JPH06186473A - Automatic focusing camera - Google Patents

Abstract

PURPOSE:To provide an automatic focusing camera which can execute high- speed continuous photographing while high focusing accuracy is maintained. CONSTITUTION:A first sensor 9 for receiving the light of an object image formed by a focus detection optical system 7 and a second sensor 10 whose sensitivity is higher than the sensor 9 are provided. Then, the sensor 10 is preferentially actuated by a control means(microcomputer) 14 during the continuous photographing action of a continuous photographing means 16. Based on the output of the sensor 10, the defocus amount of a photographing optical system 3 is calculated by a focus detection arithmetic means 12. An optical element is drivem in accordance the with defocus amount calulated by a driving means(motor) 15. Then, the optical system 3 is focused.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an autofocus camera.

[0002]

2. Description of the Related Art A subject image formed by a focus detection optical system is received by a charge storage type sensor, and the sensor output is arithmetically processed to detect a defocus amount of a subject image plane with respect to a planned focal plane of a photographing optical system. However, there is known an automatic focusing camera that achieves the focus of a photographing optical system by driving a focusing lens according to the defocus amount.

When performing continuous shooting with this type of automatic focus (hereinafter referred to as AF) camera, high-speed continuous shooting cannot be performed if the charge storage time of the charge storage type sensor between frames becomes long, so the sensor is used during continuous shooting. A technique for increasing the output amplification gain to shorten the accumulation time is disclosed in Japanese Patent Laid-Open No. 2-
It is disclosed in Japanese Patent No. 64517.

[0004]

However, if the amplification gain of the sensor output is simply increased to shorten the accumulation time, the amount of accumulated charge before amplification is reduced, and as a result, the S / N ratio of the sensor output is reduced. Deteriorates and the detection accuracy of the defocus amount deteriorates, and continuous shooting while performing automatic focus adjustment according to the defocus amount may cause out-of-focus.

It is an object of the present invention to provide an automatic focusing camera capable of high-speed continuous shooting while maintaining high focusing accuracy.

[0006]

The present invention will be described with reference to FIG. 1 showing the configuration of an embodiment. The invention of claim 1 is directed to the optical axis direction for forming a subject image on a planned focal plane. A photographic optical system 3 including an optical element that can move in the direction of focus, a focus detection optical system 7, a first sensor 9 for receiving a subject image formed by the focus detection optical system 7, and a first sensor 9
A second sensor 10 having a higher sensitivity than the sensor 9 of
Based on the output of the first sensor 9 or the second sensor 10, the focus detection calculation means 12 for calculating the defocus amount of the image plane of the photographing optical system 3 with respect to the planned focal plane, and the focus detection calculation means 12 A driving unit 15 that drives an optical element to focus the photographing optical system 3 according to the defocus amount, and a continuous photographing unit 16 that continuously performs a photographing operation.
And during the continuous shooting operation by the continuous shooting means 16, the second
And a control means 14 for preferentially operating the sensor 10 of FIG.

In the automatic focusing camera according to claim 2, the first
When the sensor 9 and the second sensor 10 are of the charge accumulation type and charge accumulation is performed for the same brightness subject for the same time, the accumulated charge amount of the second sensor 10 is the accumulated charge of the first sensor 9. It is configured to be larger than the quantity.

According to another aspect of the automatic focusing camera of the present invention,
The sensor 9 and the second sensor 10 are configured so that their pixel areas are different from each other.

The focus detection optical system 7 of the automatic focus adjustment camera according to claim 4 has a first focus detection optical system for forming a subject image on the first sensor 9 and a subject on the second sensor 10. It has a second focus detection optical system having different optical characteristics from the first focus detection means for forming an image.

[0010]

During the continuous shooting operation, the sensor having a relatively high sensitivity among the plurality of sensors is preferentially operated to shorten the focus adjustment time.

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

[0012]

FIG. 1 is a block diagram showing the structure of an 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 composed of a half mirror in the directions of a sub mirror 5 and a finder 6. The light beam further deflected in the body bottom direction by the sub mirror 5 is guided to a focus detection optical system 7 arranged near the planned focal plane of the photographing optical system 3.

FIG. 2 shows the structures of the focus detection optical system 7 and the charge storage type sensor 8. The focus detection optical system 7 has an opening 7
0 field mask 71 and condenser lens 72
And a diaphragm mask 7 having a pair of diaphragm openings 73, 74
5 and a pair of re-imaging lenses 76 and 77. Further, the charge storage type sensor 8 includes two pairs of light receiving units 8
It is composed of 0, 81, 82 and 83. The primary image formed by the photographing optical system 3 in the vicinity of the opening 70 on the optical axis is re-imaged as a pair of secondary images on the light receiving portions 80, 82 and 81, 83.

As shown in FIG. 3, each of the light receiving portions 80 and 81 is composed of a plurality of pixels, and the pixel pitch is P1 and the pixel height is W1. On the other hand, the light receiving parts 82 and 83
Are each composed of a plurality of pixels, the pixel pitch is P2 (> P1), and the pixel height is W2 (> W1). The pixel area P2 × W2 of the light receiving portions 82 and 83 is equal to the light receiving portion 8
Since it is larger than the pixel area P1 × W1 of 0,81, the charge accumulation time for obtaining the same output level is
3 is shorter.

In addition, a monitor sensor 84 for monitoring the amount of light on the light receiving portions is provided near the light receiving portions 80 and 82.
85 is arranged, the outputs of the monitor sensors 84 and 85 are accumulated at the same time when the charge accumulation of the light receiving units 80 to 83 is started, and the accumulated charge amount of the light receiving units 80 to 83 when the accumulated output level reaches a predetermined level. Becomes a predetermined level, and the charge accumulation is terminated.

In the structure as described above, the pair of aperture openings 73 and 74 are symmetric with respect to the optical axis of the surface 30 near the exit pupil of the photographing optical system 3 by the condenser lens 72. The light beam that is projected onto the field, and forms a primary image near the field mask 71. The primary image formed in the opening 70 of the field mask 71 passes through the condenser lens 72 and the pair of aperture openings 73 and 74, and the pair of re-imaging lenses 76 and 77 allows the light receiving portion of the charge storage sensor 8 to be received. It is formed as a pair of secondary images on the light receiving portions 81 and 83 and on the light receiving portions 81 and 83.

The intensity distribution of the pair of secondary images is determined by the light receiving portions 80, 8
2 and the light receiving portions 81 and 83 perform photoelectric conversion to provide an electrical subject image signal. At this time, since the pixel areas of the light receiving units 80 and 81 are different from those of the light receiving units 82 and 83, the charge accumulation time is independently set so that the output level is appropriate for performing the focus detection calculation process.

The light receiving portions 80 and 81 form the first sensor 9 in FIG. 1, and the light receiving portions 82 and 83 form the first sensor 10. These are controlled by the control unit 11 in the microcomputer 14, which will be described later.

The pair of electrical subject image signals of the first sensor 9 or the pair of electrical subject image signals of the second sensor 10 are fetched by the microcomputer 14, and the focus detection calculation unit 12 is operated.
Detects the defocus amount d between the image plane of the photographing optical system 3 and the planned focal plane by obtaining the relative positional relationship of the subject image signal.

The drive control unit 13 in the microcomputer 14 controls the rotation direction and rotation amount of the motor 15 according to the defocus amount d. The motor 15 is connected to the photographic optical system 3, the photographic optical system 3 moves in the optical axis direction and is driven so that the defocus amount d becomes 0, and the photographic optical system 3 is brought into a focused state.

Further, the continuous photographing device 16 has a main mirror 4, a sub-mirror 5, a shutter 17, a winding device 1 according to the photographing mode (one frame photographing mode or continuous photographing mode) set by the photographer and the operation state of the release button 19.
The operation of 8 is controlled to perform one frame shooting or continuous shooting operation. The information on the shooting mode set by the photographer and the information on the operating state at the time of shooting are input to the control unit 11, and the first
The sensor 9 and the second sensor 10 are controlled.
That is, the control unit 11 operates the second sensor 10 between frames during continuous shooting, and otherwise operates the first sensor 9.
To operate.

FIG. 4 shows the control unit 11 and the focus detection calculation unit 12.
3 is an operation flowchart of a microcomputer 14 that constitutes a drive controller 13. When the power of the camera is turned on in step S100, the process proceeds to step S101 to check whether the focus detection operation is possible, and if possible, the process proceeds to step S102. Here, the focus detection operation is possible because the continuous shooting device 16 is not performing the shooting operation, the main mirror 4 and the sub-mirror 5 are arranged in the optical path, and the light flux that has passed through the shooting optical system 3 causes the subject image to be captured. Is a state formed on the first sensor 9 and the second sensor 10.

In step S102, the continuous photographing device 16
On the basis of the information from, it is checked whether or not there is a frame between continuous shootings, and if it is between frames during continuous shooting, step S10.
If not, go to step S103. If it is not between frames during continuous shooting, it is checked in step S103 whether the subject brightness is low brightness. If the brightness is low, the process proceeds to step S105, and if not, step S10.
Go to 4.

If there is a low brightness even between frames during continuous shooting, or if the brightness is low even during continuous shooting, the high-sensitivity second sensor 10 is selected to shorten the AF time between frames in step S105. Controls charge storage time. That is, when the charge accumulation time is long at low brightness and the response of automatic focus adjustment is reduced, or when the focus detection time is limited such as between frames during continuous shooting, the second sensor with high sensitivity is used. 10
To reduce the charge storage time of the sensor and improve the autofocus responsiveness.

On the other hand, if there is a high brightness between frames during continuous shooting, the first sensor 9 having a relatively low sensitivity is selected in step S104, and its charge storage control is performed. As shown in FIG. 3, the first sensor 9 has a finer pixel pitch and a smaller pixel height than the second sensor 10, so that the first sensor 9 has high detection capability for a fine subject. That is, since the responsiveness is not required when the continuous shooting is not performed and the brightness is high, the first sensor 9 having a relatively low sensitivity is selected with an emphasis on the fine detection capability.

Here, the determination of the subject brightness may be made based on the output of a photometric sensor (not shown) or based on the charge accumulation time of the first sensor 9 and the second sensor 10.

In step S106, the subject image data is read from the first sensor 9 or the second sensor 10, and in the subsequent step S107, the subject image data is processed to calculate the defocus amount d. Further, in step S108, the lens drive amount L indicating how much the photographing optical system 3 should be driven to achieve the in-focus state is calculated according to the defocus amount d. Then, in step S109, the motor 15 is driven to move the photographing optical system 3 by the lens driving amount L. Then, the process returns to step 101 and the above-described operation is repeated.

Although the second sensor 10 is selected between frames during continuous shooting in the above embodiment, the second sensor 10 may always be selected when the continuous shooting mode is set. Good.

If the brightness is high even between frames during continuous shooting, the first sensor 9 having lower sensitivity than the second sensor 10 may be selected.

FIG. 5 shows the structures of a focus detection optical system 7 and a charge storage type sensor 8 according to another embodiment. Focus detection optical system 7
Is a field mask 171 having a cross-shaped opening 170.
, Condenser lens 172, and two pairs of aperture openings 1
Aperture mask 17 having 73, 174, 273, 274
5 and two pairs of re-imaging lenses 176, 177, 276, 2
And 77. In addition, the charge storage type sensor 8
Is composed of two pairs of light receiving units 180, 181, 182, 183. The primary image formed in the vicinity of the opening 170 on the optical axis by the photographing optical system 3 is on the light receiving portions 180, 182 and 1
Re-imaging is performed on 81 and 183 as two pairs of secondary images.

FIG. 6 shows the arrangement of the light receiving parts 180 to 183. Each of the light receiving units 180 to 183 is composed of a plurality of pixels having a pitch P1 and a height W1. Light receiving parts 182, 18
Since the pixel area P1 × W1 of 3 is the same as the pixel area P1 × W1 of the light receiving units 180 and 181, the accumulation times for obtaining the same output level are the same at the same luminance. In addition, monitor sensors 184 and 185 for monitoring the amount of light on the light receiving portions are arranged near the light receiving portions 180 and 182. The outputs of the monitor sensors 184 and 185 are accumulated at the same time when the charge accumulation of the light receiving units 180 to 183 starts, and when the accumulated output level reaches a predetermined level, the accumulated charge amount of the light receiving units 180 to 183 reaches a predetermined level, It is configured to terminate the accumulation.

FIG. 7 shows the structure of two pairs of aperture openings 173, 174, 273, 274 of the aperture mask 175. The distance between the center of gravity of the apertures of the aperture openings 173 and 174 and the opening area are larger than the distance between the center of gravity of the apertures of the aperture openings 273 and 274 and the area of the apertures.

In the structure as described above, the pair of aperture openings 173 and 174 are formed by the condenser lens 172, as shown in FIG. 8, on the surface 30 near the exit pupil of the photographing optical system 3.
Is projected onto a pair of regions 131 and 132 which are symmetric with respect to the optical axis, and the other pair of aperture openings 273 and 274 are
By the condenser lens 172, a pair of regions 231, which are symmetrical with respect to the optical axis of the surface 30 near the exit pupil of the photographing optical system 3,
232. Area S of the regions 131 and 132
1 is larger than the area S2 of the regions 231 and 232, and the center-of-gravity interval X1 of the regions 131 and 132 is the regions 131 and 132.
Is larger than the center of gravity interval X2.

The light flux passing through these areas is the field mask 17
First, a primary image is formed near 1. The primary image formed in the opening 170 of the visual field mask 171 is a condenser lens 172, two pairs of aperture openings 173, 174, 273, 2.
2 re-imaging lenses 176, 177, 27
6, 277, the light receiving portion 18 of the charge storage sensor 8.
Two pairs of secondary images are formed on the light receiving portions 181, 183 and on the light receiving portions 181, 183.

The intensity distributions of the two pairs of secondary images are as follows:
Photoelectric conversion is performed by 182 and the light receiving units 181, 183, and an electrical subject image signal is obtained. At this time, the light receiving parts 180, 1
Although 81 and the light receiving units 182 and 183 have the same pixel area, they receive a subject image formed by light fluxes passing through pupil regions having different areas. Therefore, when the subject has the same brightness,
When the charge accumulation time is set so that the output level is appropriate for the focus detection calculation process, the light receiving unit 180,
The charge accumulation time of 181 is shorter than the charge accumulation time of the light receiving portions 182 and 183. That is, the light receiving units 180 and 181
Corresponds to the second sensor 10 having high sensitivity,
183 corresponds to the first sensor 9 having relatively low sensitivity.

The operation of the focus detection optical system 7 and the charge storage type sensor 8 of this embodiment is similar to the operation using the focus detection optical system and the charge storage type sensor shown in FIG.
The second sensor 10 having high sensitivity is selected when the responsiveness is required such as low brightness or continuous shooting, and the first sensor 9 having relatively low sensitivity is selected when high brightness or continuous shooting is not performed. In this embodiment, the reason why the first sensor 9 having a relatively low sensitivity is selected when high brightness or continuous shooting is not being performed is that, as shown in FIG. 8, the center-of-gravity interval X2 of the regions 231 and 232 corresponding to the first sensor 9 is selected. Is smaller than the center-of-gravity interval X1 of the regions 131 and 132 corresponding to the second sensor 10, the image shift amount with respect to the defocus amount is small, and even if the same image shift amount is compared, a defocus amount larger than the second sensor 10 is detected. Because you can. That is, when the responsiveness of the automatic focus adjustment is required, the second sensor 10 is selected with emphasis on the responsiveness, and when the responsiveness is not required, the first sensor 9 is selected with emphasis on the defocus detection ability. Will be selected.

FIG. 9 shows the structures of a focus detection optical system 7 and a charge storage type sensor 8 of another embodiment. Focus detection optical system 7
Has three re-imaging optical systems corresponding to the center of the screen and the three focus detection areas on the left and right thereof. The focus detection optical system 7
Field mask 37 having openings 370, 470, 570
1 and condenser lenses 372, 472, 473,
Three pairs of aperture openings 373, 374, 473, 474, 5
A diaphragm mask 375 having 73, 574 and three pairs of re-imaging lenses 376, 377, 476, 477, 576, 5
And 77. In addition, the charge storage type sensor 8
Are three pairs of light receiving parts 380, 381, 480, 481, 5
It is composed of 80,581.

The primary image formed by the taking optical system 3 in the vicinity of the opening 370 on the optical axis is treated as a pair of secondary images by the light receiving section 38.
The primary image formed in the vicinity of the opening 470 on the light receiving portions 480 and 481 on the light receiving portions 480 and 481 and the opening 5
The primary image formed in the vicinity of 70 is re-imaged as a pair of secondary images on the light receiving portions 580 and 581 as a pair of secondary images.

FIG. 10 is a side view of the focus detection optical system 7 shown in FIG. 9 as seen from a direction perpendicular to the direction in which the openings 370, 470, 570 are arranged. It is shown that the re-imaging magnifications of the left and right re-imaging optical systems are also small. The reason why the magnification of the re-imaging optical system is changed between the center and the left and right in this way is that the re-imaging lens 37 is used.
6, 377, 476, 477, 576, 577 are integrally molded, adjustment of the direction of the line segment connecting the optical axes of the reimaging lenses 376, 377 and the alignment direction of the light receiving portions 380, 381, and reimaging Adjustment of the direction of the line segment connecting the optical axes of the lenses 476 and 477 and the arrangement direction of the light receiving units 480 and 481, and the direction of the line segment connecting the optical axes of the re-imaging lenses 576 and 577 and the arrangement of the light receiving units 580 and 581. When the adjustment of the direction is performed independently, the light receiving units 380, 381, 480, 481, 58
0, 581 need to be formed on separate chips 382, 482, 582, and different magnifications are used to avoid mutual dimensional interference when they are formed on separate chips. This is because it is necessary to place the chips.

Three pairs of light receiving parts 380, 381, 480, 4
81, 580, and 581 each include a plurality of pixels as shown in FIG. 11, and the pixel pitch is P1,
It is the height W1 of the pixel. FIG. 12 shows the re-imaging lens 37.
6 is a view in which the light receiving units 380 and 381 are projected onto the primary image plane by 6, 377, and the pitch of the projected pixels is P3 and the height of the pixel is W3. Further, FIG. 13 shows the re-imaging lens 4
76, 477, 576, 577 for receiving light units 480, 4
81, 580 and 581 are projected onto the primary image plane, and the pitch of the projected pixels is P4 (<P3) because the re-imaging magnification is larger than that of the central optical system, and the height of the pixel is W4 (<P3).
W3).

Pixel area P3 × W of the light receiving portions 380 and 381
3 is larger than the pixel area P4 × W4 of the light receiving units 480, 481, 580, 581, the charge storage time for obtaining the same output level is the same for the light receiving units 380, 381 as the light receiving units 480, 481, 580, 581. It gets shorter. That is, the light receiving units 380 and 381 are highly sensitive to the second sensor 10.
The light receiving portions 480, 481, 580, 581 correspond to the first sensor 9 having a relatively low sensitivity.

Also, monitor sensors 384, 484, 584 for monitoring the amount of light on the light receiving portions are arranged in the vicinity of the light receiving portions 380, 480, 580, and the outputs of the monitor sensors 384, 484, 584 are received. Part 3
At the same time when the charge accumulation of 80, 381, 480, 481, 580, 581 is started at the same time, and the accumulated output level reaches a predetermined level, the light receiving portions 380, 38
The charge storage amount of 1, 480, 481, 580, 581 reaches a predetermined level, and the charge storage is terminated.

In the above structure, three pairs of aperture openings 373, 374, 473, 474, 573, 574 are used.
Is projected by the condenser lenses 372, 472, and 572 onto a pair of regions 331 and 332 that are symmetrical with respect to the optical axis of the surface 30 in the vicinity of the exit pupil of the photographing optical system 3, and the light flux passing through these regions has a field of view. First, a primary image is formed near the mask 371. The primary image formed in the opening 370 of the field mask 371 passes through the condenser lens 372, the pair of aperture openings 373 and 374, and the pair of re-imaging lenses 37.
6, 377, the light receiving portion 38 of the charge storage sensor 8
It is formed as a pair of secondary images on 0,381. Also,
The primary image formed in the opening 470 of the field mask 371 is the condenser lens 472 and the pair of aperture openings 47.
3, 474 and a pair of re-imaging lenses 476, 477
Thus, a pair of secondary images is formed on the light receiving portions 480 and 481 of the charge storage type sensor 8. Further, the primary image formed in the opening 570 of the visual field mask 371 passes through the condenser lens 572 and the pair of aperture openings 573 and 574, and the pair of re-imaging lenses 576 and 577 allows the charge storage sensor 8 to be detected. Formed as a pair of secondary images on the light receiving portions 580 and 581. The intensity distributions of the three pairs of secondary images are photoelectrically converted by the light receiving units 380, 381, 480, 481, 580, 581 and become electrical object image signals.

The operation of this embodiment is similar to the operation when the focus detection optical system shown in FIG. 2 is used, and is highly sensitive when low brightness or responsiveness is required such as during continuous shooting. The second sensor 10, that is, only the light receiving units 380 and 381 corresponding to the focus detection area at the center of the screen are selected and operated. Further, when the brightness is high or when continuous shooting is not being performed, all the sensors, that is, the light receiving units 380, 381, 48.
0, 481, 580, 581 may all be operated to calculate three defocus amounts, and an appropriate one may be selected from them, or a focus detection area manually selected by the photographer may be selected. Alternatively, only the corresponding light receiving unit may be selectively operated. That is, when responsiveness of automatic focus adjustment is required, the second sensor 10 is selected with emphasis on responsiveness, and when responsiveness is not required, the first sensor 9 or the second sensor 10 is selected by the photographer. 10
Will be selected, or both the first sensor 9 and the second sensor 10 will be selected.

In the structure of the above embodiment, the photographing optical system 3 is the photographing optical system, the focus detecting optical system 7 is the focus detecting optical system, the first sensor 9 is the first sensor, and the second sensor 10 is the second sensor. The second sensor, the focus detection calculation unit 12 constitutes the focus detection calculation means, the motor 15 constitutes the drive means, the continuous photographing device 16 constitutes the continuous photographing means, and the microcomputer 14 constitutes the control means.

[0046]

As described above, according to the present invention, the first sensor and the second sensor having higher sensitivity than the first sensor for receiving the object image formed by the focus detection optical system.
Sensor is provided, the second sensor is preferentially operated during continuous shooting operation, the defocus amount of the shooting optical system is calculated based on the output of the second sensor, and the calculated defocus amount is set to the calculated defocus amount. In response to this, the shooting optical system is driven to focus, so the focus adjustment time between frames during continuous shooting operation can be shortened, and automatic focus adjustment with high detection accuracy is possible even for high-speed continuous shooting with short frames. It will be possible. Further, even when the brightness is low, it is possible to perform automatic focus adjustment with high detection accuracy and high-speed continuous shooting without reducing the frame speed.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment.

FIG. 2 is a perspective view showing configurations of a focus detection optical system and a charge storage type sensor according to an embodiment.

3 is a diagram showing a configuration of a sensor shown in FIG.

FIG. 4 is a flowchart showing the operation of the microcomputer.

FIG. 5 is a diagram showing another configuration example of a focus detection optical system and a charge storage type sensor.

6 is a diagram showing a configuration of the sensor shown in FIG.

7 is a diagram showing a configuration of a diaphragm mask of the focus detection optical system shown in FIG.

8 is a diagram showing a pupil region corresponding to the focus detection optical system shown in FIG.

FIG. 9 is a perspective view showing another configuration example of the focus detection optical system and the charge storage sensor.

10 is a side view of the focus detection optical system shown in FIG.

11 is a diagram showing a configuration of the sensor shown in FIG.

FIG. 12 is an explanatory diagram when the left and right sensors shown in FIG. 9 are projected on the primary image plane.

FIG. 13 is an explanatory diagram showing a case where the sensor at the center of the screen shown in FIG. 9 is projected on the primary image plane.

[Explanation of symbols]

1 Body 2 Lens 3 Photographing Optical System 7 Focus Detection Optical System 8 Sensor 9 1st Sensor 10 2nd Sensor 11 Control Section 12 Focus Detection Calculation Section 13 Drive Control Section 14 Microcomputer 15 Motor 16 Continuous Imaging Device 30 Pupil Plane 31, 32 , 131, 132, 231, 232, 33
1,332 areas 70, 73, 74, 170, 173, 174, 273
274, 370, 470, 570, 373, 374, 4
73, 474, 573, 574 Aperture 71, 171, 371 Field-of-view mask 72, 172, 372, 472, 572 Condenser lens 75, 175, 375 Aperture mask 76, 77, 176, 177, 276, 277, 37
6,377,476,477,576,577 Re-imaging lens 80-83, 180-183, 380, 381, 48
0,481,580,581 Light receiving part 84,85,184,185,384,484,584
Monitor sensor

Claims (4)

[Claims] 1. A photographing optical system including an optical element movable in an optical axis direction to form a subject image on a planned focal plane, a focus detection optical system, and a subject image formed by the focus detection optical system. A first sensor for receiving light, a second sensor having a higher sensitivity than the first sensor, and the photographing optical for the planned focal plane based on the output of the first sensor or the second sensor. Focus detection calculation means for calculating the defocus amount of the image plane of the system, and drive means for driving the optical element in accordance with the defocus amount calculated by the focus detection calculation means to focus the photographing optical system. An automatic focusing system comprising: a continuous photographing means for continuously performing a photographing operation; and a control means for preferentially operating the second sensor during the continuous photographing operation by the continuous photographing means. Adjusting the camera. 2. The autofocusing camera according to claim 1, wherein the first sensor and the second sensor are charge storage type, and charge is stored for the same time for a subject having the same brightness. An automatic focusing camera characterized in that the amount of accumulated charges of the second sensor is larger than the amount of accumulated charges of the first sensor. 3. The automatic focusing camera according to claim 1, wherein the first sensor and the second sensor have different pixel areas from each other. camera. 4. The automatic focusing camera according to claim 1, wherein the focus detection optical system includes a first focus detection optical system for forming a subject image on the first sensor. An automatic focus adjustment camera, comprising: a second focus detection optical system having a different optical characteristic from the first focus detection means for forming a subject image on the second sensor.