JP5015677B2 - Imaging apparatus and control method thereof - Google Patents

Description

  The present invention relates to an imaging device and a control method thereof.

  2. Description of the Related Art Digital cameras that photoelectrically convert subject light using an image sensor such as a CCD or CMOS and convert an image signal obtained thereby to digital image data are widely used. When a dark subject is photographed with a digital camera, for example, an appropriate exposure amount (received light amount) can be obtained by slowing down the shutter speed. However, since a low shutter speed is used, camera shake tends to occur. When a low shutter speed is used, subject blurring occurs when the subject is moving, resulting in the same result as camera shake.

  Some recent digital cameras have a camera shake correction function for preventing camera shake. There are various camera shake correction functions depending on the correction method. In general, the movement of a digital camera, that is, camera shake is detected, and a part of the photographing lens or the image sensor is placed on a surface perpendicular to the photographing optical axis. By moving the digital camera, the subject image with respect to the image sensor does not move even if the digital camera moves during shooting.

On the other hand, when photographing a dark subject, a digital camera is also known in which a strobe light is irradiated or the sensitivity of the digital camera is increased so that it can be photographed at a shutter speed higher than a certain level. For example, there is known a digital camera that calculates a shutter speed at which shooting can be performed without causing camera shake from the detected amount of camera shake, and increases the sensitivity so that the set shutter speed is higher than the calculated shutter speed. (For example, refer to Patent Document 1).
JP 2001-194701 A

  By the way, the camera shake correction function as described above is effective in generating or reducing camera shake, but is not effective in preventing subject shake. Further, as in Patent Document 1, in the case of increasing the sensitivity when reducing blur, it is effective in reducing camera shake, but is also ineffective in subject blur. In addition, the gain for amplifying the image signal output from the image sensor is increased to increase the sensitivity. However, increasing the gain increases the effect of noise in the image signal and degrades the image quality of the captured image. There was a problem that was inevitable.

In order to solve the above-described problem, the present invention provides a method for controlling an image taking apparatus according to claim 1, wherein when the camera shake correction function is off, a constant low-sensitivity standard image taking sensitivity and a camera shake limit shutter speed are obtained. For an appropriate exposure value that is greater than or equal to the first exposure value determined by the combination with the open aperture, the shutter speed is changed in a speed range that is greater than the camera shake limit, and the aperture is changed to maintain the standard imaging sensitivity. For an appropriate exposure value smaller than the first exposure value, a first program for setting the photographing sensitivity higher than the standard photographing sensitivity to the limit necessary to maintain a shutter speed equal to or higher than the camera shake limit under the open aperture. Determine the shutter speed, aperture, and shooting sensitivity based on the diagram,
When the camera shake correction function is on, the temperature of the image sensor is detected, and when the detected temperature is higher than a predetermined first reference temperature, the shutter speed, the aperture, and the photographing are taken based on the first program diagram. Sensitivity is determined, and when the detected temperature is equal to or lower than a predetermined first reference temperature, a proper exposure equal to or higher than a second exposure value determined by a combination of the standard photographing sensitivity, the shutter speed at the lower limit of the high speed range, and the open aperture. For the value, the aperture is changed to maintain the standard shooting sensitivity and the shutter speed within a high speed range, and for an appropriate exposure value smaller than the second exposure value, the aperture is fast under the open aperture. The shutter speed, the aperture, and the shooting sensitivity are determined based on the second program diagram that sets the shooting sensitivity higher than the standard shooting sensitivity to the limit necessary to maintain the shutter speed within a certain speed range. That.

3. The method according to claim 2, wherein when the camera shake correction function is off, the first exposure value determined by a combination of a constant low sensitivity standard shooting sensitivity, a shutter speed at a camera shake limit, and an open aperture. For the above appropriate exposure value, the shutter speed is changed in a speed range equal to or higher than the camera shake limit, the aperture is changed to maintain the standard photographing sensitivity, and the appropriate exposure value is smaller than the first exposure value. Is based on the first program diagram that sets the shooting sensitivity higher than the standard shooting sensitivity to the limit necessary to maintain the shutter speed above the camera shake limit under the open aperture. Decide
When the camera shake correction function is on, the aperture is changed for an appropriate exposure value greater than or equal to the second exposure value determined by the combination of the standard shooting sensitivity, the lower shutter speed of the high speed range, and the open aperture. Standard exposure sensitivity and shutter speed within a high speed range are maintained, and for an appropriate exposure value smaller than the second exposure value, it is higher than the standard exposure sensitivity and lower than the maximum sensitivity under the open aperture. Taking the set intermediate sensitivity as the upper limit, the shooting sensitivity is increased to the limit necessary to maintain the shutter speed within the high speed range, and the shutter speed above the camera shake limit is maintained under the intermediate sensitivity. For a proper exposure value smaller than the third exposure value determined by the shutter speed at the camera shake limit and the open aperture, the limit necessary to maintain a shutter speed above the camera shake limit under the open aperture Taken with It is obtained so as to determine the photographic sensitivity and aperture shutter speed based on the third program chart to increase the degrees.

According to a third aspect of the present invention, there is provided a method for controlling an imaging apparatus, wherein when the camera shake correction function is on, the temperature of the image sensor is detected, and the higher the detected temperature of the image sensor, the higher the imaging sensitivity of the third program diagram. The upper limit of is reduced.

5. The method of controlling a photographing apparatus according to claim 4, wherein when the camera shake correction function is off, the first exposure value determined by a combination of a constant low sensitivity standard photographing sensitivity, a shutter speed at a camera shake limit, and an open aperture. For the above appropriate exposure value, the shutter speed is changed in a speed range equal to or higher than the camera shake limit, the aperture is changed to maintain the standard photographing sensitivity, and the appropriate exposure value is smaller than the first exposure value. Is based on the first program diagram that sets the shooting sensitivity higher than the standard shooting sensitivity to the limit necessary to maintain the shutter speed above the camera shake limit under the open aperture. Decide
When the camera shake correction function is on, the temperature of the image sensor is detected. When the detected temperature is equal to or lower than a predetermined first reference temperature, the standard photographing sensitivity, the shutter speed at the lower limit of the high speed range, the open aperture, For an appropriate exposure value greater than or equal to the second exposure value determined by the combination of the above, the aperture is changed to maintain the standard imaging sensitivity and the shutter speed within a high speed range, and an appropriate exposure smaller than the second exposure value. For the value, the shutter speed based on the second program diagram that makes the photographing sensitivity higher than the standard photographing sensitivity to the limit necessary to maintain the shutter speed within the high speed range under the wide aperture. Determine the aperture and sensitivity,
When the detected temperature is higher than the first reference temperature, for a proper exposure value greater than or equal to the second exposure value, the aperture is changed to maintain the standard photographing sensitivity and the shutter speed within a high speed range, For an appropriate exposure value smaller than the second exposure value, a shutter speed within a high speed range with an intermediate sensitivity set higher than the standard photographing sensitivity and lower than the maximum sensitivity as the upper limit under the wide aperture. The third exposure is determined by the intermediate sensitivity, the shutter speed at the camera shake limit, and the open aperture. For a proper exposure value smaller than this value, the shutter speed is based on the third program diagram that increases the shooting sensitivity under the maximum aperture necessary to maintain the shutter speed above the camera shake limit. And aperture It is obtained so as to determine the sensitivity.

In the method for controlling an imaging apparatus according to claim 5 , when the shutter speed, the aperture, and the imaging sensitivity are determined based on the first program diagram, the upper limit of the imaging sensitivity is set to be higher than the maximum imaging sensitivity that can be set in the apparatus. It is designed to be low.

In the control method of the photographing apparatus according to claim 6, when the shutter speed, the aperture, and the photographing sensitivity are determined based on each program diagram, the shutter speed equal to or higher than the shutter speed of the camera shake limit is determined using the upper photographing sensitivity. When the shutter speed cannot be obtained, the shutter speed is set to be slower than the shutter speed at the camera shake limit.

According to a seventh aspect of the present invention, there is provided a combination of an appropriate exposure value determining means for determining an appropriate exposure value by measuring subject brightness, a constant low sensitivity standard imaging sensitivity, a shutter speed at a camera shake limit, and an open aperture. For an appropriate exposure value that is equal to or greater than the first exposure value that is determined, the shutter speed is changed in a speed range that is greater than or equal to the camera shake limit, and the aperture is changed to maintain the standard photographing sensitivity, which is smaller than the first exposure value. For proper exposure value, the shutter speed, aperture, and sensitivity are determined by setting the shooting sensitivity higher than the standard shooting sensitivity to the limit necessary to maintain the shutter speed above the camera shake limit under the open aperture. For an appropriate exposure value greater than or equal to a second exposure value determined by a combination of the first storage means storing the first program to be executed, the standard photographing sensitivity, the shutter speed at the lower limit of the high speed range, and the open aperture Changes the aperture to maintain the standard shooting sensitivity and the shutter speed within the high speed range, and for an appropriate exposure value smaller than the second exposure value, within the high speed range under the wide aperture. A second storage means for storing a second program for determining the shutter speed, the aperture, and the photographing sensitivity by setting the photographing sensitivity higher than the standard photographing sensitivity to the limit necessary for maintaining the shutter speed ; A temperature sensor that measures the temperature, and the first program is selected when camera shake correction is off, and the first program is detected when the temperature of the image sensor detected when it is on is higher than a predetermined first reference temperature. select program chart, when the temperature of the image sensor is less than a predetermined first reference temperature selects the second program, and a proper exposure value determined in accordance with the selected program shutter speed Is obtained by a conversion means for converting the litho imaging sensitivity.

In photographing apparatus of claim 8, the proper exposure value determination means for determining a proper exposure value by measuring the object luminance, the combination of the shutter speed and the open aperture of the standard imaging sensitivity and shake limit of constant low-sensitivity For an appropriate exposure value that is equal to or greater than the first exposure value that is determined, the shutter speed is changed in a speed range that is greater than or equal to the camera shake limit, and the aperture is changed to maintain the standard photographing sensitivity, which is smaller than the first exposure value. For proper exposure value, the shutter speed, aperture, and sensitivity are determined by setting the shooting sensitivity higher than the standard shooting sensitivity to the limit necessary to maintain the shutter speed above the camera shake limit under the open aperture. For an appropriate exposure value greater than or equal to a second exposure value determined by a combination of the first storage means storing the first program to be executed, the standard photographing sensitivity, the shutter speed at the lower limit of the high speed range, and the open aperture Changes the aperture to maintain the standard shooting sensitivity and the shutter speed within the high speed range, and for the proper exposure value smaller than the second exposure value, under the open aperture, Higher than the maximum sensitivity, the upper limit is set to the intermediate sensitivity, and the shooting sensitivity is increased to the limit necessary to maintain the shutter speed in the high speed range. Under the intermediate sensitivity, the shutter speed exceeds the camera shake limit. For the appropriate exposure value smaller than the third exposure value determined by the intermediate sensitivity, shutter speed at the camera shake limit, and the open aperture, and keep the shutter speed above the camera shake limit under the open aperture. A third storage means for storing a third program for determining the shutter speed, the aperture, and the shooting sensitivity by increasing the shooting sensitivity to the limit necessary to perform the operation; Select a program If on those having a conversion means for third select the program to convert the proper exposure value determined in accordance with the selected program to the imaging sensitivity and aperture shutter speed.

According to a ninth aspect of the present invention, a temperature sensor for measuring the temperature of the image sensor is provided, and the conversion means is based on the result of the temperature of the image sensor detected by the temperature sensor, and the third is the higher the temperature of the image sensor. In this program, the upper limit of the shooting sensitivity is reduced.

According to a tenth aspect of the present invention, the conversion means sets the upper limit of the photographing sensitivity when the appropriate exposure value is converted into the shutter speed, the aperture, and the photographing sensitivity based on the first program to be lower than the maximum sensitivity. It is a thing.

In the photographing apparatus according to claim 11 , when the conversion means converts the appropriate exposure value into the shutter speed, the aperture, and the photographing sensitivity, the shutter speed equal to or higher than the shutter speed at the camera shake limit can be obtained by using the upper photographing sensitivity. If not, the shutter speed is set to be slower than the shutter speed at the camera shake limit.

  According to the present invention, when camera shake correction is turned off, low sensitivity is maintained as shooting sensitivity, and when camera shake correction is turned on, each program diagram that maintains a high shutter speed is used. Since the appropriate exposure value is converted into the shutter speed, the aperture, and the photographing sensitivity, it is possible to photograph an image having an image quality of an appropriate level of noise / blur according to whether camera shake correction is on or off.

  FIG. 1 shows a digital camera 2 that is a photographing apparatus embodying the present invention. On the front surface of the camera body 3, a photographing lens 4 and a strobe light emitting unit 5 that emits strobe light toward a subject are provided. On the top surface, a release button 6, a mode dial 7 and a camera shake correction selection switch 8 which are operated during photographing are provided.

  The release button 6 is capable of two-stage pressing operation, that is, a half-press that is shallowly pressed and a full-press that is further pressed. When the release button 6 is half-pressed, AF processing and AE processing are performed, and when the release button 6 is fully pressed, photographing processing for photographing a still image is performed. In the AF process, the photographing lens 4 is driven so that the subject is in focus. In the AE process, the subject brightness is measured, an appropriate exposure value is calculated from the subject brightness, and the calculated appropriate exposure value is converted into a shutter speed, an aperture, and a photographing sensitivity. In the shooting process, shooting is performed using the shutter speed, aperture, and shooting sensitivity determined in the AE process.

  The mode dial 7 can select various modes such as a shooting mode for shooting a still image, a playback mode, and a setting mode by rotating the dial so that an index is aligned with a mark representing each mode drawn on the mode dial 7. When the mode dial 7 is rotated from the power-off position to any position in each mode, the digital camera 2 is powered on.

  Each time the camera shake correction selection switch 8 is pressed, the camera shake correction mode can be switched on and off. When the camera shake correction mode is turned on, a camera shake correction function for detecting the movement of the digital camera 2 and correcting so as not to cause a blur of the subject image caused by the movement, that is, a camera shake is activated. In the digital camera 2, when the camera shake correction mode is off, a combination of shutter speed, aperture, and shooting sensitivity is determined using a program that prioritizes image quality so that an image with reduced noise can be obtained. When the correction mode is on, a combination of shutter speed, aperture, and shooting sensitivity is determined using a program that prioritizes blur reduction including subject blur caused by subject motion in addition to camera shake.

  A card slot into which a memory card 11 (see FIG. 2) is inserted is provided on the side surface of the camera body 3, and image data obtained by photographing is recorded on the memory card 11. Further, an LCD 12, a zoom button 13 (see FIG. 2), and the like are provided on the back of the camera body 3. The LCD 12 functions as an electronic viewfinder in the still image shooting mode, and displays a through image of the image being shot. In the playback mode, an image recorded on the memory card 11 is displayed. The zoom button 13 is operated to zoom the photographing lens 4.

  As shown in FIG. 2, each part of the digital camera 2 is controlled by the CPU 15. A ROM 15a and a RAM 15b are connected to the CPU 15, and a control program and various setting data are stored in the ROM 15a. The ROM 15a is a storage means for storing a program for determining the shutter speed, aperture, and photographing sensitivity, and stores programs corresponding to various program diagrams for determining them from the appropriate exposure values. . The CPU 15 controls each part in accordance with a program stored in the ROM 15a based on operation signals input from the release button 6, the mode dial 7, the camera shake correction selection switch 8, the zoom button 13, and the like, and obtains an appropriate exposure value from the subject brightness. Then, the appropriate exposure value is converted into the shutter speed, aperture, and photographing sensitivity. The ROM 15b is used as a work memory that temporarily stores data necessary for the CPU 15 to execute a program.

  The photographing lens 4 includes a zoom lens 4a, a focus lens 4b, and a camera shake correction lens 4c. The photographing lens 4 is zoomed by moving the zoom lens 4a in the optical axis direction. Further, the focus lens 4b is moved in the optical axis direction to focus on the subject. The zoom lens 4a and the focus lens 4b are driven by drive mechanisms 16 and 17 including a motor. The shake correction lens 4c is for optically correcting camera shake, and is configured by an actuator or the like. It is moved in a plane perpendicular to the optical axis by the machine driver 18.

  The photographing lens 4 incorporates a diaphragm blade 4d that switches a diaphragm for adjusting the amount of light incident on an image sensor 27 described later. For example, the aperture blade 4d switches the aperture at the time of shooting stepwise in the range of AV3 to AV6 (F2.8 to F8). The aperture blade 4d is driven by a drive mechanism 19.

  The motors of the driving mechanisms 16, 18, and 19 are driven and controlled by the CPU 15 via the motor drivers 21 to 23, and the actuator of the driving mechanism 18 is driven by the camera shake correction control unit 24.

  The camera shake correction control unit 24 operates when the camera shake correction mode is on, and moves the camera shake correction lens 4c so as not to cause camera shake. The camera shake correction control unit 24 calculates a movement direction, a movement amount, a moving speed, and the like of the camera shake correction lens 4c based on a sensor that detects the direction, size, speed, and the like of the camera shake. And a driver for driving the actuator of the driving machine 18 based on the calculation result of the arithmetic circuit. Thereby, even if camera shake occurs, correction is performed so that the subject image formed on the image sensor 27 does not move. The mechanism for performing camera shake correction is not limited to the above-described mechanism, and various mechanisms can be employed. For example, instead of the camera shake correction lens 4c, the image sensor 27 is placed on a surface perpendicular to the optical axis. It may be moved.

  A CCD type image sensor 27 is arranged behind the photographing lens 4. As is well known, the image sensor 27 includes a light-receiving surface in which a large number of light-receiving elements are arranged in a matrix. The image sensor 27 photoelectrically converts the subject image formed by the photographing lens 4 and outputs it as an image signal. A CMOS type image sensor may be used instead of the CCD type.

  The image sensor 27 is driven by a CCD driver 28. The image sensor 27 has a so-called electronic shutter function that adjusts the charge accumulation time. During still image shooting, the image sensor 27 uses this electronic shutter function to adjust the exposure time, that is, the shutter speed. The shutter speed can be continuously changed in the range of TV2 to TV11 (1/4 to 1/2000 seconds), for example, according to parameters set by the CPU 15 for the CCD driver 28. Instead of the electronic shutter function, a mechanical shutter may be used, or they may be used in combination.

  An image signal from the image sensor 27 is input to an analog front end circuit (AFE) 29. The AFE 29 includes a correlated double sampling circuit (CDS) 31, an auto gain control circuit (AGC) 32, and an A / D converter (A / D) 33. The CDS 31 removes reset noise components generated when charges are generated in an image signal by performing correlated double sampling.

  The AGC 32 is an amplifier that amplifies the image signal with a gain corresponding to the set photographing sensitivity. In this AGC 32, a gain corresponding to the photographing sensitivity of SV0 to SV4 (ISO200 to ISO3200) can be set according to the ISO200 standard (SV0 = ISO200). That is, the digital camera 2 has a minimum sensitivity of SV0 (ISO200) and a maximum sensitivity of SV4 (ISO3200).

  The A / D converter 33 digitally converts the image signal amplified by the AGC 32 and outputs it as image data. Image data from the A / D converter 33 is sent to the image input controller 35.

  The image input controller 35 controls input of image data to the bus 36. Connected to the bus 36 are a CPU 15, an image signal processing circuit 37, a compression / decompression processing circuit 38, an LCD driver 39, a media controller 40, an AF detection circuit 41, an AE / AWB detection circuit 42, and an internal memory 43. Each unit is controlled by the system control unit 11 via the bus 36 and can exchange data with each other.

  The image signal processing circuit 37 performs various image processing such as gradation conversion, white balance correction, and γ correction processing and YC conversion processing on the input image data. By the YC conversion process, the image data is YC converted from the RGB three-color image data into the luminance signal Y and the color difference signals Cr and Cb. When a through image is displayed under the shooting mode, the through image is displayed on the LCD 12 by sequentially sending the YC converted image data to the LCD driver 39.

  When the image data is recorded on the memory card 11, the compression / decompression processing circuit 38 compresses the YC converted image data in a predetermined compression format, for example, the JPEG format. In the reproduction mode, the image data compressed in the JPEG format read from the memory card 11 is decompressed. The media controller 40 writes and reads image data to and from the memory card 11.

  The AF detection circuit 41 integrates the high frequency components of the spatial frequency of the image data for one screen from the image input controller 35 to calculate an AF evaluation value. The CPU 15 controls the motor driver 22 so that the AF evaluation value from the AF detection circuit 41 is maximized, that is, the contrast of the subject image is maximized, and moves the focus lens 4b in the optical axis direction to perform focusing.

  The AE / AWB detection circuit 42 detects the subject luminance from the luminance signal Y and calculates a WB evaluation value for performing white balance correction based on the image data. The CPU 15 controls the image signal processing circuit 37 so that the white balance of the subject image is appropriate based on the WB evaluation value. Further, the CPU 15 calculates an appropriate exposure value based on the subject brightness detected by the AE / AWB detection circuit 42, converts the calculated appropriate exposure value into a shutter speed, an aperture, and shooting sensitivity, and performs shooting with these. Control each part. That is, a parameter is set in the CCD driver 28 so that the image sensor 27 performs photographing at the shutter speed obtained by the conversion, and the diaphragm blade 4d is moved via the motor driver 23 and the drive mechanism 19 so as to obtain an aperture. To drive. Further, a gain determined for the obtained photographing sensitivity is set in the AGC 32.

  When a through image is displayed in the shooting mode, the calculation of the appropriate exposure value and the white balance correction are continuously performed. Further, when the S1 signal in response to the half-press of the release button 6 is input to the CPU 15, the calculation of the appropriate exposure value and the white balance correction are high for taking a still image when the release button 6 is fully pressed. Do with accuracy.

  When the S1 signal in response to half-pressing of the release button 6 is input, the CPU 15 sets an exposure value “AV + TV−SV” determined by a combination of the shutter speed (TV), the aperture (AV), and the shooting sensitivity (SV). A combination of shutter speed (TV), aperture (AV), and photographing sensitivity (SV) is determined so that an appropriate exposure value is obtained.

  FIG. 3 and FIG. 4 show program diagrams for determining the shutter speed, aperture value, and photographing sensitivity when the release button 6 is set to the half-pressed position. FIG. 3 is a first program diagram used when the camera shake correction mode is turned off, and FIG. 4 is a second program diagram used when the camera shake correction mode is turned on. Is the case. In the program diagrams shown in FIGS. 3 and 4, the horizontal axis represents the shutter speed (TV), the vertical axis represents the combination of the aperture (AV) and the photographing sensitivity (SV), and the exposure value EV in the oblique direction. Is shown. The exposure value EV is expressed as a value “ISO200 = SV0”, and is also described in the following description.

  The first program diagram is a program diagram that prioritizes image quality that enables photographing of high-quality images with less noise by maintaining low sensitivity as much as possible. In this first program diagram, the shutter speed exceeds the camera shake limit under a certain low sensitivity (hereinafter referred to as standard photographing sensitivity) that provides high image quality with low noise as the photographing sensitivity so that an appropriate exposure value is obtained. If the standard exposure sensitivity and shutter speed above the camera shake limit are not combined under the widest aperture, but an appropriate exposure value cannot be obtained, the shutter speed above the camera shake limit This is a program diagram in which the photographing sensitivity is set higher than the standard photographing sensitivity so as to maintain the above.

  Specifically, the first program diagram divides the appropriate exposure value into three areas of the first to third EV areas A1 to A3, and the first EV area A1 is above the camera shake limit under the standard photographing sensitivity. This is an area for obtaining an appropriate exposure value by combining the shutter speed and the aperture. The lower limit of the first EV area corresponds to the first exposure value, and is an exposure value EVa determined by the standard photographing sensitivity, the shutter speed at the camera shake limit, and the open aperture. The range of the appropriate exposure value equal to or greater than the exposure value EVa is This is the first EV area A1.

  The standard shooting sensitivity can be determined as a shooting sensitivity that can be taken with high image quality with little noise, but it is simply set to the minimum sensitivity that can be set. The photographing sensitivity is SV0 (ISO200). If the standard shooting sensitivity is set too low, the shutter speed above the camera shake limit may not be maintained even in a shooting scene with a relatively large appropriate exposure value. When determining, it is preferable to consider the shutter speed at the camera shake limit and the open aperture. Further, as long as a similar high image quality can be obtained within a predetermined range of photographing sensitivity, it may be set appropriately, and the highest sensitivity among them may be set.

  The shutter speed at the camera shake limit is set to TV5 (1/30 seconds) in this example, but can be appropriately set to the lower limit of the shutter speed at which it can be said that there is substantially no influence by camera shake. In general, the camera shake limit may be a reciprocal speed (1 / f second) of the focal length (fmm) of the photographic lens, but such a shutter speed may be used as the camera shake limit. The shutter speed at the camera shake limit may be changed according to zooming.

  In this example, as described above, the aperture stop is AV3 (F2.8), the shutter speed at the camera shake limit is TV5 (1/30 sec), and the standard photographing sensitivity is SV0 (ISO200). The lower limit exposure value EVa of A1 is EV8.

  In the first EV range A1, the diaphragm is changed by 1 AV within a range of AV3 to AV6 (F2.8 to F8). That is, AV3 (F2.8), AV4 (F4), AV5 (F5.6), and AV6 (F8) are used. Under each aperture, the shutter speed is given a speed range, AV4, AV5 and AV6 have a speed width of 2 TV, and AV3 has a speed width of 3 TV. That is, AV4, AV5, and AV6 each correspond to a range of appropriate exposure values for 2 EV, and AV3 corresponds to a range of appropriate exposure values for 3 EV.

  Specifically, for an appropriate exposure value of EV15 to EV17, the aperture and shutter speed of AV6 (F8), TV9 to TV11 (1/500 to 1/2000 seconds) are used, and the appropriate exposure value of EV13 to less than EV15 is used. For the exposure value, the aperture and shutter speed of AV5 (F5.6), TV8 to TV10 (1/250 to 1/1000 second) are used. Also, for the appropriate exposure value of EV11 or more and less than EV13, the aperture and shutter speed of AV4 (F4), TV7 to TV9 (1/125 to 1/500 seconds) are used, and the appropriate exposure value of EV8 or more and less than EV11 is used. Uses the aperture and shutter speed of AV3 (F2.8), TV5 to TV8 (1/30 to 1/250 seconds).

  In the second EV area A2, in order to enable shooting with the occurrence of camera shake suppressed, the standard exposure sensitivity and the shutter speed exceeding the camera shake limit under the open aperture cannot be handled in combination with the appropriate exposure value. This is an area in which the photographing sensitivity is set higher than the standard photographing sensitivity to the limit necessary to maintain the shutter speed above the blur limit.

  The second EV area A2 is a range of an appropriate exposure value that is greater than or equal to the exposure value EVb and less than the exposure value EVa, and the lower limit exposure value EVb is set as the shutter speed at the camera shake limit, the open aperture, and the upper limit of the first program diagram. It is determined by the photographing sensitivity (hereinafter referred to as the first highest sensitivity).

  The first highest sensitivity can be appropriately set as a photographing sensitivity that does not increase the influence of image quality due to noise. Further, for example, a photographing sensitivity lower by 1 SV or 2 SV than the maximum sensitivity that can be set in the digital camera 2 may be determined as the first highest sensitivity. Furthermore, even when the maximum sensitivity that can be set in the digital camera 2 is used, if the influence of noise is small, it may be set as the first maximum sensitivity. In this example, the first highest sensitivity is SV3 (ISO 1600). Therefore, the lower limit exposure value EVb of the second EV region A2 is EV5.

  In the second EV area A2, the photographing sensitivity is changed by 1 SV in order to maintain a shutter speed that is equal to or higher than the camera shake limit under the full aperture, and the shutter speed is a speed range of 1 TV with the shutter speed at the camera shake limit being the lower limit. Is given. Specifically, SV1 (ISO400) for an appropriate exposure value of EV7 or more and less than EV8, SV2 (ISO800) for an appropriate exposure value of EV6 or more and less than EV7, and SV3 (for an appropriate exposure value of EV5 or more and less than EV6). ISO 1600) is set, and the shutter speed is set in the range of TV5 to TV6 (1/30 to 1/60 seconds) for any shooting sensitivity. Thus, the imaging sensitivity is increased to the limit necessary to maintain the shutter speed above the camera shake limit, that is, the lowest settable imaging sensitivity capable of maintaining the shutter speed above the camera shake limit.

  The third EV range A3 is a range of the maximum aperture and the first highest sensitivity when the appropriate exposure value at which the shutter speed exceeding the camera shake limit cannot be maintained even when the first highest sensitivity is used, that is, when the appropriate exposure value is smaller than the exposure value EVb. The area corresponding to the shutter speed slower than the camera shake limit. Since the slowest shutter speed is TV2 (1/4 second), the lower limit of the third EV area A3 is EV2.

  The second program diagram is a program diagram that prioritizes prevention of camera shake and subject blur while maintaining the highest possible shutter speed. In this second program diagram, the aperture is changed so as to maintain a shutter speed in a high speed range under the standard imaging sensitivity so that an appropriate exposure value is obtained. If a proper exposure value cannot be obtained in combination with the shutter speed in the speed range, a program diagram that makes the shooting sensitivity higher than the standard shooting sensitivity to the limit necessary to maintain the shutter speed in the high speed range, and It has become.

  Specifically, in the second program diagram, the appropriate exposure value is divided into three areas of the fourth to sixth EV areas A4 to A6, and the fourth EV area A4 has a standard photographing sensitivity and a shutter speed of a high speed area. And an appropriate exposure value by combining various apertures. The lower limit of the fourth EV area A4 corresponds to the second exposure value, and is an exposure value EVc determined by the lower limit of the shutter speed in the standard photographing sensitivity and the high speed range and the open aperture, and an appropriate exposure equal to or higher than the exposure value EVc. The value range is the fourth EV region A4.

  In the fourth EV area A4, not only blurring is reduced, but also noise is suppressed by using standard photographing sensitivity. The standard imaging sensitivity in the second program diagram is not necessarily the same as the standard sensitivity in the first program diagram, but it is preferable to set the imaging sensitivity with low noise as in the first program diagram. .

  The high speed range of the shutter speed is set as a range in which a fast-moving subject such as a moving child can be photographed without subject blurring. In this example, the lower limit is normally set to TV9 (1/500 second). However, when the aperture is AV3 (F2.8), the lower limit of the high speed range of the shutter speed of the fifth EV range A5 described later is used. As a certain TV (8 + 1/3).

  As described above, the lower limit exposure value EVc of the fourth EV area A4 has the standard photographing sensitivity SV0 (ISO200), the lower limit of the high speed range of the shutter speed is TV (8 + 1/3), and the open aperture is AV3 (F2. 8), EV (11 + 1/3).

  In the fourth EV range A4, the aperture is changed by 1/3 AV in the range of AV3 to AV6 (F2.8 to F8), and the shutter speed is changed with an appropriate speed range for each aperture. In each aperture except AV3 and AV6, the shutter speed is changed within a range of 1/3 TV in the range of TV9 to TV (9 + 1/3), and under AV3 (F2.8), the shutter speed is set to TV ( 8 + 1/3) to TV (9 + 1/3) is changed by 1 TV, and under AV6 (F8), the shutter speed is changed by 2 TV in the range of TV9 to TV11.

  The fifth EV range A5 enables shooting with reduced blurring when the appropriate exposure value is smaller than the exposure value EVc, that is, when the shutter speed in the high speed range cannot be maintained under the wide aperture and standard shooting sensitivity. For this reason, this is an area where the imaging sensitivity is increased to the limit necessary to maintain the shutter speed in the high speed range. That is, in the fifth EV range A5, the lowest setting sensitivity that can maintain the high speed range of the shutter speed is set.

  The fifth EV range A5 is a range of an appropriate exposure value that is greater than or equal to the exposure value EVd and less than the exposure value EVc. The lower limit exposure value EVd is the lower limit of the high speed range of the shutter speed, the widest aperture, and the second program diagram. It is determined by the photographing sensitivity set as the upper limit (hereinafter referred to as the second highest sensitivity).

  The second highest sensitivity is preferably set as high as possible because priority is given to suppressing the occurrence of camera shake and subject blur. In the simplest case, the maximum sensitivity of the digital camera 2 may be used. In this example, the sensitivity is SV4 (ISO 3200).

  The high speed range of the shutter speed in the fifth EV area A5 may be determined in the same manner as in the fourth EV area A4, but the shutter speed is set to TV (8 + 1/3) in order to change the photographing sensitivity by 1 SV under the open aperture. It is changed by 1 TV in the range of ~ TV (9 + 1/3). Of course, the high speed range of the shutter speed may be the same in the fourth EV area A4 and the fifth EV area A5. For example, if the photographing sensitivity is changed by 1/3 SV, the lower limit of the high speed range of the shutter speed in the fourth EV area A4 and the fifth EV area A5 can be uniformly set to TV9 (1/500 seconds).

  The sixth EV range A6 has a wide open aperture and the second highest sensitivity when the proper exposure value at which the high shutter speed range cannot be maintained even when the second highest sensitivity is used, that is, when the proper exposure value is smaller than the exposure value EVd. Are regions corresponding to shutter speeds lower than the lower limit of the high speed range of the shutter speed. Since the slowest shutter speed is TV2 (1/4 second), the lower limit of the sixth EV area A6 is EV1.

  The combination of shutter speed, aperture, and shooting sensitivity shown in FIGS. 3 and 4 is an example. For the first program diagram, priority is given to shooting a high-quality image with little noise, and the shooting sensitivity is as low as possible. Any mode may be used as long as the control is performed to maintain the above. In the second program diagram, priority is given to preventing the occurrence of camera shake and subject blur, and a constant low sensitivity is used in order to achieve both noise suppression while maintaining a high shutter speed. The aperture may be used to control the exposure value so that the exposure value is appropriate, and the imaging sensitivity may be changed secondarily to control the exposure value appropriately.

  Furthermore, although the photographing sensitivity, shutter speed, and aperture are changed stepwise, they may be changed continuously. For example, in the second EV area A2 and the fifth EV area A5, the photographing sensitivity may be continuously changed to obtain an appropriate exposure value while keeping the shutter speed constant. In the first EV area A1 and the fourth EV area A4, the shutter speed may be set. An appropriate exposure value may be obtained by continuously changing the aperture while maintaining a constant value.

  Next, the operation of the above embodiment will be described. When the digital camera 10 is set to the shooting mode, a through image is displayed on the LCD 12. In this through image display, for example, the photographing sensitivity, the aperture, and the shutter speed are determined according to the through image program diagram so as to obtain an appropriate exposure value determined based on the subject luminance.

  When shooting, operate the camera shake correction selection switch 8 to select ON / OFF of the camera shake correction mode, observe the through image, perform framing, and then press the release button 6 to operate. Take a picture.

  When the camera shake correction mode is turned on, detection of the direction, size, speed, and the like of camera shake due to camera shake is started by the camera shake correction control unit 24, and camera shake correction is performed based on the detection result. The lens 4 c is moved by the driving machine 18. As a result, movement due to camera shake of the subject image with respect to the image sensor 27 is cancelled, and shooting without camera shake can be performed. On the other hand, when the camera shake correction mode is off, the camera shake correction lens 4c is not moved, so even if camera shake occurs, it is not corrected.

  If the release button 6 is pressed halfway while the through image is displayed, an S1 signal is input to the CPU 15 to detect that the release button 6 is half-pressed, and the AE process is started.

  As shown in FIG. 5, in the AE process, first, photometry, that is, measurement of subject brightness is performed. In photometry, exposure is performed by the image sensor 27, the AE / AWB detection circuit 41 detects the subject brightness based on the obtained image data, and the CPU 15 determines an appropriate exposure value based on the detected subject brightness. Then, the CPU 15 converts the calculated appropriate exposure value into the shutter speed, aperture, and photographing sensitivity according to the program diagram selected in accordance with the camera shake correction mode on / off.

  That is, when the camera shake correction mode is off, the appropriate exposure value is converted into the shutter speed, aperture, and photographing sensitivity according to the first program diagram. When the camera shake correction mode is on, the appropriate exposure value is converted according to the second program diagram. Is converted into shutter speed, aperture, and shooting sensitivity.

  AF processing is performed after converting the shutter speed, aperture, and photographing sensitivity, and the focus lens 4b is moved in the optical axis direction so that the subject is in focus. After this, a standby state is waited for the release button 6 to be fully pressed. When the release button 6 is fully pressed and the S2 signal generated by the full press is input to the CPU 15, parameters including the shutter speed obtained in response to the input of the S1 signal are set in the CCD driver 28. Further, the diaphragm blade 4d is driven so as to obtain the diaphragm, and a gain determined with respect to the photographing sensitivity is set in the AGC 32 to perform photographing. Then, image data obtained by this photographing is written into the memory card 11.

  Shooting is performed as described above. For example, when the camera shake correction mode is off, the appropriate exposure value is converted into the shutter speed, aperture value, and shooting sensitivity using the first program diagram. If the appropriate exposure value calculated here is within the range of the first EV range A1, the combination of the shutter speed exceeding the camera shake limit and the aperture according to the appropriate exposure value under the shooting sensitivity of SV0 (ISO 200). be changed. If the appropriate exposure value is in the range of the second EV range A2, the lower the appropriate exposure value under the wide aperture and the shutter speed in the range of TV5 to TV6 (1/30 to 1/60 seconds), The shooting sensitivity is increased stepwise by 1 SV so that high shooting sensitivity is used. Further, when the appropriate exposure value is within the range of the third EV range A3, the shutter speed is set lower than the camera shake limit so as to achieve an appropriate exposure under the wide aperture and the first highest sensitivity. .

  Therefore, in a bright shooting scene in which the appropriate exposure value is in the range of the first EV range A1, there is no camera shake because a shutter speed higher than the camera shake limit is used, and the shooting sensitivity is low, so the AGC 32 is set. A high-quality image with low gain and little noise (not noticeable) can be obtained. Further, in a slightly dark shooting scene that does not fall within the first EV range A1, noise increases somewhat with an increase in sensitivity. Since the increase in shooting sensitivity is made as small as possible, an image with less noise and good image quality can be obtained. In addition, since a shutter speed exceeding the camera shake limit is used, an image with less camera shake can be obtained. Furthermore, even in a shooting scene where a shutter speed exceeding the camera shake limit cannot be obtained, the first highest sensitivity is set as a shooting sensitivity with less noise, so that an image with less noise can be obtained.

  On the other hand, when the camera shake correction mode is on, the appropriate exposure value is converted into the shutter speed, the aperture value, and the photographing sensitivity using the second program diagram. If the calculated appropriate exposure value is in the range of the fourth EV range A4, shooting is performed at a high shutter speed of TV9 (1/500 seconds or more) to TV (8 + 1/3) or more under the shooting sensitivity of SV0 (ISO200). Is done. Therefore, an image with very little camera shake and subject blur can be obtained by the camera shake correction function and a high shutter speed, and a high-quality image with little noise can be obtained because the gain set in the AGC 32 is small. it can.

  Further, if the calculated appropriate exposure value is in the range of the fifth EV range A5, the imaging sensitivity is changed in the range of SV1 to SV4 (ISO400 to ISO3200), so noise increases as the sensitivity increases. Shooting is performed with a camera shake correction function and a high shutter speed of TV8 + 1/3 or higher. Therefore, an image with extremely little blur can be obtained as in the case of the fourth EV area A4. Furthermore, even when the appropriate exposure value is in the range of the sixth EVA6, the maximum camera sensitivity SV4 (ISO 3200) of the digital camera 2 is used for shooting at the highest possible shutter speed, so that the subject blur can be minimized.

  Next, a description will be given of a second embodiment using a program that reduces blurring while considering image quality when the camera shake correction mode is on. In addition, except being demonstrated below, it is the same as that of 1st embodiment, the same code | symbol is attached | subjected to the substantially same structural member, and the description is abbreviate | omitted.

  In this example, as shown in FIG. 6, when the camera shake correction mode is on, the third program diagram shown in FIG. 7 is selected to convert the appropriate exposure value into the shutter speed, aperture, and photographing sensitivity. . In the third program diagram, the appropriate exposure value is divided into fourth to sixth EV areas A4 to A6, and the fourth EV area A4 is the same as the above-described second program diagram.

  The fifth EV area A5 is configured to obtain an appropriate exposure value by changing the photographing sensitivity with a predetermined intermediate sensitivity as an upper limit to the limit necessary for maintaining the shutter speed in the high speed range under the wide aperture. Under the sensitivity, the shutter speed above the camera shake limit is maintained, and for the appropriate exposure value at which the proper exposure value is not obtained, the shooting sensitivity is set to the limit necessary to maintain the shutter speed above the camera shake limit. A higher exposure value is obtained than the intermediate sensitivity.

  The above intermediate sensitivity is higher than the standard shooting sensitivity used in the fourth EV area A4 and lower than the highest sensitivity of the third program diagram, and is the upper limit of the shooting sensitivity that is practically acceptable without noticeable noise. It is set. In this example, the intermediate sensitivity is set to SV2 (ISO 800). The highest sensitivity of the third program diagram is the same as the second highest sensitivity of the second program diagram, and is SV4 (ISO 3200).

  The intermediate sensitivity is, for example, a sensitivity that is higher by 1 SV or 2 SV than the standard imaging sensitivity, as long as it is within the imaging sensitivity range that is higher than the standard imaging sensitivity and lower than the highest sensitivity of the third program diagram, or It can be set as a sensitivity 1 SV or 2 SV lower than the maximum sensitivity, or an intermediate value between the standard imaging sensitivity and the maximum sensitivity.

  In the range where the appropriate exposure value is EV (10 + 1/3) or more and less than EV (11 + 1/3), the shutter speed is set within a high speed range of 1 TV under the wide aperture and SV1 (ISO 400). When the appropriate exposure value is in the range of EV6 or more and less than EV (10 + 1/3), the shooting sensitivity is increased by 1 SV from the standard shooting sensitivity, and the shutter speed is set under the intermediate sensitivity SV2 (ISO800) and the open aperture. The exposure value is changed to a proper exposure value. Therefore, even when the appropriate exposure value is in the range of EV6 to EV (9 + 1/3) and the shutter speed is not in the high speed range, the shutter speed is set with the camera shake limit as the lower limit while maintaining the intermediate sensitivity. Respond by slowing down. As a result, the amount of noise is within a practically acceptable range.

  Further, when the appropriate exposure value is small, the photographing sensitivity is set higher than the intermediate sensitivity as long as it is necessary to maintain a shutter speed equal to or higher than the camera shake limit. As a result, when the appropriate exposure value is EV5 or more and less than EV6, the shooting sensitivity is SV3 (ISO1600), and when EV4 is more than EV4 and less than EV5, the shooting sensitivity is SV4 (ISO3200). If the appropriate exposure value is even smaller, the maximum sensitivity of the third program diagram is SV4 (ISO 3200), so the shutter speed is made slower than the camera shake limit.

  According to this example, since an increase in photographing sensitivity is suppressed in a scene that is bright to some extent, a good image quality with reduced noise can be obtained in many scenes although there may be a slight increase in subject blur.

  A description will be given of a third embodiment in which when the camera shake correction mode is on, a program is selected in consideration of the temperature of the image sensor, and the shutter speed, aperture, and photographing sensitivity are determined. In addition, except being demonstrated below, it is the same as that of 1st embodiment, the same code | symbol is attached | subjected to the substantially same structural member, and the description is abbreviate | omitted.

  In this example, as shown in FIG. 8, the image sensor 27 is provided with a temperature sensor 51 for measuring the temperature thereof, and the temperature of the image sensor 27 obtained by the measurement is sent to the CPU 15. As shown in FIG. 9, when the camera shake correction mode is on, the CPU 15 compares the temperature of the image sensor 27 with a preset first reference temperature.

  The first reference temperature takes into account the correlation between the noise of the image sensor 27 and the temperature, the shooting sensitivity of the program diagram to be switched at that temperature, and the noise generated by the image sensor 27, for example, increases and becomes noticeable at high sensitivity. Thus, the upper limit of the temperature at which it can be evaluated that the merit of maintaining the high-speed shutter by increasing the imaging sensitivity is higher than the demerit of the influence on the image quality.

  In the above comparison, when the temperature of the image sensor 27 is equal to or lower than the first reference temperature, the second program diagram shown in FIG. 4 is selected. On the other hand, when the temperature of the image sensor 27 is rising and the temperature of the image sensor 27 is higher than the first reference temperature, the effect of noise on the image quality is a blur caused by increasing the shooting sensitivity. Since it becomes larger than the reduction effect, the first program diagram shown in FIG. 3 is selected. Then, based on the selected program diagram, the appropriate exposure value is converted into the shutter speed, aperture, and photographing sensitivity. As a result, it is possible to prevent an image having much noise and extremely deteriorated in image quality.

  In the above example, when the camera shake correction mode is on and the temperature of the image sensor 27 is higher than the first reference temperature, the first program diagram is selected. As in the example shown in FIG. When the temperature of the image sensor 27 is higher than the first reference temperature, the third program diagram (see FIG. 6) may be selected. According to this, even when the image sensor 27 becomes high temperature and noise increases, a shutter speed that is as high as possible is maintained while maintaining good image quality, so that an effect of reducing subject blurring can be obtained. Can do.

  A description will be given of a fourth embodiment in which the upper limit of the photographing sensitivity set when the camera shake correction mode is on, that is, the highest sensitivity is changed by the temperature of the image sensor. Other than that described below, the second embodiment using the third program diagram is the same as the second embodiment, and substantially the same constituent members are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 11, when the camera shake correction mode is on, the variable sensitivity program diagram is selected. This variable sensitivity program diagram is the same as the above-described third program diagram, but the upper limit of the imaging sensitivity is changed depending on the temperature of the image sensor 27. The higher the temperature of the image sensor 27, the higher the sensitivity of the image sensor 27. Lower the upper limit of shooting sensitivity.

  When the temperature of the image sensor 27 detected by the temperature sensor 51 is equal to or lower than the first reference temperature, the upper limit of the imaging sensitivity is set to SV4 (ISO 3200). The program diagram in this case is as shown in FIG. 12A, which is the same as the third program diagram.

  When the temperature of the image sensor 27 is higher than the first reference temperature and lower than or equal to the second reference temperature, the upper limit of the imaging sensitivity is set to SV3 (ISO 1600), and the program diagram is as shown in FIG. . In this case, if the shutter speed exceeding the camera shake limit cannot be maintained with the intermediate sensitivity under the full aperture, the photographing sensitivity is set to the upper limit SV3 (ISO 1600). Even if the limit cannot be maintained, the photographing sensitivity will not be increased any more. Therefore, if the shutter speed cannot maintain the camera shake limit under SV3, the shutter speed is lower than the camera shake limit under SV3.

  When the temperature of the image sensor 27 is higher than the second reference temperature, the upper limit of the photographing sensitivity is set to SV2 (ISO 800), and the program diagram is as shown in FIG. That is, the upper limit of the photographing sensitivity is set to the intermediate sensitivity. Therefore, in this case, the shutter speed is set lower than the camera shake limit without increasing the photographing sensitivity even when the shutter speed exceeding the camera shake limit cannot be maintained with the intermediate sensitivity under the open aperture. .

  Note that the second reference temperature may be determined in consideration of the correlation between the noise of the image sensor 27 and the temperature, the imaging sensitivity of the program diagram switched at that temperature, and the like, similarly to the first reference temperature. In this example, the upper limit of the shooting sensitivity is changed stepwise according to the temperature of the image sensor 27. However, the higher the temperature of the image sensor 27, the lower the shooting sensitivity. The temperature may be continuously changed according to the temperature of 27.

  The sensitivity variable program diagram of this example is a form in which the upper limit of the maximum sensitivity of the third program diagram is changed, but may be a form of changing the upper limit of the maximum sensitivity of the second program diagram.

  In each of the above embodiments, the digital camera in which the shooting sensitivity is switched in stages has been described as an example, but the present invention can also be applied to a case in which the shooting sensitivity is switched continuously. In addition, specific numerical values such as the upper and lower limits of each EV region, the photographing sensitivity and the aperture used in each of the above embodiments are examples, and can be appropriately changed according to the characteristics of the digital camera. Furthermore, since the second to third program diagrams and the sensitivity variable program diagram can be combined with the camera shake correction mode as described above, the image capturing apparatus and camera shake without the camera shake correction mode being turned off can be obtained. You may combine with the case where another program diagram is used when the correction mode is off.

It is a perspective view which shows the external appearance of the digital camera which implemented this invention. It is a block diagram which shows the structure of a digital camera. It is a 1st program diagram used when camera shake correction mode is OFF. It is a 2nd program diagram used when camera shake correction mode is ON. It is a flowchart which shows the AE process which selects one of a 1st and 2nd program diagram. It is a flowchart which shows the AE process which selects one of a 1st and 3rd program diagram. It is a 3rd program diagram used when camera shake correction mode is ON. It is a block diagram of the principal part which shows the example which provided the temperature sensor in the image sensor. It is a flowchart which shows the AE process which selects one of a 1st and 2nd program diagram with the temperature of an image sensor, when camera shake correction mode is ON. It is a flowchart which shows the AE process which selects one of a 2nd and 3rd program diagram with the temperature of an image sensor, when camera shake correction mode is ON. 6 is a flowchart illustrating an AE process for changing an upper limit of photographing sensitivity depending on the temperature of an image sensor when a camera shake correction mode is on. It is a program diagram which shows each case which changed the upper limit of imaging sensitivity with the temperature of the image sensor.

Explanation of symbols

2 Digital camera 8 Camera shake correction selection switch 4c Camera shake correction lens 15 CPU
27 Image sensor 32 Auto gain control circuit 42 AE / AWB detection circuit

Claims (11)

A photographic lens forms a subject image on the light-receiving surface of the image sensor, amplifies the image signal of the subject image output from the image sensor with a gain corresponding to the shooting sensitivity, and corrects camera shake caused by the movement of the device itself In a method for controlling a photographing apparatus having a camera shake correction function,
When the camera shake correction function is off, the shutter speed is set for an appropriate exposure value that is equal to or higher than the first exposure value determined by the combination of the constant low standard shooting sensitivity, the shutter speed at the camera shake limit, and the open aperture. In the speed range above the camera shake limit, the aperture is changed to maintain the standard shooting sensitivity. For an appropriate exposure value smaller than the first exposure value, above the camera shake limit under the open aperture Determining a shutter speed, an aperture, and a photographing sensitivity based on a first program diagram for making the photographing sensitivity higher than the standard photographing sensitivity to the limit necessary to maintain the shutter speed of
When the camera shake correction function is on, the temperature of the image sensor is detected, and when the detected temperature is higher than a predetermined first reference temperature, the shutter speed, the aperture, and the photographing are taken based on the first program diagram. Sensitivity is determined, and when the detected temperature is equal to or lower than a predetermined first reference temperature, a proper exposure equal to or higher than a second exposure value determined by a combination of the standard photographing sensitivity, the shutter speed at the lower limit of the high speed range, and the open aperture. For the value, the aperture is changed to maintain the standard shooting sensitivity and the shutter speed within a high speed range, and for an appropriate exposure value smaller than the second exposure value, the aperture is fast under the open aperture. A shutter speed, an aperture, and a photographing sensitivity are determined based on a second program diagram for making the photographing sensitivity higher than the standard photographing sensitivity to the limit necessary to maintain a shutter speed within a certain speed range. Control method of the shadow system. A photographic lens forms a subject image on the light-receiving surface of the image sensor, amplifies the image signal of the subject image output from the image sensor with a gain corresponding to the shooting sensitivity, and corrects camera shake caused by the movement of the device itself In a method for controlling a photographing apparatus having a camera shake correction function,
When the camera shake correction function is off, the shutter speed is set for an appropriate exposure value that is equal to or higher than the first exposure value determined by the combination of the constant low standard shooting sensitivity, the shutter speed at the camera shake limit, and the open aperture. In the speed range above the camera shake limit, the aperture is changed to maintain the standard shooting sensitivity. For an appropriate exposure value smaller than the first exposure value, above the camera shake limit under the open aperture Determining a shutter speed, an aperture, and a photographing sensitivity based on a first program diagram for making the photographing sensitivity higher than the standard photographing sensitivity to the limit necessary to maintain the shutter speed of
When the camera shake correction function is on, the aperture is changed for an appropriate exposure value greater than or equal to the second exposure value determined by the combination of the standard shooting sensitivity, the lower shutter speed of the high speed range, and the open aperture. Standard exposure sensitivity and shutter speed within a high speed range are maintained, and for an appropriate exposure value smaller than the second exposure value, it is higher than the standard exposure sensitivity and lower than the maximum sensitivity under the open aperture. Taking the set intermediate sensitivity as the upper limit, the shooting sensitivity is increased to the limit necessary to maintain the shutter speed within the high speed range, and the shutter speed above the camera shake limit is maintained under the intermediate sensitivity. For a proper exposure value smaller than the third exposure value determined by the shutter speed at the camera shake limit and the open aperture, the limit necessary to maintain a shutter speed above the camera shake limit under the open aperture Taken with The method of the imaging apparatus characterized by determining the imaging sensitivity and aperture shutter speed based on the third program chart to increase the degrees. The temperature of the image sensor is detected when the camera shake correction function is on, and the upper limit of the imaging sensitivity of the third program diagram is lowered as the detected temperature of the image sensor is higher. 3. A method for controlling the photographing apparatus according to 2 . A photographic lens forms a subject image on the light-receiving surface of the image sensor, amplifies the image signal of the subject image output from the image sensor with a gain corresponding to the shooting sensitivity, and corrects camera shake caused by the movement of the device itself In a method for controlling a photographing apparatus having a camera shake correction function,
When the camera shake correction function is off, the shutter speed is set for an appropriate exposure value that is equal to or higher than the first exposure value determined by the combination of the constant low standard shooting sensitivity, the shutter speed at the camera shake limit, and the open aperture. In the speed range above the camera shake limit, the aperture is changed to maintain the standard shooting sensitivity. For an appropriate exposure value smaller than the first exposure value, above the camera shake limit under the open aperture Determining a shutter speed, an aperture, and a photographing sensitivity based on a first program diagram for making the photographing sensitivity higher than the standard photographing sensitivity to the limit necessary to maintain the shutter speed of
When the camera shake correction function is on, the temperature of the image sensor is detected. When the detected temperature is equal to or lower than a predetermined first reference temperature, the standard photographing sensitivity, the shutter speed at the lower limit of the high speed range, the open aperture, For an appropriate exposure value greater than or equal to the second exposure value determined by the combination of the above, the aperture is changed to maintain the standard imaging sensitivity and the shutter speed within a high speed range, and an appropriate exposure smaller than the second exposure value. For the value, the shutter speed based on the second program diagram that makes the photographing sensitivity higher than the standard photographing sensitivity to the limit necessary to maintain the shutter speed within the high speed range under the wide aperture. When the aperture and shooting sensitivity are determined and the detected temperature is higher than the first reference temperature,
For an appropriate exposure value greater than or equal to the second exposure value, the aperture is changed to maintain the standard photographing sensitivity and the shutter speed within a high speed range, and for an appropriate exposure value smaller than the second exposure value. Increases the shooting sensitivity to the limit necessary to maintain the shutter speed within the high speed range, with the upper limit set to the intermediate sensitivity set higher than the standard shooting sensitivity and lower than the maximum sensitivity under the open aperture. At the same time, the shutter speed exceeding the camera shake limit is maintained under the intermediate sensitivity, and for the appropriate exposure value smaller than the third exposure value determined by the intermediate sensitivity, the shutter speed at the camera shake limit and the open aperture, the open aperture is set. The shutter speed, the aperture, and the shooting sensitivity are determined based on a third program diagram for increasing the shooting sensitivity to the limit necessary to maintain the shutter speed that is above the camera shake limit. How to control the device . 2. The method according to claim 1, wherein when the shutter speed, the aperture, and the photographing sensitivity are determined based on the first program diagram, an upper limit of the photographing sensitivity is set lower than a maximum photographing sensitivity that can be set in the apparatus. 5. A method for controlling an imaging apparatus according to any one of 4 above. When determining the shutter speed, aperture, and shooting sensitivity based on each program diagram, if a shutter speed that exceeds the shutter speed of the camera shake limit cannot be obtained using the upper limit shooting sensitivity, the shutter speed is adjusted manually. the method of the imaging apparatus according to any one of claims 1 to 5, characterized in that slower than the shutter speed of the blur limit. An image sensor that converts a subject image formed on a light receiving surface by a photographing lens into an image signal and outputs it, an amplifier that amplifies the image signal from the image sensor with a gain corresponding to photographing sensitivity, and the movement of the device itself. A camera shake correction unit that detects camera shake by detecting and corrects camera shake caused by movement of the apparatus itself, and a selection member that selects on / off of camera shake correction by the camera shake correction unit. In the shooting device,
Appropriate exposure value determining means for measuring subject brightness and determining an appropriate exposure value;
For a proper exposure value greater than the first exposure value determined by the combination of constant low standard shooting sensitivity, shutter speed at the camera shake limit, and open aperture, the shutter speed is changed in the speed range above the camera shake limit. And the aperture is changed to maintain the standard photographing sensitivity. For an appropriate exposure value smaller than the first exposure value, it is necessary to maintain a shutter speed above the camera shake limit under the open aperture. A first storage means for storing a first program for determining a shutter speed, an aperture, and a photographing sensitivity by making the photographing sensitivity higher than the standard photographing sensitivity at the limit;
For an appropriate exposure value greater than or equal to the second exposure value determined by the combination of the standard shooting sensitivity, the shutter speed at the lower limit of the high-speed speed range, and the open aperture, the aperture can be changed to change the standard shooting sensitivity and high-speed speed range. The shutter speed is maintained, and for a proper exposure value smaller than the second exposure value, the photographing sensitivity is set to the standard exposure to the limit necessary to maintain the shutter speed within the high speed range under the wide aperture. A second storage means for storing a second program for determining a shutter speed, an aperture, and a photographing sensitivity higher than the sensitivity;
A temperature sensor for measuring the temperature of the image sensor;
The first program is selected when camera shake correction is off, and the first program diagram is selected when the detected temperature of the image sensor is higher than a predetermined first reference temperature when on. The second program is selected when the temperature of the image sensor is equal to or lower than a predetermined first reference temperature, and conversion means for converting an appropriate exposure value determined according to the selected program into a shutter speed, an aperture, and photographing sensitivity is provided. An imaging device characterized by that. An image sensor that converts a subject image formed on a light receiving surface by a photographing lens into an image signal and outputs it, an amplifier that amplifies the image signal from the image sensor with a gain corresponding to photographing sensitivity, and the movement of the device itself. A camera shake correction unit that detects camera shake by detecting and corrects camera shake caused by movement of the apparatus itself, and a selection member that selects on / off of camera shake correction by the camera shake correction unit. In the shooting device,
Appropriate exposure value determining means for measuring subject brightness and determining an appropriate exposure value;
For a proper exposure value greater than the first exposure value determined by the combination of constant low standard shooting sensitivity, shutter speed at the camera shake limit, and open aperture, the shutter speed is changed in the speed range above the camera shake limit. And the aperture is changed to maintain the standard photographing sensitivity. For an appropriate exposure value smaller than the first exposure value, it is necessary to maintain a shutter speed above the camera shake limit under the open aperture. A first storage means for storing a first program for determining a shutter speed, an aperture, and a photographing sensitivity by making the photographing sensitivity higher than the standard photographing sensitivity at the limit;
For an appropriate exposure value greater than or equal to the second exposure value determined by the combination of the standard shooting sensitivity, the shutter speed at the lower limit of the high-speed speed range, and the open aperture, the aperture can be changed to change the standard shooting sensitivity and high-speed speed range. The shutter speed is maintained, and for an appropriate exposure value smaller than the second exposure value, an intermediate sensitivity set higher than the standard photographing sensitivity and lower than the maximum sensitivity is set as the upper limit under the open aperture. The shooting sensitivity is increased to the limit necessary to maintain the shutter speed within the high speed range, and the shutter speed that is higher than the camera shake limit is maintained under the intermediate sensitivity. For an appropriate exposure value smaller than the third exposure value determined by the above, the shutter speed is increased by increasing the shooting sensitivity to the limit necessary to maintain the shutter speed above the camera shake limit under the open aperture. Squeezing A third storage means for storing the third program for determining a photographing sensitivity,
When camera shake correction is off, the first program is selected, and when it is on, the third program is selected. The appropriate exposure value determined according to the selected program is set as the shutter speed, aperture, and shooting sensitivity. An imaging apparatus comprising: conversion means for converting. A temperature sensor for measuring the temperature of the image sensor, and the conversion means is based on a result of the temperature of the image sensor detected by the temperature sensor, and the upper limit of the imaging sensitivity of the third program is higher as the temperature of the image sensor is higher. The photographing apparatus according to claim 8 , wherein the photographing device is lowered. And the converting means, based on the first program, the preceding claims 7, characterized in that less than maximum sensitivity limit of the imaging sensitivity in converting the imaging sensitivity and aperture shutter speed proper exposure value 9 The imaging device according to any one of the above. The conversion means converts the shutter speed, the aperture, and the photographing sensitivity into the appropriate exposure value, and if the shutter speed exceeding the shutter speed of the camera shake limit cannot be obtained using the upper photographing sensitivity, the shutter speed is set. imaging device according to any one of claims 7 to 10, characterized in that slower than the shutter speed of the camera shake limit.

Images