JPH02150176A - Exchange lens system - Google Patents

Abstract

PURPOSE:To cope with various combinations without altering a constitution, etc., on a camera side even when exchange lenses having any exposure control mechanism are combined by fixing a reference value and a code, which expresses the difference from the reference value with an EV value, beforehand concerning an exposure control, and transmitting them. CONSTITUTION:The communication data of a control signal to obtain suitable exposure are expressed by the EV value according to the luminance difference of inputs, converted into digital signals by an A/D converter 9, and connected through a camera microcomputer 10 by way of a data communication path 21 to a microcomputer 11 on a lens side. Further, they are converted into analog signals by a D/A converter 12, supplied to an AE driver circuit 13, and an iris 2 is controlled through an iris actuator 14. Thus, since an exposure control signal is digitally encoded and transmitted, the apparent difference of a gain in a camera can be ignored, and the optical exposure regulating operation is always attained even when any lenses are combined.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an interchangeable lens system, and in particular to a so-called electronic mount system that communicates data necessary for various controls between a lens unit and a camera unit. It is suitable for use in the system.

(Background Art) In recent years, the development of video equipment such as video tape recorders (hereinafter abbreviated as VTR) has been remarkable, and automatic exposure adjustment devices have come to be equipped as standard, especially in camera-integrated VTRs. There is.

A conventional exposure control system for such a camera-integrated VTR will be described below with reference to FIG.

The light beam entering from optical system 1 is exposed to the exposure adjustment mechanism (iris).
2, the amount of light is adjusted and a subject image is formed onto the image sensor 3. A signal obtained from the image sensor 3 is converted into a television video signal by a camera signal processing circuit 4 and a camera encoder 5. The video luminance signal Y obtained from the camera signal processing circuit 4 is subjected to integration processing by an integrator 6, and a calculation unit 18 generates a difference signal from a reference value 15. The driver lp and the actuator 14 use the difference signal as an exposure control signal.
This controls the iris (aperture mechanism for adjusting exposure).

(Problems to be Solved by the Invention) As described above, current camera-integrated VTRs do not pose any particular problems in automatic exposure adjustment.

However, in recent years, with the development of video equipment such as VTRs, interchangeable lenses, which have traditionally been common in silver halide cameras, have been replaced by video cameras and camera-integrated V
This is also being promoted in TR.

When an interchangeable lens system is applied to a VTR, etc., as described above, each lens has a different exposure adjustment mechanism, and from the perspective of the camera control circuit, the exposure reference value, dynamic range of the exposure signal, etc. Compatibility of control information is not sufficiently ensured, resulting in malfunctions during automatic exposure adjustment.

(Means for Solving the Problems) The present invention was made for the purpose of solving these problems, and its features include a camera unit, a lens unit that can be freely attached to and detached from the camera unit, and a lens unit that is detachably attached to the camera unit. The camera unit includes an exposure state control signal for controlling the exposure state, an exposure control signal forming means for forming a control reference value of the exposure state control signal, and an encoder for encoding the exposure state control signal. and a transmission means for transmitting the code to the camera unit, and the lens unit is characterized by comprising a control means for controlling the exposure state based on the received code. This makes it possible to always perform optimal exposure amount adjustment regardless of the combination of lenses.

(Example) Hereinafter, examples of the interchangeable lens system according to the present invention shown in the figures will be described in detail.

(First Embodiment) FIG. 1 is a block diagram showing a first embodiment of an interchangeable lens system according to the present invention.

In addition, in the figure, the same reference numerals are given to the parts having the same configuration as those of the above-mentioned conventional example, and the explanation thereof will be omitted.

Bordering the mount part MT indicated by the dashed line in the center of the figure,
Camera unit CM is on the right, lens unit LS is on the left.
It becomes.

The lens optical system 1 connects the image sensor 3 via the iris 2.
The subject image formed on the imaging surface is photoelectrically converted by the image sensor 3 and output as an image signal, and 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. The color signal C and the luminance signal Yγ are extracted as video signals, passed through an encoder 5 such as NTSC, and outputted from the camera section in the form of a composite video signal or the like.

Further, the brightness signal Y output from the camera signal processing circuit is transmitted to the AE to generate a control signal for controlling the iris 2 to obtain proper exposure according to the brightness state of the screen.
Supplied to circuits 6, 7.8.

In the AE circuit, the input luminance signal Y is integrated by an integrating circuit 6, amplified to a predetermined level by an amplifier circuit 7, and then
The level shift circuit 8 sets the reference level to a predetermined voltage.

Furthermore, this communication data setting method is obtained by adjusting the amplifier 7 and the DC level shift circuit 8 so that the communication data shown in FIG. 6 (as described later) is obtained according to the input luminance difference.

The signal generated by the AE circuit is converted into a digital signal by the AD converter 9, inputted to the camera microcomputer 10, and transmitted as a control signal to the lens unit LS via the data communication path 21 at a predetermined timing.

The data communication path 21 is the lens side microcomputer 11
All communication data is first received by the lens-side microcomputer 11, converted into an analog signal by the D/A converter 12, and sent to the AE driver circuit 13.
The iris 2 is controlled via the iris actuator 14.

The control data to be transmitted is, for example, 8 bits (256
FIG. 6 shows representative values (32) when assigned in stages).

As shown in FIG. 6, each level difference is expressed by an EV value. For example, in the case of +lEV, the IEV for the optimum exposure is
This message indicates that the exposure is overexposed by one aperture (so-called one aperture), so stop down by IEV on the lens side.

Further, the reference value for exposure control is set to 32 in this embodiment, and the iris does not move when this data is set.

The lens side receives the control data transmitted from the camera side.
The A converter 12 converts the signal back into an analog signal, which drives the actuator 14 through the driver 13 to drive the iris 2.

As described above, by digitally encoding and transmitting the exposure control signal that includes iris drive stop based on the video level as iris control information, it is possible to ignore the apparent difference in gain inside the camera. Differences in camera dynamic range are also not an issue.

In addition, compatibility can be maintained because the reference values are unified using a predetermined code.

Note that in this embodiment, communication is performed using 8 bits, but
It does not matter how many bits there are or even if the reference value is other than level 32.

Next, the flow of the control operation of the interchangeable lens system shown in FIG. 1 will be explained using FIG. 2.

First, as processing on the camera side, #1: Take in the output of the AE circuit 8 from the AD converter 9.

#2: Wait until the next Vsync (video vertical synchronization signal) input timing.

#3: Set the chip select signal.

#4; Iris data is parallel-serial converted and sent from the camera to the lens.

#5: Reset the chip select signal.

Next, as processing on the lens side, #6: Check the chip select input.

#7: Capture iris data by serial-parallel conversion.

#8: Send the received iris data to the D/A converter.

As described above, control information is communicated between the camera unit and the lens unit, and control is thereby executed.

As explained in detail above, no matter what kind of interchangeable lenses you choose and combine, you can use them without changing the camera body.
Differences in the characteristics of the exposure adjustment mechanism can be compensated for. That is, it is possible to realize a highly reliable interchangeable lens system in which the performance of the exposure adjustment mechanism does not change depending on the lens used.

(Second example) Next, a second embodiment of the present invention will be described using FIG.

In the second embodiment, a part of the AE circuit 6°7.8 of the first embodiment is incorporated into the camera microcomputer 10.

In the first embodiment, a predetermined code is generated by adjusting the bias and amplification factor, but in the second embodiment, a reference value is taken in from the reference voltage generator 17, and this is digitalized by the AD converter 16. Convert it to data and process it within the camera microcontroller.

The calculation process in this case is as follows.

Di - (Yc - Yb) / (Yr - Yb) , Yr level is set by the reference value generation circuit 17, and the Yr level is taken into the camera microcomputer 10 by the AD converter 16.

Other processing is the same as in the first embodiment.

FIG. 4 shows a flowchart illustrating the operation of the second embodiment.

First, as processing on the camera side, #1: The output of the AE circuit 8 is taken in from the AD converter 9. #9: The reference level is taken in from the AD converter.

#10: Execute the calculation #2: Wait until some Vsync (video vertical synchronization signal) input timing.

#3: Set the chip select signal.

#4 Convert the near iris data from parallel to serial and send it from the camera to the lens.

#5: Reset the chip select signal.

Next, as processing on the lens side, #6: Check the chip select input.

#7: Capture iris data by serial-parallel conversion.

#8: Send the received iris data to the D/A converter.

As described above, control information is communicated between the camera unit and the lens unit, and control is thereby executed.

(Effects of the Invention) According to the present invention, as shown in FIG. 6, a reference value and a code expressing the difference from the reference value as an EV value are determined in advance for exposure control, and this is transmitted. It is possible to combine interchangeable lenses with any type of exposure control mechanism without changing the configuration of the camera.

In other words, it is possible to construct a system with expandability that can accommodate newly designed lenses without any problems, and the possibilities for system development are dramatically expanded.

In addition, by incorporating the calculation processing of the reference value into the camera microcomputer, it is possible to reduce the number of initial adjustments and to create a system that is resistant to changes over time.

[Brief explanation of the drawing]

FIG. 1 is an overall block diagram of an embodiment of the present invention, FIG. 2 is a flowchart for explaining the operation of the embodiment of FIG. 1 of the present invention, and FIG. 3 is a second embodiment of the present invention. FIG. 4 is a flowchart for explaining the operation of the second embodiment. FIG. 5 is a block diagram showing seven examples of the apparatus before the present invention. FIG. 6 is the exposure control data of the present invention. It is a figure showing an example. Camera 1 rule: Relay side Figure 2: Camera side: Figure 4: Relay side: Figure 6

Claims (1)

[Claims] (1) Consisting of a camera unit and a lens unit that can be attached to and detached from the camera unit, the camera unit generates an exposure state control signal for controlling the exposure state and an exposure control value that forms a control reference value for the exposure state control signal. A control means that has a signal forming means, an encoder that encodes the exposure state control signal, and a transmitting means that transmits the code to the camera unit, and that the lens unit controls the exposure state based on the received code. An interchangeable lens system comprising: