JP2671992B2 - Electric zoom camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to an electric zoom camera, and more specifically, a photographer only needs to track an object to automatically determine the ratio of the main object occupied in the image frame. The present invention relates to an electric zoom camera to be set.

[Prior Art] Conventionally, when a photographer uses a zoom lens to photograph a person or the like, it suffices if the ratio of the size of the person to the image frame can be selected and set to almost several types. Nevertheless, the photographer had to set the zoom position manually or electrically each time. In particular, when shooting a moving subject, for example, when shooting a downhill form such as skiing, a zoom lens is used to track a subject that rapidly approaches the photographer or moves away from the photographer. Was a very laborious task.

Therefore, a camera having an auto-zoom function that allows the photographer to set the ratio of the person image to the image frame in advance has already been filed by the applicant in Japanese Patent Application Nos. 61-95759 and 62-53241. Have been proposed.

[Problems to be Solved by the Invention] With such an electric zoom camera, a photographer can take a desired photograph only by tracking the subject without worrying about the zoom operation. If the zooming speed is the same as the zooming speed in the manual zoom mode, the zooming cannot follow a fast-moving subject, and there is a risk of missing a shutter opportunity. In other words, in the auto zoom mode, zooming can be performed until the preset size ratio of the subject is obtained, so it should be possible to set the zooming speed as fast as possible. Since it was not, the zooming speed in the auto zoom mode was as slow as the zooming speed in the manual zoom mode.

Also, in the auto zoom mode, it is necessary to be able to change the ratio of the size of the subject appropriately, but in this auto zoom mode, the manual zoom operation with the manual zoom switch is not necessary. It would be highly desirable if it could be used as a means of changing the ratio of.

An object of the present invention has been made in view of such a problem, and an object of the present invention is to provide an electric zoom camera capable of zooming at high speed in the auto zoom mode and at low speed in the manual zoom mode. .

Another object of the present invention is to provide an electric zoom camera capable of appropriately changing and setting the ratio of the size of the subject by the manual zoom switch in the auto zoom mode.

[Means and Actions for Solving Problems] In the electric zoom camera of the present invention, in FIG. 1 showing the concept thereof, the calculating means 1 determines the focal length of the photographing lens based on the distance measurement value of the distance measuring circuit 2. The calculation is performed to make the ratio of the size of the subject to the captured image frame constant at a predetermined value. Selection means 3
Is for selecting the auto zoom mode that performs zooming according to the subject distance so that the ratio of the size of the subject to the shooting image frame is constant, and the manual zoom mode that performs zooming in response to the manual zoom switch 4. When the automatic zoom mode is selected, the first control means 5 operates, whereby the zoom motor 7 is driven at high speed based on the signal from the calculation means 1 to change the focal length of the taking lens. Further, when the selection means 3 selects the manual zoom mode, the second control means 6 operates, whereby the zoom motor 7 is driven at a low speed by the signal from the manual zoom switch 4.

As shown in FIG. 1, the electric zoom camera of the present invention further includes a changing means 8 for changing the size ratio of the subject and a switching means 9 for switching the output signal from the manual zoom switch 4. Is provided, and when the selecting means 3 selects the auto zoom mode, the output signal from the manual zoom switch 4 is input to the changing means 8 and the ratio of the size of the subject is changed by this signal. When the selection means 3 is selecting the manual zoom mode, the output signal from the manual zoom switch 4 is input to the second control means 6.

[Example] First, prior to the description of the example of the present invention, the ratio occupied by the main subject in the shooting image frame will be described.
When the subject is a human, this ratio is uniquely determined by the focal length f of the photographing lens and the subject distance d, although there are individual differences. That is, as shown in FIGS. 2A to 2C, even if the distance d from the camera 11 to the subject 10 changes, a similar composition can be obtained by the focal length f of the photographing lens. Here, FIGS. 2A to 2C respectively show a case where the distance d is short and a case where the distance d is gradually increasing.
The ratio of 10 in the image frame is equal in the left-right direction. That is, if this ratio is r, the following equation is established.

r = w / (d tan θ) (1) However, in the equation (1), w is a half length of the subject 10 in the left-right direction, and θ is a shooting angle of view. Since w can be regarded as substantially constant, when the ratio r is set in the above equation (1), if either the distance d or the angle of view θ is determined, the other is determined by itself.

FIG. 3 is a graph showing the relationship between the angle of view θ and the focal length f. From this graph and the above equation (1), it is clear that the subject distance d from the focal length f and the focal length f from the subject distance d can be obtained by a functional relationship once the ratio r, that is, the composition is determined. Therefore, referring to FIG. 5, the focal length f
The following is a description of the method of calculating ## EQU2 ## If half of the image frame on the film surface 40 is l, then the relationship of tan θ = 1 / f (2) holds. Therefore, when the above equation (2) is substituted into the above equation (1), w / rd = l / f (3) Therefore, the formula of f = (lr / w) d (4) holds. Here, since l and w can be regarded as constants, it is clear that the focal length f can be automatically calculated if the distance d is known.

FIG. 4 (A) is a plan view of an electric zoom camera showing one embodiment of the present invention, and FIG. 4 (B) is a front view of the same camera. An electric zoom lens barrel 13 is mounted on the front surface of a main body 12 of the electric zoom camera 11, and a light emitting element 15 including a strobe 14 and an LED for giving a warning in a self mode is provided on the side thereof. Is provided. An AF (autofocus) distance measurement window 22a and a viewfinder objective window 16a are provided in the upper center of the camera body 12, and a position on the top surface of the camera body 12 that can be operated with the right hand while looking into the viewfinder eyepiece window 16b on the back surface. Further, a release button 17 and push button type changeover switches 18, 19, 20 are provided. The changeover switch 18 is a changeover switch for setting the self mode, and the changeover switch 19 is a mode changeover switch for changing the photographing mode between the manual zoom mode and the automatic zoom mode. Further, the changeover switch 20 is a switch for switching strobe light emission to automatic light emission, light emission inhibition, and forced light emission. Further, on the upper surface of the camera body 12 on the left-hand side opposite to the side where the above-mentioned changeover switches 18 to 20 are provided, a liquid crystal display panel 21 and a push button type switch.
31,32 are provided. The liquid crystal display panel 21 has an electrode pattern structure as shown in FIG. 6, and a graphic composition display portion 21a is formed on the panel 21. This composition display portion 21a is provided with a mode switch 19
After the auto zoom mode is set by, the ratio r occupied by the main subject is sequentially changed by pressing the switch 31 or 32, and any one of the three types of predicted shooting compositions shown in FIGS. The display is similar to that composition. When the switch 31 is pressed, the ratio r increases,
When the switch 32 is pressed, the ratio r becomes smaller. That is, the switches 31 and 32 are ratio setting switches in the auto zoom mode. In manual zoom mode, they are a zoom up switch and a zoom down switch, respectively. That is, in the manual zoom mode, pressing the zoom up switch 31 moves the zoom lens in the direction of increasing the focal length, and pressing the zoom down switch 32 moves the zoom lens in the direction of decreasing the focal length. Moving.

FIG. 8 is a block diagram of an electric zoom camera showing an embodiment of the present invention. AF (autofocus) distance measuring unit 22
Is independent as a distance measurement block, and starts distance measurement according to a command from the CPU 30. In this case, distance measurement is performed by relative data based on a certain distance, for example, 3 m, and when the distance measurement is completed, a distance measurement end signal is sent to the CPU 30. CPU30
When receiving this distance measurement end signal, the serial clock
The data is sent to the AF distance measuring unit 22, and in response to this, the distance measuring data is read as a serial signal from the AF distance measuring unit 22 into the CPU 30, and
F Distance measurement operation ends.

Here, when the release button 17 (see FIG. 4 (A)) is half-pressed, the CPU 30 determines that the auto zoom mode is selected by turning on the mode changeover switch 19.
The focal length f is calculated by the equation (4), and the zoom motor 24 is driven through the motor driving unit 26 including the interface IC 23 which also serves as the AE (automatic exposure) photometry unit and the bridge circuit. The position of the zoom motor 24 is fed back to the CPU 30 via the interface IC 23 by the encoder 25 composed of a photo interrupter or the like.
The zoom motor 24 based on the information from the encoder 25.
Can be controlled. Further, since the magnification in the finder 16 changes in conjunction with the zoom motor 24, the photographer can confirm the actual image frame by looking through the finder eyepiece window 16b. Therefore, at this time, by pressing the switch 31 or the switch 32, the ratio of the size of the subject to the photographing image frame can be changed and set.

After that, the lens motor 27 is driven in the normal direction via the interface IC 23 and the motor drive unit 26, and the photographing lens is driven to the focus position calculated based on the distance measurement value from the AF distance measurement unit 22. In this case also, the position of the shooting lens is
It is controlled by being fed back to the CPU 30 via the interface IC 23 by the 28. Subsequently, when the release button 17 is fully pressed, the lens motor 27 is driven in the reverse direction so that the shutter operation is performed and the exposure is performed. Thereafter, the film is fed by the wind motor 29, and a series of operations is completed.

Incidentally, the AF distance measurement data, to convert the lens position data, mechanical variation of the lens position, but variations in zoom factor is considered, when these values are produced, the E ² -PROM33 as the adjustment data Remembered So, CP
U30 can be calculated accurate lens position by the data of the AF distance measurement data and E ² -PROM33. Interface IC
Since 23 is originally a photometric IC, the CPU 30 controls the shutter based on the photometric value of the interface IC 23.
In this case, E ² -PROM33 is stores the error of photometric values,
CPU30 calculates the correct exposure time by the data of the photometric data and E ² -PROM33. Signal transmission / reception between the E ² -PROM 33 and the CPU 30 is performed by writing and reading data by serial communication, and controlling their states directly by lines.

By the way, the zoom motor 24, the lens motor 27, the wind motor 29, and the encoders 25 and 28 are selected by the CPU 30.
2 signal lines I, II from the IC to the interface IC23, and 2 bits x 2 according to the combination shown in Table 1 below.
Book = 4 types of motor and encoder pairs can be selected.

That is, as is clear from Table 1 above, when the signal line I is set to the “L” level and the signal line II is set to the “H” level, the zoom motor 24 is selected and the signal of the encoder 25 is sent to the CPU 30.
To the signal line I at "H" level,
When the signal line II is set to “L” level, the lens motor 27
Is selected and the signal from the encoder 28 is fed back to the CPU 30. When both the signal lines I and II are set to the “L” level, the wind motor 29 is selected. In this way, since the interface IC23 also has the function of a decoder, it is possible to control up to four motors with two input / output ports of the CPU30, which contributes to a reduction in the number of input / output ports and a reduction in signal lines. doing.

The strobe 14 is charged by the signal from the CPU 30.
When the strobe is completely charged, the CPU 30 detects it and sends a charge stop signal to the strobe 14. Subsequent flash light emission is also performed by a signal from the CPU 30. The ceramic oscillator 34 is for generating the basic clock of the CPU 30. Also, in synchronization with the turning on of the external power switch, the CP
Only when the switch input state control line 35 of the U30 goes to "L" level, ON / OFF of the self mode switch 18, the mode changeover switch 19, the flash changeover switch 20 and the switches 31 and 32 can be accepted. .

The operation of this embodiment having the above configuration will be described below with reference to the flow charts of FIGS.

As shown in FIG. 9, when the release button 17 is half-pressed and the first release is turned on, the routine immediately shifts to the distance measuring routine. In this distance measurement routine, the AF distance measurement unit 22
As a result, AF distance measurement is performed, the photographing lens is driven based on the distance measurement result, and the photographing lens is moved to the in-focus position. Subsequently, photometry is performed by the interface IC23.

Next, it is determined by the mode switch 19 whether or not the auto zoom mode is set. If the auto zoom mode is set, the <f calculation> subroutine is executed,
From the ratio r and the subject distance d, which is AF distance measurement data, the focal length f is calculated from the equation (4). This <f calculation> subroutine will be described later. Then, the zoom lens is moved to the position of the focal length f at high speed. As will be described later, this high-speed drive uses pulse drive (duty 50%) for low-speed drive in the manual zoom mode, whereas full speed (duty 100%).
It is done in. The high speed driving and the low speed driving may be realized by changing the motor driving voltage, or may be realized by controlling the voltage change and the pulse driving together.

On the other hand, when the zoom mode is not the automatic zoom mode, the zoom mode is the manual zoom mode, and therefore the second release is checked immediately without calculating the focal length f. If the second release is off without fully pressing the release button 17, it is checked whether the first release is on or off. When the first release is on, the second release waiting loop is performed, and when it is off, the process returns.

Next, when the release button 17 is fully pressed and the second release is turned on, it is subsequently checked whether or not the self mode is set. If the self mode is not set, the exposure operation (strobe light emission and shutter operation in the case of strobe light emission) is performed immediately, but in the self mode, the self timer is counted and the exposure operation is performed after a certain self time elapses. Then, after the exposure is finished, the film is wound up, and this routine is finished.

By the way, when the switch 31 or 32 is pressed, an interrupt occurs and the interrupt routine shown in FIG. 10 is executed.
In this interrupt routine, first, it is checked whether or not the mode is the auto-zoom mode. If the mode is not the auto-zoom mode, the manual zoom mode is selected. In the auto zoom mode, it is checked which of the switch 31 and the switch 32 is on. If the switch 31 is on, the ratio r is increased, and if the switch 32 is on, the ratio r is decreased.

Fig. 11 shows the <Manual Zoom> subroutine in the manual zoom mode. When the manual zoom mode is selected and the switch 31 or 32 is pressed, the process proceeds to the flow of FIG.

Then, first, the motor flag is set. Setting the motor flag means turning on the zoom motor 24, and resetting means turning off the zoom motor 24. Next, the timer counter is reset and started, and is used to judge the elapse of a certain time as described later. At this time, the switches 31 and 32 correspond to the zoom-up switch and the zoom-down switch, respectively. Therefore, when the switch 31 is pressed, the zoom motor
When the switch 32 is pressed, the zoom motor 24 rotates in reverse and the zoom lens is retracted. After the zoom motor 24 rotates in the normal direction or the reverse direction, the motor flag is inverted, and the normal rotation of the zoom motor 24 is continued until the timer counter finishes measuring a fixed time or the zoom lens reaches the wide end or the tele end. Or the reversal continues. For example, zoom motor 24
After the normal rotation continues for a certain period of time, the timer counter is reset and started again to check the motor flag. Since the motor flag has been reset by reversing the motor flag, the zoom motor 24 is turned off. Then, the motor flag is inverted again, and after the elapse of a certain time, the above operation is repeated. In this way, the zoom-up motor drive is performed by pulse drive with a duty ratio of 1: 1 (50%). In the case of zooming down, similarly, the motor is driven by pulse driving. The duty ratio of pulse driving is not limited to 1: 1 and may be changed to an arbitrary value as necessary, and the driving frequency is also the same.

When it is confirmed by the encoder 25 that the zoom lens has reached the wide end or tele end, or the switch 31,3
When both 2 are off, the zoom motor 24 turns off and the process returns to the main routine.

Here, the calculation of the focal length f will be described in more detail based on the flow of the <f calculation> subroutine shown in FIG. First, the focal length f is calculated from the set ratio r and the subject distance d that is AF distance measurement data. Next, when the calculated focal length f is smaller than the minimum value f _MIN of the focal length of the zoom lens, the focal length f is fixed to this minimum value f _MIN , and the calculated focal length f is zoomed. When it is larger than the maximum focal length f _{MAX of the} lens, the focal length f is fixed to this maximum f _MAX . Then, when f _MIN ≤f ≤f _MAX , the calculated focal length f is used as it is. This is the ratio r
On the other hand, when the distance is too close or too far, it is impossible to set the ratio r. In this case, a warning may be displayed on the liquid crystal display panel 21, or a warning sound may be emitted by using a ceramic sounding element or the like.

As described above, according to the present invention, in the manual zoom mode, zooming is performed at a low speed so that the photographer can confirm the change in the ratio of the size of the subject to the image frame, but the automatic zoom is performed. In the mode, the photographer sets the ratio to a predetermined value in advance, and zooming is performed at high speed until the set value is obtained. Therefore, there is a possibility that the photographer may miss a photo opportunity even for a fast-moving subject. Significantly reduced. Also, since zoom operation is not required in the auto zoom mode, if the ratio of the size of the subject can be changed by using the manual zoom switch, the operation members can be shared and the operation members can be saved and the CPU I / O
It is possible to save ports.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of an electric zoom camera of the present invention, and FIGS. 2A to 2C are a camera and an object for explaining a relationship between an object distance d and an angle of view θ. FIG. 3 is a characteristic diagram showing the relationship between the focal length f and the angle of view θ, and FIGS. 4 (A) and 4 (B) are plan views of an electric zoom camera showing an embodiment of the present invention. FIG. 5 is a plan view of the camera and the object for explaining the relationship between the object distance d, the object width W, and the image frame 1, and FIG. 6 is shown in FIG. 4 (A). Plan views showing the electrode pattern structure of the liquid crystal display panel on the camera body, and FIGS. 7 (A) to 7 (C) respectively show the respective patterns of the composition displayed on the liquid crystal display panel shown in FIG. A plan view and FIG. 8 are block diagrams of electric circuits of the camera shown in FIGS. 4 (A) and 4 (B). The 9-12 figure the FIG. 4 (A), is a flowchart for explaining the operation of the camera shown in (B). 1 ... Calculation means 2 ... Distance measuring circuit 3 ... Selection means 4 ... Manual zoom switch 5 ... First control means 6 ... Second control means 7, 24 ... Zoom motor 8 ... Change means 9 ... ... Switching means 11 ... electric zoom camera 19 ... mode changeover switch (selection means) 23 ... interface IC (first control means, second control means) 26 ... motor drive section (first control means, second control) Means) 30 ... CPU (calculation means, selection means, changing means, switching means) 31,32 ... switch (manual zoom switch, changing means)

Claims (2)

(57) [Claims] 1. A manual zoom switch provided on the outside of the camera, and a focal length of a photographing lens so that a ratio of a size of a subject to a photographing image frame is constant at a predetermined value based on a distance measurement value to the subject. A means for calculating, a changing means for changing the predetermined value, a zoom motor for changing the focal length of the photographing lens, and zooming according to the subject distance so that the ratio of the size of the subject to the photographing frame is constant. And an selecting means for selecting a manual zoom mode in which zooming is performed in response to the manual zoom switch, and the selecting means operates when the automatic zoom mode is selected, and the zoom motor is operated in the above-described manner. First control means for driving based on a signal from the means, and when the selection means selects the manual zoom mode The second control means for driving the zoom motor by the signal from the manual zoom switch and the output signal from the manual zoom switch when the selecting means selects the automatic zoom mode. Switching means for inputting to the means, changing the predetermined value with the output signal, and inputting to the second control means when the selecting means selects the manual zoom mode. An electric zoom camera. 2. A zoom camera having distance measuring means, a zoom motor for driving a zoom optical system, a manual zoom switch for manually operating the zoom motor, and a photographing operation based on an output of the distance measuring means. A means for calculating the focal length of the photographing lens so as to keep the ratio of the size of the subject to the image frame at a predetermined value, a selecting means for selecting between the auto zoom mode and the manual zoom mode, and this selecting means First control means for operating the zoom motor in response to an output from the computing means when the zoom mode is selected; and the manual zoom switch for the zoom motor when the selection means does not select the auto zoom mode. Second control means for operating in accordance with the operation of, and the selection means is in the automatic zoom mode. By operating the manual zoom switch when is selected,
A zoom camera, wherein the predetermined value is changed.