JP2006121385A - Exposure control apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exposure control apparatus in which, even when lens brightness changes with zoom magnifications, high speed focusing and flicker do not come out in focusing from full closure in iris diaphragm. <P>SOLUTION: Even when the lens brightness changes with filter wearing or the zoom magnifications, in order to newly create a target value from a target value by an external photometric element after a brightness correction is performed and from the target value by an imaging device, the coexistence of preventing a luminance level difference and a precision become possible. In the exposure control apparatus, the high speed focusing and the flicker do not come in focusing from the full closure in iris diaphragm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to exposure control, and more particularly to an exposure control apparatus for an imaging apparatus including an imaging unit that converts a subject image into an electrical signal.

  2. Description of the Related Art Conventionally, in an imaging apparatus that performs moving image shooting, a diaphragm is controlled by detecting a luminance level of a video signal obtained from an imaging means such as a solid-state imaging device such as a CCD. Since the output signal of the image sensor is used in this way, highly accurate exposure control based on photometric information without parallax is possible. However, the readout of the image sensor output signal has a feedback control configuration because it is an accumulation readout system that accumulates for a certain period of time.

Therefore, in order to improve the responsiveness of this exposure control, the aperture is controlled to an appropriate light amount control value by the external photometric element until the image sensor operates normally. There is a configuration that selectively switches and controls the aperture to an appropriate light amount control amount (see, for example, Patent Document 1).
Japanese Examined Patent Publication No. 2-29273 (page 4, Fig. 2) JP-A-10-155100

  However, for example, when the zoom magnification is high or when the filter is mounted, the lens brightness F value becomes dark, so that a difference occurs in the photometric results of the external photometric element and the image sensor output signal. In the case of moving image shooting, if the photometry results are selectively switched in a state where there is a discrepancy, there is a problem that the recorded image luminance is blinked by the luminance corresponding to the difference in the photometry results.

  In addition, in the method of detecting the luminance level of the video signal obtained from the image sensor, the evaluation range is small particularly on the zoom telephoto side because the luminance of only the amount of light that reaches the image sensor, that is, within the angle of view is detected. Even if panning is performed a little, the evaluation range moves greatly, and there is a problem that exposure control is performed so that the screen responds to blinking. Similarly, during zooming operation, there is a problem that exposure control is performed such that the screen responds to blinking as the evaluation range is enlarged or reduced.

  The present invention has been made paying attention to the above points, and even when the lens brightness differs depending on the filter mounting and zoom magnification, the target value by the external photometric element after the brightness correction and the target value by the image sensor In order to create a new target value from the above, it is possible to achieve both an accuracy control and prevention of a brightness step, and to provide an exposure control device that can converge at high speed and not blink even when the iris is fully closed. To do.

  The present invention can solve the above problems by providing the following configuration.

  (1) Lens means capable of variable magnification photography, an image sensor that converts a subject image into an electrical signal, an exposure control target generation means via an image sensor that calculates an exposure control target based on an output level of the image sensor, Photometry means for detecting the brightness of a subject other than the image sensor, exposure control target generation means via photometry means for calculating an exposure control target based on the output level of the photometry means, and the magnification and dimming of the lens means An exposure multiple calculation unit that calculates an exposure multiple that is a coefficient for correcting an increase in exposure according to the filter loading state, and a value after correction by the target value of the exposure control target generation unit via the image sensor and the calculated exposure multiple A composition ratio calculating means for determining a target value composition ratio according to a difference from a target value of the exposure control target generating means via the photometric means; a target value of the exposure control target generating means via the image sensor; and the calculation. An exposure control target synthesis unit that synthesizes the target value of the exposure control target generation unit via the photometry unit after being corrected by the exposure multiple, and the amount of light irradiated to the imaging unit. An exposure control apparatus comprising: a light amount adjusting unit; and a control unit that drives and controls the light amount adjusting unit according to a target value of the exposure control target combining unit.

  (2) a lens unit capable of variable magnification shooting, an image sensor that converts a subject image into an electrical signal, an exposure control target generation unit via an image sensor that calculates an exposure control target based on an output level of the image sensor, Exposure based on the output level of the panning progression direction area of the photometry means when panning is detected, and a photometry means capable of photometry divided into a plurality of areas for detecting the brightness of the subject other than the image sensor Exposure control target generation means via photometry means for calculating a control target, exposure multiple calculation means for calculating an exposure multiple that is a coefficient for correcting an increase in exposure according to the magnification ratio of the lens means and the light filter filter installed state, Responding to the difference between the target value of the exposure control target generation means via the image sensor and the target value of the exposure control target generation means via the photometry means after being corrected by the calculated exposure multiple. And a target value of the exposure control target generation means via the photometric means after correction with the target value of the exposure control target generation means via the image sensor and the calculated exposure multiple. Exposure control target synthesis means for synthesizing the image at the calculated synthesis ratio, light quantity adjustment means for adjusting the amount of light applied to the imaging means, and drive control of the light quantity adjustment means according to the target value of the exposure control target synthesis means An exposure control apparatus comprising control means for performing

  (3) Lens means capable of variable magnification photography, an image sensor that converts a subject image into an electrical signal, an exposure control target generation means via an image sensor that calculates an exposure control target based on an output level of the image sensor, A photometric means capable of photometry divided into a plurality of areas for detecting the brightness of a subject other than the image sensor, a lens zoom operation detecting means, and a zoom-out direction area of the photometric means when a lens zoom-out operation is detected, that is, Exposure control target generation means via photometry means for calculating an exposure control target based on the output level of the outer edge area, and an exposure multiple that is a coefficient for correcting an increase in exposure according to the magnification ratio of the lens means and the light filter filter loading state Exposure multiple calculation means for calculating the exposure value, and the exposure control via the photometry means after correction with the target value of the exposure control target generation means via the image sensor and the calculated exposure multiple A composition ratio calculating means for determining a target value composition ratio in accordance with a difference between the target value of the target generating means and the target value of the exposure control target generating means via the image sensor and the corrected exposure multiple after the correction. Exposure control target synthesis means for synthesizing the target value of the exposure control target generation means via photometry means at the calculated synthesis ratio, light amount adjustment means for adjusting the amount of light applied to the imaging means, and the exposure control target synthesis means An exposure control apparatus comprising control means for drivingly controlling the light amount adjusting means according to the target value.

  (4) a lens unit capable of zooming, an image sensor that converts a subject image into an electrical signal, an exposure control target generation unit via an image sensor that calculates an exposure control target based on an output level of the image sensor, Photometric means capable of photometry divided into a plurality of areas for detecting the brightness of a subject other than the image sensor, photometric area selecting means for selecting the area of the photometric means according to the magnification of the lens means, and the photometric area selection An exposure control target generation unit that calculates an exposure control target based on an output level of the photometry unit in an area selected by the unit, and an exposure multiple that serves as a coefficient for correcting an increase in exposure according to a light filter installed state An exposure multiple calculation means for calculating the exposure control target generation means after correction with the target value of the exposure control target generation means via the image sensor and the calculated exposure multiple A composition ratio calculating means for determining a target value composition ratio according to a difference from the standard value; and exposure via the photometric means after correction with the target value of the exposure control target generation means via the image sensor and the calculated exposure multiple. Depending on the target value of the exposure control target combining means, the exposure control target combining means for combining the target values of the control target generating means at the calculated combining ratio, the light amount adjusting means for adjusting the light amount irradiated to the imaging means, and the exposure control target combining means An exposure control apparatus comprising control means for driving and controlling the light amount adjusting means.

  According to the exposure control device of the first aspect of the present invention, even when the lens brightness varies depending on the filter mounting and zoom magnification, the target value by the external photometric element after the brightness correction and the target value by the image sensor are newly added. Since the target value is created, it is possible to achieve both the prevention of the luminance step and the accuracy, and there is an effect that the convergence from the iris fully closed and the blinking does not occur.

  According to the exposure control apparatus of the second aspect of the present invention, the responsiveness of the exposure control characteristic within the angle of view can be adjusted using the photometric information outside the angle of view pre-read in the panning progression direction during panning photographing. There is an effect.

  According to the exposure control apparatus of the third aspect of the present invention, the responsiveness of the exposure control characteristic within the angle of view is adjusted using the photometric information outside the angle of view pre-read in the direction of change of the angle of view when zooming out. There is an effect that can be.

  According to the exposure control apparatus of the fourth aspect of the present invention, the shift of the photometric range due to the zoom magnification is prevented, and the target value by the external photometric element after the brightness correction and the image sensor even when the lens brightness is different due to the filter mounting. Since the target value is newly created from the target value obtained by the above, it is possible to achieve both the prevention of the luminance step and the accuracy, and there is an effect that the convergence from the fully closed iris and the blinking do not occur.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to examples.

  FIG. 1 is a block diagram showing an embodiment in which the exposure control apparatus according to the present invention is applied to a video camera.

  100 is an imaging lens optical system, 101 is an iris that adjusts the amount of incident light, 102 is a CCD that photoelectrically converts an image formed on the imaging surface by the imaging lens optical system and the amount of light is adjusted by the iris into an imaging signal , 103 is a double correlation sampling circuit (CDS) that reduces noise of accumulated charges of the image sensor, 104 is an AGC circuit that automatically adjusts the gain of the image signal, and 105 is an image signal output from the AGC circuit 104 The camera signal processing circuit 106 converts the video signal output from the camera signal processing circuit into a signal suitable for recording on a video tape recorder or the like. An image signal processing circuit 107 is a recording means such as a video tape recorder or a disk recorder.

  108 is a gate circuit that divides the imaging screen into a plurality of screens and gates a signal output from the AGC circuit 104 to extract an image signal corresponding to an arbitrary area, and 109 is an imaging screen selected by the gate circuit 108. An integrator 110 that integrates an image pickup signal corresponding to a specified area in the image to obtain an average light amount, and 110 converts an output signal from the integrator into a digital signal that can be processed by a system control microcomputer 121 described later. It is a converter.

  111 is a CCD drive circuit that controls the accumulation operation, readout operation, reset operation, and the like of the image sensor 102, 112 is an iris motor that drives the iris 101, 113 is an iris drive circuit that drives the iris motor, and 114 is the iris opening amount, An iris encoder constituted by a hall element or the like for detecting an aperture value, 115 an amplifier for amplifying the output of the iris encoder 114, and 116 an output of the iris encoder 114 amplified to a predetermined level by the amplifier 115, which will be described later. It is an A / D converter that converts it into a digital signal that can be processed by.

  Reference numeral 117 denotes an external photometric means using an external photometric element such as SPC. Reference numeral 118 denotes a gyro that detects a shake of the taking lens optical system 100 as an angular velocity. Reference numeral 119 denotes zoom means for controlling the zoom lens. An A / D converter 120 converts the output of the gyro 118 into a digital signal that can be processed by the system control microcomputer 121 described later. Reference numeral 121 denotes a system control microcomputer constituted by a micro computer that comprehensively controls the entire video camera system in the present embodiment. Reference numeral 122 denotes a key SW for inputting menu selection and operation to the system control microcomputer 121.

  The system control microcomputer 121 controls the characteristics of the camera signal processing circuit 105 and the image signal processing circuit 106 according to the shooting mode, and also controls the gate pulse supplied to the gate circuit 108 according to the shooting mode. Sets the photometry area for detecting the light quantity. Further, the integration reset pulse supplied to the integrator 109 is controlled to control the selection characteristic of the integration operation. Then, an integrated value corresponding to the shooting mode of the image pickup signal in the photometry area acquired via the gate circuit 108 is acquired, an iris control signal corresponding to the shooting state is calculated, supplied to the iris drive circuit 113, and AGC. A gain control signal is supplied to the circuit 104 to perform control to vary the gain of the AGC circuit 104 in accordance with the shooting mode and the shooting situation, and a control signal is also supplied to the CCD drive circuit 111 to change the shooting mode and shooting situation. Accordingly, control is performed on the storage time (electronic shutter) of the image sensor, the readout timing, the reset timing, and the like. The system control microcomputer 121 refers to the output from the external photometry means 117 according to the photographing mode and uses it as auxiliary information when calculating the iris control signal.

  Further, referring to the output from the gyro 118, the state of camera shake is detected. Further, the zoom unit 119 is controlled according to the operation of the photographer. From the key SW 122, exposure multiple information of the external optical filter is input.

  FIG. 2 is a flowchart of an iris control target calculation mode selection routine executed inside the system control microcomputer 121.

  With reference to FIG. First, in S201, the imaging apparatus is in a state after the start from the iris fully closed and the exposure control has not converged yet, that is, the state where the iris is closed immediately after the power is turned on or the shuttered operation is performed. Judge whether it is recovery from. If true, the process proceeds to S202, and if false, the process proceeds to S204.

  In S202, the iris control target calculation is performed in the start-up mode. Details will be described later. Then, the process proceeds to S203. In S204, it is determined whether the camera photographing is in the field angle changing operation such as panning or tilting. The angle of view changing operation detection method is well known in “Image blur prevention device” disclosed in Japanese Patent Laid-Open No. 05-323436, and the description thereof is omitted.

  If an angle of view changing operation is detected, the process proceeds to S205, and if not detected, the process proceeds to S206. In S205, the iris control target calculation is performed in the panning mode. Details will be described later. Then, the process proceeds to S203. In S206, it is determined whether camera shooting is in a zoom-out execution state. If it is in the zoom-out execution state, the process proceeds to S207, and if not, the process proceeds to S208.

  In S207, the iris control target calculation is performed in the zoom mode. Details will be described later. Then, the process proceeds to S203. In S208, the iris control target calculation is performed in the normal mode. Details will be described later. Then, the process proceeds to S203. In S203, the iris control target and the position output of the iris encoder 114 are compared, and a drive signal is output to the iris drive circuit 113 to control the iris motor 112 so that the difference becomes small, and the process proceeds to S209. Unless the power is off in S209, the process loops to S201 and performs an iris control target calculation mode selection routine.

  FIG. 3 is a flowchart of S202 in FIG. FIG. 4 is a time chart showing how the iris control target is calculated. The horizontal axis represents time, and the vertical axis represents the iris position.

  In S301 of FIG. 3, the iris position control target as shown in FIG. 4L1 is created with reference to the output of the external photometry unit 117, and the process proceeds to S302. In S302, the zoom magnification of the zoom means 119, the exposure multiple of the external optical filter and the exposure multiple of the internal ND filter input in advance from the key SW 122 are referred to calculate the total exposure multiple, and the process proceeds to S303.

  The increase in exposure (exposure multiple) according to the zoom magnification can be obtained by exposure multiple = (1 + N) (1 + N), where N is the zoom magnification. The number of exposure multiples of the optical filter is fixed. Compared with the external photometry means 117 photometry area divided into 24 areas as shown in FIG. 6, the frame 1 is a range in which the light beam reaches the image sensor when wide, and the range in which the light beam reaches the image sensor as zooming is To change. Therefore, it is possible to change the external photometry unit 117 photometry area in accordance with the zoom magnification.

  In S303, as shown in FIG. 4L1, the iris position control target obtained from the external photometry unit 117 is corrected for brightness according to the overall exposure multiple calculated in S302, and the process proceeds to S304. In S304, the corrected iris position control target is calculated as shown in FIG. 4G1, and the process proceeds to S305. In S305, the process proceeds to S306 with reference to the luminance level via the CCD. In S306, the brightness difference of proper exposure is converted into an encoder movement amount, and the process proceeds to S307. In step S307, the iris encoder position is referred to, and the process proceeds to step S308. The iris encoder position from which the luminance is obtained in S308 and the necessary encoder movement amount are calculated as an iris position control target as shown in FIG. 4G2, and the process proceeds to S309. In S309, the difference between the corrected iris position control target for external photometry as shown in FIG. 4G1 and the iris position control target via the CCD as shown in FIG. 4G2 is calculated, and the process proceeds to S310. In S310, it is determined whether or not the difference is equal to or smaller than the predetermined value A as shown in FIG. 4. If it is equal to or smaller, the process proceeds to S312; otherwise, the process proceeds to S311. When the difference is larger than the predetermined value A at time S311 from time 0 to t1 in FIG. 4, the processing is ended as the control target G3 for passing the iris position control target G1 for external metering to the S203 iris position servo in FIG.

  As a result, even when the iris position control target via the CCD is not reliable, such as before the iris is opened, it is possible to control to a substantially approximate position. In S312, it is determined whether or not the difference is equal to or smaller than the predetermined value B as shown in FIG. 4. If the difference is equal to or smaller than the predetermined value B, the process proceeds to S314, and if not, the process proceeds to S313. In S313, when the difference is larger than the predetermined value B from time t1 to time t2 in FIG. 4, the intermediate value between the iris position control target G1 for external photometry and the iris position control target G2 via the CCD is set to S203 iris in FIG. The processing ends as a control target G3 to be transferred to the position servo.

  Thus, if the predetermined value B is set to the iris position target difference in which the luminance change cannot be recognized on the screen, and the predetermined value A is doubled to the predetermined value B, the iris position control target of external photometry is changed to the iris position control target via the CCD. When changing, iris position control can be performed without causing an excessive luminance change due to the target value step. In S314, when the difference is equal to or less than the predetermined value B after time t2 in FIG. 4, the process is ended as the control target G3 passing the iris position control target G2 via the CCD to the S203 iris position servo in FIG.

  FIG. 5 is a flowchart of S205 in FIG. FIG. 6 is a diagram showing a region division state of the external photometry element, and is a diagram in which the photometry range is divided into 4 parts in the vertical direction and 6 parts in the horizontal direction, and 24 parts in total. FIG. 7 is a diagram showing the photometry area setting and weighting of the external photometry element. The numbers inside are weighting factors, and the larger the numbers, 0, 0.5, 1.0, the higher the weighting. FIG. 8 is a time chart showing the iris control target calculation. The horizontal axis represents time, and the vertical axis represents the iris position.

  Compared with the external photometry means 117 photometry area divided into 24 areas as shown in FIG. 6, the frame 1 is a range in which the light beam reaches the image sensor when wide, and the range in which the light beam reaches the image sensor as zooming is It becomes so narrow. In S501 of FIG. 5, the setting is made to increase the weight of the photometry area in the left direction in FIG. 7 from the external photometry means 117 divided as shown in FIG. 6 in the panning direction as shown in FIG. Frame 1 is frame 2 at the current zoom ratio within the range in which the light beam reaches the image sensor when wide. In S502 of FIG. 5, an iris position control target such as L1 of FIG. 8 is created with reference to the set region output of the external photometry means 117, and the process proceeds to S503. In S503, the zoom magnification of the zoom means 119, the exposure multiple of the external optical filter and the exposure multiple of the internal ND filter input in advance from the key SW 122 are referred to calculate the total exposure multiple, and the process proceeds to S504. In S504, the iris position control target obtained from the area output of the external photometry unit 117 set as shown in FIG. 8L1 is corrected for brightness according to the overall exposure multiple calculated in S503, and the process proceeds to S505. . In S505, the corrected iris position control target is calculated as shown in FIG. 8G1, and the process proceeds to S506. In S506, the process proceeds to S507 with reference to the luminance level via the CCD. In S507, the brightness difference of appropriate exposure is converted into an encoder movement amount, and the process proceeds to S508. In step S508, the iris encoder position is referred to, and the process proceeds to step S509. In step S509, the iris encoder position from which the luminance is obtained and the necessary encoder movement amount are calculated as an iris position control target as shown in FIG. 8G2, and the process proceeds to step S510. In S510, the difference between the corrected iris position control target for external photometry as shown in FIG. 8G1 and the iris position control target via the CCD as shown in FIG. 8G2 is calculated, and the process proceeds to S511. In S511, it is determined whether or not the difference is equal to or smaller than the predetermined value C as shown in FIG. 8. If the difference is equal to or smaller, the process proceeds to S513, and if not, the process proceeds to S512. In S512, when the difference is larger than the predetermined value C from time t3 to t4 in FIG. 8, the intermediate value between the iris position control target G1 for external photometry and the iris position control target G2 via the CCD is set to S203 iris in FIG. The processing ends as a control target G3 to be transferred to the position servo.

  Thus, the iris position can be controlled by pre-reading the photometric information in the panning direction and limiting an excessive luminance change. In S513, when the difference is equal to or less than the predetermined value C after time t4 in FIG. 8, the process is ended as the control target G3 passing the iris position control target G2 via the CCD to the S203 iris position servo in FIG.

  FIG. 9 is a flowchart of S207 in FIG. FIG. 10 is a diagram showing the photometry area setting and weighting of the external photometry element. The numbers inside are weighting factors, and the larger the numbers, 0, 0.5, 1.0, the heavier the weighting is. FIG. 11 is a time chart showing how the iris control target is calculated, where the horizontal axis represents time and the vertical axis represents the iris position. Compared with the external photometry means 117 photometry area divided into 24 areas as shown in FIG. 6, the frame 1 is a range in which the light beam reaches the image sensor when wide, and the range in which the light beam reaches the image sensor as zooming is It becomes so narrow.

  In S901 of FIG. 9, the setting is made to increase the weight of the photometric area in the outer peripheral direction in FIG. 10 from the external photometric means 117 divided into areas as shown in FIG. 6 to the zoom-out direction as shown in FIG. Frame 1 is frame 2 at the current zoom ratio within the range in which the light beam reaches the image sensor when wide. In S902 of FIG. 9, an iris position control target like L1 of FIG. 11 is created with reference to the set region output of the external photometry means 117, and the process proceeds to S903. In S903, the zoom magnification of the zoom means 119, the exposure multiple of the external optical filter and the exposure multiple of the internal ND filter input in advance from the key SW 122 are referred to calculate the total exposure multiple, and the process proceeds to S904. In S904, the iris position control target obtained from the area output of the external photometry unit 117 set as shown in FIG. 11L1 is corrected for brightness according to the overall exposure multiple calculated in S903, and the process proceeds to S905. . In S905, the corrected iris position control target is calculated as shown in FIG. 11G1, and the process proceeds to S906. In S906, the process proceeds to S907 with reference to the luminance level via the CCD. In S907, the brightness difference of appropriate exposure is converted into an encoder movement amount, and the process proceeds to S908. In S908, referring to the iris encoder position, the process proceeds to S909. In step S909, the iris encoder position from which the luminance is obtained and the necessary encoder movement amount are calculated as an iris position control target as shown in FIG. 11G2, and the process proceeds to step S910. In S910, the difference between the corrected iris position control target of external photometry as shown in FIG. 11G1 and the iris position control target via the CCD as shown in FIG. 11G2 is calculated, and the process proceeds to S911. In S911, it is determined whether or not the difference is equal to or smaller than the predetermined value D as shown in FIG. 11. If the difference is equal to or smaller, the process proceeds to S913, and if not, the process proceeds to S912. In S912, when the difference is larger than the predetermined value D from time t5 to t6 in FIG. 11, the intermediate value between the iris position control target G1 for external photometry and the iris position control target G2 via the CCD is set to S203 iris in FIG. The processing ends as a control target G3 to be transferred to the position servo. Thus, the iris position can be controlled by prefetching the photometric information in the zoom-out direction and limiting an excessive luminance change.

  In S913, when the difference is equal to or less than the predetermined value D after time t6 in FIG. 11, the process is ended with the iris position control target G2 via the CCD as the control target G3 to be passed to the S203 iris position servo in FIG. The process of S208 in FIG. 2 is the same algorithm as the conventional auto iris control.

  The iris control signal calculation in S203 will be described. The position information of the iris encoder 114 is referred to via the A / D converter 116. The control signal output to the iris drive circuit is calculated and output so that the difference from the control target G3 is calculated and the difference becomes zero. This calculation process is the same as the cycle of S202, S205, S207, and S208 on the flowchart, but it is a target update cycle, and internally, a servo process that calculates a control signal at a higher cycle than the update cycle is performed. It is repeating. In FIG. 3S302, FIG. 5S503, and FIG. 9S903, the exposure multiple of the external optical filter is referred to from the key input. This can be input by calibration, and will be described below.

  FIG. 12 is a flowchart for determining the exposure multiple including the external optical filter. FIG. 13 is a diagram showing the photometry area setting and weighting of the external photometry element. The internal numbers are weighting factors, and the larger the numbers, 0 and 1.0, indicate that the weighting is heavier. is there.

  In S1201 of FIG. 12, the setting is made to increase the weight of the photometric area of frame 1 that is the range in which the light beam reaches the image pickup device in the wide area in FIG. 13 from the external photometric means 117 divided as shown in FIG. Move processing. In S1202, the use of the internal ND filter is canceled, and the process proceeds to S1203. In S1203, the zoom is canceled and the zoom lens is set to the wide end side, and the process proceeds to S1204. Referring to the area output of the external photometry unit 117 set in S1204, the iris position control target L1 is created as shown in FIG. 11L1 in S1205, and the process proceeds to S1206. In S1206, the process proceeds to S1207 with reference to the luminance level via the CCD. In S1207, the brightness difference of appropriate exposure is converted into an encoder movement amount, and the process proceeds to S1208. In step S1208, the iris encoder position is referred to, and the process proceeds to step S1209. The iris position control target G2 as shown in FIG. 11G2 is calculated from the iris encoder position from which the luminance is obtained in S1209 and the necessary encoder movement amount, and the process proceeds to S1210. In S1210, the ratio between the iris position control target of external photometry as shown in FIG. 11L1 and the iris position control target via the CCD as shown in FIG. 11G2 is calculated, and the process proceeds to S1211. In S1211, the brightness is corrected in accordance with the ratio of the iris position control target L1 for external metering calculated in S1210, and the process proceeds to S1212. In S1212, the difference between the corrected iris position control target G1 for external photometry and the iris position control target G2 via the CCD is calculated, and the process proceeds to S1213. In S1213, it is determined whether the difference is zero. If the difference is zero, the process proceeds to S1214, and if not, the process returns to S1204.

  In S1213, the ratio between the iris position control target L1 for external photometry calculated in S1210 and the iris position control target G2 via the CCD is stored as the exposure multiple in the current lens state.

  Thus, even if an external filter is attached, the exposure multiple in the current lens state can be calibrated. Further, the correction of the exposure multiple by using the zoom state or using the internal ND filter is known if the specification is fixed, so if it is stored in the ROM, the combined total exposure multiple can be calculated.

  FIG. 14 shows a second embodiment of step S202 in FIG. 1 and 4 are the same as those in the first embodiment. Compared with the external photometry means 117 photometry area divided into 24 areas as shown in FIG. 6, the frame 1 is a range in which the light beam reaches the image sensor when wide, and the range in which the light beam reaches the image sensor as zooming is To change. Accordingly, there is an effect of correcting the change in brightness due to the zoom magnification by changing the external photometry means 117 photometry area to an area equivalent to the range where the light beam reaches the image sensor in accordance with the zoom magnification.

  In S1401 of FIG. 14, the photometry area is selected by the zoom magnification and the output of the external photometry means 117 is referred to create an iris position control target as shown in FIG. 4L1, and the process proceeds to S1402. In step S1402, the exposure multiple of the external optical filter and the exposure multiple of the internal ND filter input in advance from the key SW 122 are referred to calculate the filter exposure multiple, and the process proceeds to step S1403. The number of exposure multiples of the optical filter is fixed. In S1403, as shown in FIG. 4L1, the iris position control target obtained from the external photometry unit 117 in the selected area is corrected for brightness according to the filter exposure multiple calculated in S1402, and the process proceeds to S1404. In S1404, the corrected iris position control target is calculated as shown in FIG. 4G1, and the process proceeds to S1405. In step S1405, the process proceeds to step S1406 with reference to the luminance level via the CCD. In S1406, the brightness difference of appropriate exposure is converted into an encoder movement amount, and the process proceeds to S1407. In step S1407, the iris encoder position is referred to, and the process proceeds to step S1408. In step S1408, the iris encoder position from which the luminance is obtained and the necessary encoder movement amount are calculated as an iris position control target as shown in FIG. 4G2, and the process proceeds to step S1409. In S1409, the difference between the corrected iris position control target for external photometry as shown in FIG. 4G1 and the iris position control target via the CCD as shown in FIG. 4G2 is calculated, and the process proceeds to S1410. In S1410, it is determined whether the difference is equal to or smaller than the predetermined value A as shown in FIG. 4. If the difference is equal to or smaller than the value, the process proceeds to S1412. If not, the process proceeds to S1411. When the difference is larger than the predetermined value A at time S1411 from time 0 to t1 in FIG. 4, the processing is ended as the control target G3 to pass the iris position control target G1 for external metering to the S203 iris position servo in FIG.

  As a result, even when the iris position control target via the CCD is not reliable, such as before the iris is opened, it is possible to control to a substantially approximate position.

  In S1412, it is determined whether the difference is equal to or smaller than the predetermined value B as shown in FIG. 4. If the difference is equal to or smaller than the predetermined value B, the process proceeds to S1414; When the difference is larger than the predetermined value B at time S1413 from time t1 to time t2 in FIG. 4, the intermediate value between the iris position control target G1 for external metering and the iris position control target G2 via the CCD is set to S203 iris in FIG. The processing ends as a control target G3 to be transferred to the position servo.

  Thus, if the predetermined value B is set to the iris position target difference in which the luminance change cannot be recognized on the screen, and the predetermined value A is doubled to the predetermined value B, the iris position control target of external photometry is changed to the iris position control target via the CCD. When changing, iris position control can be performed without causing an excessive luminance change due to the target value step.

  In S1414, when the difference is equal to or less than the predetermined value B after time t2 in FIG. 4, the process is ended as the control target G3 passing the iris position control target G2 via the CCD to the S203 iris position servo in FIG.

The block diagram which shows the Example of the exposure control apparatus in this invention Flow chart of system control microcomputer Flowchart of S202 in FIG. Time chart showing the iris control target calculation Flowchart of S205 in FIG. The figure explaining the area division state of an external photometry element The figure explaining the photometry area setting and weighting of an external photometry element Time chart showing the iris control target calculation Flowchart of S207 in FIG. The figure explaining the photometry area setting and weighting of an external photometry element Time chart showing the iris control target calculation Flow chart for determining the exposure multiple including external optical filter The figure explaining the photometry area setting and weighting of an external photometry element Flowchart of S202 in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Image pickup lens system 101 Iris 102 Image pick-up element 103 Double correlation sampling circuit 104 AGC circuit 105 Camera signal processing circuit 106 Image signal processing circuit 107 Recording means 108 Gate circuit 109 Integrator 110 A / D converter 111 CCD drive circuit 112 Iris motor 113 Iris Drive Circuit 114 Iris Encoder 115 Iris Encoder Amplifier 116 A / D Converter 117 External Metering Unit 118 Gyro 119 Zoom Unit 120 A / D Converter 121 System Control Microcomputer 122 Key SW

Claims (4)

  Lens means capable of variable magnification photography, an image sensor that converts a subject image into an electrical signal, an exposure control target generation means via an image sensor that calculates an exposure control target based on an output level of the image sensor, and the image sensor Photometric means for detecting the brightness of the subject other than the above, exposure control target generation means via the photometric means for calculating the exposure control target based on the output level of the photometric means, the magnification ratio of the lens means and the light filter loading state Exposure multiple calculation means for calculating an exposure multiple that is a coefficient for correcting an increase in exposure according to the above, and the photometry means after correction with the target value of the exposure control target generation means via the image sensor and the calculated exposure multiple A composition ratio calculating means for determining a target value composition ratio according to a difference from a target value of the via exposure control target generating means, and a target value of the image sensor via exposure control target generating means and the calculated An exposure control target combining unit that combines the target value of the exposure control target generation unit via the photometric unit after correction with a multiple of magnification with the calculated combination ratio, and a light amount adjustment that adjusts the amount of light irradiated to the imaging unit And an exposure control apparatus comprising: a control means for drivingly controlling the light amount adjusting means according to a target value of the exposure control target synthesizing means.   Lens means capable of variable magnification photography, an image sensor that converts a subject image into an electrical signal, an exposure control target generation means via an image sensor that calculates an exposure control target based on an output level of the image sensor, and the image sensor The exposure control target is determined based on the output level of the panning progression direction area of the photometry means when panning is detected, and the photometry means capable of performing photometry divided into a plurality of areas for detecting the brightness of the subject other than Via exposure metering means for calculating exposure control target generation means, exposure multiple calculation means for calculating an exposure multiple that is a coefficient for correcting an increase in exposure according to the magnification ratio of the lens means and the light filter installed, and via the image sensor Depending on the difference between the target value of the exposure control target generation means and the target value of the exposure control target generation means via the photometry means after correction with the calculated exposure multiple, A composite ratio calculating means for determining a value composite ratio; a target value of the exposure control target generating means via the image sensor; and a target value of the exposure control target generating means via the photometric means after being corrected by the calculated exposure multiple. Exposure control target combining means for combining at the calculated combining ratio, light amount adjusting means for adjusting the amount of light applied to the imaging means, and control for driving and controlling the light amount adjusting means according to the target value of the exposure control target combining means An exposure control apparatus comprising: means.   Lens means capable of variable magnification photography, an image sensor that converts a subject image into an electrical signal, an exposure control target generation means via an image sensor that calculates an exposure control target based on an output level of the image sensor, and the image sensor A photometric means capable of photometry divided into a plurality of areas for detecting the brightness of the subject, a lens zoom operation detecting means, and a zoom-out direction area of the photometric means when a lens zoom-out operation is detected, that is, an outer edge area An exposure control target generation unit via a photometric unit that calculates an exposure control target based on an output level, and an exposure multiple that is a coefficient for correcting an increase in exposure according to a magnification ratio of the lens unit and a light-reducing filter loaded state. Exposure multiple calculation means, exposure control target generation via the photometry means after correction with the target value of the exposure control target generation means via the image sensor and the calculated exposure multiple A composition ratio calculating means for determining a target value composition ratio according to a difference from the target value of the means, and the photometry means after being corrected with the target value of the exposure control target generating means via the image sensor and the calculated exposure multiple An exposure control target combining unit that combines the target value of the via exposure control target generation unit with the calculated combination ratio; a light amount adjusting unit that adjusts the amount of light applied to the imaging unit; and a target of the exposure control target combining unit An exposure control apparatus comprising control means for drivingly controlling the light amount adjusting means according to a value.   Lens means capable of variable magnification photography, an image sensor that converts a subject image into an electrical signal, an exposure control target generation means via an image sensor that calculates an exposure control target based on an output level of the image sensor, and the image sensor The photometric means that can divide and measure the brightness of the subject in other areas, the photometric area selection means that selects the photometric means area according to the magnification ratio of the lens means, and the photometric area selection means An exposure control target generation unit that calculates an exposure control target based on the output level of the photometric unit in the area, and an exposure multiple that is a coefficient for correcting an increase in exposure according to the state of the neutral density filter installed. Target value of exposure multiple calculation means, target value of exposure control target generation means via image sensor and target value of exposure control target generation means via photometry means after being corrected by the calculated exposure multiple A composite ratio calculating means for determining a target value composite ratio in accordance with the difference between the exposure value and the exposure control target generation via the photometric means after correction with the target value of the exposure control target generation means via the image sensor and the calculated exposure multiple Exposure control target combining means for combining the target value of the means at the calculated combining ratio; light amount adjusting means for adjusting the amount of light applied to the imaging means; and adjusting the light amount according to the target value of the exposure control target combining means An exposure control apparatus comprising control means for driving and controlling the means.

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