JP6153324B2 - Interchangeable lens and shooting system - Google Patents

Description

  The present invention relates to an interchangeable lens, and an imaging system including an interchangeable lens and a camera body to which the interchangeable lens is detachable.

  Japanese Patent Application Laid-Open No. 2004-228561 discloses an imaging system in which an extender is provided on the image side of a zoom lens so that the extender can be inserted into and retracted from the optical path, and zooming is performed in a range different from the zooming range of only the zoom lens. Japanese Patent Application Laid-Open No. 2004-228688, when the magnification of the extender detects switching, moves the zoom lens so that the focal lengths match before and after the switching, and automatically switches the extender magnification when the zoom lens reaches the wide end or the tele end. A system is disclosed.

Japanese Patent Laid-Open No. 02-079810 JP 2001-51183 A

  However, if an interchangeable lens with a built-in extender is attached to a camera body that is not supposed to be attached, the camera body will not be able to accurately grasp the presence or absence of the extender and the timing of insertion / extraction, resulting in a problem with automatic focus adjustment (AF). There is a risk. This is because the brightness decreases due to the insertion of the extender into the optical path, and the brightness is not such that focus detection is possible.

  An exemplary object of the present invention is to provide an interchangeable lens and an imaging system capable of preventing a focus adjustment problem when an interchangeable lens with a built-in extender is mounted on a camera body that is not supposed to be mounted. And

The interchangeable lens of the present invention is an interchangeable lens that can be attached to and detached from a camera body capable of performing automatic focus adjustment, has a control unit that communicates with the camera body and a photographing optical system, and the photographing optical system includes: An optical unit that changes an F number of the photographing optical system, and the optical unit is retracted from the optical path of the photographing optical system and a position inserted in the optical path without removing the interchangeable lens from the camera body. It is possible to change the F number of the photographing optical system by moving between the positions, and the optical unit moves while the camera body is mounted with the interchangeable lens on the camera body. wherein a camera is not configured to recognize the change in F-number, and the F-number by the movement of the optical unit caused by In response to the camera body may not be able to perform automatic focusing by changed, said control means transmits a first signal for executing the automatic focusing on the interchangeable lens from the camera body A second signal for preventing the camera from being transmitted is transmitted to the camera body.

  According to the present invention, it is possible to provide a photographing system capable of preventing a focus adjustment defect when an interchangeable lens with a built-in extender is attached to a camera body that is not supposed to be attached.

It is a block diagram of the imaging system of this embodiment. It is a flowchart explaining operation | movement of CPU102 in a lens when the extender shown in FIG. 1 is inserted / extracted. (Example 1) It is a flowchart explaining operation | movement of CPU102 in a lens when the extender shown in FIG. 1 is inserted / extracted. (Example 2)

  FIG. 1 is a block diagram of the photographing system of the present embodiment. The photographing system includes an interchangeable lens 101 and a single-lens reflex digital camera (hereinafter referred to as “camera body 115”).

  The interchangeable lens 101 is configured to be detachable from a camera body 115 having a focus detection function via a mount (not shown), and the camera body 115 and the interchangeable lens 101 communicate information via communication terminals 117 and 104. Can do. The interchangeable lens 101 is also supplied with power from the camera body 115 via the communication terminals 117 and 104.

  For example, the interchangeable lens 101 transmits lens-specific optical information (information such as the current focal length, F value, focus sensitivity, focus correction amount), characteristic information, and other information to the camera body 115. Similarly, the interchangeable lens 101 receives specific information of the camera body 115, for example, the type of the camera body 115, the name of the camera body 115, and the version of the control program of the camera body 115.

  “Optical information” means optical unique information that changes in accordance with the state of zoom, focus, diaphragm blades, and the like. “Characteristic information” is basically unique information that does not change depending on the state, for example, the name of the interchangeable lens 101 (ID information for specifying the model), the maximum communication speed, the open F value, and whether or not it is a zoom lens. , It means information such as image height that can be AF. The other information includes information such as an operation state, a setting state, various information request commands (transmission requests), and drive commands.

  When the camera body 115 acquires characteristic information and optical information unique to the interchangeable lens 101, the camera body 115 can appropriately perform AF, auto exposure (AE), image correction, and the like.

  The interchangeable lens 101 includes a photographing optical system, various driving units, an in-lens CPU 102, and a switch (SW) 125.

  The photographing optical system forms an optical image of an object (subject), and includes a focus lens 105, a variable power lens (zoom lens) 103, a diaphragm 107, and a camera shake correction lens 110 along the optical axis OA in order from the object side. Each lens has one or a plurality of lenses and is unitized. However, for the sake of simplicity, each lens is illustrated as a single lens.

  The focus lens 105 is moved in the direction of the optical axis OA by a driving unit (not shown) (for example, a stepping motor) to adjust the focus. During AF, the driving means is driven by the focus driving circuit 106 and controlled by the CPU 102 within the driving lens by the focus lens driving circuit 106. The focus lens 105 is driven by a user manually operating an MF drive unit 126 such as a focus ring during manual focus adjustment (manual focus (MF)).

  The zoom lens 103 is moved in the optical axis direction by a driving unit (not shown) to change the focal length.

  The diaphragm 107 adjusts the amount of light incident on the image sensor 121 of the camera body 115, and the diaphragm blades that change the size of the aperture diameter (diaphragm diameter) are driven by the diaphragm drive circuit 108.

  The camera shake correction lens 110 is moved in a direction orthogonal to the optical axis OA by the camera shake correction driving circuit 112 to correct image blur. The “perpendicular direction” only needs to have a component orthogonal to the optical axis OA, and may be moved obliquely with respect to the optical axis OA.

  Further, the photographic optical system is provided with an extender 113 that can be manually inserted into and retracted from the optical path of the photographic optical system by a photographer by means of an unillustrated insertion / extraction operation member. The extender 113 is a built-in extender built in the interchangeable lens 101. The insertion / removal detection means 114 detects that the extender 113 has been inserted / removed with respect to the optical axis OA of the photographing optical system, and transmits the detection result to the in-lens CPU 102.

  The extender 113 is an optical unit that can be inserted into and retracted from the optical path of the photographing optical system without attaching or detaching the interchangeable lens 101 and the camera body 115, and changes the focal length of the photographing optical system. When the extender 113 is inserted into and removed from the optical axis, the brightness (F number) of the photographing optical system also changes. FIG. 1 shows a state in which the extender 113 is retracted from the optical path. It is also possible to provide a drive circuit for driving the extender 113 and automatically insert and remove the extender 113 in the optical path.

  In addition, there is an optical filter as an optical unit that changes the brightness by being inserted into and removed from the optical path of the photographing optical system without attaching / detaching the interchangeable lens 101 and the camera body 115. Examples of such an optical filter include a polarizing filter, an ND filter, a sharp cut filter, and an ultraviolet filter.

  The in-lens CPU 102 is a control unit that includes a microcomputer and controls each part of the interchangeable lens 101 and can communicate with the in-camera CPU 116. The in-lens CPU 102 stores characteristic information and optical information unique to the interchangeable lens 101, a program related to the control method of FIG. 2 or FIG. 3 and necessary values in an internal memory (not shown), and controls each part of the interchangeable lens 101. Control means. The “optical information” includes focus lens 105 sensitivity information, focus correction amount information, and the like obtained from a matrix such as the position of the focus lens 105, the position of the zoom lens 103, and the state of the diaphragm 107.

  The switch (SW) 125 is selection means for selecting automatic focus adjustment (AF) or manual focus adjustment (MF). The state of the SW 125 is also communicated via the communication terminals 104 and 117.

  The camera body 115 includes an in-camera CPU 116, a main mirror 119a, a sub mirror 119b, a finder optical system, a shutter 120, an image sensor 121, and a display unit 124.

  The main mirror 119a and the sub mirror 119b are configured to be displaceable between a mirror-down state shown in FIG. 1 and a mirror-up state (not shown). The main mirror 119a and the sub mirror 119b are arranged on the optical axis OA in the mirror down state, and in the mirror up state, the main mirror 119a and the sub mirror 119b are retracted from the optical axis OA so that the light from the object reaches the image sensor 121.

  The main mirror 119a is composed of a half mirror, and in the mirror-down state, a part of the light from the object is reflected by the finder optical system so that it can be observed by the user, and the remaining light is transmitted and transmitted to the sub mirror 119b. The sub mirror 119b reflects light from the object to the AF sensor 118 in the mirror down state. This embodiment is also applicable to a mirrorless camera that does not have a main mirror 119a and a sub mirror 119b. The finder optical system includes a pentaprism 122 and a finder 123, and allows the user to observe the subject.

  The AF sensor 118 performs so-called phase difference type focus detection by detecting a phase difference between signals of a pair of subject images, and the in-camera CPU 116 performs AF based on the detection result of the AF sensor 118 ( Phase difference AF). In the phase difference AF, vignetting may occur in the light beam used for focus detection depending on the F value of the photographing optical system, and the focus detection accuracy may be lowered, causing a problem in the phase difference AF.

  The camera body 115 of the present embodiment has an AF sensor 118 different from the image sensor 121. However, the method of performing phase difference AF using a part of pixels of the image sensor and the method of performing AF using the contrast information of the image obtained by the image sensor also realize the focus detection function of the camera body. It can be used as a method.

  The in-camera CPU 116 is a control unit that is configured by a microcomputer and controls each part of the camera body 115, communicates with the in-lens CPU 102, and transmits various commands to the in-lens CPU 102.

  In principle, the in-camera CPU 116 calculates the driving amount of the focus lens 105 for obtaining the in-focus state based on the detection result of the AF sensor 118 when the switch 125 selects AF. The in-camera CPU 116 transmits the calculated driving amount of the focus lens 105 to the in-lens CPU 102, and the in-lens CPU 102 controls the lens driving circuit 106 in accordance with this to drive the focus lens 105 to the in-focus position. When the switch 125 selects MF, the user operates the driving unit 126 to drive the focus lens 105 to a predetermined position. As will be described later, even if the switch 125 selects AF, the camera CPU 116 may not perform AF.

  The in-camera CPU 116 calculates the drive amount of the aperture 107 according to the photometric result of the photometric sensor (not shown) or the aperture value set by the user in response to a half-press operation of a release switch (not shown) provided in the camera body 115. And transmitted to the in-lens CPU 102. The in-lens CPU 102 drives the diaphragm 107 by controlling the diaphragm driving circuit 108 according to this.

  The in-camera CPU 116 transmits a camera shake correction start command to the in-lens CPU 102 in response to a half-press operation of the release switch. When receiving the camera shake correction start command, the in-lens CPU 102 controls the camera shake correction drive circuit 112 to hold the camera shake correction lens 110 at the control center position, and then controls the lock drive circuit 111 to drive the mechanical lock 109. To release the locked state. Thereafter, the camera shake correction drive circuit 112 is controlled according to the detection result of the camera shake detection circuit (not shown) to drive the camera shake correction lens 110 to correct the camera shake.

  The in-camera CPU 116 drives the shutter 120 installed in front of the main mirror 119 and the image sensor 121 in response to the full pressing operation of the release switch, guides the light flux from the imaging optical system to the image sensor 121, and performs imaging. .

  The imaging element 121 is configured by a photoelectric conversion element such as a CCD sensor or a CMOS sensor. The in-camera CPU 116 generates image data based on the output from the image sensor 121 and records it on a recording medium. Here, the image to be shot is a still image if the still image shooting mode is selected by a mode selection switch (not shown), and a moving image if the moving image shooting mode is selected. Alternatively, a recording start button for moving image shooting may be provided separately, and the recording of the moving image may be started when the button is pressed.

  The display unit 124 displays still images, moving images, and other information. In the present embodiment, the display unit 124 displays that fact when the in-lens CPU 102 transmits a signal representing MF even though the switch 125 selects AF.

  FIG. 2 is a flowchart illustrating the operation of the in-lens CPU 102 when the extender 113 is inserted and removed, and “S” represents a step. The flowchart shown in FIG. 2 can be embodied as a program for causing a computer to execute the function of each step.

  First, the in-lens CPU 102 determines whether or not the extender 113 is inserted into or removed from the optical axis OA of the photographing optical system based on the detection result of the insertion / extraction detection unit 114 (S101). If the extender 113 is not inserted / removed (N of S101), S101 is repeated and confirmed.

  On the other hand, if the extender 113 is inserted / removed (Y in S101), the brightness changes, so the in-lens CPU 102 checks the current state of the optical system and determines whether AF is possible (S102). As a determination criterion, whether or not the open F value of the interchangeable lens 101 exceeds a predetermined value (for example, F8) by inserting and removing the extender 113 is determined. That is, the in-lens CPU 102 determines that AF cannot be performed if the open F value exceeds a predetermined value, and determines that AF can be performed if the open F value is equal to or less than the predetermined value. In addition, a method of checking and determining information related to the degree of vignetting of the light to the AF sensor 118 based on data stored in the in-lens CPU 102 is also conceivable.

  When determining that AF is possible (Y in S102), the in-lens CPU 102 transmits the state of the switch 125 to the in-camera CPU 116 (S103). The in-camera CPU 116 starts the AF operation if the switch 125 selects AF, and waits if the MF is selected (without starting the drive sequence of the focus lens 105), thereby enabling the user to perform MF. .

  On the other hand, if the in-lens CPU 102 determines that AF is not possible (N in S102), a signal indicating that the switch 125 selects MF is transmitted to the in-camera CPU 116 regardless of the state of the switch 125 (S104). . The in-camera CPU 116 waits because the switch 125 recognizes that the MF is selected (does not start the drive sequence of the focus lens 105). As a result, the in-camera CPU 116 can prevent AF defects without detecting that the characteristics of the photographing optical system have changed due to the insertion / extraction of the extender 113 of the interchangeable lens 101.

  The display unit 124 displays the current focus adjustment state (AF or MF). In particular, in S104, the user can know the mismatch between the setting (AF) by the switch 125 and the actual setting (MF).

  Even if AF is not possible (N in S102), there is no problem because the same result is obtained even if the process proceeds to S103 when the switch 125 selects MF. Further, the signal transmitted in S104 is not limited to the signal indicating that MF is selected, and the signal that causes the camera body 115 to stop transmitting a signal for performing automatic focus adjustment from the camera body 115 to the interchangeable lens 111. If it is good. In this embodiment, the “signal for performing automatic focus adjustment from the camera body 115 to the interchangeable lens 111” is a signal corresponding to the driving amount of the focus lens 105 calculated based on the detection result of the AF sensor 118. .

  The in-lens CPU 102 may execute the flow shown in FIG. 2 when determining that the camera body 115 does not support the extender 113 based on information of the camera body 115 acquired by communication. When the camera body 115 is compatible with the extender 113, the camera body 115 can perform the setting of S104 in the case of N in S102.

  FIG. 3 is a flowchart for explaining the operation of the in-lens CPU 102 when the extender 113 is inserted / removed, and “S” represents a step. Steps similar to those in FIG. 2 are given the same reference numerals. The flowchart shown in FIG. 3 can be embodied as a program for causing a computer to execute the function of each step. The in-lens CPU 102 may execute the flow shown in FIG. 3 when determining that the camera body 115 does not support the extender 113 based on information of the camera body 115 acquired by communication.

  If the extender 113 is inserted / removed (Y in S101), the in-lens CPU 102 uses a different value depending on the information of the camera body 115 acquired from the in-camera CPU 116 as a threshold value (predetermined value) for determining whether AF is possible (predetermined value). S201). Here, two types of F8 and F5.6 are used as the predetermined values, but three or more types may be used. The information of the camera body 115 is unique information of the camera body 115 acquired by communication, and includes, for example, the type of the camera body, the name of the camera body, and the version of the control program for the camera body.

  If the predetermined value for the camera body 115 is F8, the in-lens CPU 102 confirms the current state of the optical system, and determines whether AF is possible based on whether the open F value exceeds F8 (S202). If the predetermined value for the camera body 115 is F5.6, the in-lens CPU 102 confirms the current state of the optical system, and determines whether or not AF is possible based on whether or not the open F value exceeds F5.6. (S203). Of course, other methods may be used, such as checking and determining information on the degree of vignetting on the AF sensor 118 based on data stored in the in-lens CPU 102.

  When the in-lens CPU 102 determines that AF is possible (Y in S202, Y in S203), it transmits the state of the switch 125 to the in-camera CPU 116 (S103). On the other hand, if the in-lens CPU 102 determines that AF is not possible (N in S202, N in S203), a signal indicating that the switch 125 selects MF is transmitted to the in-camera CPU 116 regardless of the state of the switch 125. (S104). As a result, the in-camera CPU 116 can prevent AF defects without detecting that the characteristics of the photographing optical system have changed due to the insertion / extraction of the extender 113 of the interchangeable lens 101.

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

  The optical apparatus of the present invention is applicable to an interchangeable lens or a photographing system including an interchangeable lens and a camera body to which the interchangeable lens can be attached and detached.

DESCRIPTION OF SYMBOLS 101 ... Interchangeable lens, 102 ... In-lens CPU (control means), 105 ... Focus lens (imaging optical system), 103 ... Variable magnification lens (imaging optical system), 113 ... Extender, 115 ... Camera body, 124 ... Optical axis, 125 ... Switch (selection means)

Claims (8)

An interchangeable lens that can be attached to and detached from a camera body capable of performing automatic focusing, has a control means for communicating with the camera body and a photographing optical system,
The photographing optical system includes an optical unit that changes an F number of the photographing optical system,
The optical unit moves between a position inserted in the optical path of the photographic optical system and a position retracted from the optical path without removing the interchangeable lens from the camera body, thereby allowing F of the photographic optical system to move. It is possible to change the number ,
The camera body is a camera not configured to recognize a change in the F number caused by the movement of the optical unit with the interchangeable lens attached to the camera body, and the optical unit In response to the fact that the camera body is unable to perform automatic focus adjustment due to the change in the F-number due to movement of the first lens, the control means causes the interchangeable lens to perform the automatic focus adjustment. An interchangeable lens, wherein a second signal for preventing a signal from being transmitted from the camera body is transmitted to the camera body. Before SL control means when the open F-number of the photographing optical system is greater than a predetermined value, the interchangeable lens according to claim 1, wherein transmitting the second signal to said camera body. The interchangeable lens according to claim 2 , wherein the control unit receives unique information of the camera body through communication with the camera body, and varies the predetermined value according to the unique information. The interchangeable lens according to claim 3 , wherein the unique information includes information on at least one of a type of the camera body, a name of the camera body, and a version of a control program of the camera body. Said second signal, the interchangeable lens according to any one of claims 1 to 4, characterized in that a signal indicating that you have selected the manual focusing. The interchangeable lens according to any one of claims 1 to 5 , wherein the optical unit is an extender that changes a focal length of the photographing optical system. The interchangeable lens according to any one of claims 1 to 5 , wherein the optical unit is an optical filter. Imaging system, characterized in that it comprises an interchangeable lens according to any one of claims 1 to 7, a camera body to perform automatic focus detection operation, the.