JPH0290131A - Interchangeable lens and interchangeable lens system - Google Patents

Abstract

PURPOSE:To realize an interchangeable lens system which can be handled easily and is high in interchangeability by absorbing changes in characteristics caused by the characteristic fluctuation at the time of mass production and a difference in diaphragm value detecting sensors on the lens side and controlling the lens side from a camera side through prescribed procedures irrespective the kind of the lens. CONSTITUTION:A member to be controlled on a lens side is changed by means of data transmitted from a camera side. A camera microcomputer 9 transmits digital controlling data to a lens microcomputer 10 side. The data are converted into analog signals by a D/A converter 11 and a diaphragm mechanism 2 is driven by driving an actuator 13 through a driver circuit 12. A driven result is detected by a diaphragm sensor 14 and inputted to the lens microcomputer 10 after the result is converted into a digital signal by means of an A/D converter 16. The microcomputer 10 performs correction for converting the output of the detecting means 14 into a prescribed signal which is absolutely common to plural areas. Therefore, a high-interchangeability interchangeable lens system which can be controlled commonly irrespective of the characteristics of the diaphragm value detecting sensor can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application of the Invention The present invention relates to an interchangeable lens and an interchangeable lens system in which information is exchanged between a lens and a camera.

<Prior Art> The aperture in a conventional video camera is controlled by detecting the aperture value in the photographic state using a sensor such as a Hall element provided at the aperture of the lens.

In the case of a video camera in which the lens and camera body are integrated, the aperture value detection signal is transmitted from the lens side to the camera side as an analog signal.

If the camera and lens are made removable, the detection signal will be converted into a digital signal by an A/D converter and transmitted.

However, if the detection signal is directly A/D converted, the quantization level differs depending on the characteristics of each interchangeable lens, causing a problem in compatibility as an interchangeable lens system.

<Problems to be Solved by the Invention> According to the conventional aperture control method, the new type of lens is subject to the technical constraints of the old type of lens design, and optimal design cannot be achieved.

Since optimization was performed for a predetermined lens, when looking at the entire system in chronological order, it was not optimized, and as a result, there were problems such as a lack of scalability of the system.

<Object of the present invention> An object of the present invention is to solve the above-mentioned problems and to realize an interchangeable lens system that does not malfunction even when changing lenses and has high system expandability in the future.

<Means for Solving the Problems> In order to solve the above object, the interchangeable lens of the present invention includes a driving means that is controlled by data transmitted from the camera side to the lens side and changes a controlled member on the lens side. , a detection means for detecting the state of the drive means, and a correction means for converting the output of the detection means into a predetermined absolute common signal of a plurality of regions.

Further, the interchangeable lens system of the present application includes a detection means for detecting the state of a controlled member within the lens, and a correction means for converting the detection output of the detection means into an absolute common signal of a plurality of regions. and a camera including the interchangeable lens and a control means which is removable and which forms a control signal for controlling the control member 11 by photoelectrically converting an image through the lens.

<Function> As a result, the output of the aperture value detection sensor is corrected so that the apparent response characteristic of the aperture value detection sensor as seen from the camera body side becomes linear, and this linear area is divided into predetermined fixed areas. Therefore, highly compatible interchangeable lenses and interchangeable lens systems that can perform common control regardless of the characteristics of the aperture value detection sensor can be realized.

<Explanation of Examples> FIG. 1 shows a configuration diagram of an embodiment of the present invention.

Aperture control in a video camera having a configuration that can be divided into two parts, LS on the lens side and CM on the camera side, will be described below.

The subject (not shown) is captured through the optical system l on the lens side and the aperture 2.
The resulting light is imaged onto the bottle imaging element 3 on the camera side.

An image signal is supplied from the image sensor 3 to the camera signal circuit 4 according to the imaging state, and the color signal C and luminance signal Y are taken out as video signals. is output from the camera section. In addition, the luminance signal Y is determined according to the luminance state of the screen.
The signal is supplied to an AE circuit 7 which generates an aperture control signal for controlling the aperture 2 to obtain proper exposure.

That is, the luminance signal extracts only the photometric portion of the screen via the signal gate circuit 6 controlled by the camera microcomputer 9, and is supplied to the AE circuit 7. The AE circuit 7 generates a signal for controlling the diaphragm 2 provided on the lens side in order to maintain the image pickup screen in a proper exposure state by dividing the input signal. The control signal is converted into a digital signal by an AD converter 8 and input to a camera microcomputer 9.

The camera microcomputer 9 transmits the digital control data to the lens microcomputer IO via a direct connection point (not shown).

The lens side D/A the control data transmitted from the camera side.
The converter 11 converts the signal back into an analog signal and drives the actuator 13 through the driver circuit 12.

The aperture mechanism 2 is driven by the actuator 13.

The driving result is detected by an aperture sensor 14 such as a Hall element, passed through a sensor amplifier 15, converted into a digital signal by an A/D converter 16, and inputted to the lens microcomputer IO. In the lens microcomputer IO, the digital signal and D/A
It compares the control signal output to the converter 11 and continues driving until the instructed result is obtained.

In this way, an in-lens servo lube is formed that monitors whether the diaphragm mechanism is driven as instructed by the control data transmitted from the camera microcomputer 9.

In forming the above servo loop, the following points must be considered.

1. Variations in the individual characteristics of the sensor 14.

2. Differences in characteristics depending on the type of sensor 14 and detection method.

3. Differences in characteristics depending on the shape, structure, and number of blades of the aperture mechanism 2.

In order to absorb these characteristic differences and realize a sensor system that always has apparently linear input/output characteristics, a look-up table (correction table) 17 made of a memory such as an EEPROM is used. The contents of this lookup table will be explained below with reference to FIG.

First, set the standard characteristics, for example a) in Figure 2.
The difference from the raw data from the sensor I4 (b in FIG. 2) is determined and written into the correction table 17 as correction data.

Next, as a process during aperture drive, the output of the A/D converter 16, which is the raw data of the sensor 14, is used as an address to access the ROM table of the correction table, read out the previously stored correction value, and use it as the reference. Convert it into a characteristic.

The vertical axis of the characteristic conversion table shown in FIG. 2 is the final output of the aperture sensor.

In the present invention, the vertical axis is divided into signals of eight absolute common areas. Each area corresponds to an aperture value.

A specific example of eight divisions is shown in FIG.

The horizontal axis indicates the F value indicating the state of the aperture.

For example, each fixed area can be divided as follows.

1: F=1.4 or less 2: F=1.4 ~ 2.0 3: F = 2.0 ~ 2.8 4: F = 2.8 ~ 4.0 5: F = 4.0 ~ 5 .6 6: F=5.6 ~ 8.0 7: F = 8.0 ~ 11,0 8: F = 11.0 or more Taking three lenses a, b, and c as an example, the present invention A method of such area division will be explained.

Both lenses a and b have an open F number of F=1.8. a is divided into "C8" based on the open F value,
b is the division in the fixed area exemplified above. On the other hand, C is F
It is a lens with an open F value of =1.2, and is divided into fixed areas like b. However, regarding A as well, the small aperture state is grouped together in the eighth region.

As can be seen from the above examples, the same area can be used even for lenses with different aperture f-numbers, so the aperture information obtained in this way can be easily adapted to the camera body for lens compatibility. Used to control the above servo loop. Alternatively, the aperture mechanism 2. Non-life insurance element 3, camera signal processing circuit 4, gate circuit 6, AE circuit 7, A/D converter 8, camera microcomputer 9, lens microcomputer 1O1D/A converter 11, driver circuit 12, actuator 13. A large servo loop called an aperture mechanism 2 is formed for exposure control.

FIG. 3 is a flowchart showing an example of the operation of the microcomputer 10 in the lens LS. In #l, the control data sent from the camera to the lens is received, and in #2, the drive flag is set to FL.
Set this flag to 1.0 Then, in #3, send this flag to the camera microcomputer 9, and then generate drive data Di in #4 based on the data received from the camera in #1. The data (Si) is taken in and the address of the correction table is set in #6. Furthermore, in #7, the correction data Ci is taken in, and in #8, Si*C1=Ai.
The calculation for data correction is performed, and this data Ai
The difference between and Di is determined in #9. And Di is 0 at #10
Repeat the above loop so that it becomes 0, and when it becomes 0, #11
The drive is stopped at #2, and the flag FL is set to O at #2 and sent to the camera.

<Effects of the Invention> As described in detail above, the lens side absorbs variations in characteristics during mass production and changes in characteristics due to differences in aperture value detection sensors, and regardless of the type of lens, the lens can be adjusted according to the specified procedure from the camera side. You can control the side. This makes it possible to realize an interchangeable lens system that is extremely easy to handle and has high compatibility. Moreover, the output of the aperture value detection sensor is corrected so that the apparent response characteristics of the aperture value detection sensor as seen from the camera body side are linear, and this linear area is converted into a predetermined absolute common Since it is divided into a plurality of fixed areas, it is possible to realize highly compatible interchangeable lenses and interchangeable lens systems that can perform common control regardless of the characteristics of the aperture value detection sensor.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of an embodiment of the present invention, Fig. 2 is a characteristic conversion diagram of an embodiment of the present invention, Fig. 3 is a flowchart of an embodiment of the present invention, and Fig. 4 is a region of an embodiment of the present invention. FIG. 3 is a diagram showing an example of division.

Claims (2)

[Claims] (1) A drive means that is controlled by data transmitted from the camera side to the lens side and changes a controlled member on the lens side, a detection means that detects the state of the drive means, and an output of the detection means that is controlled by a predetermined absolute value. An interchangeable lens having a correction means for converting signals into a common signal of a plurality of regions. (2) An interchangeable lens having a detection means for detecting the state of a controlled member within the lens, and a correction means for converting the detection output of the detection means into an absolute common signal of multiple regions; and the interchangeable lens. and a camera that is detachable and includes a control means for forming a control signal for controlling the controlled member by photoelectrically converting an image through the lens.