JPS6261487A - Video camera and exchange lens - Google Patents

Abstract

PURPOSE:To improve an operability by providing a memory means for electrically storing the information indicating a spectral characteristic peculiar to a lens in an exchange lens and providing a means for reading the information corresponding to the spectral characteristic stored in the memory means in a camera body. CONSTITUTION:The exchange lens has a memory means for storing electrically the information corresponding to a spectral characteristic peculiar to the lens. A video camera has a reading means for electrically reading the information stored in the memory means and a means 5 for adjusting a white balance based on the read information. Accordingly, at every use of the lens, the white balance can be adjusted. To the means for adjusting the while balance in the video camera, the memory means for storing the information indicating the spectral characteristic peculiar to the exchange lens is provided, thereby at every time exchanging the lens, the readjustment of while balance in the video camera is not necessary.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a video camera equipped with an adjusting means for adjusting the white balance of a color imaging signal, and an interchangeable lens that is detachable from the video camera.

[Conventional technology]

Conventionally, in video cameras, etc., the white balance of a color image signal is determined by setting the most standard spectral characteristics of a commonly used lens, and then adjusting the color temperature due to the set spectral characteristics and the light from the subject. Adjustments have been made based on the information.

[Problem that the invention seeks to solve]

However, in conventional video cameras with interchangeable lenses, the spectral characteristics differ depending on the lens used, so even if you set the spectral characteristics of the standard lens and adjust the white balance based on color temperature information from the subject, it is difficult to actually use it. Depending on the interchangeable lens used, the spectral characteristics differ greatly from those of the standard lens, and this has the disadvantage that white balance cannot be adjusted well even for the same subject.

The present invention eliminates the above-mentioned drawbacks and provides an interchangeable lens (video camera) and such (
The aim is to provide interchangeable lenses suitable for video cameras.

[Means for solving problems]

In order to achieve this object, the first invention of the present application provides a video camera with an interchangeable lens, the interchangeable lens having a storage means for electrically storing information indicating spectral characteristics specific to the lens. The camera body is characterized in that the camera body has a readout means for reading out information stored in the storage means and corresponding to the nine-fold characteristic, and white balance adjustment is performed based on the readout information. A second invention of the present application provides a storage means for electrically storing information read out by the video camera body in an interchangeable lens that is detachable from the video camera and that indicates spectral characteristics specific to the interchangeable lens. (Function) A storage means for storing information corresponding to the spectral characteristics of the lens provided on the interchangeable lens side is read out by the video camera body side, and this readout is used as the next output. Accordingly, the white balance of the Shikaji imaging signal is adjusted by the white balance adjustment means. Therefore, it is possible to perform excellent white balance adjustment for each interchangeable lens used.

<Embodiment> FIG. 1 is a schematic diagram of a video camera according to an embodiment of the present invention. In Fig. 1, 1 indicates the spectral characteristics of the photographic lens (the photographic lens that stores the corresponding color information), and 2 indicates the photographic lens 1.
an element that converts an incident image into an electrical signal,
3 and 4 are R and B amplifiers that amplify the red and blue signals output from camera element 2, respectively, and 5 is an automatic tracking white balance sensor that detects the color temperature of the light source.

The sensor is arranged so as to receive the averaged light surrounding the imaging device through an achromatic filter. 6 is a system controller that outputs a digital control voltage value D"4.D% that controls the gain of the R amplifier 3B amplifier 4 based on the data sent from the lens 1 and the white balance sensor 5. 7 is a D/A converter that converts the digital control voltage values D%, D% obtained by the system controller 6 into analog voltages vR,6, v%.

This is a signal processing system that converts signals R', G, and B' whose color balance has been adjusted by an R amplifier and a B amplifier into predetermined signals.

Next, FIG. 2 is a block diagram of the photographing lens 1 and the camera body 2 for explaining a communication method between the photographing lens 1 and the camera body 2 in the embodiment shown in FIG. In the figure, G1 is the camera's microcomputer, C2 is the main interface, C21 is the power output terminal, and C22 is the main interface.
is the data terminal, C23 is the beige terminal, and C24 is the G terminal.
This is an ND terminal. C3 is a ROM in which the main microcomputer program is stored, C4 is a power supply section, C5 is a disk drive section that drives a disk for recording images provided in the camera body 2, C6 is a photometry system, and C7 is a distance measurement system. It is a system. Further, the photographing lens 1 is removably attached to the camera body 2. Ll is the lens microcomputer, L2 is the lens interface, L21 is the power supply terminal, L22 is the data terminal, L23 is the bus terminal, Ll4 is the GND terminal, and L3 stores various information about the lens 10 and programs for the sub-microcomputer, which will be described later. ROM.

L4 is an aperture drive system, L5 is a focus drive system, and L6 is a zoom drive system.

Next, various information on the lens 10 stored in the ROM L3 of the photographic lens 1 will be explained using FIG.

In Fig. 3, the commands sent from the camera 2 through the data terminals C22 and L22 of the photographing lens 11'C, the code of the command, the content of the command, the number of bytes of data sent from the photographing lens 1, and the allocation to the bytes. indicates the type of data collected. In addition, data content column 9 “←
Data marked with ゝ indicates that the content is the same as that shown in the content column.

Here, the data read by the command shown as Te5t By max is 2-byte data that indicates how many steps can be stopped down from the current aperture value to the minimum aperture value, and each byte can compensate for h-step accuracy. Data indicating the minimum aperture value and the number of steps that can be stopped down to the minimum aperture value that can compensate for step-down accuracy are assigned. The contents read by the command shown as Te5tColor are the spectral characteristics of the lens, and are LRPG, L'BG based on the ratio of R, G, and H of the light that passes through the lens.
It consists of 2 bytes of data indicating. Also Te
The contents read by the command shown in 5t ID are data indicating the manufacturer, type, and function of the lens, and several bytes are appropriately allocated to each of them, and the data consists of 7 bytes in total.

Next, the commands and data shown in Figure 3 are sent to the camera body 2.
The order in which data is exchanged between the camera and the lens 1 will be explained using FIGS. 4 and 5. FIG. 4 is a flowchart executed by the microcomputer CI of the camera body 2, and FIG. 5 is a flowchart executed by the lens 10 microcombinator L1.

First, the operation of the camera body 2 starts, and when step 70- shown in FIG. 4 +σ9 starts, the step 70- shown in FIG. sent to.

On the other hand, when the operation of the lens 1 is started, steps 70- shown in FIG. 5 φ- are started, and ÷1 is executed. The steps shown in Figure 5+1 determine whether or not a command is sent from the camera body 2 to the lens 1, repeating the loop when no command is sent, and repeating the loop when a command is sent. Proceed to ÷2. Therefore, when the operation of the camera body 2 is started and +1 in Figure 4 is executed, the lens 1
The flow of the microcomputer L1 is to receive the transmitted command and proceed from FIG. 5+1 to FIG. 5+2.

Lens 2 determines whether the transmitted command is an executable command in t45 diagram φ2, and if it is an executable command, it goes to Figure 5-3, and if it is not executable, it goes to Figure 5+4. move on.

Here, +3 in FIG. 5 is a step in which the command sent from the camera body 2 to the lens 1 is sent as is (return command) from the lens 1 to the camera body 2. Here, Figure 5 +
After executing command 3, lens 1 executes the command (ta
(Fig. 5 φ5) Next, the operation proceeds as shown in the command (Fig. 5 +5) where the specified data is sent to the camera 2. Also, Fig. 5 +4 is the step of "sending data indicating command error 1 to the camera 2". In other words, if the command sent from the camera body 2 to the lens 1 is an executable command, the lens 1 transmits the transmitted command directly from the lens L to the camera body. If the command sent from the camera body 2 to the lens 1 is a command that cannot be executed, the lens 1 sends a "command error 1" to the camera 2 indicating that the sent command cannot be executed. This shows the transmission flow. In this state, as shown in Fig. 4, the camera body 2 is in a state to receive commands sent from the lens 1 as shown in Fig. 4+2, and the lens 1 is Data transmitted from the lens 1 to the camera body 2 is received by executing the steps shown in FIG. 5+3 or FIG. 5+4 described above.

Next, the camera body 2 is attached to the lens 1 as shown in Fig. 4+3.
The data sent from the camera body 2 to the camera body 2 is
It is determined whether the command matches the command sent to lens 1. If they match, the camera body 2 receives the next transmitted data and performs an operation corresponding to the data, as shown in Figure 4+4, and ends 70-, but if they do not match, The flow moves from Figure 4 +3 to φ5,
At +3 in FIG. 4, it is determined whether the data transmitted from the lens 1 to the camera 2 is data indicating a 1-command error 1. If the data sent there is determined to be "command error 1", the flow moves again to FIG. Either the command sent from camera 2 to lens L was sent to lens 1 by mistake, or the data sent from lens 1 to camera 2 was sent to camera 2 by mistake, but in any case, Since this is an error, 70- stops there.

Here, the LRP6. The LB/G data is sent to the system controller 6 shown in FIG. 1, added to the data W% and W% sent from the white balance sensor 5, and sent to the R Control voltage values yB,6, yR, that control the gains of amplifier 3 and B amplifier 4
6, and the white balance is corrected taking into consideration the spectral characteristics of the lens.

Therefore, according to this embodiment, the white balance can always be adjusted appropriately regardless of the spectral characteristics of the lens.

By the way, in the method of FIG. 1 described above, the R amplifier 3.
When the control voltage value that controls the gain of the B amplifier 4 is varied over a wide range, the gain of the R amplifier 31B amplifier 4 loses linearity with respect to the control voltage value, as shown in FIG. R amplifier for control voltage,
The gain of the B amplifier tends to saturate with respect to the control voltage value.

Due to such saturation, the gains of the R amplifier and the B amplifier are different from the gains for adjusting a proper white balance, and come to include errors, resulting in a disadvantage that the white balance is disrupted.

In order to eliminate this drawback, the system controller 6 adds the spectral characteristics of the lens transmitted from the lens 1 and the signal obtained from the white balance sensor 5, and the R amplifier 3. Calculate the gain in the B amplifier 4, and calculate the gain in the R amplifier 3 from the gain % and % obtained by the calculation. B amplifier 4
Considering the characteristics shown in Fig. 6, the control voltage value VB/6
, vRGVc conversion is sufficient. The configuration of the system controller 6 having such a function will be explained using FIG. 7. In FIG. 7, 6-A is an addition circuit that adds the data L% and LBI 6 transmitted from the lens 1 and the data W% and Wt transmitted from the white balance sensor 5, respectively. 6-B is the R amplifier 3.B from the data calculated by the adder circuit 6-AK. This is a converter that converts a control voltage value into a digital value that takes into account the control voltage-gain characteristics of the B amplifier 4.

From the adder circuit 6-A and the converter 6-BK, the R amplifier 3. A control voltage value that takes into consideration the control voltage-gain characteristics of the B amplifier 4 can be obtained.

By the way, according to the above embodiment, it is possible to perform white balance adjustment that is not affected by the spectral characteristics of the lens, but depending on the lens, the amount of correction that supplements the spectral characteristics of the lens can be adjusted depending on the color temperature of the light source. It has to change.

This will be explained using FIG. 8. In Fig. 8, light sources ◆1 and N2 indicate the spectral distributions of light sources with different color temperatures, R filters and G filters indicate the transmission characteristics of the red filter and green filter provided in front of the sensor for white balance, Reference lens A, lens ÷1. ÷
2 shows the spectral characteristics of the lens. For example, for a lens with spectral characteristics having almost the same distribution as the reference lens A, such as lens +1 shown in FIG. Doesn't require quantity.

In other words, the correction amount for the light source φIVC and the correction amount for the light source ÷2 shown in FIG. 8 do not change much. However, in the case of lens ÷ 2, the sensitivity on the short wavelength side is extremely low compared to the reference lens, so light source ◆1. There is a difference in the amount of correction depending on ÷2. In other words, with light source φ1 with a low color temperature, the amount of correction of red component R with respect to green component G may be small, but with light source 2 with high color density, The amount of correction must be large.

My suggestion is that Lensuna 2 shown in Figure 8 has a low color temperature.
It is less sensitive to light source +2, which is a bluish light source with a higher color temperature, than light source φ1, which is reddish light source, so under light source 2, the correction amount for the spectral characteristic of lens ÷ 2 is made larger, and red to green is It is necessary to increase the signal strength.

Therefore, an example of correcting the white balance f: 14M for a lens as shown in ÷2 in FIG.
This will be explained using figures.

In the embodiment shown in Figure 9, data L''/6 from lens 1, along with L''4, depending on the color temperature of the light source.

Correction coefficient α for correcting data from lens 1
is sent to the camera body 2tC, and from the data L%, L% and correction coefficient α, and the data W%, W% sent from the white balance sensor, the white balance is properly calculated under any color temperature light source. The system controller 6 that performs the adjustment will be described. FIG. 9 is a block diagram of another embodiment of the system controller 6 shown in FIG.

In FIG. 9, 6-C is the control voltage of the R amplifier based on the spectral characteristic information L to L% from the lens 1, the correction coefficient α, and the outputs w"7 and wla of the white balance sensor 5. This block derives the control signals R/G' and B/G' obtained in this block.
The value is corrected depending on the difference in color temperature of the light source, and can be expressed by the following equations (1) and (2).

wealth=W%'+<w%・α+5%)・・・・・・(1)”
/6'= *%+(w%・α+5%)...(2
) Here, as mentioned above, w'56, w% is -y-ta of the color ma of the light source obtained from the sensor for white balance, for example, WRPG-4dn, r, RpG = 1aB α-0
,05.

(1) The part in ) is w%・α+LR/G−-4x
O105+1 becomes -1.2 dB, and the loss becomes 5.2 dB.

In other words, in this case, the color temperature correction amount (%) including lens correction is 1. In addition to the original lens correction amount of 1 dB, wRPG
, the amount of correction depending on the color temperature expressed in w% (w RpG
xα=0.2dB) is added, and from this,
It can be seen that the correction amount is further adjusted depending on the color temperature of the light source at the time of shooting.

6-B is an exchanger similar to the converter shown in FIG. With the correction blocks 6-C and 6-H, it is possible to correct the color of the lens according to the difference in color temperature of the light source at the time of photographing, as described above.

According to the above-described embodiment, the white balance can always be adjusted appropriately even if the color temperature of the photographing light source is different.

In this embodiment, the storage means for electrically storing the spectral characteristics of the photographic lens is the ROMC 5, but other bubble memories or other magnetic memories may be used. Further, although the microcomputer C1 and interface C2 shown in FIG. 2 which operate according to the flow shown in FIG. 4 are used as means for reading data stored in the storage means, other heart logic may be used.

<Effects of the Invention> As explained above, according to the first invention of the present application, in the video camera 9Yc using an interchangeable lens, the interchangeable lens electrically stores information corresponding to the spectral characteristics specific to the lens. The video camera is provided with a reading means for electrically reading out the information stored in the storage means VC, and a means for adjusting the white balance based on the read information. Complete white balance adjustment can be performed for each lens used. Furthermore, according to the second invention of the present application, the means for adjusting the white balance in the video camera is provided with a storage means for storing information indicating the spectral characteristics peculiar to the interchangeable lens, so that it is possible to adjust the white balance every time the lens is replaced. There is no need to re-adjust the white balance inside the video camera.

This has the effect of improving operability.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a video camera according to an embodiment of the present invention. FIG. 2 shows a photographic lens 1 for explaining the communication method between the photographic lens 1 and the camera body 2 in the embodiment shown in FIG.
A block diagram of the camera body 2 and the camera body 2, and Figure 3 shows the photographing lens 1.
, a diagram showing commands and data exchanged with the camera body 2, FIG. 4 is a flowchart executed by the microcomputer CI in the camera body 2, and FIG. 5 is a flowchart executed by the microcomputer L1 in the photographic lens 1. The flowchart shown in FIG. 6 is a flowchart of the R amplifier 3. shown in FIG. FIG. 4 is a diagram showing the relationship between the gain of B amplifier 4 and control voltage. FIG. 7 shows the R amplifier 3 shown in FIG. A block diagram showing the configuration of the system controller 6 that performs control considering the characteristics of the B amplifier 4. Figure 8 shows the light sources φ1, ÷2 and the R and G color filter lenses φ.
1. FIG. 9 is a block diagram showing the configuration of the system controller 6 that performs control in consideration of the spectral characteristics of the filter/lens shown in FIG. 8. 1......Photographing lens 2...Camera body C1, Ll...Microcomputer 6...
...System Controller Representative Gi Marushima −
j ; [- Bow No. 6 No. 9 Procedural Amendment Stamp Color 1, Indication of Case 1985 Patent Application No. 201371 2, Name of Invention Video Camera and Interchangeable Lens 3, Person Making Amendment Relationship with Case Patent Applicant address 3-30-2 Shimomaruko, Ota-ku, Tokyo Name (IOQ
) Canon Co., Ltd. Representative Noh Kaku 3 Department 4, Agent address: Canon Co., Ltd., 3-30-2 Shimomaruko, Ota-ku, Tokyo 148 (telephone: 758-2111) 5, Specification subject to amendment 6, Amendment Contents (1) rGIJ described in page 5, line 8 of the specification is corrected to rcIJ. (2) Correct "BIGE 1 TERMINAL" written in page 5, line 11 of the specification to "BIGE 1 terminal". (3) The statements from page 6, line 15 to page 7, line 1 of the specification are amended as follows. "The data read out by the command shown as Te5t Loss here is data indicating the transmittance of the photographing lens. Also, the "No." described in page 14, line 14 of the Te5t Loss specification is changed to " Correct the ratio of the number to ``.

Claims (2)

[Claims] (1) In a video camera with an interchangeable photographic lens, the interchangeable lens has a storage means for electrically storing information corresponding to the spectral characteristics specific to the lens, and the camera body has a storage means for electrically storing information corresponding to the spectral characteristics specific to the lens, and the camera body has a storage means for electrically storing information corresponding to the spectral characteristics specific to the lens. A video camera comprising: reading means for electrically reading out information corresponding to spectral characteristics; and means for controlling white balance based on the read information. (2) An interchangeable lens for a video camera, characterized by having a readable storage means that electrically stores information corresponding to the spectral characteristics of the lens.