JP2873877B2 - Camera interchangeable lens adapter and interchangeable lens camera system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a video signal processing system of a video camera capable of automatic exposure control and an interchangeable lens system for a still camera capable of automatic exposure control. The present invention relates to an interchangeable lens adapter and an interchangeable lens camera system.

[Conventional technology]

In recent years, in a video movie system, an interchangeable lens system for a movie, in which various lenses can be exchanged, has been proposed, unlike an ordinary camera / lens integrated system. As such an interchangeable lens system,
In general, a still camera system such as a single-lens reflex camera is known. In this system, various lenses including special lenses adapted to various applications have already been supplied to the market. However, since video movie systems are still in their introductory period and the market has not been developed,
In the early stage, it is not realistic to create a variety of special lenses that should be a feature of the interchangeable lens system. Therefore, using an interchangeable lens for a still camera such as the above-mentioned single-lens reflex camera, which has already been introduced to the market and recognized by users, has become an effective means. In order to connect the video movie camera and the still camera interchangeable lens, an exchange adapter is required mainly for the following reasons (a) to (c).

(A) Since the mount in the video movie interchangeable lens system is different from the mount in the still camera interchangeable lens system, it is necessary to match them.

(B) Since the distance between the imaging surface of the video movie camera and the still camera and the mount position are different, it is necessary to adjust the optical path difference.

(C) Since the video movie interchangeable lens system and the still camera interchangeable lens system have different communication formats for transferring various data required for control, and have different data formats / control formats. Need to be consistent.

Here, there is a considerable difference between the video movie camera and the still camera in terms of its form, imaging state, function, and the like. Therefore, there is a difference in the AE (automatic exposure) control method. Next, an outline of the AE control method will be described.

First, an AE control method of a conventional camera-integrated VTR will be described with reference to FIG. After the amount of the imaging light incident from the lens optical system 1 is adjusted by the iris diaphragm 2, an image of a subject is formed on the imaging element 3, where the image is photoelectrically converted. Then, the signal obtained from this image sensor 3 is
The video signal is converted into a television composite video signal by the camera signal processing circuit 4 and the camera encoder 5 and output to the outside. At that time, the luminance signal R _gamma was Tokura from the camera signal processing circuit 4 is integrated processed by the integrator 6, the difference signal between the reference level from the reference value generating circuit 19 is generated in the arithmetic unit 18. This difference signal is used as an AE control signal by the driver 13.
The iris diaphragm (a diaphragm mechanism for exposure adjustment) is controlled via the actuator 14.

Next, an AE control method in an exchange level VTR will be described with reference to FIG. The camera unit C is on the right side of the mount part MT shown by the dashed line in the center of the figure.
M, the left side is the lens unit LS. The subject image formed on the imaging surface of the imaging device 3 from the lens optical system 1 through the iris diaphragm 2 is photoelectrically converted by the imaging device 3 and output as an imaging signal. Image pickup signal supplied to the camera signal processing circuit 4 from the imaging device 3, gamma (gamma) conversion or the like is applied, is taken out as an image signal of the color signal C and luminance signal Y _gamma, camera encoder 5 such as the NTSC system And is output from the camera unit to the outside in the form of a composite video signal. Also, the luminance signal Y _gamma output from the camera signal processing circuit, so as to generate an AE control signal for controlling the iris diaphragm 2 so proper exposure is obtained in accordance with the luminance state of the screen, AE circuit , Amplifier (AMP) 7 and DC level shift circuit 8
Supplied to In this AE circuit, the input luminance signal Y
_{After γ} is integrated by the integrator 6 and amplified by the amplifier 7 to a predetermined level, the DC level shift circuit 8 sets the reference level to a predetermined voltage. The setting method of the AE control data based on the level difference from the reference level is as follows. The amplifier 7 and the DC level shift circuit 8 are set so that the signal data shown in FIG. This is done by adjusting. The signal generated by the AE circuit is converted into a digital signal by the A / D converter 9 and then input to the microcomputer 10 on the camera side, via the data communication path 21 at a predetermined timing. The signal is transmitted to the lens unit LS as an AE control signal. At this time, the data communication path 21 is connected to the lens-side microcomputer 11, and all communication data is once received by the lens-side microcomputer 11, converted into an analog signal by the D / A converter 12, and then sent to the driver circuit 13. Supplied. Then, the iris diaphragm 2 is controlled via the actuator 14. FIG. 8 shows representative values when AE control data transmitted to the lens unit LS is assigned, for example, in 8 bits (256 steps). As shown in this figure, each level difference is expressed by an EV (aperture) value. For example, in the case of +1 EV, it indicates that the optimum exposure is to be narrowed down by 1 EV (a so-called one aperture).

In this case, the reference value of the AE control is 32, and the iris does not move at the time of this data. Then, on the lens side, the control data transmitted from the camera side is converted into an analog signal again by the D / A converter 12 as described above,
The actuator 14 is driven through the driver 13 to drive the iris diaphragm 2. As described above, by digitally encoding and transmitting the control signal including the iris drive stop based on the video signal level as the AE control information, the apparent difference in the camera gain can be ignored. However, the difference in the dynamic range of the camera is not a problem. In addition, since the reference value is unified with a predetermined code, compatibility is maintained.

Finally, the AE control method in the still camera will be described with reference to FIG. The light quantity of the imaging light incident from the lens optical system 1 is adjusted by the iris diaphragm 2 in the same manner as described above, and then the photometric element 3A for performing partial and average photometry is used.
And the light is input to a photometric element 3B for performing spot photometry. The outputs of the photometric elements 3A and 3B
After being amplified by A and 7B, it is input to the photometric circuit 23. In the photometric circuit 23, the photocurrent is converted into a logarithmically compressed voltage, which is supplied to the camera microcomputer 10. Then, the camera microcomputer 10 performs an exposure calculation for obtaining an appropriate exposure according to various AE modes (AE modes such as a shutter priority AE, an aperture priority AE, and a depth priority AE). It is obtained as a difference between the aperture and the open aperture, that is, a value corresponding to the number of aperture stages. The number of stops is transmitted to the lens microcomputer 11 of the lens unit LS via the data transmission path 21.

The number of aperture stages input from the camera side is converted into the number of steps of the stepping motor (M) 20 by the lens side microcomputer 11, and the stepping motor 14 is driven via the driver 13 according to the number of steps. As a result,
The iris diaphragm 2 opens and closes, and exposure control is performed. At this time, the relationship between the stepping motor 20 and the iris diaphragm 2 is such that the diaphragm changes by 1/8 step with respect to the rotation of the stepping motor 14 by one pitch of the rotor.

[Problems to be solved by the invention]

By the way, in the above control method, the AE control method in the interchangeable lens system for a video movie camera sends a difference value between a reference light amount and a current light amount to the lens side, and the lens side outputs the difference value. The light amount is controlled by driving the diaphragm structure from the current position in analog fashion, and finally the reference light amount and the actual incident light amount are controlled to be equal. The AE control method in the interchangeable lens system for still cameras is
The camera converts the difference between the current absolute value information of the aperture and the absolute value information of the target aperture according to the lens-side driving means (for example, the number of pulses of a pulse motor), and transmits the converted data to the lens. On the lens side, the lens side controls the light quantity by digitally driving a designated pulse number diaphragm mechanism, and finally controls the aperture (light quantity) intended by the user. For this reason, from the camera side in the interchangeable lens system for video movie cameras
The AE control data cannot be directly used as the AE control data of the interchangeable lens in the interchangeable lens system for a still camera, and there is a problem that AE control cannot be performed.

The present invention has been made in order to solve the above-described problems. By matching two different AE control methods, an interchangeable lens system for a still camera is used as an interchangeable lens system for a video camera. The purpose of the present invention is to obtain an interchangeable lens adapter for a camera that can perform good AE control.

[Means for solving the problem]

In order to achieve the above object, according to the adapter for a camera interchangeable lens of the present invention, an aperture drive on a video camera lens unit side based on an exposure control signal relating to a level difference between a video signal level and a predetermined reference level. Controlling the aperture control means based on the information on the absolute drive amount of the aperture supplied from the camera side to a video camera which performs automatic exposure control so that the video signal level becomes equal to the reference level. The video camera lens unit, which performs exposure control, is an interchangeable adapter for mounting a still camera interchangeable lens unit having a different aperture driving characteristic from the video camera lens unit, and a video signal level output from the video camera and a predetermined reference level. The exposure control signal relating to the level difference with the aperture drive of the interchangeable lens unit for the still camera. Signal converting means for converting the information into the absolute driving amount of the aperture for controlling the moving means.

According to the adapter for a camera interchangeable lens of the present invention, the diaphragm driving means on the video camera lens unit side is driven based on an exposure control signal relating to a level difference between a video signal level and a predetermined reference level, and the video signal is The video camera lens unit for performing open loop control of aperture driving means based on information on the absolute driving amount of the aperture supplied from the camera side for a video camera that performs feedback control so that the level is equal to the reference level. Is a conversion adapter for mounting an interchangeable lens unit for a still camera having a different aperture drive characteristic, the exposure control signal relating to a level difference between a video signal level output from the video camera and a predetermined reference level, Controlling the aperture driving means of the interchangeable lens unit for the still camera. Signal conversion means for converting the information into an absolute drive amount of the aperture for the purpose of the present invention.

Further, according to the interchangeable lens camera system of the present invention, the diaphragm driving unit on the video camera lens unit side is driven based on an exposure control signal relating to a level difference between a video signal level and a predetermined reference level, and the video signal level is reduced. A video camera that performs feedback control so as to be equal to the reference level; and a video camera lens unit that performs open loop control of aperture driving means based on information on the absolute driving amount of the aperture supplied from the camera. A still camera interchangeable lens unit having different driving characteristics, and a conversion adapter for attaching the still camera interchangeable lens unit to the video camera, wherein the conversion adapter has a video signal level output from the video camera. The exposure relating to a level difference from a predetermined reference level The control signal, characterized in that it comprises a signal converting means for converting said diaphragm absolute driving amount of information for controlling the throttle driving means of the interchangeable lens unit for the still camera.

[Action]

In the camera interchangeable lens adapter of the present invention,
With the function of the signal conversion means, when viewed from the video camera, the still camera interchangeable lens can be treated as if it were a video camera interchangeable lens, and there is no need to be aware of the difference between the lenses. Further, the still camera interchangeable lens operates as if processing data from the still camera, and can be used as a lens without any conversion.

〔Example〕

FIG. 1 is a block diagram showing the configuration of one embodiment of the present invention. The same components as those of the above-described conventional example are denoted by the same reference numerals, and detailed description thereof will be omitted. In the figure, the parts divided by the mount parts MT1 and MT2 indicated by two dashed lines are the camera unit CM, the conversion adapter AD, and the lens unit LS from the right, respectively. , 11. And conversion adapter AD
Control and AF (auto focus) by microcomputer 17 for conversion
Controllable video movie camera (camera unit CM)
The AE control signal generated from the output of the video signal processing circuit (camera signal processing circuit 4, camera encoder 5, etc.)
Signal conversion means for converting to an AE control signal corresponding to a still camera interchangeable lens system (lens unit LS system) capable of control AF control is configured.

In the camera unit CM, the AF control signal finally generated by the AE circuit in the same manner as in FIG.
After being converted to a digital signal by the camera microcomputer
The data is input to 10 and data processing described later is performed. that time,
The output of the reference level of the reference value generating circuit 19 is taken into the camera-side microcomputer 10 as the reference value Yr via the A / D converter 16, and is processed together with the output Yc of the A / D converter 9. This arithmetic processing is as follows.

Di = (Yc−Yb) / (Yr−Yb) × Dc (1) where Di: AE control data (Diris) Yc: AE control signal input to the microcomputer on the camera side Yr: Yc at reference level Level Yb: Yc level when the image sensor is shielded Dc: AE control data at the reference level (center value) The calculated AE control data Di is transmitted to the conversion adapter AD via the data communication path 21 at a predetermined timing. Sent as an AE control signal. At this time, the data communication path 21 is connected to the conversion microcomputer 17 of the conversion adapter via a direct connection contact (not shown) of the mount part MT1, and all communication data is once received by the conversion microcomputer 17. If the transmitted control data is allocated in, for example, 8 bits (256 steps), and the representative value (Dc) is 32 in consideration of the video signal and the general characteristics of the iris diaphragm 2, each representative value is: This is the value shown in FIG. In FIG. 8, each level difference is expressed by an EV value. For example, in the case of +1 EV, it indicates that the optimum exposure is to be narrowed down by 1 EV (so-called one stop). In this case, the reference value of the AE control is set to 32, and the iris diaphragm 2 does not move at the time of this data. And
The AE control data Di (Diris) is set based on communication data transmitted from the camera body and taking into account the level difference, the sign of the control direction, and the like.

FIG. 2 is a flowchart showing a specific processing operation of the above-described camera unit CM, and shows processing contents of the camera-side microcomputer 10.

First, in step S1, the output of the video signal level of the AE circuit is
At the same time, the output of the reference level of the reference value generation circuit 19 is read via the A / D converter 16 in step S2. Then, in step S3, the calculation (video signal level−black level) / (reference level−black level) × 32 of the above equation (1) is executed to obtain AE control data Di. Next, in step S4, wait until the input timing of some _Vsync (video vertical synchronization signal).
The chip select signal is set in S5. Then, in step S6, the AE control data Di is converted from parallel to serial and transmitted from the camera unit CM to the conversion adapter AD (serial communication).
Then, the chip select signal is reset in step S7.

As described above, information for AE control is created in the camera unit CM. Here, the conversion microcomputer 17 in the conversion adapter AD converts the data based on the AE control data (relative difference data) created on the camera side and transmitted through the data communication path 21 as described above. It is necessary to convert the data into absolute stop difference data that can be used by the lens unit LS. Thus, the relationship between the AE control transmission data and the EV value based on FIG. 8 is a graph as shown in FIG. The conversion means at this time may of course convert the figure into an arithmetic expression and execute it, but it is not advisable to cause the microcomputer to execute a complicated operation in consideration of the capability and cost of the microcomputer. Therefore, it is practical to have a value obtained in advance by calculation (or from a graph) as the conversion table 15. For example, when the minimum resolution of the aperture driving mechanism is set to, for example, 1 / 8-step in the lens group of the interchangeable lens system for a still camera (when a pulse motor is used, the aperture changes by 1 / 8-step by driving one pulse of the pulse motor. In addition, one stop, that is, one EV changes by eight pulse driving.)
4 is shown in FIG. In the figure, the pulse number shows only the absolute value.

The pulse number data obtained from FIG. 4 is transmitted as an AE control signal to the lens via the data communication path 22. At this time, the data communication path 22 is connected to the lens-side microcomputer 11 via a direct contact (not shown) of the mount part MT2, and all communication data is once received by the lens-side microcomputer 11.

FIG. 5 is a flowchart showing a specific processing operation of the conversion adapter described above, and shows the processing contents of the conversion microcomputer 17.

First, in step S11, the chip select input of the microcomputer 17 is confirmed, and if it is selected, A is determined in step S12.
E Convert control data to serial-parallel and capture. Next, at step S13, the above-mentioned number of driving pulses corresponding to the acquired data is obtained from the conversion table 15. Then, in step S14, the magnitude relationship with the reference value is checked based on the data to determine the driving direction of the pulse motor (stepping motor 20), and in step S15, it is checked whether the lens is in a communication standby state. At this time, if it is in the standby state, the data of the driving pulse number and the driving direction are converted from parallel to serial in step S16 and serially transmitted from the conversion adapter AD to the lens side, and in step S17 the completion of driving on the lens side is confirmed. I do.

As described above, the information for AE control is converted in the conversion adapter AD. At this time, as the processing of the lens unit LS, the above processing is performed by the conversion adapter AD, so the data sent from the conversion microcomputer 17 via the data transmission path 22 is sent from the still camera. There is no difference from the data that comes (it is in form). Therefore, the operation in the normal processing range is performed.

As described above, since the relative drive value for AE control transmitted from the video camera to the conversion adapter is converted into an absolute drive value capable of controlling (driving) the interchangeable lens group for the still camera, two different AE controls are provided. The system can be matched, and the interchangeable lens of the still camera can be used for the interchangeable lens system of the video camera, and good AE control can be performed.

〔The invention's effect〕

As described above, according to the present invention, the interchangeable lens of the still camera can be used as the interchangeable lens system of the video camera, and an advantageous effect that good AE control can be achieved is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of one embodiment of the present invention, FIG. 2 is a flowchart showing the processing operation of the camera unit of FIG. 1, and FIG. 3 is a diagram showing the relationship between iris control data and EV values. FIG. 4 is a diagram showing an example of the conversion table of FIG. 1, FIG. 5 is a flowchart showing the processing operation of the conversion adapter of FIG. 1, FIG. 6 is a block diagram showing the configuration of the camera-integrated VTR, FIG. 7 is a block diagram showing the configuration of an interchangeable lens type VTR, FIG. 8 is a diagram showing the relationship between video signals and iris control data in the VTR of FIG. 7, and FIG. 9 is a block showing the configuration of a still camera. FIG. DESCRIPTION OF SYMBOLS 1 ... Lens optical system 2 ... Iris diaphragm 3 ... Image sensor 4 ... Camera signal processing circuit 5 ... Camera encoder 6 ... Integrator (AE circuit) 7 ... Amplifier (AE circuit) 8 ... DC level Shift circuit (AE circuit) 10 Camera microcomputer 11 Lens microcomputer 13 Driver 14 Stepping motor 15 Conversion table 17 Conversion microcomputer 19 (signal conversion means) 19 Reference Value generation circuit

Claims (3)

(57) [Claims] An aperture driving means on a video camera lens unit side is controlled based on an exposure control signal relating to a level difference between a video signal level and a predetermined reference level so that the video signal level becomes equal to the reference level. A video camera that performs automatic exposure control, performs aperture control by controlling aperture drive means based on information on the absolute drive amount of the aperture supplied from the camera side. An interchangeable adapter for mounting a different still camera interchangeable lens unit, wherein the exposure control signal relating to a level difference between a video signal level output from the video camera and a predetermined reference level, the still camera interchangeable lens. A signal converter for converting the information into an absolute drive amount of the aperture for controlling the aperture drive means of the unit; An adapter for an interchangeable lens of a camera, comprising: a step; 2. A video camera according to claim 1, wherein said aperture driving means on said video camera lens unit is driven based on an exposure control signal relating to a level difference between said video signal level and a predetermined reference level so that said video signal level becomes equal to said reference level. A still camera having an aperture drive characteristic different from that of the video camera lens unit, wherein the aperture drive means is subjected to open loop control based on information on the absolute drive amount of the aperture supplied from the camera side to the video camera that performs feedback control. A conversion adapter for mounting an interchangeable lens unit, wherein the exposure control signal relating to a level difference between a video signal level output from the video camera and a predetermined reference level, the still camera interchangeable lens unit of the Conversion into information on the absolute drive amount of the aperture for controlling the aperture drive means An adapter for an interchangeable lens of a camera, comprising: signal conversion means. 3. An aperture driving means on a video camera lens unit side is controlled based on an exposure control signal relating to a level difference between a video signal level and a predetermined reference level so that the video signal level becomes equal to the reference level. A video camera for performing feedback control on the aperture control means based on the information on the absolute drive amount of the aperture supplied from the camera side, and a lens unit for a still camera having a different aperture drive characteristic from the video camera lens unit. An interchangeable lens unit, and a conversion adapter for attaching the still camera interchangeable lens unit to the video camera, wherein the conversion adapter has a level between a video signal level output from the video camera and a predetermined reference level. The exposure control signal relating to the difference An interchangeable lens camera system, characterized by comprising signal converting means for converting said diaphragm absolute driving amount of information for controlling said diaphragm driving means of the unit.