JP2003295041A - Camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera capable of performing a focusing operation meeting the photographer's intention more quickly. <P>SOLUTION: The selection of the end part of the moving direction of a focusing lens provided in a photographic lens 101 is performed by the operation of a closest range selection button 1168 and an infinity selection button 1169 or according to a setup menu, or is automatically set in relation to a photographic scene. For example, when any of an ordinary photographing mode, a person photographing mode and a close-up mode is selected by a scene setting button 1164, an end on the closest range side is automatically set as the end part of the moving direction. Since a subject on the closest range side is brought into focus in such a photographic scene, the focusing lens exists on the closest range side. Therefore, movement to the end is performed quickly, so that the focusing operation can be performed quickly. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera that performs AF operation by a contrast method.

[0002]

2. Description of the Related Art Conventionally, as one of AF methods for cameras, there is one called a contrast method. With this method,
An image of a subject is picked up by an image pickup device such as a CCD, a focus evaluation value is calculated using an image pickup signal in a focus area, and a focus position is determined based on the focus evaluation value. Further, as the AF operation modes, there are a single AF mode in which the focusing operation is performed by half-pressing the release button, and a continuous AF mode in which the focusing operation is repeated at predetermined intervals regardless of the half-pressing operation.

Generally, in the case of a contrast type camera, a focusing operation called "mountain climbing type" is adopted for the continuous AF mode. In the mountain climbing focusing operation, the focusing lens is moved by a predetermined amount,
The focus evaluation values before and after the movement are compared, and the same processing is performed by further moving a predetermined amount in the direction in which the evaluation value increases. Then, by repeatedly executing such processing, the focusing lens is moved to a position where the focus evaluation value has a peak.

In such a contrast type AF camera, the peak position is searched by scanning the focusing lens over the entire movable range when the single AF mode is half-pressed or during the first focusing operation in the continuous AF mode. Then, the focusing lens is moved to the peak position. At this time, the entire area scan is performed after moving from the lens stop position to the end point of the movable range.

[0005]

However, since the end points are predetermined, there is a disadvantage that if the end points are farther from the lens stop position, it takes a moving time.

An object of the present invention is to provide a camera capable of more quickly performing a focusing operation according to a photographer's intention.

[0007]

(1) A camera according to the invention of claim 1 is based on an image pickup device for picking up a subject image formed by a photographing optical system, and an image pickup signal of a predetermined image pickup region of the image pickup device. Evaluation value calculation means for calculating the focus evaluation value of the subject image, driving means for changing the lens position of the focusing lens provided in the photographing optical system, and the end portion on the near side and the end portion on the infinity side of the movable range of the focusing lens. A first moving operation for controlling the focusing lens to move in one direction to the edge selected by the edge selecting means by controlling the edge selecting means and the driving means, and after the first operation. Movement control means for respectively performing a second movement operation for moving the focusing lens in one direction from the selected end portion to the other end portion, and an evaluation value calculator during the second movement operation. Based on the focus evaluation value calculated by, the peak detection means for detecting the peak position of the focus evaluation value, and the focusing means for moving the focusing lens to the peak position detected by the peak detection means. To achieve. (2) A camera according to a second aspect of the present invention calculates a focus evaluation value of a subject image based on an image pickup element that picks up a subject image formed by a photographing optical system and an image pickup signal of a predetermined image pickup area of the image pickup element. Evaluation value calculation means, end selection means for selecting either the near end or the infinity end of the movable range of the focusing lens of the photographing optical system, and the end selected for the focusing lens by the end selection means. To the first movement means for moving in one direction, and after the movement operation by the first movement means, focusing in the movement direction determined from the focus evaluation value at the start of movement and the focus evaluation value calculated before that. The above-described object is achieved by providing a focusing unit that repeatedly performs the movement operation of moving the lens to move the focus lens to the peak position of the focus evaluation value. (3) The invention according to claim 3 is the camera according to claim 1 or 2, wherein the focusing means moves the focusing lens to a peak position closest to the end selected by the end selecting means. . (4) The invention according to claim 4 is the camera according to any one of claims 1 to 3, further comprising: shooting mode selection means for selecting one of a plurality of shooting modes according to shooting conditions, and edge selection means. Is to select either the close-up side end or the infinity side end according to the shooting mode selected by the shooting mode selection means. (5) According to the invention of claim 5, in the camera according to claim 4, when the shooting mode is any one of the normal shooting mode, the portrait shooting mode and the close-up shooting mode, the end selection means is in the focusing lens movable range. Select the near end. (6) According to the invention of claim 6, in the camera according to claim 4, when the shooting mode is a landscape shooting mode or a night view shooting mode, the end selection means selects an end on the infinite side of the movable range of the focusing lens. To do.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a functional block diagram of an AF (autofocus) digital camera according to an embodiment of the present invention. Reference numeral 101 denotes an electric zoom type photographing lens, which has a focusing lens (not shown) for performing focus adjustment and a variable power lens for changing the focal length. The focusing lens is driven by the driver 113, and the variable power lens is driven by the driver 118. Each of the drivers 113 and 118 includes a drive mechanism that drives the lens and a drive circuit thereof, and is controlled by the CPU 112.

The taking lens 101 forms a subject image on the image pickup surface of the image pickup element 103. The image pickup element 103 is a photoelectric conversion image pickup element that outputs an electric signal according to the light intensity of the subject image formed on the image pickup surface, and a CCD type or MOS type solid state image pickup element is used. The image sensor 103 is driven by a driver 115 that controls the timing of signal extraction. A diaphragm 102 is provided between the taking lens 101 and the image sensor 103. The diaphragm 102 is driven by a driver 114 including a diaphragm driving mechanism and a driving circuit therefor.

The image pickup signal from the image pickup device 103 is inputted to the analog signal processing circuit 104, and the analog signal processing circuit 104 performs processing such as correlated double sampling processing (CDS processing). Analog signal processing circuit 104
The image pickup signal processed in (1) is input to the digital signal processing circuit 106 after being converted from an analog signal to a digital signal by the A / D converter 135. The digital signal processing circuit 106 includes signal processing circuits such as a gain control circuit, a luminance signal generation circuit, and a color difference signal generation circuit,
Various image processing such as contour enhancement, gamma correction, and white balance adjustment is performed on the input image pickup signal.

The image pickup signal input to the digital signal processing circuit 106 is temporarily stored in the buffer memory 105, read from the buffer memory 105 for each processing described above, and the processed signal is stored in the buffer memory 105 again. To be done. The buffer memory 105 is a frame memory that can store data for a plurality of frames captured by the image sensor 103.

The image data that has undergone a series of processes in the digital signal processing circuit 106 is stored in the buffer memory 105.
Stored in. After that, the recording / reproducing signal processing circuit 110
It is recorded in the external storage medium 111 such as a memory card via the. When recording the image data in the external storage medium 111, data compression is generally performed in a predetermined compression format, for example, the JPEG method. Recording / reproducing signal processing circuit 110
Then, the data compression when recording the image data in the external recording medium 111 and the data decompression process when reading the compressed image data from the external storage medium 111 are performed. Record
The reproduction signal processing circuit 110 also includes an interface for performing data communication with the external storage medium 111.

Reference numeral 109 is a monitor for displaying a subject image, for example, a liquid crystal display device is used. In a shooting mode described later, an image pickup signal picked up by the image pickup device 103 at predetermined time intervals is subjected to signal processing by the analog signal processing circuit 104, the A / D converter 135, and the digital signal processing circuit 106, and then the buffer memory. 105
Is stored in the RAM and transferred to the VRAM 108, VR
An image based on the image data stored in the AM 108 is displayed on the monitor 109. Therefore, the photographer uses the monitor 109
The subject can be visually recognized from the image displayed on. On the other hand, in the reproduction mode, the external storage medium 111
The image read from is transferred to the VRAM 108 and reproduced and displayed on the monitor 109.

The CPU 112 is a digital signal processing circuit 10.
6 and drivers 113 to 115, 118, etc., and performs sequence control of camera operation. CPU 112
In the AE calculation unit 1121, the automatic exposure calculation is performed based on the image signal from the image sensor 103, and the AWB calculation unit 112
In 2, the white balance adjustment coefficient is calculated. The band pass filter (BPF) 1124 extracts a high frequency component in a predetermined band based on the image pickup signal in the focus detection area provided in the image pickup area. When a plurality of focus detection areas are set, the signals in each area are sequentially read, and the extraction processing for each area is performed by the bandpass filter (BPF) 1124. In the following, a case where there is one focus detection area will be described as an example.

The output of the BPF 1124 is the evaluation value calculator 1
Input to 125. The evaluation value calculation unit 1125 integrates the absolute values of the high frequency components to calculate the focus evaluation value for the subject image in the focus detection area. The AF calculation unit 1126 performs AF calculation by the contrast method based on the calculated focus evaluation value. The CPU 112 controls the driver 118 based on the calculation result of the AF calculation unit 1126, adjusts the position of the focusing lens provided in the taking lens 101, and performs the focusing operation.

The operation unit 116 connected to the CPU 112 has a power switch 1161 for turning the power of the camera on and off, a full-push switch 1162 for turning on and off in conjunction with a release button (not shown), and a half-push switch 11.
63, a scene setting button 1164 for selecting setting conditions according to the shooting scene, a monitor button 1165 for turning on / off the monitor 109, a menu button 1166 for displaying a menu such as a setup menu on the monitor 109, and mode selection Select dial 116
7, a near-field selection button 1168 and an infinite selection button 1169 for manually selecting an end portion in the moving direction described later are provided.

When these switches or buttons are operated, a signal corresponding to the operation is input to the CPU 112. The select dial 1167 rotates the dial to change the mode of the camera to the shooting mode, the playback mode,
It is possible to switch to either the setup mode or the communication mode. The details of the operation mode of the camera will be described later.

The AF auxiliary light 122 illuminates a subject when the luminance is low. The CPU 112 has a storage unit 1123 for storing various data and a timer 1127. Timer 1
127 is generally called a half-press timer,
Counting is started when the half-press operation of the release button is released, or after the first focus after the power is turned on, as described later. Further, the camera of this embodiment has an auto power-off function. For example, when the operation of the operation unit 116 is completed, the timer 1127 starts counting, and when a predetermined time elapses, the camera automatically powers off (sleeps). Called the state). If the release button is pressed halfway or the monitor button 1165 is operated in the sleep state, the sleep state is canceled and the power-on state is set. That is, the camera is restarted.

A communication unit 123 is connected to the CPU 112 and can transmit and / or receive image data to / from an external device 124 such as a PC (personal computer). When the above-mentioned select dial 1167 is set to the communication mode, the communication unit 123 is activated to establish communication with the external device 124. As the communication form,
In addition to the wireless type as shown in FIG. 1, communication with the external device 124 via a communication cable may be used. When using a communication cable, the communication unit 123
When the external device 124 is connected to the external device 124, the communication unit 123 is activated to enter the communication mode, and the communication with the external device 124 is established. On the contrary, when the connection between the communication cable and the communication unit 123 is released, the operation mode before the connection is restored.

In the camera of this embodiment, AF calculation is performed by the contrast method. In the contrast method, focusing is performed by utilizing the fact that there is a correlation between the degree of blurring of an image and the contrast, and the contrast of the image becomes maximum when the image is in focus. The size of the contrast can be evaluated by the size of the high frequency component of the image pickup signal. That is, the BPF 1124 extracts the high frequency component of the image pickup signal, and the evaluation value calculation unit 1125 integrates the absolute value of the high frequency component to obtain the focus evaluation value. The focus evaluation value becomes the maximum value when the in-focus state is reached and the contrast becomes maximum.

As described above, the AF calculation unit 1126 performs AF calculation based on the focus evaluation value. CPU 112 is A
The driver 113 is based on the calculation result of the F calculation unit 1126.
Is controlled to drive the focusing lens of the taking lens 101 to the in-focus position. FIG. 2 is a diagram showing an example of the focus evaluation value, and the focus evaluation value L0 has a peak at the focus position P. In FIG. 2, the horizontal axis represents the lens position of the focusing lens. When searching for the peak of the focus evaluation value, a scan operation and a hill climbing operation described later are performed. When the peak position P of the focus evaluation value is obtained by these operations, the position of the focusing lens of the taking lens 101 is driven to the peak position P.

<Explanation of Modes> In the camera of the present embodiment, in addition to the shooting mode, the reproduction mode, the setup mode and the communication mode selected by the operation of the select dial 1167, the AF mode is a single mode. It has an AF mode (S-AF mode) and a continuous AF mode (C-AF mode).
In the S-AF mode, the AF operation is performed only when the half-push switch 1163 is half-pushed, and once in-focus, the in-focus state is maintained until the half-push is released.

On the other hand, in the C-AF mode, the focusing operation is repeated at predetermined intervals even if the half-press switch 1163 is not operated. The AF mode is set by operating the menu button 1166 in the shooting mode to call the setup menu in the shooting mode on the monitor 109. The state in which this setup menu is displayed is called the setup mode and is treated as one of the operation modes.

In the present embodiment, the case where the C-AF mode is set and the shooting mode is selected by the select dial 1167 is called the C-AF shooting mode. On the other hand, when the S-AF mode is set and the shooting mode is selected, it is called the S-AF shooting mode. When the reproduction mode is selected by the select dial 1167, the reproduction mode is called regardless of the AF mode. These C-AF shooting mode, S-AF shooting mode, playback mode, setup mode, and communication mode will be referred to as operation modes.

A scene condition that can be set with the scene setting button 1164 is also called a mode, and a normal shooting mode that can widely cover normal shooting conditions, a distant view shooting mode suitable for landscape shooting, and a person stand out against the background. There are several modes such as portrait mode that allows you to shoot, close-up mode that allows you to shoot a subject from a very close distance, and night-view mode that allows you to capture beautiful nightscapes. When the scene setting button 1164 described above is operated in the shooting mode, the scene setting menu is displayed on the monitor 109. Note that these modes (scene conditions) will be considered separately from the above-mentioned operation modes.

<< Description of Operation >> Next, a specific operation example of the camera will be described with reference to FIGS. FIG. 3 is a flowchart showing the processing of the operation mode. In the present embodiment, at least five modes, that is, a C-AF shooting mode, an S-AF shooting mode, a reproduction mode, a setup mode, and a communication mode, are provided as operation modes. FIG. 4 is a flowchart for performing a process according to the setting change of the camera. When the setting is changed, the condition is stored, and the operation of FIG. 3 is performed based on the stored condition. The process shown in FIG. 4 is activated at predetermined time intervals.

First, description will be made with reference to FIG. Step S20
At 0, it is determined whether the closest selection button 1168 or the infinite selection button 1169 is operated. Step S2
If it is determined that the operation has been performed at 00, the process proceeds to step S205, and if it is determined that the operation is not performed at step S201.
Go to. When the process proceeds from step S200 to step S201, it is determined whether or not the auto power off is canceled in step S201, that is, when the auto power off operates and the power is off.
3 and monitor button 1165 are operated. If it is determined in step S201 that it has been released, the process proceeds to step S204, and if it is determined that it has not been released, the process proceeds to step S202.

In step S202, the storage unit 11 shown in FIG.
The camera setting stored in 23 is compared with the current setting to determine whether the operation mode setting or the end setting has been changed. Here, the setting change of the operation mode is the mode switching by the select dial 1167 of FIG. 1 or the switching between the C-AF mode and the S-AF mode by the menu operation. The end part setting is a setting of the end part in the moving direction when moving the focus lens, which will be described later.
There are a near end and an infinite end. Edge setting is done by menu operation. That is, in the shooting mode, the setup menu is displayed on the monitor 109 to set the end portion. Edge settings have been changed, select dial 116
When the mode is switched by 7, it is determined that the setting has been changed.

If it is determined in step S202 that the setting has been changed, the process proceeds to step S203, and if it is determined that the setting has not been changed, the process of FIG. 4 is terminated. Step S20
In 3, the mode setting stored in the storage unit 1123 is replaced with the current mode setting. Then, step S2
When the process of the operation mode of FIG. 3 is restarted at 04,
A series of processing ends.

On the other hand, steps S200 to S2
If the processing proceeds to 05, AF is performed in step S205.
It is determined whether the mode is the S-AF mode or the C-AF mode. If the S-AF mode is determined in step S205, the process proceeds to step S201, and if the C-AF mode is determined, the process proceeds to step S206. In step S206, the end of the moving direction corresponding to the operation of the closest selection button 1168 or the infinite selection button 1169 is stored in the storage unit 1123.

This end in the moving direction is stored separately from the end setting by the above-mentioned setup menu. That is, when the closest selection button 1168 is operated, the closest side end is stored as the moving direction end, and the infinite selection button 11
When 69 is operated, the end on the infinite side is stored as the end in the moving direction. The moving direction edge setting stored in the storage unit 1123 is performed by the closest selection button 1168 and the infinite selection button 116.
When 9 is operated, it is rewritten each time. Next, in step S207, the focus lens moving process shown in FIG. 5 is started, and a series of processes is ended.

The focus lens moving process of FIG. 5 will be described. In step S300, the movement of the focus lens to the end portion in the movement direction is started. The moving direction end portion at this time is the moving direction end portion stored in step S206 of FIG. 4, and is the end portion selected by the operation of the closest selection button 1168 or the infinite selection button 1169. In step S301, it is determined whether or not the end portion in the moving direction has been reached, and when it is determined that the end portion has been reached, the process proceeds to step S302. Next, in step S302, driving of the focus lens is stopped. In step S303, the BPF 1124 processes the image pickup signal in the focus detection area, and the evaluation value calculation unit 1125 performs in-area integration (focus evaluation value calculation) on the signal. Then, step S1 of FIG. 7 described later.
Proceed to 27.

Next, the flowchart of FIG. 3 will be described.
The flowchart of FIG. 3 shows the power switch 116 of the camera.
It starts when 1 is turned on. Also, when there is a restart instruction by the processing of step S204 of FIG. 4, the processing is started from step S100. In step S100, it is determined whether the operation mode is the communication mode. If the communication mode is determined in step S100, the process proceeds to step S102, and communication mode processing is executed. In the communication mode, the communication unit 123 of FIG. 1 is activated and, for example, a process of transferring the image data stored in the external storage medium 111 to the external device 124 is executed. The details of the communication mode processing are omitted.

On the other hand, if it is determined in step S100 that the communication mode is not set, the process proceeds to step S101, and the operation mode is (a) S-AF shooting mode or C-AF shooting mode,
It is determined whether the mode is (b) playback mode or (c) setup mode. (A) S in step S100
If it is determined to be the -AF shooting mode or the C-AF shooting mode, that is, if the select dial 1167 is set to the shooting mode, the process proceeds to step S103.
If (b) the reproduction mode is determined, the step S
Proceeding to 104, a series of processing relating to the reproduction mode is executed. Furthermore, if it is (c) the setup mode, the process proceeds to step S105, and a process relating to the setup is executed.

(B) The reproduction mode is a mode in which an image based on the image data stored in the external storage medium 111 is reproduced on the monitor 109, and is set by switching the select dial 1167 to the reproduction mode. Also, (c)
The setup mode is a mode in which various settings of the camera are performed, and a setup menu is displayed on the monitor 109 to set each item. As described above, when the select dial 1167 is set to the shooting mode or the reproduction mode and the menu button 1166 is operated, the setup menu corresponding to each mode is displayed on the monitor 109.

For example, setup menu items when the shooting mode is set include folder setting of the mounted external storage medium 111, setting of the monitor 109 and power off setting. Note that step S104
The description of the reproduction process of step S105 and the details of step S105 will be omitted. In the following, (a) S-AF shooting mode or C-AF
A case in which it is determined that the shooting mode is selected and the process proceeds from step S101 to step S103 will be described.

In step S103, the image pickup signal is read from the CCD 103, and the A / D converter 135 performs A / D conversion of the image pickup signal. Further, it is fetched from the digital signal processing circuit 106 into the buffer memory 105, and AE calculation is performed by the AE calculation unit 1121. In step S106, it is determined whether the subject brightness calculated by the AE calculator 1121 is equal to or lower than a predetermined level. That is, it is determined whether the brightness is low. If it is determined in step S106 that the subject brightness is less than or equal to the predetermined level, the process proceeds to step S107, and if it is determined that the subject brightness is higher than the predetermined level, the process proceeds to step S112.

When the process proceeds from step S106 to step S107, it is determined in step S107 whether or not the gain setting is the upper limit value. The gain here is a product of the A / D output in the digital signal processing circuit 106. If it is determined in step S107 that the gain setting is not the upper limit value, the process proceeds to step S108 and the gain setting is increased by one step. For example, ISO sensitivity is 100
If set to, increase the sensitivity by one step to increase the sensitivity to 200.
Set to.

Then, from step S108 to step 1
Returning to 06, it is determined whether the subject brightness after changing the gain setting is equal to or lower than a predetermined level. On the other hand, if it is determined in step S107 that the gain setting is the upper limit value, that is, if it is determined to be the final stage of ISO sensitivity (for example, 800), the AF auxiliary light 1 is determined in step S109.
22 is turned on. It should be noted that the lighting of the auxiliary light is continued until the focusing operation is completed.

In the following step S110, the CCD 103
It is determined whether or not the frame rate setting of the image pickup signal output from is the lower limit value. If it is determined to be the lower limit value in step S110, the process proceeds to step S112, and if it is determined that it is not the lower limit value, the process proceeds to step S111. When the process proceeds to step S111, the frame rate is decreased by one step in step S111, and then the process returns to step S106. That is, since the subject brightness is low, step S11
In 1, the frame rate is lowered and the storage time of the CCD 103 is lengthened. Similar to the gain setting, a plurality of settings are prepared in advance for the frame rate setting. In step S112, the absolute position of the focusing lens is detected by a photo coupler or the like to determine the reference position of the lens.

In step S113, it is determined whether the AF mode is set to the C-AF mode or the S-AF mode. If the C-AF mode is determined in step S113, the process proceeds to step S116 in FIG. 6, and if the S-AF mode is determined, the process proceeds to step 114. In step S114, it is determined whether or not the halfway press switch 1162 is on. If it is determined to be off (no), the process returns to step S113, and if it is determined to be on (yes), the process proceeds to step S116 of FIG.

In step S116 of FIG. 6, it is determined whether the set end (the end in the moving direction) set by the setup menu and stored in the storage unit 1123 is the close end or the infinite end. If it is determined in step S116 that it is the close-up side end, the process proceeds to step S117 to move the focusing lens to the close-up side end. Step S118
Then, it is determined whether or not the focus lens has reached the close end, and if it is determined that the focus lens has arrived, the process proceeds to step S121. On the other hand, if it is determined that it has not arrived, step S1
Return to 17 and continue moving to the closest end.

If it is determined in step S116 that the end portion is on the infinity side, the flow advances to step S119 to move the focusing lens to the end portion on the infinity side. In step S120, it is determined whether or not the focus lens has reached the end on the infinity side. If it is determined that the focus lens has reached the end, the process proceeds to step S121. On the other hand, if it is determined that it has not arrived, step S1
Return to 19 and continue moving to the end on the infinite side.

During the movement in steps S117 and S119, either focus evaluation value calculation may be performed or not. Even if the focus evaluation value calculation is performed, the focus evaluation value is not used for peak detection. Therefore, the moving speed of the lens may be higher than the moving speed at the time of focus evaluation value sampling described later.

In step S121, the movement of the focusing lens to the other end is started. That is, step S
When the process proceeds from step 118 to step S121, the movement to the end on the infinite side is started, and from step S120 to step S121.
When the process proceeds to 121, the movement to the near end is started. In step S122, the image pickup signal in the focus detection area is processed by the BPF 1124, and the evaluation value calculation unit 1125 performs in-area integration on the signal. The calculation result is stored in the storage unit 1123 as a pair with the lens position at the time of sampling.

In step S123, it is determined whether or not the focus lens has reached the other end. If it is determined in step S123 that the other end is reached, the process proceeds to step S124 to stop the lens driving. On the other hand, if it is determined in step S123 that the other end has not been reached, the process returns to step S122, and the focus evaluation value is calculated and stored again. Therefore,
Through the processing of steps S121 to S123, the focus evaluation value is stored in the storage unit 1123 for each sample position from one end to the other end that is the movable range of the focusing lens.

In step S125, the peak position is detected based on the obtained focus evaluation value. The detected peak position is not limited to one, and there may be a plurality of peak positions within the movable range. In step S126, the focus lens is moved to the peak value closest to the end in the moving direction stored in the storage unit 1123 among the obtained peak positions. When the movement of the focus lens to the peak position is completed, the process proceeds to step S127 in FIG.

In step S127 of FIG. 7, the camera A
It is determined whether the F mode setting is C-AF mode or S-AF mode. If the C-AF mode is determined in step S127, the process proceeds to step S134 in FIG. 8, and if the S-AF mode is determined, the process proceeds to step S128. First, S
The case of the AF mode, that is, the case of proceeding from step S127 to step S128 will be described.

In step S128, the focus lens is AF locked at the peak position. A in step S128
If F-locked, a flag representing the release permission state is set in the following step S129. Step S130
Then, it is determined whether the half-push switch 1163 is on. The half-pushed state is being continued and Y is returned in step S130.
If it is determined to be ES, the process proceeds to step S131, and if the half-pushed state is released and NO is determined, the process proceeds to step S133.

When the process proceeds from step S130 to step S131, it is determined in step S131 whether the full-press switch 1162 is on. Step S13
If YES is determined in 1, the process proceeds to step S132, the photographing processing operation is executed, and then the process returns to step S127. On the other hand, when the process proceeds from step S130 to step S133, it is determined in step S133 whether the AF mode setting is the C-AF mode or the S-AF mode.
If the C-AF mode is determined in step S133, the process returns to step S127, and if the S-AF mode is determined, the process returns to step S113 in FIG.

Next, the case where the C-AF mode is set and the process proceeds from step S127 to step S134 in FIG. 8 will be described. In step S134, the timer 1127 of FIG. 1 starts counting. Step S135
Now stop driving the focusing lens. In step S136, it is determined whether the half-push switch 1163 is turned on. When it is determined in step S136 that the push switch 1163 is turned on, step S1
If it is determined that the button is not pressed halfway, the process proceeds to step S141.

When the process proceeds from step S136 to step S141 while the half-push switch 1163 remains off, it is determined in step S141 whether restart is necessary. For example, it is determined whether or not the restart is necessary depending on whether or not the restart time interval Δt has elapsed. Step S1
When it is determined that Δt has not elapsed in 41, the process returns to step S135, and when it is determined that Δt has elapsed, the process proceeds to step S142. In step S142, a well-known hill climbing focus operation is executed. The outline of the mountain climbing focusing operation will be described later.

In a succeeding step S143, it is determined whether or not the focus position is found and the focus is achieved. Step S
Since the in-focus position is not always found by the hill climbing operation of 142, if it is determined that the in-focus cannot be achieved, the process proceeds to step S144 to move the focusing lens to the end set as the end in the moving direction, and then It returns to step S134. On the other hand, if it is determined to be in focus in step S143, the process returns to step S135. It should be noted that the focus evaluation value data obtained during the hill climbing focus operation is obtained in
The data is stored in the storage unit 1123 separately from the data at the time of full-area sampling stored in 122. The data obtained and stored by the hill climbing focusing operation is replaced with new data every time the hill climbing focusing operation is performed.

On the other hand, steps S136 to S1
If the process proceeds to 37, it is determined in step S137 whether the focus evaluation value is within the release permission range. This is a step of checking the degree of change in the focus evaluation value from the time of focusing. If it is determined that the change is larger than the predetermined value, that is, if the focus evaluation value exceeds the release permission range, the process proceeds from step S137 to step S138, and the same hill climbing operation as in step S142 is performed. On the other hand, if it is determined in step S137 that it is within the release permission range, the process proceeds to step S128 in FIG.

In step S139, step S143
Similarly to the above, it is determined whether or not the focus can be achieved by the hill climbing operation. If it is determined in step S139 that the image is in focus, the process proceeds to step S128 in FIG. 7, and if it is determined that the image cannot be in focus, the process proceeds to step S140. Step S140 is the same process as step S144, and moves the focusing lens to the set end. Then, it progresses to step S128 of FIG.

(Explanation of Mountain Climb Focusing Operation and Scan Focusing Operation) Here, step S138 and step S142.
The difference between the focusing operation by the hill climbing movement performed in step S4 and the focusing operation by the scan movement performed by the processing from step S121 to step S123 in FIG. 6 will be described.

First, the hill-climbing focusing operation will be described.
FIG. 9 is a diagram for explaining the concept of the hill-climbing focusing operation.
Indicates a focus evaluation value curve obtained for the subject. x3 is the position of the focusing lens at the start of hill climbing, and the focus evaluation value at that time is y3. The lens position x3 and the focus evaluation value y3 are stored in the storage unit 1123. When the focusing operation is started, for example, the lens is moved toward the closest side by a predetermined amount, and the focus evaluation value y4 at the position x4 after the movement is calculated. The focus evaluation values may or may not be weighted by the lens position.

Next, the calculated focus evaluation value y4 and the focus evaluation value y at the start of movement stored in the storage unit 1123.
Compare with 3. In the case of FIG. 9, the obtained focus evaluation value y4
Is larger than the focus evaluation value y3, the focus evaluation value tends to increase in the moving direction, and the position P at which the focus evaluation value peaks is determined to be closer to the lens position x4. In this way, when it is determined to be on the close side, the focusing lens is moved further to the close side by a predetermined amount, and the focus evaluation value y5 at the lens position x5 after the movement is calculated. Then, the focus evaluation value y4 and the focus evaluation value y5 are compared.

In the second movement, it is determined that the focus evaluation value y5 at the lens position x5 is smaller than the focus evaluation value y4 at the lens position x4. That is, it is determined that the peak position P is on the infinite side of the lens position x5. Therefore, interpolation processing based on the data (x3, y3), (x4, y4), (x5, y5) is performed to calculate the peak position P of the focus evaluation value, and the focusing lens is moved to the peak position P. As described above, in the hill climbing focusing operation, the focusing lens is moved to the peak position P of the focus evaluation value by repeatedly performing a series of processes of “lens movement” → “calculation of focus evaluation value” → “comparison of focus evaluation value”. Move to. When the lens is moved, the moving direction is determined by comparing the focus evaluation value at the current position with the focus evaluation value obtained last time.

On the other hand, in the focusing operation by the scan movement,
The focusing lens is moved in one direction from one end to the other end of the scan area. Then, a plurality of focus evaluation values are calculated during the movement, and the focus evaluation values are stored in the storage unit 1123 as a pair with the position data. The moving form of the focusing lens may be continuous movement or stepwise movement.

This scan focusing operation is largely different from the hill-climbing focusing operation in that the hill-climbing operation is a feedback operation in which the moving direction is determined each time by comparison with the previous focus evaluation value. Then, the scanning movement is performed in one predetermined direction. After obtaining a plurality of focus evaluation values in the scan area, the peak position P is calculated by comparing the magnitudes of the focus evaluation values.
Then, the focusing lens is moved to the calculated peak position P.

<< Relationship with Focusing Operation with Shooting Scene >> In the above-described embodiment, the selection of the end portion in the moving direction is set by the setup menu, the closest selection button 1168, or the infinite selection button 1169. It may be set by setting. For example, the scene setting button 116
When any one of the normal shooting mode, the portrait shooting mode, and the close-up shooting mode is selected by 4, the close-up side end is automatically set as the above-mentioned moving direction end.

That is, in such a shooting scene, since the subject on the near side is focused, the focusing lens is at the near side position. Therefore, if the end portion in the moving direction is the closest end portion, it is possible to quickly move to the end portion. Further, in the C-AF mode, since the hill climbing operation is performed after the focus lens is moved to the peak position on the near side where the focus is desired, the focusing operation suited to the photographer's intention can be performed quickly. be able to.

On the other hand, when the landscape shooting mode or the night view shooting mode is selected by the scene setting button 1164, the end on the infinite side is automatically set as the end in the moving direction. In this case as well, the same effect as when automatically set to the close side is obtained.

Although an electronic camera has been described as an example in the above-described embodiments, the present invention is not limited to an electronic camera and can be similarly applied to a camera such as a silver salt camera which performs AF by a contrast method.

In the correspondence between the embodiment described above and the elements of the claims, the close-up selection button 1168, the infinite selection button 1169 and the operation unit 116 are end selection means, the driver 113 is driving means, and the CPU 112 is The AF control unit 1126 constitutes a peak detecting unit, the CPU 112 and the driver 113 constitute a focusing unit, the first moving unit and the second moving unit, and the scene setting button 1164 constitutes a photographing mode selecting unit. .

[0067]

As described above, according to the present invention,
The moving direction of the focusing lens when calculating the focus evaluation value for detecting the peak position can be selected by the end selecting means. Therefore, the focusing operation can be performed according to the photographer's intention.

[Brief description of drawings]

FIG. 1 is a functional block diagram of an AF digital camera according to an embodiment of the present invention.

FIG. 2 is a diagram showing a focus evaluation value curve L0.

FIG. 3 is a flowchart showing a process of an operation mode.

FIG. 4 is a flowchart for performing processing according to a setting change of a camera.

5 is a flowchart showing a procedure of a moving process in step S207 of FIG.

FIG. 6 is a flowchart showing a process following the flowchart of FIG.

FIG. 7 is a flowchart showing a process following the flowchart of FIG.

FIG. 8 is a flowchart showing the processing executed when it is determined in step S127 in FIG. 7 that the mode is the C-AF mode.

FIG. 9 is a diagram illustrating a mountain climbing focusing operation.

[Explanation of symbols]

101 shooting lens 102 aperture 103 image sensor 104 Analog signal processing circuit 106 digital signal processing circuit 109 monitor 111 External storage medium 112 CPU 113-115, 118 driver 116 Operation part 123 Communication unit 124 External device 135 A / D converter 1125 Evaluation value calculation unit 1126 AF calculation unit 1161 power switch 1162 full-press switch 1163 Half-press switch 1164 Scene setting button 1168 Close selection button 1169 Infinite selection button 1167 Select dial

Continued front page    (72) Inventor Toshiaki Maeda             Marunouchi 3 2-3 No. 3 shares, Chiyoda-ku, Tokyo             Ceremony Company Nikon (72) Inventor Hideomi Hibino             Marunouchi 3 2-3 No. 3 shares, Chiyoda-ku, Tokyo             Ceremony Company Nikon (72) Inventor Masaru Ota             Tokyo Stock Exchange 1-325, Futaba 1-32             Company Nikon technical workshop F-term (reference) 2H011 BA31 CA24 CA29 DA00 DA06                 2H051 BA47 CE14 DA22 EA09 EB16                       FA38 FA47                 5C022 AB28 AC32 AC42 AC54 AC74                 5C024 CY17 EX42 GY00 HX20

Claims (6)

[Claims] 1. An image pickup device for picking up a subject image formed by a photographing optical system, and an evaluation value calculation means for calculating a focus evaluation value of the subject image based on an image pickup signal of a predetermined image pickup region of the image pickup device. Driving means for changing a lens position of a focusing lens provided in the photographing optical system, and end selecting means for selecting one of a close end and an infinite end of a movable range of the focusing lens, A first moving operation for controlling the driving means to move the focusing lens in one direction to the end selected by the end selecting means; and, after the first operation, moving the focusing lens to the selected end. Movement control means for respectively performing a second movement operation for moving in one direction from one part to the other end portion, and the evaluation value calculation means during the second movement operation. Based on the focus evaluation value calculated by the following, a peak detection unit for detecting a peak position of the focus evaluation value, and a focusing unit for moving the focusing lens to the peak position detected by the peak detection unit are provided. A camera characterized by. 2. An image pickup device for picking up a subject image formed by a photographing optical system, and an evaluation value calculation means for calculating a focus evaluation value of the subject image based on an image pickup signal of a predetermined image pickup region of the image pickup device. An end selection unit that selects one of a near-side end and an infinite-side end of a movable range of the focusing lens of the photographing optical system; and the focusing lens up to the end selected by the end selection unit. In a moving direction determined by the focus evaluation value at the start of movement and the focus evaluation value calculated before that, after the moving operation by the first moving means, A camera comprising: a focusing unit configured to repeatedly perform a moving operation of moving the focusing lens to move the focus lens to a peak position of a focus evaluation value. 3. The camera according to claim 1, wherein the focusing unit moves the focusing lens to the peak position closest to the end selected by the end selecting unit. A camera to do. 4. The camera according to claim 1, further comprising shooting mode selection means for selecting one of a plurality of shooting modes according to shooting conditions, wherein the end selection means is configured to perform the shooting. A camera characterized in that either the close-up side end portion or the infinity side end portion is selected in accordance with the photographing mode selected by the mode selection means. 5. The camera according to claim 4, wherein when the shooting mode is any one of a normal shooting mode, a portrait shooting mode, and a close-up shooting mode, the end selection unit is on the near side of the focusing lens movable range. A camera characterized by selecting an end portion. 6. The camera according to claim 4, wherein, when the shooting mode is a landscape shooting mode or a night view shooting mode, the end selection unit selects an end on the infinite side of the movable range of the focusing lens. A camera characterized by.