JPH04273231A - Conversion adapter device for interchangeable lens system - Google Patents

Abstract

PURPOSE:To perform excellent AF control on a camera side by providing a conversion means for converting information on the acting position of an exposure control means in a lens part to a state which can be discriminated on the camera side. CONSTITUTION:A position information conversion means 21 for generating iris position information required by a camera for video movie based on various kinds of information transmitted from a lens for a still camera to a conversion adapter AD and by internally counting iris driving pulses is provided. Namely, a microcomputer 19 in the conversion adapter AD has the means 21 for generating the iris position information for the video movie based on the various information for the still lens transmitted from the lens side LS. The iris position information generated by using the means 21 is changed according to a previously fixed format and transmitted to the camera side CM through a duplex data communication line 11A as the position information.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adapter device in an interchangeable lens system that allows lenses and cameras of different standards to be connected.

[Background Art] In recent years, in video movie systems, an interchangeable lens system for movies has been proposed in which various lenses can be used interchangeably, unlike ordinary camera/lens integrated systems. By the way, speaking of interchangeable lens systems, systems for single-lens reflex cameras (systems for still cameras) are generally known. Various lenses for this system, including special lenses tailored to various uses, are already available on the market. Since the video movie system is still in its introductory period and the market has not yet been developed, it is not realistic to produce a wide variety of special lenses, which should be a feature of the interchangeable lens system, at this early stage. Therefore, there has been a demand to use interchangeable lenses for single-lens reflex cameras that have already been introduced in the market and are recognized by users. Therefore, a conversion adapter is required to connect a video movie camera and a still camera lens. This conversion adapter is designed to: (1) match the mounts of the video movie interchangeable lens system and the still camera interchangeable lens system since they are different; and (2) match the imaging plane and mount position of the video movie camera and still camera. (3) Because the video movie interchangeable lens system and the still camera interchangeable lens system have different communication formats for passing data to the various devices required for control. , and the data formats/control formats are different, so it is necessary to match them mainly for the above three reasons.

By the way, there are considerable differences between a movie camera and a still camera in terms of their form, shooting conditions, functions, and other conditions. Therefore, there are also differences in exposure control methods. First, a brief explanation of the exposure control method will be given.

First, the exposure control method in the interchangeable lens system of the video movie system will be explained below with reference to FIG. The camera unit CM is on the right side, and the lens unit LS is on the left side, with the mount part MT indicated by the dashed line in the center of the figure as a border. A subject imaged by the lens optical system 1 on the imaging surface of the image sensor 3 via the aperture mechanism (iris) 2 is photoelectrically converted by the image sensor 3 and output as an image signal. The image signal is supplied from the image sensor 3 to the camera signal processing circuit 4, where it is subjected to γ (gamma) conversion, etc., and the color signal C and luminance signal Yγ are extracted as video signals, and then passed through a camera encoder 5 such as NTSC to form a composite video signal. It is output from the camera unit in the form of . Also, the luminance signal Y output from the camera signal processing circuit
is supplied to the AE circuits 6, 7, and 8 in order to generate a control signal for controlling the iris 2 to obtain proper exposure according to the brightness state of the screen. In the AE circuit, the input luminance signal Y is integrated by an integrator 6, amplified to a predetermined level by an amplifier circuit 7, and then set to a reference level by a DC level shift circuit 8 to a predetermined voltage. The signal generated by the AE circuit is converted into a digital signal by the A/D converter 9 and input to the camera microcomputer 10. Control signals for controlling the iris in the camera microcomputer are converted into information according to a predetermined format in order to satisfy control compatibility of interchangeable lenses, and are sent to the lens via a bidirectional data communication path 11 at a predetermined timing. Unit LS
is sent as a control signal to

The bidirectional data communication path 11 is connected to a lens-side microcomputer 12, and all communication data is once received by the lens-side microcomputer 12, and the iris control data transmitted from the camera side is transferred to D.
The /A converter 13 converts the signal back into an analog signal, drives the actuator 15 through the driver 14, and drives the iris 2. The state of iris 2 is Hall element 1
6 is detected by an encoder such as A/D converter 17
The signal is converted into a digital signal and provided to the lens microcomputer 12. The lens microcomputer 12 exchanges the iris position information according to a predetermined format to satisfy control compatibility of interchangeable lenses, and transfers the iris position information to the camera side CM via the bidirectional data communication path 11 at a predetermined timing. Send as information. This information is used as determination information for control such as TTL AF control on the camera side.

Next, an exposure control method in a still camera will be explained below using FIG. 2. The light intensity of the light beam incident from the optical system 1 is adjusted by an exposure adjustment mechanism (iris) 2, and a photometric element 3A for performing partial/average photometry.
, is input to the photometric element 3B for performing spot photometry. The outputs of the photometric elements 3A and 3B are amplified by amplifier circuits 7A and 7B, respectively, and then input to the photometric circuit 18. The photometry circuit 18 converts the photocurrent into a logarithmically compressed voltage and supplies it to the camera microcomputer 10. The camera microcomputer 10 performs exposure calculations to obtain appropriate exposure according to various A modes (AE modes such as shutter priority AE, aperture priority AE, depth priority AE, etc.). The result of the exposure calculation is
It is determined as the difference between the shooting aperture and the open aperture, that is, the value corresponding to the number of aperture steps. This aperture stage number is sent to the lens microcomputer 12 on the lens side LS via the data transmission line 11.

The number of aperture steps input from the camera is converted by the lens microcomputer 12 into the number of pulses of the pulse motor 15, and the pulse motor is driven via the drive circuit 14 according to the number of pulses, the iris 2 is opened and closed, and exposure control is performed. Ru. The relationship between the pulse motor 15 and the iris 2 is such that, for example, the aperture changes by 1/8 step for one pulse of the pulse motor 15. The iris 2 has an opening SW 16 for detecting whether the iris is in an open state, and its output is given to the lens microcomputer 12. The lens microcomputer 12 converts the information of the open switch according to a predetermined format, and transmits it to the camera side CM via the bidirectional data communication path 11 at a predetermined timing. This information is used on the camera side to confirm the reference position of the iris drive (during open metering).

Next, using FIG. 3, the camera side C in FIG.
A case will be described in which M and the lens side LS in FIG. 2 are connected using a conversion adapter AD. The iris control signal created by the camera-side CM using the means described in FIG. 1 is transmitted as a control signal to the conversion adapter AD via the bidirectional data communication path 11A. The bidirectional data communication path 11A is connected to the adapter microcomputer 19, and all communication data is once received by the adapter microcomputer 19, and the video movie iris control data transmitted from the camera side is converted to the still camera by the control signal conversion means 20. This signal is converted into an iris control signal for use with the lens, and is transmitted as a control signal to the lens side LS via the bidirectional data communication path 11B. This control data output to the lens side has the same format as the data output from the camera side in Figure 2, so the processing on the lens side LS is as shown in Figure 2.
The processing on the lens side is the same as in .

[0009]

[Problems to be Solved by the Invention] The problem here is that control data from the camera side CM to the lens side LS can be obtained by using a control signal conversion means in the conversion adapter as described above. However, regarding the iris position information required for AF control of video movie interchangeable lens systems, there is no iris encoder for still camera lenses that corresponds to the iris encoder installed in lenses for video camera interchangeable lens systems. This means that the position information becomes unknown, and the depth of field information cannot be used in AF control, which means that the AF control on the camera side will not be optimal.

(Object of the Invention) The object of the present invention is to solve the above-mentioned problems, and to solve the problems described above, so that even when a still camera lens is connected via a conversion adapter, a video movie lens is connected. The aim is to create a conversion adapter that creates positional information similar to that of the camera and enables good AF control on the camera side.

[0011]

[Means for Solving the Problems] In order to solve such problems, the conversion adapter according to the present invention has various information that is transmitted from the still camera lens to the conversion adapter.
and position information conversion means for creating iris position information required by the video movie camera by internally counting the number of iris drive pulses.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings.

In FIG. 3 already mentioned, the microcomputer 19 in the conversion adapter operates a position information conversion means 21 for creating iris position information for video movies based on various information for the still lens transmitted from the lens side LS. have The iris position information created using this conversion means is exchanged in accordance with a predetermined format to satisfy control compatibility of the interchangeable lenses of the video movie interchangeable lens system, and is sent to the camera via the bidirectional data communication path 11A. It is sent to the CM as location information. S10: Set the internal counter created in S6 to 0 (=
open state). The above processing is executed in the initial state. In FIG. 5, each processing step will be explained as follows.
21: Perform serial communication with the camera. (Actually, the camera side is the master of this serial communication, and the conversion microcomputer handles, for example, an external interrupt, but this expression is used for convenience of explanation because it does not affect the content of the present invention.) S22: AE control data is extracted from the data received in S21. S23: It is determined whether the AE control command given in S22 is a command to actually drive the iris. If it is a drive command, the process advances to S28. S24: It is determined whether the AE control command given in S22 is a command requesting iris position information. If it is not the instruction, the process returns to S21. S25: Perform the calculation F1'+C/8. Let this value be E. S26: Since E is the number of stages (2 series) from F1.0, it is converted into an F value. Let the converted value be E'. S27: Send the value of E' to the camera as iris position information. →S21 to S28: The number of drive pulses for driving the pulse motor of the lens is obtained according to the content of the iris drive command from the camera (drive amount, etc.) by following an arithmetic expression or selecting from a table. Let this value be Q. S29: The driving direction of the iris driving command from the camera is determined. S3 if it is a drive command to the open side
Proceed to step 5. If it is a drive command to the small aperture side, the process advances to S30. S30: It is determined whether the value of the internal counter is equal to the value of P obtained in S5. If they are equal, it is determined that the position cannot be narrowed down any further, and the process returns to S21. S31: The current drive pulse number Q is stored in the internal counter C.
is added to obtain a new internal counter value C.

Next, a specific example of the position information converting means will be explained.

Data from the still lens is required for this position information conversion. This is also necessary for performing AE control in still cameras, and it is something that can be obtained from the still camera lens in some way or is otherwise uniformly determined. This is due to the range of the aperture that the lens can take (open F-No. and minimum F-No.), the amount of change in the aperture per drive unit (if it is a pulse motor, the amount of aperture change per pulse), and the camera's aperture metering. This is information on the open end SW of . In this embodiment, the aperture range is such that the open F-No and minimum F-No can be directly obtained as absolute values through communication with the lens. It is also assumed that the amount of change in aperture per pulse of the pulse motor is 1/8 step regardless of the lens. Under the above assumption, the processing within the conversion microcomputer for position information conversion will be explained in detail using the flowcharts shown in FIGS. 4 and 5. Note that this flowchart is limited to the portions related to the present invention. (Other various processes will be omitted.) The internal adapter process flowchart (1) shown in FIG. 4 represents the process for preparing for position information conversion in an initial state. In addition, the adapter internal processing flowchart (2) shown in Figure 5
shows a specific method for creating position information to be sent to the camera side during actual iris control. In Figure 4,
To explain each processing step, S1: communicate with the lens and obtain the open F-No.
Let this value be F1. S2: Communicate with the lens and obtain the minimum F-No.
Let this value be F2. S3: Convert F1 to the number of stages (2 series) from F1.0 and set this value as F1'. S4: Convert F2 to the number of stages (2 series) from F1.0 and set this value as F2'. S5: Find (F2'-F1')×8. This value becomes the total number of pulses (P) of the pulse motor of the lens. S6: Create an internal counter corresponding to P. S7: Drive the aperture to the open side. (The number of driving pulses is arbitrary.) S8: Communicate with the lens and obtain the open SW state. S9: The open SW is determined, and if it is not in the open state, the process returns to S7 and is driven to the open side again. This loop is open S
This is repeated until W is turned on. S32: It is determined whether the value of the internal counter is equal to the value of P obtained in S5. S3 if small
Proceed to step 4. S33: If the value of the internal counter is equal to or exceeds the value of P determined in S5, replace the value of the internal counter with P, which is the maximum value of the number of pulses. S34: Output a Q pulse drive command to the small aperture side to the lens and return to S21. S35: Determine whether the value of the internal counter is 0 or not. If they are equal, it is determined that the position cannot be opened any further, and the process proceeds to S40. S36: Current drive pulse Q from internal counter C
is subtracted to obtain a new internal counter value C. S37: Compare the value of the internal counter with 0. If it is larger, the process advances to S39. S38: If the value of the internal counter is less than or equal to 0, replace the value of the internal counter with 0, which is the minimum value of the number of pulses. S39: Output a drive command to the Q pulse opening side to the lens. S40: Communicates with the lens and obtains the open SW state. S41: Determine whether the switch is open and if it is not in the open state, proceed to S43. S42: When in the open state, set the internal counter value to 0.
It is initialized to , and returns to S21. S43: The internal counter C is determined. If the value of the internal counter is not 0, the process returns to S21. S44: Since the opening switch is not in the open state and the internal counter is 0 (minimum value), the value of the internal counter is temporarily set to "1" to absorb the discrepancy between the actual aperture position of the lens and the internal counter C. The process returns to S21.

Even if this amount of deviation is greater than 1, S
When the operation of step 44 is repeated and there is no deviation, the process branches to step S42 based on the determination in step S41, and the two states match.

As a result, even if there is no encoder on the lens side that directly detects the operating state of the aperture, the operating state of the aperture can be accurately detected on the camera side, improving the accuracy of AF control, etc. Accurate control can be performed.

In the above embodiment, the iris position information to be sent to the camera is sent by F-No.
The operating range of the diaphragm may be divided into a plurality of areas as shown in the figure, and the area code for each area may be converted and sent to the camera side. As for the processing within the adapter, instead of converting the processing in S26 in the flowchart of FIG. 5 into an F-No., it may be converted into an area code as shown in FIG. 6 using calculations or a table.

[0019]

Effects of the Invention By using the above means, the position information conversion shown at 21 in FIG. 3 is achieved. This allows the camera side to perform AF and AE control on a still camera lens in the same manner as a video movie lens.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of AE control in an interchangeable lens video camera system.

FIG. 2 is a block diagram of AE control in the still camera system.

FIG. 3 is a block diagram of E control using a conversion adapter.

FIG. 4 is a flowchart showing the processing of the conversion microcomputer in the embodiment of the present invention.

[Figure 5] Continuation of Figure 4 flowchart

[Figure 6] An example showing the relationship between F-No and iris area code

Claims (1)

[Claims] 1. A conversion adapter device for attaching and detaching a lens unit to and from a camera unit, wherein the camera unit and the lens unit use different exposure state determination methods for determining the operating state of an exposure control means, 1. A conversion adapter device for an interchangeable lens system, comprising a conversion device that converts operating position information of an exposure control device in a lens unit into a form that can be determined on the camera side.