JPH07128586A - Focus detecting device and focus detecting method - Google Patents

Abstract

PURPOSE:To improve response for focus detecting at the time of switching a focus detecting area without degradation of response for normal focus detecting by repeating electric charges accumulating operation with a longer period than a repetition period of electric charges accumulating operation of a pair of photoelectric conversion means corresponding to a selected focus detecting area. CONSTITUTION:Plural pairs of electric charges accumulation type photoelectric conversion means 80, 81, 82, 83 which output picture signals corresponding to light intensity distribution of an object image formed by an optical system 7 are provided. And a sequence control means 90 repeats electric charges accumulating operation by an accumulation control means 90 for a pair of photoelectric conversion means corresponding to selected focus detecting areas by an area selecting means. Also, the sequence control means 90 repeats electric charges accumulating operation by the accumulation control means 90 with a longer period than a repetition period of electric charges accumulating operation of a pair of photoelectric conversion means corresponding to a selected focus detecting area for a pair of photoelectric conversion means corresponding to a focus detecting area not selected by the area detecting means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focus detection device and a focus detection method for detecting the focus adjustment state of a taking lens in a plurality of focus detection areas.

[0002]

2. Description of the Related Art There is known a focus detecting device capable of selecting an arbitrary focus detecting area from a plurality of focus detecting areas set in a photographing screen. For example, in an auto-focus camera, several focus detection areas are set in the center and the periphery of the shooting screen, the photographer selects an arbitrary focus detection area with the operation member provided on the camera body, and the selected focus detection area is selected. At, the focus adjustment state of the taking lens is detected.

In general, the focus detection device uses a charge storage type image sensor such as CCD as a light receiving means. When focus detection is performed using the charge storage type image sensor, it is necessary that the subject image signal output from the image sensor be at an appropriate level for a processing circuit for processing it. For example, when a subject image signal is digitally processed by a microcomputer, an AD built in the microcomputer is used.
If the object image signal does not overflow to the input range of AD conversion of the converter and the level does not have a certain level, the quantization error due to AD conversion becomes large and the focus detection accuracy deteriorates.

In order to bring the object image signal to an appropriate level in the brightness range from low brightness to high brightness, the storage time of the charge storage type image sensor is controlled. For example, if the current accumulation time Tn is determined as in Expression 1 using the peak value Pn-1 of the previous object image signal, the accumulation time Tn-1 and the target peak value Px, the object image signal overflows the AD conversion range. The level is appropriate for the focus detection calculation within the range.

[Equation 1] Tn = Tn-1 · Px / Pn-1

[0005]

However, the above-described focus detection device has the following problems. When the focus detection area is switched, the charge storage type image sensor corresponding to the newly selected focus detection area is initialized, and the subject image signal output from this image sensor is converged to a level suitable for focus detection calculation. In order to do so, it is necessary to repeat the cycle of storage time control according to Formula 1 several times. At the time of initialization, since there is no previous object image signal data, the charge time of the image sensor is stored by setting the storage time corresponding to the set predetermined brightness. However, since the brightness of the subject changes by about 2 to the 20th power, when the difference between the actual subject brightness and the set brightness is large, the peak value of the obtained object image signal overflows or the numerical value is changed by quantization. In some cases, it may become 0, and the next accumulation time may not be calculated according to Equation 1. Therefore,
If the peak value of the subject image signal overflows, the next accumulation time is set to a fraction of the current accumulation time, and if the peak value of the subject image signal is less than or equal to the predetermined value,
The formula 1 is applied only when the peak value of the subject image signal falls within the predetermined range by repeating the control of making the next accumulation time several times the current accumulation time. Therefore, there is a delay until a focus detection result is obtained when the focus detection area is switched, which causes a problem of low focus detection responsiveness.

In order to improve the responsiveness of the focus detection when the focus detection areas are switched, it may be considered that the image sensor corresponding to the non-selected focus detection area always performs the focus detection operation. However, normally, the AD conversion and the focus detection calculation are performed by one microcomputer for cost reduction, and the AD conversion operation and the focus detection calculation operation of the object image signal output from the image sensor in the selected focus detection area. In addition to this, the AD conversion operation and the focus detection calculation operation of the object image signal output from the image sensor in the unselected focus detection area must be performed, which increases the focus detection cycle time, resulting in normal operation. The responsiveness of the focus detection operation deteriorates.

An object of the present invention is to improve the responsiveness of focus detection when the focus detection area is switched without lowering the responsiveness of normal focus detection.

[0008]

The inventions of claims 1 to 4 will be described with reference to FIG. 1 and FIG. 4 showing the configuration of an embodiment. A plurality of pairs of charge storage type photoelectric conversion means provided corresponding to each of the plurality of focus detection areas set above and outputting an image signal according to the light intensity distribution of the subject image formed by the optical system 7. Focus detection calculation means 90 for calculating the focus adjustment state of the photographing optical system 3 based on 80, 81, 82, 83 and the pair of image signals output from the photoelectric conversion means 80, 81, 82, 83 of these pairs. And each pair of photoelectric conversion means 8
Storage control means 90 for controlling the charge storage of the photoelectric conversion means of the pair based on at least one of the image signals of the pair output from 0, 81, 82 and 83.
With respect to the area selection means 11 for selecting an area for focus detection from a plurality of focus detection areas and the pair of photoelectric conversion means corresponding to the focus detection area selected by the area selection means 11, accumulation is performed. The charge storage operation is repeatedly performed by the control unit 90, and the focus detection calculation unit 90 performs focus detection calculation based on the pair of image signals output from the pair of photoelectric conversion units, and the area selection unit 11 does not select. For the pair of photoelectric conversion units corresponding to the focus detection area, the charge control operation is performed by the storage control unit 90 at a cycle longer than the repetition cycle of the charge storage operation of the pair of photoelectric conversion units corresponding to the selected focus detection area. And a sequence control means 90 for repeatedly performing the above, thereby achieving the above object. According to a second aspect of the present invention, an area for performing focus detection is selected from a plurality of focus detection areas set on the photographing screen of the photographing optical system 3, and a plurality of pairs of photoelectric cells corresponding to each of the plurality of focus detection areas are selected. In the pair of photoelectric conversion units corresponding to the focus detection area selected as the focus detection area among the conversion units 80, 81, 82, 83, the pair of image signals output from the pair of photoelectric conversion units is detected. The charge accumulation operation is repeated based on at least one of the image signals, and the focus adjustment state of the photographing optical system 3 is calculated based on the image signal of the pair, and it is not selected as the area for focus detection. In the pair of photoelectric conversion units corresponding to the focus detection area, based on at least one of the image signals of the pair of image signals output from the pair of photoelectric conversion units. By repeating the charge storage operation cycle longer than the repetition period of the charge accumulation operation of the photoelectric conversion means of pair corresponding to the selected focus detecting area, to achieve the above object.

According to a third aspect of the present invention, the light intensity distribution of the subject image formed by the optical system 7 is provided corresponding to each of the plurality of focus detection areas set on the photographing screen of the photographing optical system 3. On the basis of a plurality of pairs of charge storage type photoelectric conversion means 80, 81, 82, 83 for outputting image signals according to the above, and a pair of image signals output from these pairs of photoelectric conversion means 80, 81, 82, 83. The focus detection calculation unit 90 for calculating the focus adjustment state of the photographing optical system 3 and at least one of the pair of image signals output from the pair of photoelectric conversion units 80, 81, 82, 83. Storage control means 90 for controlling the charge storage time of the pair of photoelectric conversion means, and each photoelectric conversion means 80 to.
Transfer means 87 for transferring the image signal output from 83 to the focus detection calculation means 90, and area selection means 1 for selecting an area for focus detection from a plurality of focus detection areas.
1 and the pair of photoelectric conversion units corresponding to the focus detection area selected by the area selection unit 11, the transfer operation of the image signal by the transfer unit 87 and the focus detection calculation operation by the focus detection calculation unit 90 are performed. And a sequence control means 90 for executing at least one of the operations of the sequence control means 90 prior to the transfer operation and the accumulation time calculation operation of the pair of photoelectric conversion means corresponding to the focus detection area not selected by the area selection means 11. And thus achieve the above objective. According to a fourth aspect of the present invention, an area for performing focus detection is selected from a plurality of focus detection areas set on the photographing screen of the photographing optical system 3, and a plurality of pairs of photoelectric cells corresponding to each of the plurality of focus detection areas are selected. Among the conversion means, for the pair of photoelectric conversion means corresponding to the focus detection area selected as the area for performing focus detection, the transfer operation of the pair of image signals output from the pair of photoelectric conversion means, and At least one of the operations of the focus adjustment state of the photographing optical system based on the image signal of the pair is performed with respect to the pair of photoelectric conversion units corresponding to the focus detection area not selected as the area for focus detection. The above-described object is achieved by executing the transfer operation and the charge accumulation time calculation operation with priority.

The inventions of claims 5 to 8 will be described with reference to FIGS. 1 and 13 showing the configuration of an embodiment.
Of the invention is provided corresponding to each of a plurality of focus detection areas set on the photographing screen of the photographing optical system 3, and outputs an image signal according to the light intensity distribution of the subject image formed by the optical system. A plurality of pairs of charge storage type photoelectric conversion means 80,
81, 82, 83 and photoelectric conversion means 80 of these pairs,
Focus detection calculation means 90A for calculating the focus adjustment state of the photographing optical system 3 based on the pair of image signals output from 81, 82, 83, and photoelectric conversion means 80, 81, 82, of each pair.
The charge accumulation time is calculated based on at least one of the pair of image signals output from 83,
Storage control means 90A for controlling charge storage of the photoelectric conversion means of the pair, and a plurality of monitor means 80 for outputting signals according to the light intensity incident on the photoelectric conversion means of each pair.
1, 802, area selection means 11 for selecting an area for focus detection from a plurality of focus detection areas, and a pair of photoelectric conversion means corresponding to the focus detection area selected by the area selection means 11. Is the storage control means 9
0A repeats the charge accumulation operation, and the focus detection calculation unit 90A performs focus detection calculation based on the pair of image signals output from the pair of photoelectric conversion units, and the focus detection not selected by the area selection unit 11 is performed. The photoelectric conversion means of a pair corresponding to the area is provided with a sequence control means 90A for prohibiting charge accumulation by the accumulation control means 90A and for monitoring the light intensity by the monitoring means of the photoelectric conversion means of the pair. ,
This achieves the above object. According to another aspect of the focus detecting device of the present invention, when the sequence control means 90A switches the focus detecting area by the area selecting means 11,
At the time of charge storage immediately after switching the pair of photoelectric conversion units corresponding to the newly selected focus detection area, the charge control unit 90A stores the charge storage time based on the result of monitoring the light intensity by the monitoring unit of the pair of photoelectric conversion units. Is calculated, and the charges are accumulated for the calculated charge accumulation time. According to a seventh aspect of the present invention, an area for performing focus detection is selected from a plurality of focus detection areas set on the photographing screen of the photographing optical system 3, and a plurality of pairs of photoelectric cells corresponding to the plurality of focus detection areas are selected. Among the conversion means, in the pair of photoelectric conversion means corresponding to the focus detection area selected as the area for performing focus detection, at least one of the pair of image signals output from the pair of photoelectric conversion means. The charge accumulation time is calculated based on the image signal, the charge accumulation operation is repeated, and the focus adjustment state of the photographing optical system 3 is calculated based on the image signal of the pair, and the area is not selected as the focus detection area. In the pair of photoelectric conversion units corresponding to the focus detection area, charge accumulation is prohibited, and the intensity of light incident on the pair of photoelectric conversion units is monitored to To achieve the target. According to the focus detection method of claim 8, when the area for performing focus detection is switched, the charge of the pair of photoelectric conversion means corresponding to the newly selected focus detection area immediately after the switching is accumulated, the photoelectric conversion means of the pair of photoelectric conversion means is stored. The charge storage time is calculated based on the result of monitoring the light intensity, and the charge is stored in the calculated charge storage time.

The inventions of claims 9 to 11 will be described with reference to FIG. 17 showing an embodiment. According to the invention of claim 9, a plurality of focus detection areas 40 to 40 are set on the photographing screen of the photographing optical system. A plurality of pairs of charge storage type photoelectric conversion means, which are provided corresponding to each of the photoelectric conversion means 43, output image signals according to the light intensity distribution of the subject image formed by the optical system, and the photoelectric conversion means of these pairs. Focus detection calculation means for calculating the focus adjustment state of the photographing optical system based on the output pair of image signals, and at least one of the pair of image signals output from the photoelectric conversion means of each pair. A plurality of focus detection blocks 38 and 39 are classified into a plurality of focus detection areas 40 to 43 which are close to each other, and a plurality of focus detection blocks 38 and 39 which are classified according to the plurality of focus detection areas. Constitution , Block selecting means for selecting a block for performing focus detection from the plurality of focus detecting blocks 38, 39, and for the focus detecting block selected by the block selecting means, the focus belonging to the focus detecting block. The charge control operation is repeatedly performed by the storage control means in the pair of photoelectric conversion means corresponding to the detection area, and the focus detection calculation means performs the focus detection calculation based on the pair image signal output from the pair photoelectric conversion means. For a focus detection block not selected by the block selection means, sequence control is performed in which the charge control operation is repeatedly performed by the storage control means by a pair of photoelectric conversion means corresponding to a specific focus detection area belonging to the focus detection block. And means for achieving the above object. In the focus detection device of the tenth aspect, a plurality of focus detection areas belonging to the focus detection blocks 38 and 39 are arranged so as to intersect with each other. According to an eleventh aspect of the present invention, a plurality of focus detection areas set on the photographing screen of the photographing optical system are classified into adjacent focus detection areas to form a plurality of focus detection unit locks 38 and 39. A block for focus detection is selected from a plurality of focus detection blocks 38 and 39, and the selected focus detection block is charged by a pair of photoelectric conversion units corresponding to the focus detection areas belonging to the focus detection block. While repeatedly performing the accumulation operation, the focus adjustment state of the photographing optical system is calculated based on the pair of image signals output from the pair of photoelectric conversion units, and the focus detection block not selected as the focus detection block is detected. , By repeatedly performing the charge accumulation operation by a pair of photoelectric conversion means corresponding to a specific focus detection area belonging to the focus detection block,
To achieve the above objectives.

[0012]

In the pair of photoelectric conversion means corresponding to the focus detection area selected as the area for performing focus detection, at least one of the pair of image signals output from the pair of photoelectric conversion means is converted into an image signal. Based on the image signals of the pair, the focus adjustment state of the photographing optical system 3 is calculated and the photoelectric conversion of the pair corresponding to the focus detection area not selected as the area for focus detection is performed. In the means, the charge accumulation operation of the pair of photoelectric conversion units corresponding to the selected focus detection area is performed based on at least one of the image signals of the pair of image signals output from the pair of photoelectric conversion units. The charge accumulation operation is repeated at a cycle longer than the repetition cycle. As a result, the charge accumulation control cycle of the photoelectric conversion unit corresponding to the selected area becomes longer than the charge accumulation control and focus detection cycle of the selected area, and the load of the accumulation control operation of the non-selected area of the microcomputer becomes lighter. In addition to being able to maintain the responsiveness of the normal focus detection operation with respect to, the storage time of the photoelectric conversion means corresponding to the switched focus detection area is switched so that the level of the subject image signal is appropriate for focus detection calculation. Since the control is performed before the focus detection area is switched, accurate focus detection can be performed immediately after the focus detection area is switched, and the responsiveness of focus detection is improved.

For the pair of photoelectric conversion means corresponding to the focus detection area selected as the area for performing focus detection, the transfer operation of the pair of image signals output from the pair of photoelectric conversion means and the pair of photoelectric conversion means are performed. At least one of the operations of the focus adjustment state of the photographing optical system 3 based on the image signal is transferred to a pair of photoelectric conversion units corresponding to a focus detection area not selected as an area for focus detection. And the operation of calculating the charge accumulation time is executed with priority. As a result, the responsiveness of the focus detection operation does not deteriorate with respect to the focus detection operation of the selected area, and the accumulation time of the photoelectric conversion means corresponding to the switched focus detection area is the focus detection level of the subject image signal. Since the control is performed before the switching so as to be appropriate for the calculation, the responsiveness of the focus detection when the focus detection area is switched is improved.

With respect to the pair of photoelectric conversion means corresponding to the focus detection area selected as the area for focus detection, at least one of the pair of image signals output from the pair of photoelectric conversion means. The charge accumulation time is calculated based on the image signal and the charge accumulation operation is repeated, and the focus adjustment state of the photographing optical system 3 is calculated based on the image signal of the pair, and the area is not selected as the focus detection area. For the pair of photoelectric conversion units corresponding to the focus detection area, charge accumulation is prohibited and the intensity of light incident on the pair of photoelectric conversion units is monitored. When the focus detection area is switched, the charge accumulation time based on the result of monitoring the light intensity of the photoelectric conversion means of the pair when the charge is immediately stored in the photoelectric conversion means of the pair corresponding to the newly selected focus detection area. Is calculated, and charges are accumulated for the calculated charge accumulation time. This allows
The charge accumulation control of the photoelectric conversion means corresponding to the non-selected area becomes unnecessary, the load on the microcomputer is lightened, and the responsiveness of the focus detection operation in the selected area is secured. Further, the accumulation time of the photoelectric conversion elements corresponding to the switched focus detection areas is based on the monitoring results of those photoelectric conversion means before being switched so that the level of the subject image signal becomes appropriate for focus detection calculation. Since it is controlled, the responsiveness when the focus detection area is switched is improved.

For the focus detection block selected as the focus detection block, the photoelectric conversion means of the pair corresponding to the focus detection area belonging to the focus detection block repeats the charge accumulation operation, and at the same time, the photoelectric conversion of the pair is performed. The focus adjustment state of the photographing optical system is calculated based on the pair of image signals output from the conversion means, and for the focus detection block not selected as the block for performing focus detection, a specific focus detection block belonging to the focus detection block is selected. The charge accumulation operation is repeatedly performed by the pair of photoelectric conversion units corresponding to the focus detection area. Accordingly, for the non-selected block, the charge accumulation operation is performed only by the photoelectric conversion unit corresponding to the specific focus detection area representative of the plurality of focus detection areas.
It is not necessary to carry out the charge storage operation in all photoelectric conversion units corresponding to a plurality of focus detection areas, and the load of the storage control operation of the non-selected blocks is reduced as compared with the focus detection operation of the selected block, and the normal focus detection operation is performed. High responsiveness can be maintained in operation. Moreover, the accumulation time of the photoelectric conversion means corresponding to the representative focus detection area of the switched focus detection block is set so that the level of the subject image signal output from this photoelectric conversion means becomes appropriate for focus detection calculation. Since the control is performed before switching, when the focus detection block is switched, the accumulation time of the photoelectric conversion unit corresponding to another focus detection area included in the block is the photoelectric conversion unit corresponding to the specific focus detection area. Can be referred to, and the responsiveness when the focus detection block is switched is improved.

Incidentally, in the section of means and action for solving the above-mentioned problems for explaining the constitution of the present invention, the drawings of the embodiments are used in order to make the present invention easy to understand. It is not limited to.

[0017]

【Example】

First Embodiment FIG. 1 shows the configuration of a camera equipped with the focus detection device of the first embodiment. The lens 2 is configured to be replaceable with respect to the body 1, and the figure shows a state in which the lens 2 is mounted on the body 1. A photographing optical system 3 is provided in the lens 2, and a light flux from a subject passing through the photographing optical system 3 is split by a main mirror 4 which is a half mirror in a direction of a sub mirror 5 and a viewfinder 6.

The light beam further deflected toward the bottom of the body by the sub-mirror 5 is guided to a focus detecting device 9 arranged near the planned focal plane of the photographing optical system 3. Focus detection device 9
Is composed of a focus detection optical system, a charge detection sensor, and a focus detection calculation unit including a microcomputer, detects a focus adjustment state of the photographing optical system, and a lens driving device 10 including a motor or the like according to the detection result. Is controlled to move the photographing optical system 3 connected to the lens driving device 10 in the optical axis direction to achieve a focused state.

The area selection device 11 is a device for selecting an area for performing focus detection from a plurality of focus detection areas set on the photographing screen, and automatically or according to the photographing mode of the camera. It is manually operated by the photographer. The focus detection device 9 performs a focus detection operation or an automatic focus adjustment operation for the area selected by the area selection device 11.

FIG. 2 shows a configuration example of the focus detection optical system and the charge storage type image sensor. The focus detection optical system 7 includes a field mask 71 having openings 70A and 70B, condenser lenses 72A and 72B, and two pairs of aperture openings 73A and 7B.
A diaphragm mask 75 having 4A, 73B and 74B, and two pairs of re-imaging lenses 76A, 77A and 76B, 77B. Further, the charge storage type image sensor 8 includes two pairs of light receiving portions 80, 81 and 82, 83. Each light receiving unit 80,
Each of 81, 82, and 83 is composed of a plurality of pixels.

In the above structure, the two pairs of aperture openings 73A, 74A and 73B, 74B are symmetrical with respect to the optical axis of the surface 30 near the exit pupil of the photographing optical system 3 by the condenser lenses 72A, 72B. The light beam projected on the pair of areas 31 and 32 passes through this area and the field mask 7
First, a primary image is formed near 1. The primary images formed in the openings 70A and 70B of the field mask 71 are further condensed into condenser lenses 72A and 72B, and two pairs of aperture openings 73.
A, 74A and 73B, 74B through two pairs of re-imaging lenses 76A, 77A and 76B, 77B, and two pairs of secondary on the light receiving portions 80 and 81 and the light receiving portions 82 and 83 of the charge storage type sensor 8. Formed as an image. Then, the light receiving unit 80,
The relative positional relationship between the pair of secondary images on 81 and the relative positional relationship between the pair of secondary images on the light receiving portions 82 and 83 are respectively determined by the focus state of the photographing optical system 3. It changes accordingly.

The light receiving portions 80 and 81 and the light receiving portions 82 and 83 can independently control the start and end of charge accumulation.
The light receiving units 80 and 81 and the light receiving units 82 and 83 start the charge accumulation when receiving the charge accumulation start signal, and terminate the charge accumulation when receiving the charge accumulation end signal. Then, by the well-known CCD shift register provided in the light receiving unit, the charges accumulated in the light receiving units 80, 81, 82, and 83 are serially transferred to the outside in pixel units as analog object image signals according to the transfer pulse signal. . Therefore, the light intensity distributions of the two pairs of secondary images are determined by the light receiving units 80 and 81 and the light receiving unit 8.
2, 83 is photoelectrically converted and output as an electrical subject image signal, and the relative positional relationship between the secondary images of each pair is detected based on these subject image signals.
The focus adjustment state of the photographing optical system 3 can be detected.

With the above configuration, as shown in FIG. 3, on the photographing screen 35, the first focus detection area 36 corresponding to the light receiving portions 80 and 81 and the second focus detection area corresponding to the light receiving portions 82 and 83. Area 37 will be set. Note that, hereinafter, the light receiving units 80 and 81 are referred to as a first light receiving unit, and the light receiving units 82 and 83 are referred to as a second light receiving unit.

Next, FIG. 4 is a functional block diagram showing the structure of the focus detection device 9. The focus detection device 9 includes the focus detection optical system 7 and the charge storage image sensor 8 described above.
And a microcomputer 90. The image sensor 8 includes a first light receiving portion (the above-described pair of light receiving portions 80, 8
1) and a second light receiving portion (the pair of light receiving portions 82 and 83 described above).
And a peak hold circuit 84 for detecting the peak value of the output signals of the first light receiving portion and the second light receiving portion, and a control signal for storage control and transfer control of the first light receiving portion and the second light receiving portion. And a control circuit 85 for controlling them, which are formed as one chip on the same semiconductor substrate. The microcomputer 90 is means for performing storage operation control of the first light receiving units 80 and 81 and the second light receiving units 82 and 83 and calculation for focus detection, and includes an AD conversion unit 91 and a focus detection calculation unit 92. And a sensor control unit 93.

Next, the operation of the focus detection device 9 will be described. First light receiving portions 80, 81 and second light receiving portions 82, 83
Charge is stored for a predetermined storage time under the control of the control circuit 85, and the subject according to the light intensity distribution of each pair of subject images formed on the respective light receiving portions by the focus detection optical system 7. An image signal is generated and output to the microcomputer 90 via the common output line 87. The method of determining the charge storage time will be described later. In addition, the first output section 80, 81 and the second output section 8 are connected to the common output line 87.
The storage timings of the first light receiving units 80, 81 and the second light receiving units 82, 83 are controlled from the outside so that the outputs of 2, 2 and 83 do not appear at the same time. The peak hold circuit 84 is arranged in parallel with the output line 87, and while the subject image signals of the first light receiving units 80 and 81 or the second light receiving units 82 and 83 are output and transferred, peak values of these subject image signals ( The signal value corresponding to the brightest part) is detected and held, and the peak value detected when the output transfer of the subject image signal is completed is output to the outside via the output line 87.

FIG. 5 is a time chart of the subject image signal output from the image sensor 8. At time T1, the accumulation of the first light receiving units 80 and 81 is completed, and the first light receiving unit 8
The transfer of the charges accumulated in 0 and 81 is started. Time T
From 1 to time T2, a signal for each pixel is output according to the transfer pulse signal. When the transfer ends at time T2, the peak value of the subject image signal output from time T1 to time T2 is output as a peak signal. Further, when the storage of the second light receiving units 82 and 83 is finished at time T3 and the transfer of the charges stored in the second light receiving units 82 and 83 is started, the subject image signal is output instead of the peak signal. During the period from time T3 to time T4, a signal for each pixel is output according to the transfer pulse signal. When the transfer ends at time T4, the peak value of the subject image signal output from time T3 to time T4 is output as a peak signal.

The AD converter 91 is connected to the output line 87 and AD-converts the subject image signal and the peak signal. When the first focus detection area 36 is selected by the area selection device 11, the focus detection calculation unit 92 detects the first focus based on the AD-converted object image data corresponding to the first light receiving units 80 and 81. The focus adjustment state of the area 36 is detected. When the second focus detection area 37 is selected by the area selection device 11, the second light receiving unit 82,
The focus adjustment state of the second focus detection area 37 is detected based on the AD-converted object image data corresponding to 83. The sensor control unit 93 adjusts the output level of the subject image signal output from the first light receiving unit 80, 81 and the second light receiving unit 82, 83 so that the output level of the subject image signal falls properly within the AD conversion range of the AD conversion unit 91. 1 light receiving portion 80, 81, second light receiving portion 82, 8
3 is determined and a command is sent to the control circuit 85 via the control line 86 to control the accumulation time of the first light receiving units 80, 81 and the second light receiving units 82, 83.

The AD value of the peak signal corresponding to the first light receiving portions 80 and 81 is PA, the accumulation time when the peak signal PA is obtained is TAP, and the AD of the peak signal corresponding to the second light receiving portions 82 and 83 is AD. When the value is PB, the accumulation time when the peak signal PB is obtained is TAB, and the target peak value is PX, the next accumulation time TAN of the first light receiving units 80 and 81 and the second light receiving units 82 and 83 is , TBN are calculated by Equation 2.

[Formula 2] TAN = TAP * PX / PA TBN = TBP * PX / PB By determining the next accumulation time in this way, it can be expected that the next peak value will be the target value PX.

6 and 7 are operation flowcharts of the microcomputer 90 of the first embodiment. Step S1
At 00, the power is turned on and the process proceeds to step S101. At this time, a timer built in the microcomputer 90 is started and time counting starts. In step S101, the storage time of the light receiving unit corresponding to the focus detection area selected by the area selection device 11 is controlled. Here, the following description will be made assuming that the first focus detection area 36 is selected. In this case, the charge storage operation of the first light receiving units 80 and 81 is performed. Since the formula 2 cannot be applied to the accumulation time immediately after the power is turned on, a fixed value or a value according to the output of the photometric means (not shown) is set. The stored accumulation time TAN is adopted. The accumulation time at this time is TAP
Memorize as. In step S102, the first light receiving unit 8
The object image signals of 0 and 81 are transferred, AD-converted for each pixel, and the AD-converted data is stored in the memory. Step S1
In 03, a well-known image shift detection calculation is performed based on the obtained AD conversion data, and the focus adjustment state of the first focus detection area 36 is detected. In step S104, the peak signal appearing after the transfer of the subject image signal is AD-converted to obtain the peak value PA.

In step S105, the peak value PA
And the accumulation time TAP, the next accumulation time TAN is calculated and stored according to Equation 2, and the process proceeds to step S106. In step S106, the time measured by the timer is detected, and it is checked whether a predetermined time has elapsed. If the predetermined time has not elapsed, the process returns to step S101 and the above-described operation is repeated. When the predetermined time has elapsed, the timer is reset and the process proceeds to step S107. In step S107, the second light receiving unit 8 corresponding to the non-selected focus detection area, that is, the second focus detection area 37 in this case.
The charge accumulation operation of 2,83 is performed. Storage time is power O
Immediately after N, it is a fixed value or a value according to the output of the photometric means (not shown), and if it is not immediately after the power is turned on, the accumulation time TB determined by equation 2 in step S110 described later.
Adopt N. The storage time at this time is stored as TBP. In step S108, the subject image signals of the second light receiving units 82 and 83 are transferred, and in the following step S109, the peak signal that appears after the transfer of the subject image signals is AD-converted to obtain the peak value PB. In step S110, the next storage time TBN is calculated and stored according to Equation 2 based on the peak value PB and the storage time TBP, and then, in step S110.
Returning to 101, the above-described operation is repeated.

When the area selecting device 11 is switched while repeating such operations, the operations of the first light receiving portions 80 and 81 and the second light receiving portions 82 and 82 in the above description are performed.
The operation of 83 is exchanged.

In the above operation, the timer is set to a time sufficiently longer than the focus detection cycle of the selected focus detection area (the operation time from step S101 to step S106 in FIG. 6). It should be noted that instead of measuring a predetermined time with a timer, step S101
The process may branch to step S107 after detecting that the focus detection cycle from step S106 to step S106 has been performed a predetermined number of times.

The predetermined time or the predetermined number of times is
You may make it change according to the brightness | luminance decided according to the storage time of a light-receiving part, or the output of a photometric sensor. In this case, since the accumulation time is long when the brightness is low, the responsiveness of the focus detection operation to the selected area deteriorates when the light receiving section corresponding to the non-selected area is operated. Therefore, the above operation may be performed only when the brightness is equal to or higher than the predetermined brightness, and the operation of the light receiving unit corresponding to the non-selected area may not be performed when the brightness is lower than the predetermined brightness.

On the other hand, when the brightness is high, the accumulation time is short, and it does not take time for the output level of the image sensor to converge to the optimum value when the selected area is switched. In the above case, the light receiving unit corresponding to the non-selected area may not be operated.

Further, in the operation flowcharts shown in FIGS. 6 and 7, although the subject image signal of the light receiving portion corresponding to the non-selected area is not AD-converted for each pixel and therefore focus detection calculation is not performed, the non-selected area The subject image signal of the light-receiving unit corresponding to can also be subjected to AD conversion for each pixel and focus detection calculation performed.

FIG. 7 is an operation time chart of the first embodiment. The signal of the first stage is a signal indicating the light receiving portion corresponding to the focus detection area selected by the area selection device 11, and in the case of H, the first light receiving portions 80 and 81 are selected,
In the case of L, the second light receiving portions 82 and 83 are selected. The second-stage signal is a timer timing signal, and a pulse is generated each time a predetermined time elapses. The signal of the third stage is the first light receiving unit 8
0, 81 is the accumulation operation signal, and ON indicates accumulation.
OFF indicates non-accumulation. The signal of the fourth stage is the first light receiving portion 8
The transfer operation signals are 0 and 81. When ON, the object image signal is being transferred, and when OFF, it is not being transferred. The signal of the fifth stage is the operation signal of the first light receiving units 80 and 81, and when ON, focus detection calculation or accumulation time calculation calculation is performed based on the subject image signal of the first light receiving units 80 and 81. Is indicated, and indicates that no calculation is performed when OFF. The signal of the sixth stage is the accumulation operation signal of the second light receiving units 82 and 83,
ON indicates accumulation, and OFF indicates non-accumulation. The signal at the seventh stage is a transfer operation signal of the second light receiving units 82 and 83,
ON indicates that the subject image signal is being transferred, and OFF indicates that it is not transferring. The signal of the eighth stage is a calculation operation signal of the second light receiving units 82 and 83, and when ON, focus detection calculation or accumulation time calculation calculation is performed based on the subject image signal of the second light receiving units 82 and 83. Is indicated, and indicates that no calculation is performed when OFF.

At time T10, the storage of the first light receiving portions 80 and 81 is started. At time T11, the storage of the first light receiving units 80 and 81 is finished, and the transfer of the subject image signal is started. Time T12
Then, the transfer of the subject image signals of the first light receiving units 80 and 81 is finished, and the calculation is started. At time T13, the first light receiving units 80, 8
The calculation for 1 is ended, and the accumulation of the first light receiving units 80 and 81 is started again. A predetermined time elapses while the above operation is repeated, and the timer generates a pulse at time T14. After the pulse signal of this timer is generated, the calculation of the first light receiving units 80 and 81 is finished and the accumulation of the second light receiving units 82 and 83 is started at time T15. At time T16, the accumulation in the second light receiving units 82 and 83 is completed, and the transfer of the subject image signal is started. At time T17, the transfer of the subject image signals of the second light receiving units 82 and 83 is completed and the calculation is started. Then, at time T18, the calculation related to the second light receiving units 82 and 83 is finished,
The accumulation of the first light receiving units 80 and 81 is started again.

When the area selecting device 11 is switched to the time T19 while repeating the above operation, at the time T20 immediately after the area switching, the calculation of the first light receiving units 80 and 81 is completed and the second light receiving units 82 and 83 are completed. Start accumulating. At time T20, the storage of the second light receiving units 82 and 83 is completed, and the transfer of the subject image signal is started. Second at time T21
The transfer of the subject image signals of the light receiving units 82 and 83 is completed, and the calculation is started. At time T22, the calculation related to the second light receiving unit is finished, and the accumulation of the second light receiving unit is started again. While the above operation is repeated, the predetermined time elapses and the timer is set to time T24.
Generate a pulse. After the timer generates the pulse signal, the calculation of the second light receiving units 82 and 83 ends at time T25 and the accumulation of the first light receiving units 80 and 81 starts. At time T26, the storage of the first light receiving units 80 and 81 is finished, and the transfer of the subject image signal is started. First at time T27
The transfer of the subject image signals of the light receiving units 80 and 81 is completed, and the calculation is started. At time T28, the calculation related to the first light receiving units 80 and 81 ends, and the accumulation of the second light receiving units 82 and 83 starts again.

As described above, in the first embodiment, the focus detection area in which the focus detection operation including accumulation, transfer, and calculation is not selected for the light receiving portion corresponding to the focus detection area selected by the area selection device 11. Is performed more frequently than the focus detection operation of the light receiving unit corresponding to.

-Second Embodiment- Next, a second embodiment of the present invention will be described. The configuration of the second embodiment is similar to that of the first embodiment shown in FIG. In the first embodiment, the focus detection operation of the light receiving section corresponding to the focus detection area that is not selected is performed every predetermined time, whereas in the second embodiment, the focus detection area that is not selected is selected. When the focus detection operation of the corresponding light receiving unit and the focus detection operation of the light receiving unit corresponding to the unselected focus detection area are performed in parallel and the operations are in conflict (for example, accumulation can be done at the same time but transfer and calculation can be done at the same time) (No) does the operation of the selected focus detection area with priority. That is, the transfer of the charge accumulated in the light receiving portion corresponding to the non-selected focus detection area and the focus detection calculation are performed during the accumulation of the light receiving portion corresponding to the selected focus detection area.

9 to 11 are operation flowcharts of the microcomputer 90 of the second embodiment. The operation of the second embodiment will be described with reference to these flowcharts. Here, a case where the first focus detection area 36 is selected will be described as an example. In step S200, the power is turned on, and the process proceeds to step S201. At this time, the fixed time is set in the timer B to start the accumulation in the second light receiving units 82 and 83. In step S201, accumulation of the light receiving unit corresponding to the focus detection area selected by the area selection device 11 is started. In this case, the first light receiving unit 8
0, 81 charge accumulation is started. The storage time is managed by the built-in timer A. For example, timer A before the start of accumulation
Set the set time of the timer A
And start the timer A interrupt when the set time is reached. As for the storage time, since the above-mentioned formula 2 cannot be applied immediately after the power is turned on, a fixed value or a value according to the output of the photometric means (not shown) is set, and the power is turned on.
If it is not immediately after N, the formula 2
The storage time TAN determined by is adopted. The accumulation time at this time is stored as TAP.

In step S202, the second light receiving section 8
It is determined whether or not Nos. 2 and 83 are accumulating. If they are accumulating, the process proceeds to step S203, and waits for the end of accumulation (timer A interrupt) of the first light receiving units 80 and 81. Step S204
Then, when the accumulation end interrupt (timer A interrupt) of the first light receiving units 80 and 81 is applied, the accumulation of the first light receiving units 80 and 81 is ended. In step S205, the first light receiving unit 8
Object image signals of 0 and 81 are transferred, AD conversion is performed for each pixel, and AD conversion data is stored in the memory. Step S
At 206, a well-known image shift detection calculation is performed based on the obtained AD conversion data, and the focus adjustment state in the first focus detection area 36 is detected. In the following step S207, the peak signal appearing after the transfer of the subject image signal is AD-converted to obtain the peak value PA. In step S208, the next storage time TAN is calculated and stored from the peak value PA and the storage time TAP based on Equation 2, and the process returns to step S201 to repeat the above-described operation.

In step S202, the second light receiving portions 82 and 83
Is not being accumulated, the process proceeds to step S209. In step S209, it is determined whether or not the storage of the second light receiving units 82 and 83 is completed and the transfer waiting state is established. If the transfer waiting state is established, the process proceeds to step S210. In step S210, it is determined whether or not the transfer time of the subject image signal of the second light receiving units 82 and 83 is shorter than the storage time of the first light receiving units 80 and 81. If it is short, the process proceeds to step S211 to transfer. If it is long, the transfer of the subject image signals of the first light receiving units 80 and 81 is started during the transfer of the subject image signals of the second light receiving units 82 and 83. The process returns to step S203 without transferring the signal. In step S211, the subject image signals of the second light receiving units 82 and 83 are transferred, and in the following step S212, the peak signal that appears after the end of the subject image signal transfer is AD converted, the peak value PB is detected, and the process returns to step S203.

On the other hand, if it is not in the transfer waiting state in step S209, the process proceeds to step S213 and the second light receiving unit 8
It is determined whether or not the storage time calculation of 2 and 83 is waiting or being calculated. If the storage time calculation is being waited or is being calculated, the process proceeds to step S214, and the next storage time TBN is calculated and stored from the peak value PB and the storage time TBP based on Formula 2. In step S215, the second light receiving unit 8
The accumulation of 2,83 is started. The built-in timer B manages the storage time of the second light receiving units 82 and 83. The set time of the timer B is set before starting the accumulation, the timer B is started at the same time when the accumulation is started, and the timer B interrupt is set when the set time is reached. As the storage time, the storage time TBN determined by Equation 2 in step S214 is adopted. The accumulation time at this time is stored as TBP, and the process returns to step S203. Steps S214 and S215
If the timer A is interrupted during the process of 1, the state of the second light receiving units 82 and 83 is set to the state of calculation and the process proceeds to step S204.

In step S220 of FIG. 11, the second light receiving unit 8
When a storage end interrupt (timer B interrupt) of No. 2, 83 is applied, the storage of the second light receiving units 82, 83 is ended at step S221, and the program returns to the program shown in FIGS. 9 and 10 at subsequent step S222.

When the area selection device 11 is switched while repeating such operations, the operations of the first light receiving portions 80 and 81 and the second light receiving portions 82 and 82 in the above description are performed.
The operation of 83 is exchanged.

Further, in the flow charts of FIGS. 9 to 11, the subject image signal of the light receiving portion corresponding to the non-selected area is not AD-converted for each pixel, and therefore focus detection calculation is not performed, but it is performed in the non-selected area. The subject image signal of the corresponding light receiving portion may be AD-converted for each pixel and focus calculation may be performed.

FIG. 12 is an operation time chart of the second embodiment. At time T30, accumulation of the first light receiving units 80 and 81 and the second light receiving units 82 and 83 is started. At time T31, the storage of the first light receiving units 80 and 81 is finished, and the transfer of the subject image signal is started. At time T32, the transfer of the subject image signals of the first light receiving units 80 and 81 is finished and the calculation is started. At time T33, the calculation related to the first light receiving units 80 and 81 is finished, the accumulation of the first light receiving units 80 and 81 is started again, and at the same time, the transfer of the subject image signal of the second light receiving units 82 and 83 is started. Time T3
Then, the transfer of the subject image signals of the second light receiving units 82 and 83 is completed. At time T35, the storage of the first light receiving units 80 and 81 is completed, and the transfer of the subject image signal is started. First at time T36
The transfer of the subject image signals of the light receiving units 80 and 81 is completed, and the calculation is started. At time T37, the calculation related to the first light receiving units 80 and 81 is ended, the accumulation of the first light receiving units 80 and 81 is started again, and at the same time, the calculation related to the second light receiving units 82 and 83 is started. At time T38, the accumulation of the first light receiving units 80 and 81 is finished, and the transfer of the subject image signal is started, and at the same time, the calculation related to the second light receiving units 82 and 83 is stopped halfway. In this case, it is assumed that the calculation time for the second light receiving units 82, 83 is longer than the accumulation time for the first light receiving units 80, 81. At time T39, the transfer of the subject image signals of the first light receiving units 80 and 81 is finished, and the calculation is started. At time T40, the calculation related to the first light receiving units 80 and 81 is completed, and the accumulation of the first light receiving units 80 and 81 is started again.
The calculation regarding 83 is restarted. At time T41, the calculation regarding the second light receiving units 82 and 83 ends. By repeating the above operation, the focus detection operation of the second light receiving units 82 and 83 is performed after the focus detection operation of the first light receiving units 80 and 81.

When the area selecting device 11 is switched to the time T50 while repeating the above operation, the focus detecting operations of the first light receiving portions 80 and 81 and the second light receiving portions 82 and 83 are reversed.

As described above, in the second embodiment, for the light receiving portion corresponding to the focus detection area selected by the area selection device 11, a series of focus points including charge accumulation and transfer and focus detection calculation are performed. The detection operation has priority over the focus detection operation of the light receiving unit corresponding to the focus detection area that is not selected.

-Third Embodiment- Next, a third embodiment of the present invention will be described. The structure of the third embodiment is substantially the same as the structure of the first embodiment shown in FIG. 1, and only the differences will be described. In the first embodiment, the accumulation operation is performed also on the light receiving portions corresponding to the focus detection areas that are not selected, and the accumulation time is controlled, whereas in the third embodiment, the focus that is not selected is selected. The point of improving the responsiveness when the focus detection area is switched by monitoring the output of the light quantity monitor light receiving element provided near the light receiving section without performing the accumulation operation of the light receiving section corresponding to the detection area. Is different.

FIG. 13 is a functional block diagram showing the structure of the third embodiment. The focus detection optical system 7 is not shown in FIG. The focus detection device 9A of the third embodiment is
In the focus detection device 9 of the first embodiment, the first monitor light receiving element 801 is arranged in the vicinity of either one of the first light receiving portions 80 and 81 of the image sensor 8A, and the second light receiving portion 8 is provided.
The second monitor light receiving element 802 is arranged in the vicinity of either one of
1st capacity 8 for accumulating the electric charge which 1,802 generates
03 and a second capacitor 804, a predetermined voltage generation circuit 807, a first comparison circuit 80 for comparing a predetermined voltage and the output of each capacitor.
5 and a second comparison circuit 806 are provided.

Next, the operation of the focus detection device 9A will be described. The first monitor 801 and the second monitor 802 generate charges according to the amount of incident light, and the generated charges are accumulated in the first capacitor 803 and the second capacitor 804, respectively, and generate a voltage corresponding to the accumulated charge amount. . The first capacitor 803 and the second capacitor 804 reset the charges accumulated under the control of the control circuit 85A. First capacity 803, second capacity 804
Is generated by the first comparison circuit 805 and the second comparison circuit 8
The comparison result signal is inverted when the generated voltage exceeds the predetermined voltage by comparing with 06. The comparison result signal is output to the sensor control unit 93A of the microcomputer 90A via the output lines 808 and 809, respectively. Therefore, the sensor control unit 93A uses the first capacitance 8
03, the second capacitor 804 through the line 86 to the control circuit 8
By measuring the time from resetting to 5 A until each comparison signal is inverted, information about the brightness of the first light receiving units 80, 81 and the second light receiving units 82, 83 can be obtained.

14 and 15 are operation flowcharts of the microcomputer 90A of the third embodiment. In addition,
Hereinafter, the case where the first focus detection area 36 is selected will be described as an example. In step S300, the power source O
If N, the process proceeds to step S301. At this time, the timer built in the microcomputer 90A is also started and the time counting is started. In step S301, the electric charge accumulated in the capacitance of the monitor light receiving element in the vicinity of the light receiving portion corresponding to the unselected focus detection area is reset. Here, since the second focus detection area 37 is not selected, the second capacitor 804 is reset. Further, the charge generated by the second monitor light receiving element 802 is started to be accumulated in the second capacitor 804, and the built-in timer is reset and started.

In step S302, the area selection device 1
The storage time of the light receiving portion corresponding to the focus detection area selected by 1 is controlled. In this case, the first light receiving unit 8
The charge storage operation of 0 and 81 is performed. The formula 2 cannot be applied to the accumulation time immediately after the power is turned on, so a fixed value or a value according to the output of the photometric means (not shown) is set, and if not immediately after the power is turned on, it is determined by the formula 2 in step S306 described later. The accumulated storage time TAN is adopted. The storage time at this time is stored as TAP. In step S303, the subject image signals of the first light receiving units 80 and 81 are transferred, AD-converted for each pixel, and the AD-converted data is stored in the memory. In a succeeding step S304, a well-known image shift detection calculation is performed based on the obtained AD conversion data, and the focus adjustment state in the first focus detection area 36 is detected. In step S305, the peak signal appearing after the transfer of the subject image signal is AD-converted to obtain the peak value PA. In step S306, the next accumulation time TAN is calculated and stored from the peak value PA and the accumulation time TAP based on Equation 2,
It returns to step S301 and repeats the above-mentioned operation.

When the output voltage of the second capacitor 804 reaches a predetermined voltage, the comparison result signal of the second comparison circuit 806 is inverted, and this signal causes a monitor interrupt in step S310. In step S311, the time of the built-in timer is stored as the brightness information of the focus detection areas that are not selected. In a succeeding step S312, the accumulation of the monitor light receiving element in the vicinity of the light receiving portion corresponding to the unselected focus detection area is completed, and the electric charge accumulated in the corresponding capacitance is reset. Here, since the second focus detection area 37 is not selected, the second capacitor 804 is reset. Further, the charge generated by the second monitor light receiving element 802 is started to be accumulated in the second capacitor 804, the built-in timer is reset and started, and the program returns to the program of FIG. 14 in the following S313. While repeating such operation,
When the area selection device 11 is switched, the operations of the first light receiving units 80 and 81 and the operations of the second light receiving units 82 and 83 are switched in the above description. Immediately after the operations of the first light receiving units 80 and 81 and the operations of the second light receiving units 82 and 83 are switched, the accumulation time of the light receiving units corresponding to the focus detection area selected by the area selection device 11 is changed to
It is determined based on the stored brightness information obtained from the monitor light receiving element.

As described above, in the third embodiment, a series of focus detection operations including charge accumulation and transfer and focus detection calculation are performed on the light receiving portions corresponding to the focus detection areas not selected by the area selection device 11. The luminance information of the focus detection area is monitored by the corresponding monitor light receiving element without performing the operation. Then, when the focus detection area is switched, the accumulation time of the newly selected light receiving portion is determined based on the stored luminance information, and the electric charge is accumulated.

In each of the first, second and third embodiments, the case where two focus detection areas are set has been described as an example. However, the number of focus detection areas is different in each of the above embodiments. The present invention can be applied to a focus detection device having three or more focus detection areas without limitation.

Further, the structures of the focus detection optical system 7 and the image sensor 8 are not limited to those shown in FIG. 2, and similar effects can be obtained even with the structure shown in FIG. 16, for example. In FIG. 16, elements similar to those shown in FIG. 2 are assigned the same reference numerals and explanations thereof are omitted. The focus detection optical system 7A is
A field mask 71 having openings 70A and 70B, a condenser lens 72C, and a pair of aperture openings 73 and 74.
Aperture mask 75A having a pair of re-imaging lenses 76
Charge accumulation type image sensor 8 including C and 77C
B and 8C are a pair of light receiving portions 80A, 81A and 8A, respectively.
2A and 83A are provided.

In the configuration as described above, the pair of aperture openings 73 and 74 are symmetrical with respect to the optical axis of the surface 30 near the exit pupil of the photographing optical system 3 by the condenser lens 72C.
It is projected on the pair of areas 31 and 32. These areas 31,
The light flux passing through 32 first forms a primary image near the field mask 71. The primary images formed in the openings 70A and 70B of the field mask 71 are further condensed by a condenser lens 72C,
The charge storage type image sensor 8 is passed through the pair of aperture openings 73 and 74 and the pair of re-imaging lenses 76C and 77C.
Two pairs of secondary images are formed on the light receiving portions 80A and 81A of B and the light receiving portions 82A and 83A of the charge storage type image sensor 8C. The relative positional relationship between the pair of secondary images on the light receiving portions 80A and 81A and the relative positional relationship between the pair of secondary images on the light receiving portions 82A and 83A are as follows.
It changes according to the focus state of each. The light intensity distributions of the two pairs of secondary images are the light receiving portions 80A, 81A and the light receiving portion 82.
It is photoelectrically converted by A and 83A and is output as an electrical subject image signal. The focus adjustment state of the photographing optical system 3 can be detected by detecting the relative positional relationship between the secondary images of each pair based on these subject image signals.

-Fourth Embodiment- Next, a fourth embodiment of the present invention will be described. The configuration of the fourth embodiment is substantially the same as that of the first embodiment, and only the configuration and operation of the focus detection optical system are different. Here, the difference will be mainly described. In the first embodiment, the area selection device 11
Selects a focus detection area for performing focus detection from a plurality of focus detection areas, whereas in the fourth embodiment, a plurality of focus detection blocks including a plurality of focus detection areas are set, and an area selection device is used. 11 is different in that a focus detection block for performing focus detection is selected from a plurality of focus detection blocks. Then, with respect to the focus detection block that is not selected, only the light receiving portion corresponding to the specific focus detection area belonging to this block performs the charge accumulation operation.

FIG. 17 shows the arrangement of focus detection areas according to the fourth embodiment. The focus detection areas 40, 4 are provided on the photographing screen 35.
A first focus detection block 38 in which 1 is arranged in a cross shape;
The second focus detection block 39 in which the focus detection areas 42 and 43 are arranged in a cross shape is set.

FIG. 18 shows an example of a focus detection optical system for forming a cross-shaped focus detection block. The focus detection module 20 includes a field mask 21 having a cross-shaped opening 211, a condenser lens 22, an aperture mask 24 having two pairs of aperture openings 241, 242, 243, 244, and two pairs of reconnections. Image lenses 251, 252, 25
3, 254, a focus detection optical system, and an image sensor 26 such as a CCD having two pairs of light receiving units 261, 262, 263, 264, and a primary formed on the optical axis by the photographing optical system 3. Two pairs of light receiving parts 261 and 26
It is re-imaged as two pairs of secondary images on 2,263,264. Each of the light receiving units 261, 262, 263, 264 is composed of a plurality of pixels. The opening 211 of the field mask is arranged near the planned focal plane on the optical axis,
As a result, the focus detection position is set on the optical axis of the screen.

In the above configuration, the two pairs of aperture openings 241, 242, 243, 244 are two pairs symmetrical with respect to the optical axis of the surface 12 near the exit pupil of the photographing optical system 3 by the condenser lens 22. Areas 121, 122, 12
Projected on 3,124. These areas 121, 12
The light flux passing through 2, 123, and 124 first forms a primary image near the field mask 21. Opening 21 of field mask 21
The primary image formed on 1 is further the condenser lens 2
Two or two pairs of aperture openings 241,242,243,244
Through the two reimaging lenses 251, 252, 253,
Two pairs of light receiving portions 261 and 26 of the sensor 26 are provided by 254.
Formed as two pairs of secondary images on 2,263,264. The light intensity distributions of the two pairs of secondary images are the light receiving parts 261 and 26.
Photoelectric conversion is performed at 2, 263 and 264, and an electrical subject image signal is obtained. As is well known, by detecting the relative positional relationship of the secondary images paired on the sensor 26 in the light receiving section pair alignment direction using the subject image signal generated by the sensor 26, The defocus amount between the image plane and the planned focal plane can be detected. By arranging the focus detection module 30 having the same structure as the focus detection module 20 symmetrically with respect to the optical axis 301 as shown in FIG.
As shown in, a cross-shaped first focus detection block 38 and second cross-shaped focus detection block 39 can be set on the photographing screen 35.

FIG. 20 is an operation flowchart of the microcomputer 90 in the fourth embodiment. The operation of the fourth embodiment will be described with reference to this flowchart, taking as an example the case where the first focus detection block 38 is selected by the area selection device 11. In step S400, the power is turned on, and the process proceeds to step S401. At this time, the timer built in the microcomputer 90 is also started,
Start timing. In step S401, the storage time of the light receiving unit corresponding to the focus detection areas 40 and 41 belonging to the first focus detection block 38 selected by the area selection device 11 is controlled. Since the formula 2 cannot be applied to the accumulation time immediately after the power is turned on, a fixed value or a value according to the output of the photometric means (not shown) is set. The storage time decided for each area is adopted. The storage time at this time is saved. In step S402, the subject image signal of the light receiving portion corresponding to the focus detection areas 40 and 41 is transferred, AD-converted for each pixel, the AD converted data is stored in the memory, and the peak that appears after the transfer of the subject image signal is completed. The signal is AD-converted to obtain the peak value. In step S403, a well-known image shift detection calculation is performed based on the obtained AD conversion data, and the focus adjustment state of the focus detection areas 40 and 41 is detected.

In step S404, the next accumulation time is calculated and stored for each focus detection area from the peak value and the accumulation time based on the equation 2, and the process proceeds to step S405.
In step S405, the time measured by the timer is detected,
It is checked whether or not a predetermined time has elapsed. If the predetermined time has not elapsed, the process returns to step S401 and the above operation is repeated.
When the predetermined time has elapsed, the timer is reset and the process proceeds to step S406. In step S406, the focus detection block that is not selected, that is, the second focus detection block in this case, is selected.
Focus detection areas 42 and 4 belonging to the focus detection block 39
The focus detection area 42 in the vertical direction of the screen of 3 is set as the representative area, and the charge accumulation operation of the light receiving portion corresponding to the focus detection area 42 is performed. The storage time is set to a fixed value or a value according to the output of the photometric means (not shown) immediately after the power is turned on.
The storage time determined by Equation 2 in 9 is adopted. The storage time at this time is saved. In step S407, the subject image signal of the light receiving portion corresponding to the focus detection area 42 is transferred, and in the following step S408, the peak signal appearing after the end of the subject image signal transfer is AD-converted to obtain the peak value. Further, in step S409, the next accumulation time is calculated and stored from the peak value and the accumulation time based on Expression 2, and the process returns to step S401 to repeat the above operation.

When the area selection device 11 is switched while repeating such operation, the operation of the light receiving portion corresponding to the focus detection area belonging to the first focus detection block 38 and the second focus in the above description. Detection block 39
The operation of the light receiving unit corresponding to the focus detection area belonging to the above item is switched. That is, the focus detection area 40 in the longitudinal direction of the screen among the focus detection blocks not selected and the focus detection areas 40 and 41 belonging to the first focus detection block 38 is set as the representative area, and only the light receiving portion corresponding to the focus detection area 40 is set. Charge accumulation operation is performed. Immediately after the operation of the light receiving unit corresponding to the focus detection area belonging to the first focus detection block 38 and the operation of the light receiving unit corresponding to the focus detection area belonging to the second focus detection block 39 are switched,
The accumulation time of the light receiving unit corresponding to the focus detection area belonging to the focus detection block selected by the area selection device 11 is determined based on the accumulation time stored in the representative area.

In the above operation, the focus detection cycle of the selected focus detection area (step S
It is set to be sufficiently longer than the operation time from 401 to step S405). Also, instead of the predetermined time, step S
The process may branch to step S406 after detecting that the focus detection cycle from 401 to step S405 has been performed a predetermined number of times.

The predetermined time and the predetermined number of times may be changed according to the accumulation time of the light receiving section and the brightness determined based on the output of the photometric sensor. In this case, since the accumulation time is long when the brightness is low, when the light receiving unit corresponding to the non-selected area is activated, the responsiveness of the focus detection operation in the selected area deteriorates. Therefore, the above operation may be performed only when the brightness is equal to or higher than the predetermined brightness, and the operation of the light receiving unit corresponding to the non-selected area may not be performed when the brightness is lower than the predetermined brightness.

On the other hand, when the brightness is high, the accumulation time is short, and it does not take time for the output level of the image sensor to converge to the optimum value when the selected area is switched. When the brightness is equal to or higher than the predetermined brightness, the light receiving unit corresponding to the non-selected area may not be operated.

Further, in the flowchart of FIG. 20, the subject image signal of the light receiving portion corresponding to the representative area is not AD-converted for each pixel, and therefore focus detection calculation is not performed, but the light receiving portion corresponding to the non-selected area is received. The subject image signal of a part may be AD-converted for each pixel to perform focus detection calculation.

In the configuration of the above embodiment, the light receiving section 80
.About.83, 80A to 83A are photoelectric conversion means, and the microcomputers 90, 90A are focus detection calculation means, storage control means and sequence control means, and area selection device 1
1 constitutes area selecting means, and the output line 87 constitutes transferring means.

[0073]

As described above, according to the present invention, in the pair of photoelectric conversion means corresponding to the focus detection area selected as the area for performing focus detection, the pair of photoelectric conversion means output from the pair of photoelectric conversion means. The charge accumulation operation is repeated based on at least one of the image signals, and the focus adjustment state of the photographic optical system is calculated based on the image signal of the pair to select the area for focus detection. In the photoelectric conversion means of the pair corresponding to the focus detection area was not, based on at least one of the image signals of the pair of image signals output from the photoelectric conversion means of the pair, in the selected focus detection area Since the charge accumulation operation is repeated at a cycle longer than the repetition cycle of the charge accumulation operation of the corresponding pair of photoelectric conversion means, it corresponds to the non-selected area. The charge accumulation control cycle of the photoelectric conversion means is longer than that of the charge accumulation control and focus detection cycle of the selected area, the load of the accumulation control of the non-selected area of the microcomputer is lightened, and the responsiveness of normal focus detection operation to the selected area In addition, the storage time of the photoelectric conversion means corresponding to the switched focus detection area is controlled before switching so that the level of the subject image signal is appropriate for focus detection calculation. Immediately after the focus detection area is switched, accurate focus detection becomes possible, and the responsiveness of focus detection is improved. Further, with respect to the pair of photoelectric conversion means corresponding to the focus detection area selected as the area for performing focus detection, the transfer operation of the pair of image signals output from the pair of photoelectric conversion means, and the image of the pair. At least one of the operation of calculating the focus adjustment state of the photographic optical system based on the signal is performed by transferring a charge and a charge to a pair of photoelectric conversion units corresponding to a focus detection area not selected as an area for focus detection. Since the priority is given to the calculation operation of the accumulation time, the responsiveness of the focus detection operation does not deteriorate with respect to the focus detection operation of the selected focus detection area, and the switched focus detection area is not changed. Since the storage time of the photoelectric conversion means corresponding to is controlled before switching so that the level of the subject image signal becomes appropriate for focus detection calculation, Responsiveness of focus detection is improved in the case where the focus detection area is switched. Furthermore, in the pair of photoelectric conversion means corresponding to the focus detection area selected as the area for performing focus detection, based on at least one of the image signals of the pair of image signals output from the pair of photoelectric conversion means. The charge accumulation time is calculated by performing the charge accumulation operation repeatedly, and the focus adjustment state of the photographing optical system 3 is calculated based on the image signal of the pair, and the focus detection area not selected as the focus detection area is calculated. In the corresponding pair of photoelectric conversion means, charge accumulation is prohibited and the intensity of light incident on the pair of photoelectric conversion means is monitored. Then, when the focus detection area is switched, during charge accumulation immediately after switching to the photoelectric conversion means of the pair corresponding to the newly selected focus detection area, the charge is calculated based on the result of monitoring the light intensity of the photoelectric conversion means of the pair. Since the charge accumulation time is calculated and the charge is accumulated according to the calculated charge accumulation time, the charge accumulation control of the photoelectric conversion means corresponding to the non-selected area becomes unnecessary, reducing the load on the microcomputer and reducing the load on the selected area. The responsiveness of the focus detection operation is ensured. Further, the accumulation time of the photoelectric conversion element corresponding to the switched focus detection area is
Since the level of the subject image signal is controlled based on the monitor results of those photoelectric conversion means before it is switched so that it becomes appropriate for focus detection calculation, the responsiveness when the focus detection area is switched is improved. To do. Furthermore, for the focus detection block selected as the block for focus detection, the photoelectric conversion means of the pair corresponding to the focus detection area belonging to the focus detection block repeatedly perform the charge accumulation operation, and the photoelectric conversion of that pair is performed. The focus adjustment state of the photographing optical system is calculated based on the pair of image signals output from the conversion means, and the focus detection block not selected as the block for performing focus detection is identified by the specific focus detection block. Since the pair of photoelectric conversion means corresponding to the focus detection area repeatedly performs the charge accumulation operation, the photoelectric conversion means corresponding to a specific focus detection area representing a plurality of focus detection areas is selected for the non-selected block. Since the charge accumulation operation is performed only by itself, the charge accumulation operation can be performed by all photoelectric conversion units corresponding to multiple focus detection areas. Cormorants eliminates the need for focus detection operation of the selected block, is reduced burden of accumulation control operation of Hisen block, it is possible to maintain a high responsiveness in normal focus detection operation. Furthermore, the accumulation time of the photoelectric conversion element corresponding to the representative focus detection area of the switched focus detection block is set so that the level of the subject image signal output from this photoelectric conversion means becomes appropriate for focus detection calculation. Since the control is performed before switching, when the focus detection block is switched, the accumulation time of the photoelectric conversion means corresponding to another focus detection area included in the block is the photoelectric conversion means corresponding to a specific focus detection area. Can be referred to, and the responsiveness when the focus detection block is switched is improved.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing a configuration of a camera including a focus detection device according to a first embodiment.

FIG. 2 is a perspective view showing a configuration of a focus detection optical system and a charge storage type image sensor.

FIG. 3 is a diagram showing an arrangement of focus detection areas on a shooting screen.

FIG. 4 is a functional block diagram showing the configuration of the first embodiment.

FIG. 5 is a time chart showing the output of the image sensor.

FIG. 6 is an operation flowchart of the microcomputer of the first embodiment.

FIG. 7 is an operation flowchart of the microcomputer according to the first embodiment, following FIG. 6;

FIG. 8 is a time chart showing the operation of the first embodiment.

FIG. 9 is an operation flowchart of the microcomputer of the second embodiment.

FIG. 10 is an operation flowchart of the microcomputer according to the second embodiment, following FIG. 9;

FIG. 11 is a flowchart showing a storage control interrupt routine of a light receiving unit corresponding to a non-selected area according to the second embodiment.

FIG. 12 is a time chart showing the operation of the second embodiment.

FIG. 13 is a functional block diagram showing the configuration of a third embodiment.

FIG. 14 is an operation flowchart of the microcomputer of the third embodiment.

FIG. 15 is a flowchart showing a monitor interrupt routine of the third embodiment.

FIG. 16 is a perspective view showing the configuration of another focus detection optical system and a charge storage type image sensor.

FIG. 17 is a diagram showing an arrangement of focus detection areas on a shooting screen according to a fourth embodiment.

FIG. 18 is a perspective view showing the configuration of a focus detection module according to a fourth embodiment.

FIG. 19 is a perspective view showing the arrangement of a focus detection module of the fourth embodiment.

FIG. 20 is an operation flowchart of the microcomputer of the fourth embodiment.

[Explanation of symbols]

 1 Body 2 Lens 3 Photographic Optical System 4 Main Mirror 5 Sub Mirror 6 Finder 7, 7A Focus Detection Optical System 8, 8A, 8B, 8C Charge Accumulation Image Sensor 9, 9A Focus Detection Device 10 Lens Drive Device 11 Area Selector 20, 30 focus detection module 26 image sensor 35 photographing screen 36 first focus detection area 37 second focus detection area 38 first focus detection block 39 second focus detection block 40-43 focus detection area 80-83, 80A-83A light receiving section 84 Peak hold circuit 85,85A Control circuit 86 Control line 87 Output line 90,90A Microcomputer 91 AD conversion unit 92 Focus detection calculation unit 93 Sensor control unit 801 First monitor light receiving element 802 Second monitor light receiving element 803 First capacitance 804 2 capacity 805 first comparator circuit 806 the second comparison circuit 807 a predetermined voltage generating circuit 808 and 809 output lines

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location H04N 5/232 A 8411-2K G03B 3/00 A (72) Inventor Tsutomu Naruzawa Marunouchi, Chiyoda-ku, Tokyo 3 2-3 No. 3 In stock company Nikon

Claims (11)

[Claims] 1. An image signal is provided corresponding to each of a plurality of focus detection areas set on a photographing screen of a photographing optical system, and outputs an image signal according to a light intensity distribution of a subject image formed by the optical system. A plurality of pairs of charge storage type photoelectric conversion means, a focus detection calculation means for calculating a focus adjustment state of the photographing optical system based on a pair of image signals output from these pairs of photoelectric conversion means, and each pair. Storage control means for controlling charge storage of the photoelectric conversion means of the pair based on at least one of the image signals of the pair of image signals output from the photoelectric conversion means of the plurality of focus detection areas Area selection means for selecting an area for performing focus detection from the above, and a pair of photoelectric conversion means corresponding to the focus detection area selected by the area selection means are charged by the accumulation control means. And performs repeatedly the product operation, performs focus detection calculation by the focus detection computing unit based on the image signal pair output from the photoelectric conversion means of the pair,
For the pair of photoelectric conversion units corresponding to the focus detection areas not selected by the area selection unit, the cycle is longer than the repetition period of the charge accumulation operation of the pair of photoelectric conversion units corresponding to the selected focus detection area. A focus detection apparatus comprising: a sequence control unit that repeatedly performs a charge storage operation by the storage control unit at a cycle. 2. A plurality of pairs of photoelectric conversion means corresponding to each of the plurality of focus detection areas by selecting an area for performing focus detection from a plurality of focus detection areas set on a photographing screen of a photographing optical system. Of the pair of photoelectric conversion means corresponding to the focus detection area selected as the area for performing focus detection, at least one of the pair of image signals output from the pair of photoelectric conversion means. The charge accumulation operation is repeatedly performed based on the pair, and the focus adjustment state of the photographing optical system is calculated based on the image signal of the pair, and the photoelectric conversion of the pair corresponding to the focus detection area not selected as the focus detection area is performed. In the means, based on at least one of the pair of image signals output from the pair of photoelectric conversion means, the selected focus detection area is selected. A focus detection method characterized in that the charge accumulation operation is repeatedly performed at a cycle longer than the repetition cycle of the charge accumulation operation of the pair of photoelectric conversion units corresponding to (a). 3. An image signal according to the light intensity distribution of a subject image formed by the optical system, which is provided corresponding to each of a plurality of focus detection areas set on the photographing screen of the photographing optical system. A plurality of pairs of charge storage type photoelectric conversion means, a focus detection calculation means for calculating a focus adjustment state of the photographing optical system based on a pair of image signals output from these pairs of photoelectric conversion means, and each pair. Storage control means for calculating the charge storage time based on at least one of the image signals of the pair of image signals output from the photoelectric conversion means, and controlling the charge storage of the pair of photoelectric conversion means; Transfer means for transferring the image signal output from each photoelectric conversion means to the focus detection calculation means; area selection means for selecting an area for focus detection from the plurality of focus detection areas; A) For the pair of photoelectric conversion units corresponding to the focus detection area selected by the selection unit, at least one of the image signal transfer operation by the transfer unit and the focus detection calculation operation by the focus detection calculation unit. Sequence control means for performing the above operation with priority over the transfer operation and the accumulation time calculation operation of the pair of photoelectric conversion means corresponding to the focus detection area not selected by the area selection means. Focus detection device. 4. A plurality of pairs of photoelectric conversion means corresponding to each of the plurality of focus detection areas by selecting an area for focus detection from a plurality of focus detection areas set on a photographing screen of a photographing optical system. Of the pair of photoelectric conversion units corresponding to the focus detection area selected as the focus detection area, the transfer operation of the pair of image signals output from the pair of photoelectric conversion units, and the pair of photoelectric conversion units. Of at least one of the calculation operations of the focus adjustment state of the photographic optical system based on the image signal of (1) to the photoelectric conversion means of the pair corresponding to the focus detection area not selected as the area for focus detection. And a focus detection method characterized in that the focus detection method is executed prior to the calculation operation of the charge accumulation time. 5. An image signal is provided corresponding to each of a plurality of focus detection areas set on the photographing screen of the photographing optical system, and outputs an image signal according to the light intensity distribution of the subject image formed by the optical system. A plurality of pairs of charge storage type photoelectric conversion means, a focus detection calculation means for calculating a focus adjustment state of the photographing optical system based on a pair of image signals output from these pairs of photoelectric conversion means, and each pair. Storage control means for calculating the charge storage time based on at least one of the image signals of the pair of image signals output from the photoelectric conversion means, and controlling the charge storage of the pair of photoelectric conversion means; A plurality of monitor means for respectively outputting a signal corresponding to the light intensity incident on each pair of photoelectric conversion means, and area selection means for selecting an area for focus detection from the plurality of focus detection areas, For the pair of photoelectric conversion means corresponding to the focus detection area selected by the area selection means, the charge control operation is repeatedly performed by the storage control means, and the pair of images output from the pair of photoelectric conversion means. Performing focus detection calculation by the focus detection calculation means based on a signal,
For the pair of photoelectric conversion means corresponding to the focus detection area not selected by the area selection means, charge accumulation by the accumulation control means is prohibited, and the light intensity of the light intensity is monitored by the monitor means of the photoelectric conversion means of the pair. A focus detection apparatus comprising: a sequence control unit that performs a monitor operation. 6. The focus detection device according to claim 5, wherein the sequence control means, when the focus detection area is switched by the area selection means, a pair of photoelectric conversions corresponding to the newly selected focus detection area. Upon charge accumulation immediately after the switching of the means, the charge accumulation time is calculated by the accumulation control means based on the monitoring result of the light intensity by the monitor means of the pair of photoelectric conversion means, and the charge accumulation is carried out at the calculated charge accumulation time. A focus detection device characterized by the above. 7. A plurality of pairs of photoelectric conversion means corresponding to each of the plurality of focus detection areas are selected from a plurality of focus detection areas set on the photographing screen of the photographing optical system. In the pair of photoelectric conversion means corresponding to the focus detection area selected as the area for performing focus detection, at least one of the pair of image signals output from the pair of photoelectric conversion means A focus detection area not selected as an area for focus detection is calculated based on the paired image signal, and the focus adjustment state of the photographing optical system is calculated based on the paired image signal. In the pair of photoelectric conversion means corresponding to, the charge detection is prohibited and the intensity of light incident on the pair of photoelectric conversion means is monitored. How to get out. 8. The focus detection method according to claim 7, wherein when a focus detection area is switched, charge accumulation immediately after switching to a pair of photoelectric conversion units corresponding to the newly selected focus detection area is performed. A focus detection method characterized in that the charge accumulation time is calculated based on the result of monitoring the light intensity of the pair of photoelectric conversion means, and the charge is accumulated at the calculated charge accumulation time. 9. An image signal according to the light intensity distribution of a subject image formed by the optical system, which is provided corresponding to each of a plurality of focus detection areas set on the photographing screen of the photographing optical system. A plurality of pairs of charge storage type photoelectric conversion means, a focus detection calculation means for calculating a focus adjustment state of the photographing optical system based on a pair of image signals output from these pairs of photoelectric conversion means, and each pair. Of the pair of image signals output from the photoelectric conversion means of the storage control means for controlling the charge storage of the photoelectric conversion means of the pair based on at least one of the image signals; Multiple focus detection blocks are formed by classifying each focus detection area.
A block selecting means for selecting a block for performing focus detection from the plurality of focus detecting blocks, and a focus detecting block selected by the block selecting means corresponds to a focus detecting area belonging to the focus detecting block. The charge control operation is repeatedly performed by the storage control means in the pair of photoelectric conversion means, and focus detection calculation is performed by the focus detection calculation means based on the image signal of the pair output from the pair photoelectric conversion means. For focus detection blocks not selected by the block selection means, sequence control is performed in which the charge control operation is repeatedly performed by the storage control means by a pair of photoelectric conversion means corresponding to a specific focus detection area belonging to the focus detection block. And a focus detection device. 10. The focus detection device according to claim 9, wherein a plurality of focus detection areas belonging to each of the focus detection blocks are arranged to intersect with each other. 11. A plurality of focus detection areas set on a photographing screen of a photographing optical system are classified into adjacent focus detection areas to form a plurality of focus detection unit locks, and the plurality of focus detection blocks are arranged. A block for focus detection is selected from among the selected focus detection blocks, and for the selected focus detection block, charge accumulation operation is repeated with a pair of photoelectric conversion units corresponding to the focus detection area belonging to the focus detection block, and The focus adjustment state of the photographing optical system is calculated based on the pair of image signals output from the pair of photoelectric conversion units, and the focus detection block is not selected as the block for focus detection. A focus detection method characterized in that a charge accumulation operation is repeatedly performed by a pair of photoelectric conversion means corresponding to a specific focus detection area belonging to.