JPH04188124A - Camera device - Google Patents

Abstract

PURPOSE:To favorably adjust a focus at photographing by correcting a focus position worth of changed quantity of focal length when adjustment of the focal length of a zoom lens is completed, and adjusting the focus. CONSTITUTION:When the focal length of a zoom lens is changed from a long condition to a short condition, the focus position of a focusing lens 13 is adjusted based on a defined corresponding data memorized by a memory means 40, and a photographic object focused before change of the focal length is continued to be focused. When the focal length of the zoom lens 12 is changed from a short condition to a long condition, it is constituted so as to focus to the photographic object by automatic focusing. Namely, when the angle of view is adjusted with the zoom lens 12, the focusing condition is electronically maintained based on previously memorized adjustment information, and hence a mechanical focus position correcting means is given to a photographing lens 10. Hereby, the focus position of the zoom lens 12 can be corrected with a simple constitution.

Description

[Detailed description of the invention] The present invention will be explained in the following order.

A Industrial application field B Summary of the invention C Prior art D Problem to be solved by the invention E Means for solving the problem F Effect G Example G, explanation of one example G2 Description of other examples H Function A: Industrial Field of Application The present invention relates to a camera device commonly used and suitable for electronic still cameras, and more particularly to a camera device equipped with an autofocus mechanism.

B. Summary of the Invention The present invention provides a camera device with a zoom lens in which automatic focus control is performed by an autofocus mechanism, which corrects the focus position by the change in focal length when the focal length adjustment of the zoom lens is completed. At the same time, focus adjustment is also performed, so that focus adjustment can be performed satisfactorily during photographing.

C. Prior Art Conventionally, various so-called electronic still cameras have been developed that record still images on magnetic disks as electrical video signals. This electronic still camera requires focus adjustment by moving the focus ring or the like of the photographing lens, like a still camera using a normal silver halide film. In this case, some cameras have an autofocus mechanism that allows automatic focus adjustment. Conventionally, this autofocus mechanism detects the distance from the camera to the subject by some method, and moves the focus ring of the photographic lens in accordance with this distance information.

On the other hand, some video cameras detect focus information for autofocus control from the imaging signal itself and perform autofocus control without detecting distance (Japanese Patent Laid-Open No. 57-208520, etc. reference). That is, when the focus adjustment of the lens is appropriate, the outline of the subject can be photographed clearly, so the image signal contains high frequency components. On the contrary,
If the focus adjustment of the lens is not appropriate, the outline of the subject will be blurred and the image signal will not contain high-frequency components. Therefore, by detecting the amount of high-frequency components in the imaging signal, it is possible to detect whether the current focus adjustment state is appropriate or not, and autofocus control is performed.

Here, since the above-mentioned electronic still camera also uses a solid-state imaging device to obtain an electrical imaging signal, like a video camera, focus information for autofocus control is detected from this imaging signal itself. This method can be applied. By applying this autofocus method to electronic still cameras, there is no need to detect the distance from the camera to the subject, and the autofocus mechanism can be configured more easily than in still cameras that use silver halide film.

D Problems to be Solved by the Invention Incidentally, zoom lenses are widely used as photographic lenses attached to this type of camera.

By using this zoom lens as a photographic lens,
The focal length can be changed continuously, making it possible to take pictures at any angle of view from wide-angle to telephoto, for example.

However, in the case of this zoom lens, there is an inconvenience that when the focal length is changed, the focus position also changes. In other words, even if the subject is accurately focused before changing the focal length and there is no change in the distance from the camera to the subject, changing the focal length may cause the subject to become out of focus. . In order to prevent this kind of focus deviation from occurring with a general zoom lens, when the zoom ring for focal length adjustment is rotated, a mechanical part such as a cam groove will slightly shift the focus adjustment lens. The focus position is corrected in conjunction with changes in the focal length by moving the focus position step by step.

However, the focus position correction mechanism, which is made up of mechanical parts such as cam grooves, has a relatively complicated structure, which not only complicates the structure of the lens device but also increases the weight and volume of the lens device (i.e., camera device). There was an inconvenience that the number increased.

In view of this, an object of the present invention is to provide a still camera that can correct the focus position of a zoom lens with a simple configuration.

E. Means for Solving the Problems The present invention provides a zoom lens (12) that magnifies an incident optical image and a lens that focuses the incident optical image, as shown in FIGS. 1 and 2, for example. A focusing lens (13) and a motor (35) that drives the focusing lens (13)
, a photoelectric conversion unit (21) that converts an optical image incident through the zoom lens (12) and a focusing lens (13) into an electrical signal, and a focus detection unit that detects the focused state of the incident optical image. Focus detection means (31), (32), (33) are provided.
In a camera device that automatically performs focusing by driving a motor (37) to move a focusing lens (13) based on the detection result of 33), the state of the zoom lens (12) A zoom lens state detection means (38) detects the state of the focusing lens (13), a focusing lens state detection means (36) detects the state of the focusing lens (13), and a focusing lens state detection means (36) detects the state of the focusing lens (13). A storage means (40) for storing the position of the focusing lens (13) in focus, and the zoom lens state detecting means (39) changes the focus from the first state where the focal length of the zoom lens (12) is long. When movement to a second state with a shorter distance is detected,
A focusing lens (
13) from the storage means (40) and move the focusing lens (13) to this position to focus, and the zoom lens state detection means (39)
When movement from the second state to the first state is detected, the in-focus position is detected based on the video signal obtained from the output signal of the photoelectric conversion unit (21), and the focus is adjusted. This is what I did.

Further, the present invention provides, for example, as shown in FIGS. 1 and 3,
a zoom lens (12) that magnifies the incident optical image;
A focusing lens (13) that focuses the incident optical image
) and a motor (3) that drives this focusing lens (13).
5), a zoom lens (12) and a focusing lens (13)
), and a photoelectric conversion unit (21) that converts an incident optical image into an electrical signal, and focus detection means (31), (32), (33) that detects the focused state of the incident optical image.
), and focus detection means (31), (32),
In a camera device that automatically performs focusing by driving a motor (37) to move the focusing lens (13) based on the detection result of (33), the zoom lens (12) A zoom lens-like IT output means (38) for detecting the state, a focusing lens state detection means (36) for detecting the state of the focusing lens (13), and an optical Storage means (40) for storing the position of the focusing lens (13) where the image is focused
When the zoom lens state detection means (39) detects a movement of the zoom lens (step 2) from the first state in which the focal length is long to the second state in which the focal length is short, the zoom The position of the focusing lens (13) corresponding to the position of the zoom lens (12) detected by the lens state detection means (39) is obtained from the storage means (40), and the focusing lens (13) is moved to this position. After moving, the focus position is detected and focused based on the video signal obtained from the output signal of the photoelectric conversion section (21), and the zoom lens state detection means (39) detects the second When a movement from the state to the first state is detected, the photoelectric conversion unit (
The in-focus position is detected and focused based on the video signal obtained from the output signal of 21).

Further, the present invention provides, for example, as shown in FIGS. 1 and 2,
a zoom lens (12) that magnifies the incident optical image;
A focusing lens (13) that focuses the incident optical image
) and a motor (3) that drives this focusing lens (13).
5), a zoom lens (12) and a focusing lens (13)
), and a photoelectric conversion unit (21) that converts an incident optical image into an electrical signal, and focus detection means (31), (32), (33) that detects the focused state of the incident optical image.
), and focus detection means (31), (32),
In a camera device that automatically performs focusing by driving a motor (37) to move the focusing lens (13) based on the detection result of (33), the zoom lens (12) A zoom lens state detection means (38) for detecting the state, a focusing lens state detection means (36) for detecting the state of the focusing lens (13), and an optical image detection means (36) for detecting the state of the zoom lens (12). storage means (40) for storing the position of the focusing lens (13) at which the
When the zoom lens state detection means (39) detects a movement of the zoom lens (12) from the first state where the focal length is long to the second state where the focal length is short, the in-focus state is detected. After moving the focusing lens (13) to a predetermined position, the storing means ( 40), the focusing lens (13) is moved to this position to focus, and the zoom lens state detection means (39) detects the movement from the second state to the first state. When the image is captured, the in-focus position is detected and the focus is adjusted based on the video signal obtained from the output signal of the photoelectric conversion section (21).

F Function By doing this, when the focal length of the zoom lens changes from a long state to a short state (that is, from the telephoto side to the wide-angle side), the focusing lens changes based on certain corresponding data stored in the storage means. The focus position is adjusted, and the subject that was in focus before changing the focal length remains in focus. When the focal length of the zoom lens changes from a short state to a long state (that is, from a wide-angle side to a telephoto side), automatic focusing is performed and the subject comes into focus.

G Embodiment G, Description of an Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

In FIG. 1, (10) indicates the entire photographic lens, and this photographic lens (10) is composed of a fixed front lens (10).
1), a zoom lens (12) that adjusts the focal length (i.e., adjusts the angle of view), and a master lens (13) that adjusts the focus (i.e., adjusts the focus), the master lens (13) It is configured as an inner focus lens device located closest to the image forming surface. In this case, the photographic lens (10) is equipped with a master lens (1
3) It does not have a mechanism to move it.

Then, the image light passing through this photographic lens (10) is focused on the phase plate of a solid-state image sensor (hereinafter referred to as CCD imager) (21), and this CCD imager (
21), the image signal is converted into an electrical image signal by an image signal processing circuit (22), and the image signal is supplied to a recording circuit (23). After the recording circuit (23) performs recording processing, a video signal for recording is supplied to a magnetic head (24) arranged close to the magnetic disk (25), and the recording circuit (23) 1
A video signal of a still image for one field or one frame is recorded.

In addition, (30) in the figure indicates a central control unit f (CPU) that controls photography with this camera, and this central control unit (30)
) allows you to judge whether the captured image is in focus or not. That is, the imaging signal obtained by the imaging signal processing circuit (22) is supplied to the analog-to-digital converter (32) via the bypass filter (31), and the analog-to-digital converter (32) Convert only the location data to digital data. In this case, the area setting circuit (44) controls the location (timing) of this conversion. This area setting circuit (44) is supplied with a predetermined signal from the imaging signal processing circuit (22), and the data supplied from the bypass filter (31) to the analog-to-digital converter (32) is transmitted in one screen. When the data is located at a necessary location (i.e., the location to be sampled), an analog-to-digital converter (3
2) supplies a control signal to convert it into digital data.

Then, the digital data output from this analog-to-digital converter (32) is supplied to an adding circuit (33), and this adding circuit (33) adds up the data for one screen.
Central control bag for added value for the screen! (30).

Therefore, in the addition circuit (33), the high frequency components included in the imaging signals at a predetermined location in one screen are added for one screen, and the added value of the high frequency components of the imaging signals for one screen is A central control unit (30) is supplied.

Then, the central control device (30) discriminates the supplied addition data and performs focus adjustment so that the addition value of the high-frequency components extracted by the bypass filter (31) becomes the largest. That is, the central controller (30) controls the drive circuit (
The stepping motor (35) that moves the master lens (13) can be controlled via the lens (34), so that when automatic focus adjustment is performed, the added value of the high frequency component is maximized. Stepping motor (35)
to move the master lens (13). In this case, in this example, this automatic focus adjustment is
This is done only when the adjustment of the angle of view that shortens the focal length using the zoom lens (12) is completed and when the shutter is in the halfway-pressed state.

Furthermore, when the master lens (13) driven by the stepping motor (35) is at the infinity focus position, this is optically detected by the photointerrupter (36). The detection data of the presence of the central controller (30) is supplied to the central controller (30) via an analog-to-digital converter (43).

Then, the position (focus position) of the master lens (13) can be determined by the number of steps in which the stepping motor (35) is driven from this infinite position under the control of the central controller (30).

In this case, in this example, initial settings are made so that the focus position can be determined when photographing is started and autofocus control is performed for the first time. That is, the central controller (30) is equipped with a lens position memory (not shown) that stores position information of the master lens (13), and at the start of photography, the stepping motor (30) is controlled by the central controller (30). 35), the master lens (13) is moved in one direction to an infinite position, and the lens position data at this time is stored in the lens position memory.

Note that the detection position of the photointerrupter (36) does not have to be infinitely far away.

Then, when the zoom lens (12) moves in this state and the detection data of the potentiometer (39), which will be described later, changes, the master lens (13) stored in the lens position memory in the central control unit (30) should be Update location data. Then, based on this updated data, the master lens (
13) to bring the master lens (13) to an appropriate position.

Further, in this example, the angle of view (focal length) of the zoom lens (12) is also adjusted under the control of the central controller (30). That is, the motor (38) for moving the zoom lens (I2) can be controlled via the central control device (30) and the pigeon live circuit (37).
A zoom switch (4) connected to the central control unit (30)
When 1) is operated, the zoom lens (12) is moved by the motor (38), and the focal length can be adjusted to the telephoto side or the wide-angle side.

In this case, the zoom lens (
12) is detected as voltage data by a potentiometer (39) serving as a zoom lens position detection section, and this detected data is sent to the central controller (30) via an analog-to-digital converter (43). By supplying the zoom lens (1) on the central controller (30) side,
2) so that the position (focal length) can be determined at all times.

In addition, (40) in the figure indicates a non-volatile memory connected to the central control unit (30), and this memory (40) contains information on the focus position where the in-focus state is maintained when the focal length is changed. is memorized in advance. That is, when a zoom lens changes its focal length, the focal point changes, and information on the amount of change is stored for each focus position.

For this reason, for example, when the zoom lens (12) changes the focal length from the telephoto side to the wide-angle side while the subject is in focus, the adjustment amount of the master lens (13) to bring the subject into focus. is known from the information stored in this memory (40).

Then, the adjustment information stored in this memory (40) is
When the zoom lens (12) is adjusted to shorten the focal length (that is, when the angle of view is adjusted to the wide-angle side), it is read out under the control of the central controller (30). At the same time as this adjustment to shorten the focal length is performed, drive control data based on the continuously output adjustment information is sent to the drive circuit (34) of the motor (35) that drives the master lens (13). The master lens (13) is moved so that the focus position (position in focus) is kept constant.

Also, (42) in the figure indicates the shutter switch, and this shutter switch (42) is the central control switch! (30), and when the shutter switch (42) is pressed,
A central control device (30) performs predetermined operation control for photographing and records video signals on the magnetic disk (25). In this case, the shutter switch (42) is configured to be able to distinguish between three states: a half-pressed state, a fully pressed state, and an unpressed state.
It is designed so that shooting is performed when the button is fully pressed.

Furthermore, when the button is pressed halfway, the automatic focus adjustment described above is performed.

Next, the operation centered on focus control when photographing with the still camera device of this example will be explained with reference to the flowchart of FIG. 2.

In this example, automatic focus adjustment performed before shooting is performed using the zoom lens (12)! This is done when the angle of view is being adjusted to shorten the focal length and when the shutter is pressed halfway. That is, the central controller (30) first moves the master lens (I3) to an infinite position, initializes the lens position memory in the central controller (30), and then performs the steps shown in the flowchart of FIG. Thus, it is determined whether the zoom lens (12) has moved based on the data supplied from the zoom lens position detection section (38). And a zoom lens (12
) moves to shorten the focal length (from the telephoto side to the wide-angle side) and stops, the master lens (13 ) so that the subject at the same position is continuously focused on.

Also, when the zoom lens (12) moves to increase the focal length (from the wide-angle side to the telephoto side), the central controller (30) receives the integral value currently supplied from the analog-to-digital converter (33). Without determining the data, the drive circuit (36) drives the motor (37) to move the master lens (13), stops the master lens (13) at the position where the integral value is maximum, and focuses. state.

Then, until the next time the zoom lens (12) moves,
Maintain the position of the master lens (13) at this time,
A video signal obtained by photographing at the time when a shutter switch (42) is completely pressed is recorded on a magnetic disk (25).

Although not shown in the flowchart of FIG. 2, even when the shutter switch (42) is pressed halfway, the focus is automatically adjusted under the control of the central controller (30).

As described above, according to the still camera device of this example, although the photographing lens (10) has a simple configuration in which focus position correction is not performed during focal length adjustment using a mechanical component, the zoom lens (10) At the same time as the angle of view is adjusted by moving the zoom lens (12), the focus position is corrected or the focus is automatically adjusted.
Even if the angle of view is adjusted by movement in step 12), the subject remains in focus without going out of focus. In other words, assuming that the subject is in focus before adjusting the angle of view, when the angle of view is adjusted from the telephoto side to the wide-angle side, the depth of field (in-focus range) of the photographic lens (10) will change. Since the distance becomes wider, if the focus position is corrected to correspond to the change in focal length, the focus will be maintained continuously. When the angle of view is adjusted from the wide-angle side to the telephoto side, the depth of field of the photographic lens (10) becomes narrower, so simply correcting the focus position as described above will not allow you to move from the in-focus range. There is a risk of it coming off. In this example, since the focus is automatically adjusted under the control of the central control device (30) at this time, the subject comes into focus and an accident of losing focus is prevented. In this case, since this in-focus state is maintained under the control of the central control unit (30) configured with a microcomputer, the photographing lens (10) does not require a mechanism such as a cam groove, and the photographing lens (10) does not require a mechanism such as a cam groove. ) can be made small and lightweight with a simple configuration, and the camera device to which the photographing lens (lO) is attached can be made small and lightweight.

Further, since automatic focus adjustment is performed only when the angle of view is adjusted, the number of times (time) that automatic focus adjustment is performed before photographing can be minimized. Therefore, power consumption for automatic focus adjustment is minimized, and the life of the battery device that drives this camera device can be extended. Note that if the photographer wants to automatically adjust the focus without adjusting the angle of view, all he has to do is press the shutter switch (42) halfway.
You can also easily adjust the focus independently of adjusting the angle of view.

G2 Description of other embodiments Note that in the above embodiments, when the angle of view is adjusted from the telephoto side to the wide-angle side, only the focus position is corrected. The focus may be automatically adjusted later. That is,
As shown in the flowchart in Fig. 3, when the angle of view is adjusted from the telephoto side to the wide-angle side, the focus position is corrected based on the adjustment information stored in the memory (40), and after this correction, the focus position is adjusted again. Determines whether the angle of view has been adjusted from the telephoto side to the wide-angle side, and determines whether the angle of view has not been adjusted (i.e., there is no change in the angle of view after the focus position is corrected).
When it is determined that this is the case, the focus is automatically adjusted under the control of the central control device (30). Then, when the angle of view is adjusted from the wide-angle side to the telephoto side, the central controller (30) controls the analog-to-digital converter (
33), the motor (37) is driven by the drive circuit (36) to move the master lens (13), and the master lens is moved to the position where the integral value is maximum. (13) is stopped and brought into focus.

By doing this, even if the subject is not in focus immediately before the angle of view is adjusted from the telephoto side to the wide-angle side, when the angle of view is adjusted, the focus will be automatically changed. Become. Note that even if the subject is not in focus immediately before the angle of view is adjusted from the wide-angle side to the telephoto side, the focus is automatically brought into focus, as in the example in FIG. 2.

Further, the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various other configurations may be adopted.

H Effects of the Invention According to the present invention, when the angle of view is adjusted by the zoom lens, the in-focus state is maintained electronically based on adjustment information stored in advance. No correction means is required, and the configuration of the lens device and the camera device to which this lens device is attached can be simplified.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
FIG. 3 is a flowchart for explaining another embodiment of the present invention. (lO) is a photographing lens, (12) is a zoom lens, (1
3) is the master lens, (21) is the CCD imager,
(22) is an imaging signal processing circuit, (25) is a magnetic disk, (30) is a central control unit, (31) is a bypass filter, (33) is an addition circuit, (34) and (37) are drive circuits, ( 35) is a stepping motor, (38)
(36) is a photointerrupter, (39) is a potentiometer, (40) is a memory, (41) is a zoom switch, (42) is a shutter switch, and (44) is an area setting circuit.

Claims (1)

[Claims] 1. A zoom lens that magnifies an incident optical image, a focusing lens that focuses the incident optical image, a motor that drives the focusing lens, and the zoom lens and A photoelectric conversion unit that converts an optical image incident through the focusing lens into an electrical signal, and a focus detection unit that detects a focused state of the incident optical image, and a detection result of the focus detection unit. A camera device configured to automatically perform focusing by driving the motor and moving the focusing lens based on the zoom lens state detection means for detecting the state of the zoom lens; A focusing lens state detection means for detecting a state of the focusing lens; and a storage means for storing a position of the focusing lens at which the optical image is focused with respect to a position of the zoom lens, When the zoom lens state detection means detects a movement of the zoom lens from a first state in which the focal length is long to a second state in which the focal length is short, the movement of the zoom lens detected by the zoom lens state detection means The position of the focusing lens corresponding to the position of the zoom lens is obtained from the storage means, the focusing lens is moved to this position to focus, and the zoom lens state detecting means determines the position of the focusing lens. When the movement from the second state to the first state is detected, the focus position is detected and the focus is adjusted based on the video signal obtained from the output signal of the photoelectric conversion section. A camera device characterized by: 2. A zoom lens that magnifies the incident optical image, a focusing lens that focuses the incident optical image, a motor that drives the focusing lens, and a lens that passes through the zoom lens and the focusing lens. A photoelectric conversion unit that converts an incident optical image into an electrical signal, and a focus detection unit that detects a focused state of the incident optical image, and controls the motor based on the detection result of the focus detection unit. A camera device configured to automatically perform focusing by driving and moving the focusing lens, comprising: a zoom lens state detection means for detecting a state of the zoom lens; and a state of the focusing lens. and a storage means for storing the position of the focusing lens where the optical image is focused relative to the position of the zoom lens, and the zoom lens state detecting means , when a movement of the zoom lens from a first state where the focal length is long to a second state where the focal length is short is detected, the position corresponds to the position of the zoom lens detected by the zoom lens state detection means. After obtaining the position of the focusing lens from the storage means and moving the focusing lens to this position, the focusing position is determined based on the video signal obtained from the output signal of the photoelectric conversion section. is detected and focused, and when the zoom lens state detection means detects a movement from the second state to the first state, the zoom lens state detecting means detects a shift from the second state to the first state. What is claimed is: 1. A camera device characterized in that a focus position is detected and the focus is adjusted based on a video signal generated by the camera. 3. A zoom lens that magnifies the incident optical image, a focusing lens that focuses the incident optical image, a motor that drives the focusing lens, and a lens that passes through the zoom lens and the focusing lens. A photoelectric conversion unit that converts an incident optical image into an electrical signal, and a focus detection unit that detects a focused state of the incident optical image, and controls the motor based on the detection result of the focus detection unit. A camera device configured to automatically perform focusing by driving and moving the focusing lens, comprising: a zoom lens state detection means for detecting a state of the zoom lens; and a state of the focusing lens. and a storage means for storing the position of the focusing lens where the optical image is focused relative to the position of the zoom lens, and the zoom lens state detecting means When a movement of the zoom lens from a first state with a long focal length to a second state with a short focal length is detected, the focusing lens is moved to a predetermined position, and then the zoom lens is moved to a predetermined position. The position of the focusing lens corresponding to the position of the zoom lens detected by the lens state detection means is obtained from the storage means, and the focusing lens is moved to this position to focus, and the above-mentioned When a movement from the second state to the first state is detected by the zoom lens state detection means, the focusing position is determined based on the video signal obtained from the output signal of the photoelectric conversion section. A camera device characterized by detecting and focusing.