lens position detecting means for detecting a position of an objective lens; and the lens position Means for measuring the detection time of the lens, and a lens for estimating the lens position during the overlap control from a plurality of past lens positions and changes in the detection time. And a's position estimation means, by estimating the position of the objective lens by the lens position estimation means, an automatic focusing device which is characterized in that so as to reduce the lens position detection times in the overlap control. 2. A method according to claim 1, further comprising determining means for determining whether the lens is driven at a constant speed based on a plurality of changes in the lens position in the past and a change in the detection time. 2. The automatic focus adjusting device according to claim 1, wherein the lens position estimating means is operated when the operation is being performed to reduce the number of times of detecting the lens position during the overlap control. 3. A defocus amount detecting means for detecting a defocus amount, which is a difference between an image forming position of the objective lens and an image plane position of the objective lens, and a defocus amount based on the defocus amount from the defocus amount detecting means. Lens driving amount calculating means for calculating the driving amount of the objective lens; lens driving means for driving the objective lens according to the lens driving amount from the lens driving amount calculating means; and lens driving for detecting the lens driving speed during the lens driving An automatic focus adjustment device having a speed detection means and an overlap control function of continuously detecting the defocus amount and updating the lens drive amount not only during lens stop but also during lens drive. In the above, a lens position detecting means for detecting the position of the objective lens, a time measuring means for measuring the detection time of the lens position, the lens position and the detection time Lens position estimating means for estimating the lens position during the overlap control from the lens driving speed from the lens driving speed detecting means, and estimating the position of the objective lens by the lens position estimating means. An automatic focusing device, wherein the number of times of lens position detection during lap control is reduced. 4. A method for determining whether a lens drive is a constant-speed drive from a plurality of changes in the lens drive speed in the past, wherein the determination means determines that the drive is a constant-speed drive. 4. The automatic focus adjustment apparatus according to claim 3, wherein the lens position estimating means is operated to reduce the number of lens position detections during the overlap control. 5. A defocus amount detecting means for detecting a defocus amount which is a difference between an image forming position of the objective lens and an image plane position of the objective lens, and a defocus amount based on the defocus amount from the defocus amount detecting means. Lens driving amount calculating means for calculating the driving amount of the objective lens, lens driving means for driving the objective lens according to the lens driving amount from the lens driving amount calculating means, and a lens for detecting a lens acceleration / deceleration state during driving of the lens An automatic focus having an acceleration / deceleration state detecting means, and having an overlap control function of continuously detecting the defocus amount and updating the lens drive amount not only during lens stop but also during lens drive. In the adjusting device, a lens position detecting means for detecting the position of the objective lens, a time measuring means for measuring the detection time of the lens position, a plurality of lens positions in the past, Lens position estimating means for estimating the lens position during the overlap control from the detection time of, when the lens acceleration / deceleration state is a constant velocity state, the lens position estimating means determines the position of the objective lens. An automatic focusing device, wherein the number of times of lens position detection during overlap control is reduced by estimating. 6. An optical apparatus comprising the automatic focusing device according to claim 1. 7. A defocus amount detecting means for detecting a defocus amount which is a difference between an image forming position of the photographing lens and an image plane position of the photographing lens, and a defocus amount based on the defocus amount from the defocus amount detecting means. Lens driving amount calculating means for calculating the driving amount of the photographing lens; and lens driving means for driving the photographing lens according to the lens driving amount from the lens driving amount calculating means. A camera position equipped with an overlap control function for continuously detecting the defocus amount and updating the lens drive amount. A time measuring means for measuring the time; and a lens for estimating the lens position during the overlap control based on a change in the lens position and the detection time of a plurality of times in the past. A position estimating unit, and a determining unit that determines whether the lens driving is a constant-speed driving based on a change in the lens position and a detection time of the past plural times, wherein the determining unit performs the constant-speed driving. A camera system wherein the lens position estimating means functions when the determination is made, and the number of lens position detections during the overlap control is reduced. 8. The lens driving means and the lens position detecting means are provided at least on the photographing lens side,
The camera system according to claim 7, wherein the other units are provided on a camera body side, and the photographing lens is an interchangeable photographing lens. 9. A defocus amount detecting means for detecting an out-of-focus amount which is a difference between an image forming position of the photographing lens and an image plane position of the photographing lens, and a defocus amount based on the defocus amount from the defocus amount detecting means. Lens driving amount calculating means for calculating the driving amount of the taking lens; lens driving means for driving the taking lens according to the lens driving amount from the lens driving amount calculating means; and lens driving for detecting the lens driving speed during driving of the lens In a camera system having a speed detection unit, not only during the stop of the lens, but also continuously detects the defocus amount during the driving of the lens, and has an overlap control function of updating the driving amount of the lens. Lens position detecting means for detecting the position of the taking lens, timing means for measuring the detection time of the lens position, the lens position and the detection time Lens position estimating means for estimating the lens position during the overlap control from the lens driving speed from the lens driving speed detecting means, and whether the lens driving is constant speed driving based on a plurality of changes in the lens driving speed in the past plural times. When the determination unit determines that the driving at the constant speed is performed, the lens position estimation unit is caused to function to reduce the number of lens position detections during the overlap control. Camera system characterized by the above. 10. The lens driving unit, the lens position detecting unit, and the lens driving speed detecting unit are provided at least on the photographing lens side, the other units are provided on a camera body side, and the photographing lens is exchangeable. The camera system according to claim 8, wherein the camera system is a photographic lens. 11. A defocus amount detecting means for detecting a defocus amount, which is a difference between an image forming position of a photographing lens and an image plane position of the photographing lens, and a defocus amount based on the defocus amount from the defocus amount detecting means. Lens driving amount calculating means for calculating the driving amount of the photographing lens, lens driving means for driving the photographing lens according to the lens driving amount from the lens driving amount calculating means, and a lens for detecting a lens acceleration / deceleration state during driving of the lens A camera system having an acceleration / deceleration state detecting means, and having an overlap control function of continuously detecting the defocus amount and updating the lens driving amount not only during lens stop but also during lens driving. In the above, a lens position detecting means for detecting the position of the taking lens, time measuring means for measuring the detection time of the lens position, a plurality of lens positions in the past Lens position estimating means for estimating the lens position during the overlap control from the detection time of, when the lens acceleration / deceleration state is a constant speed state, the lens position estimating means determines the position of the taking lens. A camera system characterized in that the number of lens position detections during overlap control is reduced by estimation. 12. The lens driving unit, the lens position detecting unit, and the lens acceleration / deceleration state outputting unit are provided at least on the photographing lens side, and the other units are provided on a camera body side. 9. The camera system according to claim 8, wherein the camera system is an interchangeable photographing lens. 13. The interchangeable photographing lens has an image stabilizing function.
2. The camera system according to 1.