JP2009015147A - Lens device having focus limiter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a strict focus drive feasible range can not be set, and further speeding-up in autofocus using a focus limiter can not be expected, because a user can not set a desired optional focus drive feasible range in the conventional lens device equipped with a focus limiter. <P>SOLUTION: The lens device is provided with a switch to shift a mode to a mode for setting the focus drive feasible range, and decides a range where a focus lens is moved while the switch is turned on as the focus drive feasible range, thereby the user can set autofocus in the desired optional focus drive feasible range. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lens apparatus having a focus limiter capable of auto-focusing and capable of arbitrarily setting a focus driveable range.

  The reduction of the distance measurement time by autofocus depends on the focus lens drive performance of the lens apparatus and the focus lens drive possible range for the focus lens to search for the in-focus position. Conventionally, a function that can limit the focus lens drive range to a range narrower than the entire range according to the shooting situation and reduce the distance measurement time by autofocus, a so-called focus limiter function, has been adopted in the lens apparatus.

  The limit position of the focus lens driveable range in the conventional focus limiter is generally fixed by a predetermined design value within the entire range. A focus limiter that switches whether the focus lens is driven in the entire range or driven from the closest distance end to the limit position by the focus limiter depending on whether the focus limiter switch is turned on or off has been mainstream.

  However, it has been difficult for a conventional focus limiter having a limit position fixed in advance according to a design value to flexibly cope with various shooting situations and to efficiently shorten the distance measurement time by autofocus. In other words, when shooting using a conventional focus limiter, the user cannot set the flexible focus driveable range according to various shooting conditions and function the focus limiter more efficiently. Therefore, the conventional focus limiter cannot be expected to further reduce the distance measurement time by autofocus by narrowing the focus lens driveable range to an arbitrary range.

  In addition, since the limit position is fixed by the design value in the conventional focus limiter, if the user wants to perform autofocus in the distance measurement range that crosses the limit position, the autofocus is limited to the range from the limit position to infinity. It was necessary to switch between selecting whether to perform it or performing it in the range from the closest distance end to the limit position. In the end, in order to avoid the troublesome switching, it is necessary to turn off the focus limiter and perform autofocus with the focus driveable range as the entire range, and it has been impossible to shorten the distance measurement time by autofocus.

  In general, a telephoto lens device has a wide driving range of the original focus lens. Therefore, when shooting a sport from a distance, the conventional focus limiter has to divide the entire range into two by a limit position. However, even after the division, it is difficult to effectively shorten the distance measurement time because the focus driveable range is still wide.

  Japanese Patent Application Laid-Open No. 2002-214510 describes a focus limiter mechanism that mechanically limits the drive range of the focus lens. Further, it is possible to set the division of the entire range that can be driven by the focus limiter into the range of the longest distance to an arbitrary distance and the range of an arbitrary distance to the minimum distance.

  However, the setting means for the focus driveable range described in Japanese Patent Application Laid-Open No. 2002-214510 tends to cause an error because the focus driveable range is set by the distance scale of the lens device based on the subject distance measured by the user. The target subject may not be within the focus driveable range set by the focus limiter at the stage of actual autofocus shooting due to the distance measurement error due to the user's measurement and the distance scale manufacturing error of the lens device. .

  In Japanese Patent Laid-Open No. 2002-214510, since one end of the focus driveable range is fixed, the focus driveable range cannot be set from an arbitrary minimum distance to an arbitrary maximum distance. Therefore, it cannot be expected to further shorten the distance measurement time by autofocus.

  In addition, mechanically installing the focus limiter in the lens apparatus leads to an increase in size and complexity of the lens apparatus itself.

  Japanese Patent Application Laid-Open No. 8-136799 describes a focus limiter that can electrically set a focus driveable range from an arbitrary minimum distance to an arbitrary maximum distance using a long distance side limiter and a short distance side limiter. ing.

  However, in the focus drivable range setting means using the limiter switch, there is a possibility that a ranging error due to a user's measurement or a manufacturing error of a distance scale of the lens device may occur. Therefore, like the focus limiter described in Japanese Patent Laid-Open No. 2002-214510, there is a possibility that the subject distance assumed when setting the subject distance based on the user's measurement and the distance scale of the lens is different.

Further, means for setting an arbitrary minimum distance or an arbitrary maximum distance in the focus driveable range in the focus limiter described in Japanese Patent Application Laid-Open No. 2002-214510 and Japanese Patent Application Laid-Open No. 8-136799 includes a limiter switch or the like. This is troublesome because the user needs to make settings while checking the distance display of the device. For an imaging device such as a surveillance camera or a video conference camera that has been in the same shooting state for a long time, it is unlikely that the setting of the minimum distance and the maximum distance of the focus driveable range by autofocus will be frequently changed. However, when the application is photography, such as a single-lens reflex camera, there is a possibility that the focus driveable range may be changed frequently, and means that can easily change the focus driveable range is desired.
JP 2002-214510 A JP-A-8-136799

  The change of the focus driveable range in the conventional focus limiter is mainly performed by dividing the entire range into two by the limit position fixed in advance by the design value, and an arbitrary focus driveable range cannot be set. .

  Further, in the conventional focus limiter that can set the focus driveable range from an arbitrary minimum distance to an arbitrary maximum distance, the setting means is complicated. Particularly in photography, it has been difficult to change the autofocus driveable range in response to various photography situations.

  In addition, since the user can arbitrarily set the focus driveable range depends on the subject distance measured by the user's eye measurement and the distance display of the lens apparatus, the user's desired distance driving error and the distance display manufacturing error cause the user's desired measurement. There was a possibility that the focus drive range could not be set.

  In addition, the user can arbitrarily set the focus driveable range, and the user cannot set the focus driveable range while confirming the subject distance of the through image with an optical viewfinder or an electronic viewfinder.

  In order to solve the above-described problems, a lens device according to the present invention includes a detection unit that detects a focus lens position, a storage unit that stores a focus driveable range, and a switch for shifting to a mode that changes the focus driveable range. In a lens device capable of transferring lens data to the camera and capable of autofocusing, the switch is turned off within the range in which the focus lens is moved while the switch is turned on. A focus limiter that is determined later as a focus driveable range and performs autofocus within the determined focus driveable range is provided.

  According to the present invention, it is possible to perform autofocus shooting while limiting the focus driveable range from an arbitrary minimum distance to an arbitrary maximum distance. Therefore, autofocus shooting can be performed at a higher speed when it is desired to shoot a specific shooting distance range.

  Further, the focus driveable range can be set while the through image is being checked with the finder at the time of shooting regardless of only the subject distance measured by the user and the distance scale of the lens device. Therefore, a desired autofocus driveable range can be set more easily and strictly than in the past.

  In addition, even a lens apparatus having a wide autofocus driveable range can perform autofocus shooting with a high distance measurement speed.

  An embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows an interchangeable lens for a single-lens reflex camera provided with a focus limiter capable of arbitrarily setting a focus driveable range according to the present invention.

  Reference numeral 101 denotes a lens group that moves when the zoom lens apparatus is zoomed, 102 a focus lens, 103 a focus lens driving motor, 104 an aperture, 105 a focus limit range setting mode button, 106 an in-lens CPU, and 107 a memory , 108 schematically show the in-camera CPU.

  The focal length and the position of the focus lens when zoomed are detected by an MR sensor or the like and notified to the CPU 106 in the lens. The focus lens driving motor 103 and the diaphragm 104 are controlled by the in-lens CPU 106. The in-lens CPU 106 monitors whether the focus limit range setting mode button 105 is pressed. The focus driveable range arbitrarily set by the user is temporarily stored in the memory 107. The focus lens position when the focus limit range setting mode button is pressed is temporarily stored in the memory 107. The in-lens CPU 106 performs data communication with the in-camera CPU 108 to transfer lens data to the camera.

  Next, the flow of the focus driveable range setting means of the present invention during autofocus shooting will be described in detail.

  When the camera power is turned on, the in-lens CPU performs data communication with the in-camera CPU and transfers lens data such as a focal length of the lens and an open aperture F value to the camera side.

  In S201 of FIG. 2, when the power of the camera is turned on, the entire range in which the lens apparatus can originally be driven by focus is stored in the memory of the lens apparatus as an initial range.

  In S202, the lens apparatus determines whether or not the focus limit range setting mode button has been pressed. If it has not been pressed once, in S203, the initial range set in S201 is determined as it is as a focus driveable range. Auto focus shooting is performed within the determined focus drive range.

  When performing autofocus within the focus driveable range, the camera will focus by driving the focus lens within the focus range minimum value and focus range maximum value stored in the memory of the lens device. Search for the focus lens position. When the focus lens reaches the focus range minimum value or the focus range maximum value, which is the end of each focus driveable range, the camera will use the focus driveable range data stored in the memory of the lens device to reach the focus The lens position is recognized as the end. When the camera recognizes that the focus lens position has reached the end, it reverses the focus lens movement direction until immediately before and continues searching for the focus position. However, if there is no in-focus position even though the in-focus position is searched in the entire range where focus drive is possible, the camera side determines that there is an error. If it is determined that there is an in-focus position, the camera side performs shooting at the focus lens position.

  Further, since the in-lens CPU and the in-camera CPU always transfer data, the camera side may recognize the fixed focus driveable range in which data transfer is performed from the in-lens CPU and perform autofocus shooting.

  That is, when the power of the camera is turned on and the focus range setting mode button of the lens device has not been pressed, the camera drives the focus lens in the entire range of focus drive that the lens device originally has, Autofocus shooting is performed in the same way as a lens without a focus limiter.

  If it is determined in S202 that the focus limit range setting mode button has been pressed, the focus limit range setting mode is entered. When shifting to the focus limit range setting mode, the initial range set in S201 is once cleared in S205. The in-lens CPU stores the focus lens position when the focus limit range setting mode button is pressed in the memory of the lens apparatus as an initial position. At the same time, the initial position is set as the focus range maximum value and the focus range minimum value, respectively, and stored in the memory.

  According to the setting process of the focus driveable range described later, the initial position needs to be within the focus driveable range to be set. The initial position is set by the user manually adjusting the focus while confirming the through image with an optical viewfinder or an electronic viewfinder. In order to easily set the initial position, it is preferable to perform auto-focusing over the entire range in which focus drive is possible, focus on a suitable target object, and move the focus lens in advance.

  In S206, it is checked whether or not the focus range setting mode button has been pressed continuously from the point of S202. If pressed, the focus range maximum value and focus range minimum value set as the initial position in S205 are updated to the focus lens position arbitrarily changed by the user in S211 described later. The driving source for moving the focus lens may be a manual driving force from a manual focus ring (not shown) or an electric driving force from a motor.

  At first, since the focus lens position does not move while the focus range setting mode button is kept pressed, the movement of the focus lens position from the initial position is not detected in the first check in S207 and S209.

  When the focus lens is moved to an arbitrary position by the user in S211, and the focus limit range setting mode button is continuously pressed in S206, the focus range maximum value or the focus range minimum value is moved in S207 and S209. Each is updated to the focus lens position.

  In S207, the focus lens position after moving in S211 is compared with the focus range maximum value that has already been set. If the focus lens position after the movement is larger than the previously set focus range maximum value, the focus range maximum value is updated as the current focus lens position in S208 and stored in the memory of the lens apparatus.

  Similarly, in S209, the focus lens position after moving in S211 is compared with the focus range minimum value that has already been set. If the moved focus lens position is smaller than the previously set focus range minimum value, the focus range minimum value is updated as the current focus lens position in S210 and stored in the memory of the lens apparatus.

  That is, as shown in FIG. 3, while the focus limit range setting mode button is continuously pressed, the focus drive range is set to be expanded when the user moves the focus lens position from the initial position to an arbitrary position. Go.

  The focus drive possible range is repeatedly updated from S206 to S211 as described above, and when it is determined in S206 that the focus limit range setting mode button is not pressed, the focus drive possible stored in the memory in S212 is possible. Confirm the range.

  Based on the determined focus driveable range, the camera performs autofocus shooting in S213. Unless the focus limit range setting mode button is pressed again in S214, the autofocus shooting in S213 can be repeated based on the focus drivable range determined in S212.

  When the focus limit range setting mode button is pressed again in S214, the focus drivable range determined in S212 is reset, and the entire range in which the lens apparatus can originally be focus driven is set as the focus drivable range.

  In order not to inadvertently reset the determined focus driveable range, it is not simply reset by pressing only the focus limit range setting mode button as described above. A means for resetting by simultaneously pressing the release button may be adopted.

  Whether or not the lens device is in the focus limit range setting mode, and further, what kind of range the set focus driveable range is in terms of the actual distance conversion is provided in the lens device, such as a liquid crystal display. And may be displayed. Information may be displayed not on the lens apparatus but on the camera side by transmitting information to the camera side.

  The focus limit range setting mode button may be installed not on the lens apparatus but on the camera side, and information on pressing of the focus limit range setting mode button may be transmitted from the camera side to the lens apparatus.

  As described above, in the present invention, the user can arbitrarily set the focus range minimum value and maximum value of the focus driveable range at the time of autofocus shooting according to the shooting situation. Therefore, it is possible to quickly perform autofocus imaging within a focus driveable range that is further limited as compared with the conventional focus limiter function.

  In addition, when the user moves the focus lens position while pressing one focus limit range setting mode button, the focus driveable range can be changed easily and quickly.

  Further, according to the present invention, it is possible to set the focus driveable range while confirming a through image that the user confirms with an optical viewfinder, an electronic viewfinder, or the like. Therefore, the setting of the focus driveable range will not be mistaken from the distance measurement error due to the user's eye measurement or the manufacturing error of the distance display provided in the lens device, and the focus driveable range should be strictly set by the present invention. In addition, quick autofocus shooting can be performed.

It is a schematic diagram of the lens apparatus of the Example in this invention. It is a flowchart of a focus driveable range setting means in the present invention. It is the figure which showed typically the focus drive possible range setting means in this invention.

Explanation of symbols

101 Zoom Lens Group 102 Focus Lens 103 Focus Lens Drive Motor 104 Aperture 105 Focus Limit Range Setting Mode Button 106 In-Lens CPU
107 Memory 108 CPU in camera

Claims (1)

It has a detection means for detecting the focus lens position, a storage means for storing the focus driveable range, and a switch for shifting to a mode for changing the focus driveable range, and is capable of transferring lens data to the camera side, In a lens device that can autofocus,
A range in which the focus lens is moved while the switch is turned on is determined as a focus driveable range after the switch is turned off, and a focus limiter that automatically focuses within the determined focus driveable range A lens apparatus comprising: