JPH04100025A - Interchangeable lens type camera device - Google Patents

Abstract

PURPOSE:To perform control without causing hunting nor response delay by selecting a proper focusing speed matching sensitivity at all times according to initial data which is sent from a lens side and current area values of respective encoders. CONSTITUTION:A camera microcomputer 18 converts a focusing lens control signal, a stop control signal, and a zooming control signal to data format which accords with specific communication format and sends them to a lens microcomputer 11 through a CTL line 19d. The microcomputer 11, on the other hand, receives communication data, decodes the focusing lens, stop, and zooming control signals, and supplies the results to driving circuits 5, 6, and 7 respectively to control an optical system. Respective states and displacement quantities are detected by a focus encoder 8, a stop encoder 9, and a zoom encoder 10 respectively and supplied to the microcomputer 11, and they are converted to the specific communication format and then sent back to the camera microcomputer 18.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention provides a camera system with interchangeable lenses.
In particular, the present invention relates to a lens unit that can be properly controlled regardless of the lens used.

(Prior Art) Conventionally, interchangeable lenses have been implemented in the field of cameras, and an appropriate lens can be selected depending on the shooting situation and purpose.

Another trend is to automate various functions necessary to operate a camera, such as focus adjustment, exposure adjustment, and zoom adjustment, and to improve operability, and to make these automated functions standard. It is mandatory to be equipped with

On the other hand, in recent years, the development of video equipment such as video cameras and electronic still cameras has been remarkable, and the use of interchangeable lenses, which was previously only available on silver halide cameras with the exception of some special equipment, is now being proposed for video cameras as well. and implementation is underway. This makes it possible to select the optimal lens unit depending on the shooting condition and purpose, and dramatically expand the range of use of the video camera.

(Problems to be Solved by the Invention) However, with the advent of interchangeable lenses, multiple lens units with different characteristics, performance, etc. are attached, so the rate of change in optical properties may vary depending on the attached lens. This tends to cause inconveniences such as differences in the degree of change, and while interchangeable lenses have expanded functionality,
This poses problems such as deterioration in operability.

(Means for Solving the Problems) The present invention has been made for the purpose of solving the above-mentioned problems, and is characterized by a lens unit that is detachably attached to the camera body. a plurality of driving means for varying the optical characteristics of the units; a position detection means for detecting the positions of the plurality of optical units driven by the driving means; and relative position information obtained from the position pressure detection means. a converting means for converting into absolute position information, a transmitting means for transmitting the absolute position information to the camera body, and a determining means for determining characteristics of the control information transmitted from the camera body side; and a control means for changing the driving characteristics of the driving means in accordance with the determination result by the determining means.

Another feature of the present invention is a camera equipped with a detachable lens unit, the focus sensitivity being calculated using optical design values and absolute position information of a plurality of optical units detected on the lens unit side. The present invention provides a camera device comprising: arithmetic means for selecting a focusing lens driving speed according to the degree of rotation; and a transmitting means for transmitting control information for variably controlling the optical characteristics of the lens unit to the lens unit.

(Function) This allows various optical information (focal length variable range, maximum aperture value, current focal length, current aperture value, etc.) based on the definitions made for focusing speed, zoom area, iris area, etc. to be accurately transmitted from the lens side. The camera side can calculate the positional sensitivity of the attached lens, so it can select an appropriate focusing speed regardless of the type of lens, and the camera will always be able to select the appropriate focusing speed regardless of the lens type. Good focus adjustment etc. can be performed.

(Example) Hereinafter, examples of the lens unit according to the present invention will be described in detail with reference to the respective figures.

FIG. 1 is a configuration diagram of a camera system according to the present invention. In the figure, L is a lens unit, C is a camera body, and M is a mount portion that connects the camera body C and the lens unit L.

Looking at the lens unit L, 100 is the object to be photographed, 1 is a focusing lens for adjusting the focus, an optical system equipped with a zoom lens for zooming, an aperture for adjusting the amount of incident light, etc., and 2 is a focusing lens. A focus motor moves the lens in the optical axis direction, and 3 is an aperture drive motor that changes the aperture of the aperture.
(or IG meter), 4 is a zoom motor for driving the zoom lens. Further, reference numerals 5, 6, and 7 are drive circuits (drivers) for driving a focus motor, an aperture drive motor, and a zoom motor in accordance with commands from a lens microcomputer, which will be described later.

Further, reference numerals 8, 9, and 10 are a focus encoder, an aperture encoder, and a zoom encoder that detect moving position information of the focusing lens, diaphragm, and zoom lens, respectively, and supply the information to a lens microcomputer described later.

Reference numeral 11 drives and controls the entire system on the lens side based on the control information transmitted from the camera side, and converts the driving information of the focus lens, aperture, zoom lens, etc. obtained from each encoder into a predetermined format and sends it to the camera side. This is a lens-side microcomputer (referred to as a lens microcomputer) that replies to the

On the other hand, looking at the camera body C side, 12 is an image sensor, such as a CCD, which photoelectrically converts the subject image formed by the optical system l on the lens unit side and outputs an image signal, and 13 is an image sensor 12 14 is an automatic white balance circuit that performs color temperature correction based on a predetermined component in the video signal. (
AWB circuit), 15 is an AF signal processing circuit that forms an AF multiplied signal according to the degree of focus for automatic focus adjustment (AF) from the video signal output from the camera signal processing circuit 4, and 16 is from the camera signal processing circuit. This is an AE signal processing circuit that forms an exposure signal (AE multiplied signal) for performing automatic exposure control (AE) based on an output video signal.

The AF signal processing circuit 15 extracts, for example, a high frequency component from the video signal that changes depending on the degree of focus using a band pass filter, and moves the focus lens of the optical system on the lens unit side in the direction where the level is maximized. The AE signal processing circuit 16 detects the brightness signal level in the video signal and outputs a control signal to control the aperture on the lens unit side so that the brightness signal level becomes a constant level. This is what is output.

Further, 17 is a zoom switch for driving the zoom lens, and 18 is an AF signal processing circuit 15. AE signal processing circuit 1
The AF multiplier signal, the AE multiplier signal, the zoom operation signal from the zoom switch 17, and the reply information from the lens side are respectively outputted from the AF multiplier signal and the AE multiplier signal outputted from the zoom switch 17, and the response information from the lens side is captured and converted into a control signal in a format suitable for transmitting to the lens microcomputer 11 on the lens unit side. This is a camera-side microcomputer (referred to as a camera microcomputer) that converts the data and then sends it to the lens side.

Reference numeral 19 denotes a communication path for transmitting and receiving various control signals between the camera microcomputer 18 on the camera side and the lens microcomputer 11 on the lens unit side.
), 19b is a chip select line that supplies a chip select signal (C3) to inform the lens microcomputer 11 of the timing of communication, and 19C is a clock signal that supplies the communication data Φ serial communication timing. serial clock line, 1
9d is a CT L for transmitting various control information from the camera microcomputer 18 to the lens microcomputer 11;
19e is an LTC (Lens to Lens) line for returning detection information of each encoder from the lens microcomputer 11 to the camera microcomputer 18.
19f is a GND (earth) line. All information is exchanged between the camera body and the lens unit through these communication lines 19.

The configuration of the interchangeable lens type camera system according to the present invention is as described above, and the control operation thereof will now be explained in order.

A subject image formed by the optical system 1 on the imaging surface of the image sensor 12 is photoelectrically converted by the image sensor and output as an image signal. This signal is transmitted to camera signal processing circuit 1
3 into a standardized video signal and supplied to a monitor, video recorder, etc. (not shown).

The video signal output from the camera signal processing circuit 13 is AW
B signal processing circuit 14. The signal is supplied to an AF signal processing circuit 15 and an AE signal processing circuit 16, respectively.

The AWB signal processing circuit 14 performs color temperature correction on the camera signal processing circuit so that an appropriate white balance is obtained from a predetermined color signal component in the video signal.

The AF signal processing circuit 15 outputs an AF multiplied signal to the camera microcomputer 18, which is used for determining focus, such as the level of high frequency components, which changes depending on the degree of focus from the video signal.

The AE signal processing circuit 16 also outputs an AF double signal to the camera microcomputer 18 which controls the aperture so that the brightness level in the video signal is kept constant at a predetermined value and proper exposure is achieved.

The camera microcomputer 18 receives the AF signal, the zoom encoder information indicating the moving position of the zoom lens, that is, the focal length, sent from the lens microcomputer 11 via the LTC line 19e, and the zoom encoder information sent from the lens microcomputer 11 via the LTC line 19e. Based on the aperture encoder information indicating the aperture value that has been obtained, focus lens control information that takes into account the depth of field is calculated as described later.
The aperture control signal is calculated from the multiplication signal. Furthermore, a zoom control signal output from the zoom switch 17 is calculated.

Then, the camera microcomputer 18 converts these focusing lens control signals, aperture control signals, and zoom control signals into a data format based on a predetermined communication format, and sends the data to the lens microcomputer in the lens unit via the CTL line 19d of the communication path 19. Send to 11.

On the other hand, the lens microcomputer 11 receives the communication data transmitted via the communication path 19, decodes the focusing lens, aperture, and zoom control signals, and decodes the focusing lens, diaphragm, and zoom control signals for each drive circuit 5, 6.
．． 7 and control the optical system.

The status and displacement of the focusing lens, aperture, and zoom lens are determined by the focus encoder 8.
．． Aperture encoder9. It is detected by the zoom encoder 10, supplied to the lens microcomputer 11, converted into a predetermined communication format, and then sent to the camera microcomputer 18 via the communication path 19.
A reply is sent via the C line 19e.

The above is an outline of the operation of the camera system according to the present invention, and next, specific processing and calculation of various information will be explained.

FIG. 2 shows the definition of the division of the detection area and speed division of each encoder used in the interchangeable lens system of the present invention, and (a) of the same figure shows the relationship between the division area of the aperture encoder and the detected aperture value, Figure (b) shows the area division situation of the zoom encoder that detects the focal length of the zoom lens.Based on the optical design value of the focal length, for example, area O to area 15 are divided in the root double series from the focal length of 5 mm. It is divided into 16 parts.

Similarly, the iris encoder shown in FIG. 6A is divided into 16 parts from Fl and O in the root double sequence based on the optical design value of the F number (FNo).

Further, looking at the driving speed 4 of the focusing lens, each speed is defined by the rate of change of the diameter of the circle of confusion, as shown in FIG. This is to prevent the inconvenience that the driving speed changes depending on the optical system used even though the amount of blur is the same. This is because the optical system is controlled at a speed corresponding to the change.

The actual rotation time of the focusing lens for each lens (the time required to drive from the infinity end to the close end) is calculated using the representative values of the zoom encoder and iris encoder at the telephoto end and when the aperture is open.

This representative value is a numerical value used to calculate the focus speed of each lens.

For example, if we consider a nominal 6x zoom lens with a focal length of 10 mm to 59.8 mm, the typical value of the focal length of its zoom encoder is the maximum of area 8 to which the focal length of 59.8 mm belongs, as shown in Figure 2 (b9). Take the value and get 80
mm, and the typical aperture value of a lens with an aperture value of 1.45 is determined by taking the minimum value (border value on the open side) of area 2 to which 1.45 belongs, from Fig. 2 (a), and determining Fl.
.

It becomes 41.

That is, for the focal length, the maximum value of the focal length area at the telephoto end is taken, and for the aperture, the minimum value of the F-number at the telephoto end is taken.

Here, we will show how to calculate the focus speed assuming a typical front lens focus lens.

The relationship between the front lens extension amount y (mm) and the image plane movement amount can be expressed by the following equation.

b/yr = (f/l,)"... ■Here, f is the focal length of the entire lens (mm), f is the focal length of the front lens (mm), and y is from infinity. Closest end R
(m), and b is the amount of image plane movement (mm).

Further, if the F number is F, the amount of change in the diameter of the circle of confusion (mm) is d, and the time required to move from infinity to the closest end R (mm) is tr (sec), the speed of change in the diameter of the circle of confusion v ( mm/5ec) is v = d / t r = b/(t, ・F) = (f/f,) 2 ・y, / (t, -F)...
... ■ Here, in the above formula, the front lens moves from infinity to close range 1.
．． The time required to travel up to 2m is t+z. . (s
e c), substitute the focal length representative value for f, the aperture representative value for F, and the optical design value for ftx3'r, and then V and t1□. . Find the relational expression: v = K / t + to.

That is, t1□. . = K/v・・・・・・
■It becomes. In addition, K is (f/ft)2 ・ (yr-F
) is a constant that differs depending on each lens.

Then, by substituting the rate of change of the diameter of the circle of confusion into V based on the speed division mentioned earlier, the actual rotation time of the focusing lens for each speed (rate of change of the circle of confusion diameter) can be found. In order to realize the rotation time for each focus speed, a table of motor duty ratios must be stored in the ROM.

FIG. 3 shows a table storing Z-2 levels. The 2nd level is data representing (telephoto end zoom area) - (current zoom area), and the 2nd level is data representing (telephoto end aperture open area) - (current aperture area). Here, when the 2 level is constant, when the 2 level increases by 1, the value in the table increases by 2, and when it decreases by 1, the value in the table decreases by 2.

Similarly, when level 2 is constant, when level 2 increases by 1, the value in the table increases by 1, and when level 2 decreases by 1, it decreases by 1. The value in this table is called the ZI level, and this value is used to control the speed of the focusing lens.

That is, when the ZI level increases by 1, the sensitivity increases by 12 times, and when the ZI level decreases by 1, the sensitivity increases by 1/I2 times.

FIG. 4 shows the ZI-V table. From this figure, the physical speed (circle of confusion diameter change speed) actually sent to the lens microcomputer 16 is selected by the logical focus speed (speed selected depending on the blur state) in the ZI two-level microcomputer. Here, if the physical speed in the table increases by 1 ZI level, the physical speed should be increased by 1, but the focal length,
Since the image condition within the AF distance measurement frame changes depending on the aperture value, simply increasing the ZI level by 1 does not mean increasing the physical speed by 1. Therefore, it is necessary to be able to arbitrarily set the physical speed depending on the situation.

FIG. 5 shows a flowchart for explaining the control operation by the camera microcomputer 9.

In the same figure, when the control flow starts, it takes 5 steps.
In step 1, it is determined whether or not a lens unit is attached to the camera body, and if a lens unit is not attached, the camera waits until a lens is attached.

If the lens was attached in 5tep 1, 5t
Proceeding to ep2, it is determined whether initial data has been captured into the camera microcomputer through initial communication with the lens unit. If the initial data is not captured in step 2, proceed to step 5, set a command to request the lens unit for initial data from the lens that has not been captured, perform initial communication in step 1, and perform initial communication in step 1.
In step 12, import the initial data of the lens unit, return to 5 step 1 again, confirm that the lens is attached, and continue 5 tepl m5 step 2 until it is confirmed that all the initial lens data has been imported in 5 step 2.
m5tepl Om5tepl 1 m5tepl 12
m 5 step 1 process is repeated.

Note that it is possible to move from 5tepl 2 to 5step 2 instead of returning to 5tep 1, but in consideration of more reliable control, the system is configured to return to 5tep 1 and reconfirm that the lens is attached. There is.

In addition, in this initial communication, the configuration of the lens unit,
Various information including attributes is captured, and information such as open aperture value and focal length is also included.

When it is confirmed in 5tep 2 that the capture of the initial data of the lens unit has been completed, the process proceeds to 5tep 3, and communication of control data is started. And 5t
In ep4, the zoom encoder information is extracted from the control information from the lens side captured in 5tep 3.
At step 5, the iris encoder information is loaded into the camera microcomputer at step 6, and at step 6, the focus encoder information is loaded into the camera microcomputer, and at step 7, the third
ZI level calculations are performed from the ZI child table shown in the figure. This makes it possible to calculate the focusing lens driving speed in consideration of the depth of field information.

Next, proceed to step 8, select the physical speed based on the ZI level and logical focus speed using the ZI-V table shown in Figure 4, and control the transmission of the physical speed of the focusing lens to be sent to the lens unit in step 9. Set it as data and send it to the lens unit side in the next control communication. This information means focusing lens driving speed information that takes into account the current amount of blur and depth of field, that is, sensitivity.

That is, the ZI level calculation table shown in FIG.
The ZI-V calculation table shown in the section is stored in the camera microcomputer.

5 steps 1 m 5 steps 3 m until the lens unit comes off or the camera microcomputer is reset
5tep4 m5tep5 m5tep6 m5te
p7 m5tep8 m5tep9 m5tep Repeat the process of 1.

The operations performed on the camera body side are as described above. Next, the control operations on the lens unit side will be explained.

FIG. 6 is a flowchart for explaining the processing performed by the lens microcomputer on the lens unit side.

In Figure 6, when the flow is started, 5 step 2
1 communicates with the camera side. Communication between the camera and lens is performed with the camera side as the master and the lens side as the slave.

When communication is performed in 5tep21, it is determined whether or not the communication performed in 5tep22 is an initial communication. If it is an initial communication, the process proceeds to 5tep28, the lens initial data command is decoded, and the process proceeds to 5tep29. The process proceeds to set the requested lens initial data, returns to step 21, performs communication, transmits the lens initial data to the camera side, and waits for the next communication data from the camera side.

At step 522, if the communication from the camera side is not the initial communication, the process proceeds to step 523 to decode the lens control command, and proceeds to step 524 to control the focusing lens at the focus speed specified by the camera microcomputer. Other units such as the aperture and zoom lens are also controlled based on data specified by the camera.

Next, in step 525, the detected values of the zoom encoder, iris encoder, and focus encoder are read, and in step 626, each encoder information is area-converted using the information conversion table shown in FIG. However, even if the aperture aperture diameter is the same, if the F number changes depending on the focal length, it is necessary to take this into account when converting the area.

Then, in 5tep27, the area conversion data of each encoder is set, and the process returns to 5tep22 to perform communication again. After that, while controlling the lens, hold 5te until it is reset.
p21 m5tep22 m5tep23 m5tep
24m5tep25 m5tep26 m5tep27
Repeat the process of m5tep21.

What is particularly effective about the flowchart shown in Figure 5 above is that it is possible to select a focus speed that matches the sensitivity even when different lens units are attached, so the sensitivity changes as the aperture or focal length changes. This allows the operator to select an appropriate focus speed even when adjusting the focus, and the operator can always intuitively adjust the focus without changing the degree of change in the amount of blur when adjusting the focus, no matter what kind of lens is attached. It is possible to perform a constant focus adjustment operation.

(Effects of the Invention) As explained above, according to the interchangeable lens camera device of the present invention, even if a lens unit with different optical design values such as variable focal length range and maximum aperture value is attached, The ZI level is calculated from the initial data sent and the current area value of each encoder, and the appropriate focus speed can be selected according to the sensitivity, so even if the characteristics and specifications differ depending on the lens unit. , without hunting or response delays.
Similar control can be performed.

In addition, since the camera side is configured to send control information according to the attached lens unit to the lens side, there is no need to have a speed selection table on each lens side (this is possible depending on what kind of lenses are made in the future). This is extremely effective in interchangeable lens systems, as it can be handled with a single control algorithm and saves ROM capacity.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the configuration of the interchangeable lens camera system according to the present invention. Figure 2 is a diagram for explaining the area division of each encoder and the speed definition of the focusing lens driving speed. Figure 3 is a diagram showing the zT level. Figure 4 is a diagram showing the 2I-V table showing the relationship between ZI level and speed ■, Figure 5 is a flowchart showing the operation of the camera microcomputer, Figure 6 is the lens It is a flowchart showing the operation of the microcomputer. Figure 2 (a) (Aperture value area division diagram) (Focal length division diagram) Ewag 15 (Velocity definition circle of confusion diameter change speed) r-disturbance...Level of improvement (mm/5) 11 Coat 0. 0. 0. 0. 0. 0. 0. 0. 0. 2. 4. 5. 03 l 3 ■ O ■ I ■ 4 ■5 ■ 6 ■ 7 ■ 8 IO ll V], 5 Nor, 8- Mourning diagram speed■ × Each value reduces physical speed

Claims (2)

[Claims] (1) A lens unit that is detachable from the camera body, and includes a plurality of driving means for varying the optical characteristics of the lens unit, and detects the positions of the plurality of optical units driven by the driving means. a position detection means for;
A converting means for converting relative position information obtained from the position detecting means into absolute position information, a transmitting means for transmitting the absolute position information to the camera body, and control information transmitted from the camera body side. What is claimed is: 1. A lens unit comprising: a determining means for determining a characteristic of the lens; and a control means for changing a driving characteristic of the driving means in accordance with a determination result by the determining means. (2) A camera equipped with a removably attached lens unit, in which a focusing lens is used according to a focus sensitivity calculated using optical design values and absolute position information of a plurality of optical units detected on the lens unit side. A camera device comprising: arithmetic means for selecting a driving speed; and a transmitting means for transmitting control information for variably controlling optical characteristics of the lens unit to the lens unit.