JP2004191424A - Imaging unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an imaging unit realizing much higher accuracy and the speeding-up of AF by reducing a lens driving space, improving time and power consumption required for focusing, and providing both a range-finding function by an AF sensor and a climbing contrast AF function so that the shortcomings of both of them can be compensated. <P>SOLUTION: By using a photographic optical system having a variable shape mirror 4 the shape of the reflection surface of which can be varied, controlling a variable mirror driving means 80 on the basis of a 1st signal outputted from either an AF sensor 60 or a contrast detection means 30, and further controlling the driving means 80 on the basis of a 2nd signal outputted from the other, the space necessary for driving a focusing lens, which is usually required, is not required in an optical path, whereby the lens driving space is reduced, and quicker focusing operation is realized. Thus, the imaging unit realizing the high accuracy, and the speeding-up and the low power consumption of focusing operation can be obtained by complementarily using a range-finding means and a contrast detection means. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an imaging device such as a digital camera.
[0002]
[Prior art]
In general, there are a passive method and an active method as an AF sensor as a distance measuring means used in a silver halide camera. Since the AF sensor directly detects distance measuring information equivalent to a distance to a subject, the information is used as an AF sensor. The AF control can be performed speedily by reflecting the result in the lens drive control system. However, since it is not a feedback control system for controlling while detecting an image projected on the imaging system, the accuracy is lower than that of a hill-climbing contrast AF generally used in a digital camera or the like.
[0003]
On the other hand, the hill-climbing contrast AF detects the contrast of the image projected on the electronic imaging system and performs control while gradually driving the AF lens so that the contrast value reaches a peak. Since it takes time accumulated by contrast detection and AF lens driving until (focusing), it takes more time than the above-described method using the AF sensor, and depending on the method, a shutter chance may be missed for a subject with unfavorable accuracy and time lag. is there.
[0004]
In order to solve the above problem, there is a mode as shown in Japanese Patent Application Laid-Open No. 2001-255456, which includes a hill-climbing contrast AF and an external light AF (for example, a passive method) and gives priority to shortening the focusing time. There has been proposed a method for switching the system by using the method described above and improving the above problem. In addition, JP-A-10-229516 discloses a method of switching to hill-climbing AF when it is determined that an error occurs in external light AF due to temperature, and JP-A-10-293245 discloses an AF method in accordance with the setting of a macro mode for close-up photography. There has been proposed a method of performing high-speed and high-precision control by selectively using a method according to a situation by a method of switching the method.
[0005]
[Patent Document 1]
JP 2001-255456 A (pages 1-3, FIG. 1)
[0006]
[Patent Document 2]
JP-A-10-229516 (pages 1-3, FIG. 2)
[0007]
[Patent Document 3]
JP-A-10-293245 (pages 1-3, FIG. 1)
[0008]
[Problems to be solved by the invention]
However, in the mere switching of the AF method as in the prior art described above, the AF operation is performed by driving the AF lens in the optical axis direction based on the information obtained from the detection means. The loss of time required for confirmation and lens driving remains large, and there is a limit to speeding up. In particular, a conventional AF lens (focusing lens) uses a material having a high transmittance and focuses an image by refraction, so that the volume and power consumption required for driving are increased due to the lens driving space and weight.
[0009]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and has both a distance measurement function and a hill-climbing contrast AF function using an AF sensor, reducing a lens driving space, improving focusing time and power consumption. Accordingly, an object of the present invention is to provide an image pickup apparatus which can compensate for the drawbacks of both of them, and which can achieve higher accuracy and faster AF.
[0010]
[Means for Solving the Problems]
An image pickup apparatus according to claim 1 of the present invention is a distance measuring unit that measures a distance to a subject, and a functional area that generates output light obtained by converting optical characteristics of incident light according to an applied drive signal. A photographing optical system including an active optical element formed with an image, an image pickup element that photoelectrically converts a subject image formed through the photographing optical system and outputs the image as an image signal, and a contrast change between the image signals at different timings. A contrast detection means for generating a signal corresponding to the amount, an active optical element driving means for generating a drive signal to be applied to the active optical element, and an output from one of the distance measuring means and the contrast detection means Controlling the active optical element driving means based on a first signal, and further controlling the active optical element driving means based on a second signal output from the other one; It is characterized in further comprising control means for controlling the academic element driving means.
[0011]
According to a second aspect of the present invention, in the imaging apparatus according to the first aspect, the active optical element is a shape variable mirror capable of changing a shape of a reflection surface.
[0012]
As described above, according to the imaging apparatus according to the first and second aspects, instead of the focusing lens, an imaging optical system including an active optical element, particularly, a shape-variable mirror whose shape of a reflecting surface can be changed. And controlling the active optical element driving means based on a first signal output from one of the distance measuring means and the contrast detecting means, and further, a second signal output from the other. By controlling the active optical element driving means based on the signal, it is possible to reduce the lens driving space by not requiring the space necessary for driving the focusing lens, which is normally required, in the optical path, and to achieve a faster focusing operation. It is possible to achieve high precision, high speed focusing operation, and low power consumption by using the distance measuring means and the contrast detecting means complementarily. The ability.
[0013]
According to a third aspect of the present invention, in the second aspect, when the shape-variable mirror is not driven, the shape of the reflection surface is flat.
[0014]
Accordingly, when the variable shape mirror is driven, it is driven from a planar shape, so that it is not necessary to detect the extension direction of the focusing lens which is normally required, and it is possible to further speed up the focusing operation.
[0015]
Also, in the imaging apparatus according to claim 4, in claim 1, the control means outputs an output from the distance measuring means as the first signal and an output from the contrast detection means as the second signal. It is characterized in that it is used.
[0016]
According to a fifth aspect of the present invention, in the imaging apparatus according to the first aspect, the control means calculates and stores a parameter for correcting the first signal based on the second signal. Things.
[0017]
The imaging device according to claim 6 is the imaging device according to claim 1, further comprising: a still image mode for capturing a still image, a continuous shooting mode for continuously capturing a still image, or a moving image for capturing a moving image. It is characterized by comprising means for setting any one of the modes.
[0018]
In the imaging apparatus according to a seventh aspect, in the first aspect, the control unit controls the active optical element driving unit using a second signal when the first signal is an abnormal value. It is characterized by the following.
[0019]
The image pickup apparatus according to claim 8 further comprises a flash unit for generating a flash, wherein the control unit uses the second signal when the first signal is an abnormal value. Controlling the active optical element driving means to perform a focusing operation, and then, prior to photographing, controlling the flash means to emit a flash light for dimming. is there.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of an imaging device according to the present invention. Here, a case where the imaging apparatus is applied to an electronic camera will be described.
[0021]
The imaging apparatus according to the present embodiment shown in FIG. 1 includes an imaging optical system including lenses 1, 2, 3, and a variable shape mirror 4 that is an active optical element capable of changing the shape of a reflecting surface, and the imaging optical system. Means 20 for receiving an image of a subject formed by the imaging and photoelectrically converting the image to generate an imaging signal, and receiving reflected light from the subject on an optical path different from that of the imaging optical systems 1, 2, 3, and 4 to receive the subject image. The AF sensor 60, which is a distance measuring means for measuring the distance up to and outputting the result as a distance measuring signal, and the contrast of the image signal acquired at a certain timing from the luminance (Y) signal obtained from the image signal. A contrast detection unit that generates a contrast signal, obtains a change amount between the contrast signals at different timings, and outputs a signal corresponding to the change amount as a focus determination signal; Means for storing a control signal for controlling the mirror 4 in association with an address, and a variable mirror serving as an active optical element driving means for driving the shape variable mirror 4 based on the control signal read from the storage means 70 A driving unit 80, a CPU 40 serving as a control unit that controls a variable mirror driving unit 80 that reads a control signal from a storage unit 70 by designating an address according to a signal from the contrast detection unit 30 and drives the variable shape mirror 4, Release switches (hereinafter referred to as release switches) 90 and 91 for starting the ranging operation and the photographing operation, respectively, and a mode switch (hereinafter referred to as a mode switch) for setting a photographing mode such as a moving image mode, a still image (still) mode, and a continuous photographing mode. ) 92 and flash light emission control means 100 for controlling flash light emission.
[0022]
The deformable mirror 4 has a reflecting surface and a plurality of driving electrodes 4a provided on the back side of the reflecting surface so as to change the shape of the reflecting surface.
[0023]
The variable mirror driving unit 80 is operated under the control of the CPU 40 and a variable mirror driving circuit 81 that supplies a drive signal for driving the shape variable mirror 4 to the electrode 4 a based on the control signal read from the storage unit 70. , A booster circuit 82 for supplying a power supply voltage to the variable mirror drive circuit 81.
[0024]
The shape variable mirror 4, the imaging means 20, the contrast detection means 30, the CPU 40, the storage means 70 and the variable mirror driving means 80 constitute the above-mentioned hill-climbing contrast AF means. The CPU 40 performs switching control between AF by the distance measuring unit and hill-climbing contrast AF based on the setting conditions of the mode SW 92, and controls the variable mirror driving unit 80 based on one or both of the AF detection signals.
[0025]
FIGS. 2 and 3 are diagrams illustrating a configuration example of the AF sensor 60. FIG. FIG. 2 illustrates an example in which the AF sensor 60 is configured by a triangulation active method (infrared method), and FIGS. 3A and 3B illustrate an example in which the AF sensor 60 is configured by a triangulation passive method (image matching type). Is shown.
[0026]
The active method shown in FIG. 2 uses an infrared diode (IRED) for projecting light and a position detection device (PSD, abbreviation for Position Sensitive Device), and obtains a subject distance based on the principle of triangulation. Ranging is possible because of the relationship.
[0027]
L / S = f / x That is, L = S × (f / x)
Here, L is the subject distance from the light projecting lens 63 to the subject, S is the base line length, that is, the interval between the light projecting and receiving lenses 63 and 64, f is the focal length of the light receiving lens 64, and x is the ∞ equivalent light receiving position on the surface of the PSD 62. This is the length up to the light receiving position.
[0028]
The passive method shown in FIG. 3A is a method for obtaining a subject distance based on the principle of triangulation using a line sensor. By using two rows of photodiode arrays 65 and 66 as line sensors and obtaining an image phase difference from outputs of the two left and right sensor rows 65 and 66, distance information can be obtained in the following relationship.
[0029]
L / S = f / (x1 + x2) That is, L = S × (f / (x1 + x2))
Here, x1 + x2 (= x) is called an image phase difference. S is the base line length, that is, the distance between the AF lenses 67 and 68, L is the subject distance from the base line to the subject, f is the focal length of the AF lenses 67 and 68, x1 and x2 are equivalent to 各 on each surface of the sensor rows 65 and 66. This is the length from the light receiving position to the light receiving position.
[0030]
With respect to the sensor rows 65 and 66, when the image position is plotted on the horizontal axis and the output is plotted on the vertical axis, as shown in FIG. The distance L is obtained by calculating the image phase difference x with the image synthesized waveform (dotted line) at the actual light receiving position.
[0031]
The AF sensor 60 may employ a passive TTL method.
Further, as the variable mirror driving means 80, any of a DC driving type and a PWM driving type may be used.
[0032]
4 and 5 show a configuration example of the variable mirror driving means 80, FIG. 4 shows a configuration example of a DC drive type, and FIG. 5 shows a configuration example of a PWM drive type. In each of the drawings, the configuration of a variable mirror driving circuit that drives one of a plurality of electrodes 4a provided on the variable shape mirror 4 is shown. The same applies to the configuration of the variable mirror driving circuit for driving the remaining electrodes. However, the DC power supply E and the booster circuit 82 can be commonly used to drive the plurality of electrodes 4a.
[0033]
4 shows a configuration of a variable mirror driving circuit 81 for supplying a direct voltage (DC) as a driving signal to one electrode 4a of the variable mirror 4. That is, a digital control signal is input from the CPU 40 to the D / A converter 81a and is converted into an analog control signal, which is then amplified by the amplifying means 81b operating with the power supply voltage from the booster circuit 82, and is converted into a DC drive signal. It is supplied to an electrode 4a (not shown).
[0034]
5 shows a configuration of a variable mirror driving circuit 81 for supplying a PWM voltage as a driving signal to one electrode 4a of the variable mirror 4. That is, a PWM control signal is supplied from the CPU 40 directly to each control terminal of a switching circuit 81d including two switching transistors Tr1 and Tr2 through an inverting circuit (inverter) 81c, and Tr1 is turned on at a low level of the PWM signal. Tr2 is turned on at the high level, and Tr1 and Tr2 are alternately turned on and off. Therefore, when Tr1 is on and Tr2 is off, the power supply voltage from the booster circuit 82 is output from the connection point of Tr1 and Tr2, and when Tr1 is off and Tr2 is on, the reference potential of the DC power supply E is A corresponding potential is output and supplied from a connection point between Tr1 and Tr2 to an electrode 4a (not shown) as a PWM drive signal.
[0035]
The aberration correcting mirror and another another variable shape mirror may be further arranged on the optical path of the photographing optical system in FIG.
[0036]
FIG. 6 shows an example in which the aberration correction mirror 5 is further disposed on the optical path between the photographing optical systems 1 to 4 and the image pickup device 21 constituting the image pickup means 20 in FIG. Thereby, the aberration correction function can be improved. Incidentally, a plurality of aberration correcting mirrors 5 may be arranged.
[0037]
FIG. 7 is an example in which the shape variable mirror 6 is further disposed on the optical path between the imaging optical systems 1 to 4 and the imaging device 21 constituting the imaging unit 20 in FIG. Thereby, the functionality (including the aberration correction function) of the deformable mirror can be improved.
[0038]
[First Embodiment]
Next, the operation of the first embodiment will be described with reference to the flowchart of FIG.
First, the CPU 40 determines on / off of a release switch (hereinafter, release SW) 90 which is a first release (hereinafter, first release) means in step S1, and if it is on, operates the booster circuit 82. Then, AF sensor distance measurement is performed by the AF sensor 60 as shown in FIG. 2 or FIG. 3 (step S2). Next, in step S3, it is determined whether or not the result of the distance measurement determination is good. If the result of the distance measurement determination is good (that is, the result of the determination is not an abnormal value), it is stored based on the result of the distance measurement. The shape variable mirror 4 is driven via the variable mirror driving circuit 81 by referring to the address data before (near) the focusing from the means 70 (step S4).
[0039]
Subsequently, in step S5, the CPU 40 determines whether or not the mode switch 92 is set to the still mode. If the mode switch 92 is set, the process proceeds to the hill-climbing contrast AF (step S8). First, in step S9, the deformable mirror 4 is driven, and the contrast detection means 30 generates a contrast signal from the luminance signal obtained from the imaging signal at this time, and simultaneously obtains the contrast obtained at the time preceding it. An amount of change with respect to the signal is calculated, and a signal corresponding to the amount of change is output to the CPU 40 as a focus determination signal. Then, it is determined whether or not the focus determination signal indicates focus (step S10). If the focus determination signal does not indicate focus (NO in step S10), the process returns to step S8, where the shape variable mirror 4 is driven according to the focus determination signal, and a focus determination signal is generated. This loop is repeated until the focus determination signal becomes “focus”. Usually, a portion where the contrast signal has a peak value is in a focused state.
[0040]
If "focusing" is achieved in step S10 (YES in step S10), the shape of the reflecting surface of the shape-variable mirror 4 at that time is maintained. Then, the on / off state of the release SW 91, which is the second release (hereinafter, the second release) means, is determined (step S12). If the release SW 91 is on, the imaging operation (step S14) and the recording operation (step S15) are performed. If the release SW 91 is off, it is determined whether the first release is on or off (step S13). If it is on, the process returns to step S8, and if it is off, the process returns to step S2.
[0041]
The above-described hill-climbing contrast AF operation is also performed when the still mode is not selected (NO in step S5) and when the continuous shooting mode is not selected (NO in step S7).
[0042]
On the other hand, when the continuous shooting mode is set by the mode switch 92 (step S7), while the release switch 91 is being pressed (YES in steps S16 and S19), the distance measurement by the AF sensor 60 (step S2) and the shooting operation are performed. (Step S17), the recording operation (Step S18) is repeatedly performed. Thus, AF corresponding to continuous shooting when shooting a moving subject is realized.
[0043]
By configuring and operating as described above, there are the following advantages.
First, in the case where the focusing lens is formed of a normal optical system and control is performed by the hill-climbing contrast AF, it is not clear whether the focal point is located before or after the initial optical axis. Therefore, as shown in FIG. 9, it is necessary to always drive the focusing lens back and forth to check the focusing direction. In FIG. 9, when the focusing lens is moved from the closest position (initial position) to the infinity side (無限) by the hill-climbing contrast AF, for example, the contrast signal reaches a peak value at a point where the subject is focused. That is, the CPU 40 controls to drive the lens driving means so that the contrast signal has a peak value. As shown in FIG. 9, when the focusing lens is used, the lens extension direction is detected, and after the lens extension direction is confirmed, the focus lens is driven from the initial position. In addition, when performing the hill-climbing contrast AF with the shape-variable mirror from start to finish, the variable mirror 4 is driven via the mirror drive circuit 81 by repeatedly referring to the address from the storage unit 70 until the peak value in the focused state is detected. In order to read out the AF information of the AF detector, it takes time to read all the pixels and extract the information of the detector in the case of a CCD image sensor.
[0044]
On the other hand, in the embodiment of the present invention, the focusing operation is performed using the deformable mirror 4 instead of the focusing lens. Before driving, when the driving signal is not supplied, the reflecting surface of the deformable mirror 4 is kept flat, so that the AF operation starts from the flat surface, and the lens extending direction when using the focusing lens is checked. No operation is required, and since a heavy lens is not driven, wasteful time and power consumption can be reduced.
[0045]
Further, as shown in FIG. 8, distance measurement is performed by the AF sensor 60 (step S2), and when it is determined that the distance measurement is good in the distance measurement determination (YES in step S3), the shape variable mirror 4 is simultaneously moved. By driving to the vicinity of the in-focus state, the repetitive address reference to the storage unit 70 and the reading time of the AF information of the AF detection unit, which are necessary in the hill-climbing contrast AF, can be reduced, and further higher speed can be realized. At the same time, it is possible to realize a highly accurate AF function which is a feature of the hill-climbing contrast AF.
[0046]
Further, as shown in FIG. 8, when it is determined that the distance measurement by the AF sensor 60 is abnormal in the distance measurement determination (NO in step S3), the process shifts to the hill-climbing contrast AF (step S8) to perform an accurate AF operation. Can be achieved.
[0047]
As described above, according to the first embodiment, by using the variable-shape mirror 4 instead of the conventionally used focusing lens, the driving of the lens which has been a bottleneck due to the presence of the focusing lens is performed. Space and weight can be reduced, high-speed AF and low power consumption can be realized, and distance measurement by the AF sensor 60 (step S2) and hill-climbing contrast AF (step S8) are both performed as shown in FIG. With the provision, it is possible to realize high-precision and high-speed AF utilizing the advantages of both AFs.
[0048]
[Second embodiment]
Next, the operation of the second embodiment will be described.
Since the configuration of the present embodiment is the same as that of the first embodiment, a description of the configuration will be omitted.
[0049]
FIG. 10 is a flowchart illustrating the operation of the second embodiment.
[0050]
In FIG. 10, a step S6 for determining whether or not the setting of the mode switch 92 is the moving image mode is provided between steps S1 and S2 in the flowchart of FIG. In step S6, in the moving image mode, the process shifts to contrast AF (step S8) using the contrast detection means 30. Otherwise, the flow is the same as the flow in FIG.
[0051]
The present embodiment is characterized in an operation in which the CPU 40 controls the switching of the AF unit based on the setting condition of the mode SW 92 which can be set by a user operation.
[0052]
In the present embodiment, when the still mode is set, the AF operation (steps S2 to S4) is performed by the AF sensor 60, and then the still mode determination is performed (step S5). The AF operation is executed by the hill-climbing contrast AF used (step S8). On the other hand, when the moving image mode is set, the AF operation is performed by the hill-climbing contrast AF (step S8), and when the continuous shooting mode is set, only the AF operation is performed by the AF sensor 60 (steps S7, S16 to S19).
[0053]
As described above, when shooting in the still mode, there is an interval until the next shooting, and after performing the AF operation by the AF sensor 60, the hill-climbing contrast AF using the contrast detection unit 30 can be performed.
[0054]
On the other hand, when shooting in the moving image mode, in many cases, shooting is performed while following a slow-moving subject, so that hill-climbing contrast AF can be used. However, in the hill-climbing contrast AF, it is difficult to follow a subject that moves faster, such as during continuous shooting, and only the AF operation by the AF sensor 60 is performed.
[0055]
Further, as a modification of the present embodiment, the moving image mode determination (step S6) is not provided between steps S1 and S2, but the step S6 is provided between steps S5 and S7, and the moving image mode is set by the mode switch 92. In this case, the same AF drive control as in the still mode may be performed.
[0056]
[Third Embodiment]
Next, the operation of the third embodiment will be described.
Since the configuration of the present embodiment is the same as that of the first embodiment, a description of the configuration will be omitted.
[0057]
The operation of the present embodiment is the same as the flowchart of FIG. 8 or FIG.
[0058]
In the present embodiment, in the photographing operation by the AF sensor, the flash light emission control is performed based on the distance measurement information by the AF sensor, and in the photographing operation by the hill-climbing contrast AF, a preliminary flash light emission (hereinafter, referred to as pre-flash) It is characterized in that flash control is performed so as to perform flash emission control based on (flash emission).
[0059]
In the case of the AF sensor 60, the distance information is obtained from the AF sensor 60, and the main light emission amount is obtained from the data of the storage unit 70 (that is, a table indicating the correspondence of the light emission amount to the change in the distance information) via the CPU 40 via the distance information. Since it can be obtained, there is no time lag required for flash control, and the time until flash emission can be shortened.
[0060]
On the other hand, in the hill-climbing contrast AF, pre-flash light emission as reference light is performed, reflected light from a subject is received by the imaging means 20, and data of the storage means 70 (ie, (pre-flash light emission) reference light reflection) is received via the CPU 40. The main light emission amount is obtained from a table showing a correspondence relationship between the light amount and the light emission amount that is an appropriate exposure amount, and a pre-dimming control in which a control command is sent to the flash light emission control means 100 and flash light emission is used. growing.
[0061]
In FIG. 8 or FIG. 10, when it is determined that the distance measurement is abnormal (step S3) (NO in step S3), the process proceeds to the hill-climbing contrast AF (step S8), and the flash emission control unit 100 performs the shooting (step S8). In step S14), flash light is emitted by the pre-dimming control. On the other hand, in FIG. 8 or FIG. 10, if the distance measurement determination is an appropriate value (YES in step S3), flash light dimming control is performed based on the distance measured by the AF sensor 60 during shooting (step S17). This enables accurate flash dimming.
[0062]
As described above, in the present embodiment, when the AF operation by the AF sensor 60 is functioning properly, the flash control mainly based on the distance information of the AF sensor 60 is used, and the information of the AF sensor 60 is abnormal. In the case of (1), the use of the flash control by the pre-dimming control enables the flash emission control without failure.
[0063]
It is also possible to focus an object at an arbitrary distance by hill-climbing contrast AF and correct the distance measurement data of the AF sensor 60 based on the variable mirror drive control value at that time.
[0064]
【The invention's effect】
As described above, according to the present invention, the lens driving space can be reduced, the time required for focusing and the power consumption can be improved, and the distance measurement function using the AF sensor and the hill-climbing contrast AF function are both provided. It is possible to realize an imaging apparatus having a high-speed and high-precision AF function, which compensates for the drawback and enables higher precision and higher-speed AF.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an imaging device according to the present invention.
FIG. 2 is a diagram illustrating a configuration example of an AF sensor in FIG. 1;
FIG. 3 is a view for explaining another configuration example of the AF sensor in FIG. 1;
FIG. 4 is a diagram illustrating a configuration example of a variable mirror driving unit in FIG. 1;
FIG. 5 is a view for explaining another configuration example of the variable mirror driving means in FIG. 1;
FIG. 6 is a diagram showing a configuration example of another optical system using a deformable mirror.
FIG. 7 is a diagram showing a configuration example of another optical system using a deformable mirror.
FIG. 8 is a flowchart illustrating an operation of the imaging apparatus according to the first embodiment of the present invention.
FIG. 9 is an explanatory diagram when a hill-climbing contrast AF is executed.
FIG. 10 is a flowchart illustrating an operation of the imaging apparatus according to the second embodiment of the present invention.
[Explanation of symbols]
1. First group lens
2: Second group zooming lens
3. Third lens group
4. Variable shape mirror (active optical element)
5. Aberration correction mirror
6 ... deformable mirror
20 ... Imaging means
21 ... Imaging element
30 ... Contrast detecting means
40 ... CPU (control means)
60 AF sensor (distance measuring means)
70 ... storage means
80: Variable mirror driving means
81: Variable mirror drive circuit
82 ... Booster circuit
90 ... 1st release SW
91 ... 2nd release SW
92 Mode SW
100 flash light control means

Claims (8)

Distance measuring means for measuring the distance to the subject;
An imaging optical system including an active optical element in which a functional region that generates output light obtained by converting optical characteristics of incident light in accordance with the applied drive signal,
An image sensor that photoelectrically converts a subject image formed through the imaging optical system and outputs the image as an image signal,
Contrast detection means for generating a signal corresponding to a contrast change amount between the imaging signals at different timings,
Active optical element driving means for generating a drive signal to be applied to the active optical element,
The active optical element driving unit is controlled based on a first signal output from one of the distance measuring unit and the contrast detection unit, and further based on a second signal output from the other. Control means for controlling the active optical element driving means,
An imaging device having: The imaging device according to claim 1, wherein the active optical element is a shape-variable mirror whose shape of a reflection surface is changeable. The imaging device according to claim 2, wherein the shape of the reflection surface of the variable shape mirror is flat when not driven. The imaging apparatus according to claim 1, wherein the control unit uses an output from the distance measuring unit as the first signal and an output from the contrast detection unit as the second signal. The imaging apparatus according to claim 1, wherein the control means calculates and stores a parameter for correcting the first signal based on the second signal. The apparatus according to claim 1, further comprising: a mode for setting any one of a still image mode for capturing a still image, a continuous shooting mode for continuously capturing a still image, and a moving image mode for capturing a moving image as a mode for capturing a subject. 2. The imaging device according to 1. The imaging apparatus according to claim 1, wherein the control unit controls the active optical element driving unit using a second signal when the first signal is an abnormal value. Further, there is provided a flash unit for generating a flash, wherein the control unit controls the active optical element driving unit using a second signal to perform a focusing operation when the first signal is an abnormal value. 2. The image pickup apparatus according to claim 1, wherein, prior to photographing, the flash unit is controlled to emit a flash light for dimming before photographing.

Images