JP6166555B2 - Lens device and photographing apparatus having the same - Google Patents

Description

  The present invention relates to a lens apparatus used for a television camera, a video camera, and the like, and more particularly to a rear focus type lens apparatus and a photographing apparatus having the same.

  2. Description of the Related Art Conventionally, in a rear focus type zoom lens apparatus, a tracking operation for controlling the drive of a focus lens is often performed so as to keep a focused state with respect to a predetermined subject in accordance with the drive of the zoom lens. Various proposals have been made as correction techniques for filling a tolerance between a design value and an actual measurement value including an individual difference of a lens with respect to a tracking curve indicating a focus lens position with respect to a zoom lens position using an object distance as a parameter. .

  Patent Document 1 calculates a correction amount of a focus lens position at a zoom lens position by using a quadratic approximate expression to correct a deviation between a design value and an actual measurement value of a tracking curve caused by manufacturing variations. A method is disclosed.

JP-A-6-141220

  However, in Patent Document 1, since the depth of focus is not considered in the corrected tracking curve, the imaging position is not necessarily within the depth of focus in the corrected tracking curve. The subject may not be in focus. On the other hand, as another correction means, it is conceivable to correct the tracking curve by connecting the actually measured focus position. In this case, the relationship between the zoom lens position and the correction amount does not always change monotonously due to mechanical tolerances or optical errors. That is, the correction value is not a value that gives a smooth change with respect to the zoom axis direction, and may take a discontinuous value. In addition, when the number of correction points is increased in order to improve the accuracy of the tracking curve, the correction value becomes a value that fluctuates in a shorter cycle, and there is a high possibility that the correction value change rate frequently changes in a short cycle. As a result, even if the driving speed of the zoom lens is constant, the amount of change in the driving target position of the focus lens changes frequently, so unnecessary acceleration / deceleration is performed, and vibration and noise may occur.

  The solid line in FIG. 15 shows the tracking curve of the design value at a certain object distance, the vertical axis is the focus lens position, the horizontal axis is the zoom lens position, the black dot is the in-focus position for each zoom lens position, and the broken line is the in-focus position. Represents the in-focus tracking curve created.

  Here, consider a case where the zoom lens is driven at a constant speed from position P1501 to position P1509. The focus lens is driven based on the focusing tracking curve indicated by the broken line, but the driving speed in the section from position P1501 to position P1502 is different from the driving speed in the section from position P1502 to position P1503. As described above, the reason why the driving speed of the focus lens is different for each section is that the correction value of the focus lens takes a value at a change rate that frequently changes in the horizontal axis direction. For this reason, when the zoom lens is driven at a constant speed, the focus lens performs acceleration / deceleration according to this, and vibration and noise are generated.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a lens device that reduces unnecessary acceleration / deceleration of a focus lens during a tracking operation and reduces vibration and noise.

In order to achieve the above object, a lens apparatus according to the present invention includes a zoom lens, a focus lens, an optical system having a diaphragm, a zoom lens position detection unit that detects a position of the zoom lens, and the focus lens. A focus lens position detecting means for detecting the position of the stop; a stop detecting means for detecting the state of the stop; a depth of focus calculating means for calculating the depth of focus of the optical system based on the state of the stop; when the imaging position is within the depth of focus, and tracking data calculation means for calculating the tracking data is the relationship position of said focusing lens of the zoom lens at a predetermined object distance, and stores the tracking data have a storage means, said tracking data calculating means, focus relative to the position of the zoom lens Change the amount of change in the position of the lens to calculate the tracking data so as to minimize, characterized in that.

  According to the present invention, unnecessary acceleration / deceleration of the focus lens during the tracking operation can be reduced, and vibration and noise can be reduced.

1 is a configuration diagram of a lens apparatus according to a first embodiment. Flowchart of correction value calculation in the lens apparatus of Embodiment 1 Flowchart of in-focus position acquisition in the lens apparatus of Embodiment 1 Tracking curve in the lens apparatus of Example 1 Example of tracking curve region division in the lens apparatus of Embodiment 2 Tracking curve joint correction in the lens apparatus of Embodiment 2 Configuration diagram of the lens apparatus of Example 2 Overall Flowchart of Calculation of Correction Value of Lens Device of Embodiment 2 Flowchart for calculating each region correction value of the lens apparatus according to the second embodiment. Flowchart for calculating a seam correction value of the lens apparatus according to the second embodiment. Correction value during tracking operation Configuration diagram of the lens apparatus of Example 3 Flowchart for calculating each region correction value in the lens apparatus of Embodiment 3 Flowchart of tracking operation in the lens apparatus of Embodiment 3 Conventional tracking curve

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  The configuration of the zoom lens apparatus in this embodiment is shown in FIG. In the following description, in order to make the present invention easier to understand, only the main portions of the present invention are shown, and portions that are not characteristic portions of the present invention are omitted.

The zoom lens device 100 of the present invention has an optical system including a zoom lens 101, a focus lens 105, and a movable diaphragm 109.
The zoom lens 101 moves in the optical axis direction and changes the focal length of the zoom lens device 100. The zoom lens 101 is moved in the optical axis direction by a zoom motor 102 driven by a zoom driver 103. The position of the zoom lens 101 is detected by the zoom lens position detection unit 104.

  The focus lens 105 moves in the optical axis direction to change the image forming position of the zoom lens device 100. The focus lens 105 is moved in the optical axis direction by a focus motor 106 driven by a focus driver 107. The position of the focus lens 105 is detected by the focus lens position detection unit 108.

  The movable diaphragm 109 adjusts the amount of light. An iris motor 110 is connected to the movable diaphragm 109. The iris motor 110 is driven by the iris driver 111 to drive the movable diaphragm 109. The position of the movable diaphragm 109 is detected by the iris position detecting means 112.

  The control unit 113 is a microcomputer, for example, and controls driving of the zoom lens 101, the focus lens 105, and the movable diaphragm 109. The focus position acquisition unit 114 acquires the focus position of the focus lens 105 at the zoom lens position. The depth-of-focus calculation unit 115 calculates the depth of focus based on the iris position detection unit 112 and a known allowable circle of confusion. The storage unit 116 is a flash memory, for example, and stores information such as an approximate expression and a tracking curve described later.

  The tracking data calculation unit 117 calculates a tracking curve based on the zoom lens position, the focus position, and the focal depth at each object distance.

  The zoom lens apparatus 100 can be connected to an imaging apparatus (not shown) to form an imaging apparatus, and subject light from the zoom lens apparatus 100 can be captured by the imaging apparatus to obtain a subject image.

  In the zoom lens apparatus according to the first embodiment of the present invention having the above-described configuration, the correction value calculation flowchart is shown in FIG. 2, the focal position acquisition flowchart is shown in FIG. 3, and the tracking curve is shown in FIG. The zoom lens apparatus according to Example 1 of the present invention will be described in detail below with reference to FIGS.

  FIG. 2 shows a flowchart of correction value calculation in the control unit 113 of the first embodiment.

First, in step S200, the focus position of the focus lens corresponding to each zoom lens position is calculated based on the video evaluation value indicating the degree of focus at a certain object distance. Details of step S200 will be described later with reference to FIG.
In step S201, a variable n indicating a sample number of a sample point based on the zoom lens position is initialized with zero. In the present invention, the wide angle end is set to zero.

In step S202, an expression used to calculate the tracking curve is read from the storage unit 116. For example, a quadratic polynomial approximate expression such as Expression (1) is used.
Y _[n] = aX _[n] ² + bX _[n] + c (1)
Here, Y _[n] is a temporary correction value at sample number n, X _[n] is the zoom lens position at sample number n, and a, b, and c are constants calculated using, for example, the least square method.

In step S203, the focal depth [n] at the sample point n calculated in the in-focus position acquisition process in step S200 is read from the storage unit 116.
In step S204, the in-focus position [n] at the sample point n acquired in the in-focus position acquisition process in step S200 is read from the storage unit 116.
In step S205, a temporary correction value [n] is calculated from the formula read in step S202.

  In step S206, the absolute value of the difference between the in-focus position [n] read in step S204 and the temporary correction value [n] calculated in step S205 is half the focal depth [n] read in step S203, that is, one side. Judge whether the depth of focus or less. If the absolute value of the difference is larger than the one-side focal depth, the process proceeds to step S207. On the other hand, if the absolute value of the difference is equal to or less than the one-side focal depth, the process proceeds to step S208.

In step S207, the correction value [n] is rewritten using equation (2).
Off _[n] = Bp _[n] + δ / 2 (2)
In equation (2), Off _[n] is the correction value [n], Bp _[n] is the in-focus position [n], and δ / 2 is half the focal depth [n], that is, one-side focal depth. Further, the sign of δ is negative on the side where the temporary correction value [n] is smaller than the in-focus position [n], that is, on the rear side (image side).
In step S208, the temporary correction value [n] is substituted for the correction value [n].

In step S209, it is determined whether processing has been performed up to the telephoto end, that is, all sample points. If processing has been performed for all sample points, the processing is terminated. On the other hand, if all sample points have not been processed, the process proceeds to step S210.
In step S210, the sample number n is incremented, and the process proceeds to step S203 to repeat a series of processes.

  As described above, the in-focus position is adjusted in a range that falls within the depth of focus in a series of flows, and a relatively continuous tracking curve is set.

  Next, the focus position acquisition process of the control unit 113 in step S200 of FIG. 2 will be described with reference to FIG.

  First, in step S300, the movable diaphragm 109 is driven to the open position. By creating a tracking curve in this state, tracking data is created under the most strict aperture conditions (focus depth conditions) for focusing.

In step S301, the movable diaphragm position is acquired from the iris position detection means 112.
In step S302, the zoom lens 101 is driven to the wide angle end.
In step S303, a variable n indicating the sample number of the sample point is initialized with zero.
In step S304, the depth of focus is calculated from the movable aperture position acquired in step S301 and the known allowable circle of confusion. Since a specific method for calculating the depth of focus is known, the description thereof is omitted.

In step S <b> 305, the zoom lens position is acquired from the zoom lens position detection unit 104.
In step S306, the in-focus position is searched. Specifically, the entire area of the focus lens 105 is driven with a certain driving amount, and the focus lens position showing the highest video evaluation value indicating the degree of focus is set as the focus position. The image evaluation value is acquired from the outside of the lens apparatus 100, for example.

In step S307, the in-focus position searched in step S306 is acquired.
In step S308, the in-focus position [n] acquired in step S307 is stored.
In step S309, the focal depth calculated in step S304 is stored as the focal depth [n].

  In step S310, it is determined whether the zoom lens 101 has been driven to the telephoto end, that is, all sample points. When the zoom lens 101 is at the telephoto end, the focus position acquisition process is terminated. On the other hand, if the zoom lens 101 is not at the telephoto end, the process proceeds to step S311.

In step S311, the sample number n is incremented.
In step S312, the zoom lens 101 is driven to the zoom lens position of the sample point indicated by the sample number n, the process proceeds to step S305, and a series of processes is repeated.
The focus position corresponding to each zoom lens position is calculated as described above.

  Here, FIG. 4 shows a tracking curve to which the first embodiment is applied.

  FIG. 4 shows a tracking curve (design tracking data) having the same design value as that in FIG. 15 and focus tracking obtained by connecting the focus positions at the respective zoom lens positions obtained in the focus position acquisition flow shown in FIG. Shows the curve. In the figure, the vertical axis is the focus lens position, the horizontal axis is the zoom lens position, the black dots are the in-focus positions, the double lines located above and below the black dots are the focal depth range, and the thick solid lines are the tracking curves to which the present invention is applied. Represent. Since the tracking data in the design (design tracking data) and the in-focus position actually measured are shifted due to individual differences due to manufacturing tolerances, environmental conditions (temperature, etc.) used, etc., FIG. As shown in FIG. 5, the design tracking data does not always give the optimum tracking data. Here, consider a case where the zoom lens is driven at a constant speed from position P401 to position P409. In the focus tracking curve indicated by the broken line, the slope of the section from position P401 to position P402 is different from the slope of the section from position P402 to position P403. That is, acceleration / deceleration occurs in the focus lens 105 in the section from the position P401 to the position P403. However, it can be seen that the slope of the section from the position P401 to the position P402 and the slope of the section from the position P402 to the position P403 substantially coincide with each other in the thick solid tracking curve to which the present invention is applied. That is, the acceleration / deceleration of the focus lens 105 can be suppressed in the section from the position P401 to the position P403. Accordingly, since acceleration / deceleration of the focus lens 105 can be reduced, vibration and noise can be suppressed. In addition, since the tracking curve becomes the value of the position of the focus lens that does not require rapid acceleration / deceleration, the rising of the movement of the focus lens 105 is improved, and the followability can be improved.

  In this embodiment, an example in which the depth of focus is calculated has been described. Moreover, although it demonstrated using the depth of focus, the effect of this invention can be acquired even if it uses depth of field. In this embodiment, the depth of focus calculated once in step S304 is repeatedly used. However, considering the F drop, the aperture opening position is determined for each focal length, and the depth of focus is set for each zoom lens position. Even if it calculates, the effect of this invention can be acquired.

  In this embodiment, the focus lens position with the highest image evaluation value is set as the in-focus position. However, the effect of the present invention can be obtained even when the focus lens position at which an image evaluation value equal to or higher than the arbitrarily set threshold is obtained is set as the in-focus position. Can be obtained.

  In the in-focus position acquisition flowchart, the zoom lens is driven from the wide-angle end to the telephoto side to search for the in-focus position, but the in-focus position can be searched by driving from the telephoto end to the wide-angle side. Can be obtained. Furthermore, the effects of the present invention can be obtained even when the in-focus position is calculated for each of the two ways from the telephoto end to the wide-angle side and from the wide-angle end to the telephoto side, and the correction value is calculated to obtain the average value.

  In this embodiment, the sample number n is 0 at the wide-angle end, but the present invention is not limited to this as long as each sample point can be distinguished. For example, the effect of the present invention can be obtained even when the telephoto end is set to zero.

  In the present embodiment, (focus value 0) is set to the image side and the upper side is the depth of focus on the object side with respect to the tracking curve of FIG. 4, but the effect of the present invention can be obtained even if the lower side is the object side and the upper side is the image side. be able to.

  In this embodiment, equation (1) is a second-order polynomial approximation, but the effect of the present invention can be obtained even if the order is arbitrarily changed. Furthermore, the effects of the present invention can be obtained even when an approximate expression other than a polynomial approximate expression, for example, an exponential approximate curve or a two-section moving average is used.

  In the method exemplified in the present embodiment, the tracking curve is determined in consideration of the focal depth by determining the coefficient of the second-order polynomial approximation formula from the actually focused point, and determining the tracking curve. There is no limit. The tracking curve is not limited to this as long as the tracking curve can be calculated to be a continuous value within a range where the imaging position is within the depth of focus. For example, the design tracking curve is stored in advance in the storage means 116 (design data storage means), and the average value of the difference between the actually measured focus position and the design tracking curve is calculated at each zoom lens position. When the design tracking curve is moved in parallel by the calculated average value, and the imaging position is within the depth of focus at each sample point (each zoom lens position), the value obtained by moving the design tracking curve in parallel The effect of the present invention can be obtained even when the correction value [n] is used.

  In this embodiment, Equation (1) is stored in the storage unit 116 in advance. However, even if a plurality of tracking curve calculation methods are prepared in the storage unit 116 and the calculation method is selected from the relationship between the focus positions in the entire area. The effects of the present invention can be obtained.

In the present embodiment, the tracking data calculation unit 117 is configured in the control unit 113. However, the control unit 113 and the lens apparatus 100 are connected to, for example, a PC, and the tracking data calculation unit 117 is provided in the PC, and the correction value [n ] Can also be obtained.
The same applies to the following embodiments.

  A zoom lens apparatus according to the second embodiment will be described. The basic configuration of the zoom lens apparatus of the present embodiment is the same as that of the first embodiment shown in FIG.

  The most characteristic part of the zoom lens apparatus of the present embodiment relative to the first embodiment is that a tracking curve is calculated by dividing the entire drive range of the zoom lens 101 into regions. The solid line in FIG. 5 shows the tracking curve of the design value. The vertical axis indicates the focus lens position, the horizontal axis indicates the zoom lens position, the black dot indicates the in-focus position corresponding to each zoom lens position, and the broken line indicates the in-focus position. Represents a focal tracking curve. In the figure, position P501 to position P503 are defined as area 1, position P504 to position P506 as area 2, and position P507 to position P509 as area 3. In the areas 1, 2, and 3, there are variations in the in-focus positions indicated by the black dots. In the example shown in FIG. 5, the variation tends to be small on the wide angle side and large on the telephoto side. Therefore, by calculating the tracking curve so as to suppress the change in the change rate of the focus lens position more effectively within the range where the imaging position is within the depth of focus for each region, the variation characteristics for each divided region A more appropriate tracking curve reflecting the above can be obtained. That is, the data in the region with small variation can be calculated without being affected by the variation in the data in the region with large variation by calculating the tracking data within the region. On the other hand, for data in a region with large variations, by calculating tracking data within the region, it is possible to avoid the variation correction being underestimated due to the variation in the data in the regions with small variations. Here, since the tracking curve is calculated in a different area between the position P503 and the position P504, the amount of change may increase when the focus lens 105 is driven from the position P503 to the position P504. Therefore, at the region-to-region joints such as the position P503 and the position P504, the change rate of the focus lens position with respect to the zoom lens position represented by the inclination in FIG. The tracking curve data near the seam is adjusted so that the change becomes smaller. The adjustment method of the joint of an area | region will be demonstrated using FIG. The broken lines in FIG. 6 indicate tracking curves calculated within a range that falls within the depth of focus in region 1 and region 2, with the vertical axis representing the focus lens position and the horizontal axis representing the zoom lens position. Also, the black dot is the focus lens position corresponding to each zoom lens position, the star point is the focus lens position adjusted for each position P503 and position P504, and the solid line is the tracking curve after adjusting the joint between region 1 and region 2 Represents. The calculation of the star point that is the adjustment point at the zoom lens positions P503 and P504 is performed by connecting one point (P502 and P505) inside the area I and the area II from the zoom lens positions P503 and P504 at the joint. A straight line can be obtained by interpolating the adjustment points of the zoom lens positions P503 and P504 of the joint. However, the adjustment point is set so that the imaging position is within the depth of focus.

In the following description, in order to make the present invention easier to understand, only main parts of the present invention are illustrated, and the description of other parts is omitted.
FIG. 7 shows the configuration of the zoom lens apparatus in the present embodiment. The description of the same configuration as that of the first embodiment shown in FIG. 1 is omitted, and only the portions different from the first embodiment will be described.

  The area dividing unit 700 divides the entire driving range of the zoom lens 101 into a plurality of areas, and sets an area for which the trunking data calculation unit calculates track data.

  In the above-described configuration, the overall flowchart of the second embodiment shown in FIG. 8, the flowchart for calculating each region correction value of the second embodiment shown in FIG. 9, and the joint correction value shown in FIG. This will be described in detail using a calculation flowchart.

  FIG. 8 shows an overall flowchart of the second embodiment.

First, in step S800, a focus lens position corresponding to each zoom lens position is calculated based on the video evaluation value at a certain object distance. Since step S800 is the same as step S200 in FIG. 2, detailed description thereof is omitted. In step S801, a tracking curve is calculated for each region divided with respect to the sample points as each region correction value calculation processing.

  In step S802, a process of adjusting the joint between the divided areas and the areas is performed as a joint correction value calculation process.

Next, the area correction value calculation processing in step S801 will be described in detail with reference to FIG.
In this embodiment, description will be made according to the in-focus position, areas 1 to 3 and positions P501 to P509 shown in FIG.

  First, in step S900, a variable n indicating a sample number of a sample point is initialized with zero.

In step S901, the sample number 3 corresponding to the position P503 is substituted for the variable β indicating the sample number of the sample point.
In step S902, an equation for calculating a tracking curve is read from the storage unit 116. For example, it is set as Formula (1).

In step S903, the focal depth [n] calculated in step S800 in-focus position acquisition processing is read from the storage unit 116.
In step S904, the in-focus position [n] acquired in step S800 in-focus position acquisition processing is read from the storage unit 116.
In step S905, a temporary correction value [n] is calculated from the equation read in step S902.

  In step S906, the absolute value of the difference between the in-focus position [n] read in step S904 and the temporary correction value [n] calculated in step S905 is half the focal depth [n] read in step S903, that is, one side. Judge whether the depth of focus or less. If the absolute value of the difference is larger than the one-side focal depth, the process proceeds to step S907. On the other hand, if the absolute value of the difference is equal to or less than the one-side focal depth, the process proceeds to step S908.

In step S907, the correction value [n] is rewritten using equation (2).
In step S908, the correction value [n] is rewritten to the temporary correction value [n].
In step S909, the sample number n is incremented by adding 1.

  In step S910, it is determined whether the sample number n is greater than the sample number β. That is, it is determined whether processing has been performed up to the sample number β. If the process has been performed up to the sample number β, the process proceeds to step S911. On the other hand, if the process has not been performed up to the sample number β, the process proceeds to step S903 to repeat a series of processes.

In step S911, it is determined whether the sample number β is 3. If the sample number β is 3, the process proceeds to step S912. On the other hand, if the sample number β is not 3, the process proceeds to step S913.
In step S912, sample number 6 corresponding to position P506 is substituted for sample number β, and the process returns to step S902.

In step S913, it is determined whether the sample number β is 6. If the sample number β is 6, the process proceeds to step S914. On the other hand, if the sample number β is not 6, each region correction value calculation process is terminated.
In step S914, sample number 9 corresponding to position P509 is substituted for sample number β, and the process returns to step S902.
As described above, the tracking curve is calculated for each region in a series of flows.

  Next, the seam correction value calculation process in step S802 will be described with reference to FIG.

First, in step S1000, sample number 3 corresponding to position P503 is substituted for variable β indicating the sample number of the sample point.
In step S1001, a straight line connecting points (P502 and P505) on the inner side of the regions I and II from the zoom lens positions P503 and P504, respectively, is obtained as a correction straight line.

In step S1002, based on the obtained correction straight line, temporary adjustment values off1 _[β] and off1 _{[β + 1]} at the zoom lens position β and the next zoom lens position β + 1 are interpolated and calculated.
In step S1003, the temporary adjustment values off1 _[β] and off1 _{[β + 1] at the} zoom lens positions β and β + 1 and off _{[β] as the} correction value [β] are corrected according to the expressions (3) and (4). calculating the difference diff1, diff2 with the value _{[β + 1] off [β} + 1].
diff1 = off1 _[β] ― off _[β] (3)
diff2 = off1 _{[β + 1]} ― off _{[β + 1]} (4)

In step S1004, it is determined whether the absolute value of the difference diff1 is equal to or less than half the focal depth [β], that is, one-side focal depth. If the absolute value of the difference diff1 is less than or equal to the one-side focal depth, the process proceeds to step S1005. If the absolute value of the difference diff1 is larger than the one-side focal depth, the process proceeds to step S1006.
In step S1005, it rewrites the correction value [beta] adjustment value off1 _[beta] as the correction value [beta].

  In step S1006, it is determined whether the absolute value of the difference diff2 is half of the focal depth [β + 1], that is, less than the one-side focal depth. If the absolute value of the difference diff2 is less than or equal to the one-side focal depth, the process proceeds to step S1007. When the absolute value of the difference diff2 is larger than the one-side focal depth, the process proceeds to step S1008.

In step S1007, the correction value [β + 1] is rewritten with the adjustment value off1 _[ β + 1] as the correction value [β + 1].
In step S1008, it is determined whether the sample number β is 3. If the sample number β is 3, the process proceeds to step S1007. On the other hand, if the sample number β is not 3, the joint correction value calculation process is terminated.
In step S1007, sample number 6 corresponding to position P506 is substituted for sample number β, and the process returns to step S1001.

  As described above, it is possible to calculate a tracking curve with higher accuracy by calculating the tracking curve for each region in a series of flows. Further, by correcting the sample point at the joint between the regions, a tracking curve that does not cause a sudden change in the driving speed of the focus lens even between the regions can be provided, and smooth focus lens driving can be realized.

  In this embodiment, the number of regions is three. However, if the tracking curve is calculated by dividing the region into two or more regions, the effect of the present invention can be obtained. Further, although the area is determined for each sample point in advance, the effect of the present embodiment can be obtained even if the range of each area is appropriately changed according to the variation in the focus position.

In the present embodiment, one sample point belongs to one region, but the effect of the present invention can be obtained even if one sample point belongs to a plurality of regions. For example, assuming that the position P504 belongs to the area 1 and the area 2, the tracking curve is calculated for the area 1 from the position P501 to the position P504. Thereafter, the tracking curve is calculated for the region 2 from the position P504 to the position P506. The focus lens position at the position P504 may be an average of the positions calculated in the area 1 and the area 2. Alternatively, the tracking curve may be calculated in the area 2 with the position calculated when calculating the tracking curve in the area 1 as the in-focus position of the position P504.
The same applies to the following embodiments.

  A zoom lens apparatus according to the third embodiment will be described.

  The most characteristic part of the zoom lens apparatus of the present embodiment relative to the first embodiment is that the movable diaphragm is opened when the tracking curve is calculated. However, when used in actual photographing, the movable diaphragm is opened. It is the point which paid attention to being narrowed down. Compared to the case where the movable diaphragm is opened, the depth of focus becomes deeper when the diaphragm is stopped. Therefore, in this embodiment, the sample point with the focus lens position at the end of the depth of focus when calculating the tracking curve is the focus lens that gives the smoothest tracking curve when the imaging position at the time of shooting is within the depth of focus. Drive the focus lens to the position. The broken line in FIG. 11 shows a part of the tracking curve calculated at the time of adjustment, the vertical axis corresponds to the focus lens position, the horizontal axis corresponds to the zoom lens position, the black point corresponds to the in-focus position, and the double line above and below the black point corresponds to the black point. The depth of focus, and the upper and lower thick lines represent the depth of focus at the time of shooting. As indicated by the broken line, the focus lens position at the position P1100 is the image-side focal depth. The depth of focus at the time of shooting indicated by a thick line is larger than the depth of focus at the time of tracking curve calculation indicated by a double line. Therefore, at the position P1100, the tracking curve becomes a solid line by performing the tracking operation with the star point as the focus lens position. The tracking curve indicated by the solid line is a tracking curve that can reduce vibration and noise caused by driving the focus lens because the position of the focus lens changes more uniformly than the tracking curve indicated by the broken line.

In the following description, in order to make the present invention easier to understand, only main parts of the present invention are illustrated, and the description of other parts is omitted.
FIG. 12 shows the configuration of the zoom lens apparatus in the present embodiment. The description of the same configuration as that of the first embodiment shown in FIG. 1 and the second embodiment shown in FIG. 7 is omitted, and only the parts different from the first and second embodiments will be described.

The correction review unit 1200 (re-correction unit) determines whether the focus lens target position is at the end of the depth of focus at the time of calculating the tracking curve. Calculate the target position.
The tracking unit 1201 performs a tracking operation based on the focus lens target position determined by the correction review unit 1200.

  The above-described configuration will be described in detail with reference to the flowchart for calculating each region correction value of the third embodiment shown in FIG. 13 and the flowchart of the tracking operation of the third embodiment shown in FIG.

FIG. 13 shows a flowchart for calculating the tracking curve, and the description of the same parts as in FIG. 9 is omitted.
The process of FIG. 13 is executed after the focus position acquisition process shown in FIG. 3 is executed.

In step S1300, since it is determined in step S906 that the temporary correction value [n] does not fall within the one-side focal depth, the sample point is stored as the variable correction examination position [n].
As described above, when the tracking curve is calculated from the series of flows, the sample points having the correction value as one-side focal depth when the temporary correction value does not fall within the focal depth are stored.

  FIG. 14 is a flowchart at the time of the tracking operation of the present invention.

First, in step S1400, the tracking curve calculated in the flowchart for calculating each region correction value in the third embodiment shown in FIG. 13 is read.
In step S1401, the zoom lens position is acquired from the zoom lens position detection unit 104.

In step S1402, the focus lens position is acquired from the focus lens position detection unit.
In step S1403, the movable diaphragm position is acquired from the movable diaphragm position detecting means 112.

In step S1404, the depth of focus is calculated from the movable aperture position acquired in step S1403 and the known allowable circle of confusion.
In step S1405, a correction value is acquired based on the tracking curve read in step S1400 and the zoom lens position acquired in step S1401.

  In step S1406, it is determined whether the zoom lens position acquired in step S1401 is the correction examination position stored in step S1300. If the zoom lens position is stored in the variable correction examination position, the process proceeds to step S1407. On the other hand, if the zoom lens position is not stored in the variable correction examination position, the process proceeds to step S1412.

In step S1407, an expression for calculating the focus lens position with respect to the zoom lens position is read from the storage unit 116. For example, it is set as Formula (1).
In step S1408, a temporary correction value is calculated based on the formula read in step S1407.
In step S1409, the in-focus position stored in step S308 is read.

  In step S1410, it is determined whether the absolute value of the difference between the in-focus position read in step S1409 and the temporary correction value calculated in step S1408 is equal to or less than half the focal depth calculated in step S1404, that is, one-side focal depth. If the absolute value of the difference is larger than the one-side focal depth, the process proceeds to step S1412. On the other hand, if the absolute value of the difference is less than or equal to the one-side focal depth, the process proceeds to step S1411.

In step S1411, the temporary correction value calculated in step S1408 is substituted into the correction value.
In step S1412, the focus lens target position is calculated from the correction value and the focus lens position acquired in step S1402.
In step S1413, the focus lens is driven based on the focus lens target position calculated in step S1412.

As described above, when the correction value of the sample point is set at the end of the depth of focus in a series of flows, the correction value is calculated based on the depth of focus calculated from the movable diaphragm position at the time of tracking operation. It becomes possible to drive based on a simple tracking curve. Therefore, vibration and noise can be further reduced.
In this embodiment, the area is divided when calculating the tracking curve. However, the effect of the present invention can be obtained without dividing the area as in the first embodiment.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

DESCRIPTION OF SYMBOLS 100: Lens apparatus 101: Zoom lens 104: Zoom lens position detection means 105: Focus lens 107: Focus lens drive means 108: Focus lens position detection means 109: Movable aperture 112: Iris position detection means (aperture detection means)
115: Depth of focus calculation means 116: Storage means 117: Tracking data calculation means 700: Area division means 1200: Correction examination means 1201: Tracking means

Claims (7)

An optical system having a zoom lens, a focus lens, and an aperture;
Zoom lens position detecting means for detecting the position of the zoom lens;
Focus lens position detecting means for detecting the position of the focus lens;
A diaphragm detecting means for detecting the state of the diaphragm;
A depth of focus calculation means for calculating a depth of focus of the optical system based on the state of the aperture;
Tracking data calculating means for calculating tracking data that is a relationship between the position of the zoom lens and the position of the focus lens at a predetermined object distance when the imaging position of the optical system is within the depth of focus;
Storage means for storing the tracking data,
I have a,
The tracking data calculating means calculates the tracking data so that a change in a change amount of a focus lens position with respect to a position of the zoom lens is minimized;
A lens device. The lens apparatus according to claim 1 , wherein the tracking data calculation unit calculates tracking data based on an approximate expression. Design data storage means for storing design tracking data indicating the position of the focus lens corresponding to the position of the zoom lens;
The tracking data calculation unit is configured to track tracking data based on the design tracking data and an average value of a difference between the focus lens position focused at the zoom lens position and the focus lens position indicated by the design tracking data. To calculate,
The lens device according to claim 1 . Said tracking data calculation means according to claim 1, characterized in that to calculate the tracking data on the basis of a curve connecting an arbitrary position in the depth of focus corresponding to the position of any two or more of the zoom lens Lens device. An area dividing means for dividing the position of the zoom lens into a plurality of areas as an object for which the tracking data calculating means calculates tracking data;
Seam correction for correcting the change in the change rate of the focus lens position with respect to the zoom lens position from the divided area to the joint of the area to be the minimum, and correcting the focus lens position within the depth of focus Means,
Have
The tracking data calculating means calculates tracking data for each area divided by the area dividing means;
Lens device according to any one of claims 1 to 4, characterized in that. When driving the focus lens based on the tracking data calculated when the aperture is in the open state, the lens apparatus considers the depth of focus according to the aperture value when the aperture is stopped from the open state. position change of the rate of change of position of the focus lens with respect to the zoom lens has a re-correction means for re-corrected to be smaller, that the lens device according to 1, wherein any one of claims 1 to 5, characterized in. A lens device according to any one of claims 1 to 6, imaging apparatus including an imaging device for imaging a subject light from the lens apparatus.

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