JP7631012B2 - Lens device, imaging device, control method and program - Google Patents

Description

The present invention relates to a lens device, an imaging device, a control method, and a program.

There is known a television camera lens device that electrically operates (adjusts) the position of a relay lens group on the optical axis. Patent Document 1 discloses adjusting the position of the relay lens group for each of a number of shooting modes that use different wavelength ranges. Patent Document 2 discloses returning the position of the relay lens group to its initial position.

Patent No. 3997471 Japanese Patent Application Publication No. 11-281866

Patent Documents 1 and 2 do not take into consideration the linked operation of the relay lens group and the focus lens group. As a special image effect, a subject may be blurred by operating the relay lens group, and then the subject may be brought into focus by operating the relay lens group again, and then a different subject may be brought into focus by operating the focus lens group. In this case, the speed at which the focus moves may suddenly change when switching between the operation of the relay lens group and the operation of the focus lens group.

The present invention aims to provide a lens device that is advantageous for, for example, operating a relay lens group and an operating a focus lens group in succession.

In order to achieve the above-mentioned object, the lens device of the present invention has a focus lens group, a relay lens group, a focus drive unit that drives the focus lens group, a relay drive unit that drives the relay lens group, and a control unit that controls the focus drive unit, and is characterized in that when the focus lens group is driven consecutively after the relay lens group is driven , the control unit controls the focus drive unit based on the movement speed of the focal point when the relay lens group is driven.

The present invention can provide a lens device that is advantageous for, for example, operating a relay lens group and an operating a focus lens group in succession.

FIG. 1 is a configuration diagram of a first embodiment. FIG. 4 is a diagram showing a focus movement speed in the first embodiment. 5A and 5B are diagrams relating to focus speed determination in the first embodiment. 1 is a flowchart of a first embodiment. 11 is a flowchart of a second embodiment.

Below, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Figure 1 is a diagram showing the configuration of a lens device according to an embodiment of the present invention.

Below, referring to FIG. 1, a lens configuration diagram according to a first embodiment of the present invention will be described. The lens device 100 allows focus adjustment using a focus lens (focus lens group) 105 and a relay lens 101. The relay lens 101 can move in the optical axis direction for flange back adjustment and focus adjustment during macro photography, and is used for focus adjustment in special effect photography. Both the focus lens 105 and the relay lens 101 can be electrically operated. The position of the focus lens 105 is detected by a focus encoder 106, and is driven by a focus driver 107. The position of the relay lens 101 is detected by a relay encoder 103, and is driven by a relay driver 102. The focus encoder 106 and the relay encoder 103 each include an encoder and a counter that counts its pulses.

Furthermore, a focus drive signal generating unit 110 and a relay drive signal generating unit 104 are configured to generate control signals for the focus drive unit 107 and the relay drive unit 102, respectively. Next, a relay controller 300 is connected to the relay drive unit 102 via a communication unit 116, and a focus controller 200 is connected to the focus drive signal generating unit 110 via the communication unit 116, and the respective controls are input.

By configuring an imaging device having a lens device 100 and a camera device 400 having an image sensor 401 that captures an image formed by the lens device 100, it is possible to configure an imaging device that can enjoy the effects of the present invention.

A zoom lens (zoom lens group), an iris (aperture stop), and an extender lens (extender lens group) that can be inserted into or removed from the optical path are also configured. In the configuration of this embodiment, only the zoom encoder 115, iris encoder 114, and extender encoder 113, which are the position detection units, are described. Like the focus encoder 106 and relay encoder 103, these encoders also include an encoder and a counter that counts its pulses.

The focus sensitivity acquisition unit 111 calculates the movement speed of the focus (focal point) on the image. The focus speed determination unit (control unit) 109 determines a focus speed (drive speed of the focus lens) that matches the focus movement speed (speed of change of the focal distance) calculated by the focus sensitivity acquisition unit 111, based on the state of the lens device (including at least one of the position of the focus lens and the position of the relay lens). The focus operation at the focus speed determined by the focus speed determination unit 109 results in the operation of the focus lens 105 in a mode different from the operation of the focus controller 200 or the autofocus operation (automatic control to the focus target position) using the AF sensor 108.

The ROM 112 stores focus sensitivity data based on the optical state, such as focus position, zoom position, iris position (aperture diameter), extender position (magnification based on), and relay position. The focus sensitivity acquisition unit 111 calculates the focus movement speed of the relay lens 101 based on this data.

The focus speed determination unit 109 also calculates and determines the focus speed from the focus sensitivity data stored in the ROM 112. The sensitivity data may be read from a table or the like, or may be derived according to a predetermined calculation method.

Figure 2 shows the change in the focal position on the image when shooting with the aim of using relay lens 101 to focus from a blurred state on subject 1 (focusing distance A), and then immediately afterwards using autofocus to focus on subject 2 (focusing distance B). The horizontal axis shows time, and the vertical axis shows the focusing distance.

By operating a switch on the relay controller 300, the position of the relay lens 101 can be moved to the flange back position adjusted by the camera device 400 and to a position shifted from the flange back position adjusted by the camera device 400.

Figure 2(a) shows the case where the focus speed is not determined by the focus sensitivity acquisition unit 111 and the focus speed determination unit 109, and the focus lens 105 operates in normal autofocus mode. As shown in Figure 2(a), the rate of change in the focal distance differs at time T1 between when the relay lens 101 is operating (time T0 to T1) and when the focus lens 105 is operating in autofocus mode (time T1 to T2).

Figure 2 (b) is a diagram showing the case where the focus lens 105 is driven at a focus speed determined by the focus sensitivity acquisition unit 111 and the focus speed determination unit 109. The focus speed is set and controlled so that at time T1, the focus change speed (the speed at which the focal distance changes) caused by driving the relay lens 101 is equal to the focus change speed caused by the autofocus operation that drives the focus lens 105.

The AF drive at the focus speed determined by the focus speed determination unit 109 returns to the normal focus speed at a preset predetermined time (t1) after the relay lens 101 stops (time T1). Therefore, in FIG. 2(b), in the AF drive after time T4, the focus lens is driven at the normal drive speed.

Figure 3 is a diagram showing the amount of change in focus on the horizontal axis and the positions of the relay lens 101 and focus lens 105 on the vertical axis around the time when relay lens drive transitions to AF drive, which is sandwiched between time T1 in Figure 2(b). Since Figure 3 is a diagram showing the state of Figure 2(b) in which the focal distance is proportional to time, the focal distance on the horizontal axis of Figure 3 corresponds to a scale proportional to time. The value a on the horizontal axis is the depth of field when the relay lens 101 is in the flange back position and the focus lens 105 is in a position (A) where it focuses on the subject 1.

The setting of the focus speed during autofocus operation of the focus lens 105 (times T1 to T3 in FIG. 2B) will be described with reference to FIG. 3. Based on the drive speed of the relay lens 101 from time T0 to T1 in FIG. 2B and the focus sensitivity data of the relay lens 101 stored in ROM 112, the focus change speed (change in focal distance per unit time) X from -4a to -a on the horizontal axis in FIG. 3 is calculated. After that, the drive speed Y of the focus lens 105, which moves from the object distance (A) of subject 1 to the object distance (B) of subject 2, is calculated from the focus sensitivity data of the focus lens 105 stored in ROM 112 so that the focus change speed becomes X.

FIG. 4 is a flow chart of this embodiment.
In S101, it is confirmed whether the relay lens 101 is in operation, and if not, the process proceeds to S112 to perform normal autofocus operation. If the relay lens 101 is in operation, the process proceeds to S102 to prohibit autofocus, and the process proceeds to S103.

In S103, the focus movement speed X caused by driving the relay lens is calculated, and the process proceeds to S104.
In S104, it is confirmed whether the operation of the relay lens 101 is completed, and if it is not completed, the process returns to S102, whereas if it is completed, the process proceeds to S105.

In S105, the focus position of the subject 2 is identified by the AF sensor 108, and in S106, the drive speed Y of the focus lens during autofocus, which corresponds to the focus movement speed X of the relay lens, is calculated, and the process proceeds to S107.

In S107, the drive speed of the focus lens during autofocus is changed to Y, and the process proceeds to S108, where the timer is started.

In S109, autofocus is started. After autofocus is started in S109, in S110, it is checked whether the timer started in S108 has reached a specified time. If the specified time has not been reached, autofocus continues at the focus lens drive speed set in S107. If the specified time has been reached, the process proceeds to S111, where the normal autofocus speed is restored, and in S112, normal autofocus is resumed.

In this embodiment, the focus speed is set according to the speed at which the relay lens 101 moves from a blurred state to a focused state, but the focus speed may be set to the speed at which the relay lens 101 moves from a focused state to a blurred state in the opposite direction.

In addition, in this embodiment, the relay lens 101 and the focus lens 105 are operated individually and continuously, but a preset drive for driving the relay lens 101 and the focus lens 105 continuously may be registered, and the lenses may be driven by reproducing the preset operation.

In addition, in this embodiment, the focus controller 200 and relay controller 300 are configured separately, but since focus operation is prohibited while the relay lens 101 is in operation, they may be configured as a single controller with the same operating members for focus and relay.

In the first embodiment, the relay lens 101 is used to focus on the subject 1 from a blurred state, and then the operation of focusing on the subject 2 immediately thereafter is performed by autofocus that can determine the position of the subject 2. In the second embodiment, the target subject position for the operation of focusing on the subject 2 is not determined within the lens device 100, and the focus controller 200 is used to focus (manual focus operation) which is different.
A detailed description will be given with reference to the flow chart of the second embodiment shown in FIG.

In S201, it is confirmed whether the relay lens 101 is being driven, and if it is not being driven, the process proceeds to S213, where normal focusing operation is performed with focus demand. If the relay lens 101 is being driven, the process proceeds to S202.

In S202, the focus controller operation is disabled, and in S203, the focus movement speed X caused by driving the relay lens is calculated, and the process proceeds to S204.

In S204, it is confirmed whether driving of the relay lens 101 is completed, and if not, the operations of S202 and S203 are repeated. If driving of the relay lens 101 is completed, the process proceeds to S205.

In S205, a focus position error limit value Z is calculated to limit the position error, which is the difference between the focus lens position and the focus control, so that the focus lens drive speed Y, which corresponds to the focus movement speed X caused by driving the relay lens, is not exceeded (so that the focus lens drive speed is equal to or lower than the movement speed of the focal point during the drive of the relay lens).

In S206, the focus position error limit value is changed to Z. In this embodiment, the drive speed of the focus lens is not set to a drive speed of the focus lens that is equal to the focus movement speed of the first embodiment. In this embodiment, an upper limit is set to the drive speed of the focus lens to limit it so that the focus movement speed due to the drive of the focus lens does not exceed the focus movement speed X due to the drive of the relay lens. In other words, when the focus lens is driven continuously after the operation of the relay lens, the drive speed of the focus lens is set and limited based on the focus sensitivity so that the rate of change of the focus distance due to the drive of the focus lens is equal to or lower than the rate of change of the focus distance when the relay lens is operating.

In S207, a timer is started, and in S208, operations on the focus controller 200 are enabled. The focus controller 200 is a controller with an operation section that has no ends, that is, a so-called endless operation section.

In S209, it is confirmed whether the focus controller 200 is stopped. S209 is repeated until the focus controller 200 is stopped, and if the focus controller 200 is stopped, the process proceeds to S210, where communication data for setting the focus position at the time of stopping in the focus controller is transmitted from the communication unit 116 to the focus controller 200.
In S211, it is confirmed whether the timer started in S207 has reached a specified time. If the specified time has not been reached, the process returns to S209, and if the specified time has been reached, the focus position error limit is returned to the normal value in S212, and the process returns to normal focus controller operation.

In this embodiment, when the focus lens 105 is driven continuously after the operation of the relay lens 101, the drive speed of the focus lens 105 is determined based on the rate of change of the object distance using the depth of field as a reference (scale). This makes it possible to avoid giving an uncomfortable impression about the focus state of the image during and after the transition from the operation of the relay lens 101 to the driving of the focus lens 105.

Other Examples
The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.
By controlling the switching from relay lens operation to focus lens operation in this manner, it is possible to prevent a sudden change in focus movement speed at the time of switching, which may cause a viewer of the captured image to feel uncomfortable.

The above describes preferred embodiments of the present invention, but the present invention is not limited to these embodiments, and various modifications and variations are possible within the scope of the gist of the invention.

101: Relay lens 102: Relay driver 105: Focus lens 107: Focus driver 109: Focus speed determination unit (control unit)

Claims (16)

A focus lens group;
A relay lens group;
a focus driving unit that drives the focus lens group;
a relay driver that drives the relay lens group;
A control unit that controls the focus drive unit,
The control unit controls the focus drive unit based on the focal point movement speed during the driving of the relay lens group when the focus lens group is driven consecutively after the driving of the relay lens group. The lens device according to claim 1, characterized in that the control unit obtains the movement speed based on the state of the lens device. The lens device according to claim 2, characterized in that the state of the lens device relates to at least one of the position of the focus lens group and the position of the relay lens group. The lens device according to claim 2 or 3, characterized in that it has a zoom lens group, and the state of the lens device relates to the position of the zoom lens group. A lens device according to any one of claims 2 to 4, characterized in that it has an aperture stop, and the state of the lens device relates to the aperture diameter of the aperture stop. A lens device according to any one of claims 2 to 5, characterized in that it has an extender lens group that can be inserted into or removed from the optical path, and the state of the lens device relates to the insertion or removal of the extender lens group. The lens device according to any one of claims 2 to 6, characterized in that the control unit controls the focus drive unit based on the focus state. The lens device according to any one of claims 2 to 6, characterized in that the control unit controls the focus drive unit so that the focal point movement speed during the driving of the focus lens group is equal to or less than the focal point movement speed during the driving of the relay lens group. The lens device according to claim 8, characterized in that the control unit controls the focus drive unit based on the rate of change of the object distance and the depth of field. The lens device according to any one of claims 1 to 9, characterized in that the control unit controls the focus drive unit based on a target position of the focus lens group that is stored in advance. 11. The lens device according to claim 1, wherein the control unit controls the focus drive unit so as not to drive the focus lens group when driving the relay lens group. 12. A lens device according to claim 1, wherein the driving of the relay lens group focuses on a subject at a first focusing distance, and the driving of the focus lens group focuses on a subject at a second focusing distance different from the first focusing distance. 13. The lens device according to claim 1, wherein the relay lens group is movable in the optical axis direction for flange back adjustment. 13. An imaging device comprising: a lens device according to claim 1; and an imaging element for capturing an image formed by the lens device. 1. A method for controlling a lens apparatus having a focus lens group and a relay lens group, comprising:
a control method for controlling the driving of the focus lens group based on a focal point movement speed during the driving of the relay lens group when the focus lens group is driven consecutively after the driving of the relay lens group, the control method comprising: A program for causing a computer to execute the control method according to claim 15 .

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