JP2964538B2 - Camera with auto zoom function - Google Patents

Description

The present invention relates to a camera, and more particularly to a camera having an automatic program zoom function.

[Related Art] In recent years, automatic program zoom (Auto Program Zoo)
m, hereinafter referred to as “APZ”). With the APZ function, when the subject distance D is obtained, the shooting magnification is automatically obtained by a program line indicating the relationship between the subject distance D and the shooting magnification β, and “f (focal length) = β · D”. The focal length f
Is calculated, and the zoom motor is driven so that the focal length of the zoom lens is obtained when the focal length of the zoom lens is obtained.

FIG. 10 shows the principle of ranging of a camera using a so-called TTL (Through The Lens) phase difference detection method.

In the figure, incident light that has passed through a photographing lens 100 is split into two light beams by an aperture mask 104 via a relay lens 101, and is re-imaged by a re-imaging lens 102.
An image is formed in two regions of the reference portion and the reference portion set above. The amount of defocus is detected based on the interval between two images formed on the CCD 103. That is, the focus state, that is, the state of the front focus or the rear focus is determined based on the size of the interval between the images appearing on the reference portion and the reference portion of the CCD 103 with respect to the predetermined interval.

Before the relays operation, the focusing lens of the normal camera is positioned so as to focus when the subject is at an infinite position. Then, at the position of the focusing lens, the amount of defocus can be detected based on the actual image interval of the object appearing on the image sensor CCD103, and the object distance can be calculated based on the amount of defocus.

FIG. 11 is a diagram showing a photographing optical system of a camera having a zoom lens mechanism, and FIG. 12 is a diagram showing a finder optical system of the camera.

The state (a) in FIG. 11 shows the position of the zoom lens group when the focal length of the zoom lens is small (wide state), and the state (b) from the wide state to the focal point of the zoom lens. This shows the position of the zoom lens group when the lens group moves to a state where the distance is long (tele state). That is, in the wide state, the first lens group
111, the second lens group 113, and the third lens group 115 are arranged on the optical axis in a state of being moved toward the film surface 117 side.

In the finder optical system shown in FIG. 12, the focusing lens 119 is moved by the zoom motor in accordance with the operation of the zoom lens of the photographing optical system, and the subject image corresponding to the zooming operation can be observed in the finder.

In many cases, the focusing motor usually operates only when the relays button is pressed in one stage.

FIG. 13 is a diagram showing the contents of an APZ program line used for a camera having an APZ function and showing the relationship between the subject distance and the focal length of the zoom lens.

The horizontal axis represents the subject distance D, and the vertical axis represents the focal length f of the zoom lens. Depending on the program line, for a subject whose subject distance is between 1 and 11.4 m, the focal length f of the zoom lens is obtained based on the equation f = 5 × D + 45. As described above, in the camera having the APZ function, the photographing magnification is automatically determined irrespective of the subject distance, so that it is not necessary to manually perform zooming every time photographing is performed, which is convenient depending on the photographing purpose.

[Problems to be Solved by the Invention] In a camera having a function of automatically performing zooming as described above, smooth zooming may not be performed depending on the state of a subject, and an operational feeling may be impaired. For example, when the above-described automatic zooming is performed on a subject in a stationary state, unstable zooming is performed due to a distance measurement error in a place where zooming is not originally performed, which gives a camera user an uncomfortable feeling.

FIG. 14 shows the relationship between the actual distance of the subject and the subject distance detected by the camera using the TTL phase difference detection method. The figures show the cases where the focal length is 50mm, 70mm, and 90mm.As shown in the figure, the distance measurement error differs depending on the focal length, and the larger the focal length, the smaller the distance measurement error. I understand.

As described above, in the case where the subject distance is detected and the zooming is automatically performed based on the detected distance, if the detected distance includes an error, the corresponding focal length also includes the error. As a result, unstable zooming cannot be performed, and an uncomfortable operation feeling is given to the user.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a camera capable of performing automatic zooming stably.

[Means for Solving the Problems] In order to achieve the above object, a camera having an auto-zoom function according to the present invention includes a camera having a function of automatically changing a photographing magnification to a predetermined photographing magnification. Distance measuring means for detecting the distance to the camera, photographing magnification changing means for changing the photographing magnification in accordance with the detection result by the distance measuring means, and the distance obtained by the previous detection by the distance measuring means and obtained by the current detection. Determining means for determining whether or not the difference from the measured distance is smaller than a predetermined comparison value; changing means for changing the comparison value in accordance with the detection result of the distance measuring means; A control unit for prohibiting the operation of the photographing magnification changing unit when it is determined to be small.

Preferably, the camera having the auto zoom function of the present invention is characterized in that, as a result of detection by the distance measuring means, when it is detected that the distance is longer than the last time, the changing means changes the comparison value to a larger value. And

Further, the camera having the auto zoom function of the present invention,
In a camera having a function of automatically changing a photographing magnification to a predetermined photographing magnification, a distance measuring means for detecting a distance to a subject, and a photographing magnification change for changing a photographing magnification in accordance with a detection result by the distance measuring means. Means, the difference between the focal length and the focal length to be set obtained from the detection result of the distance measuring means,
Determining means for determining whether or not the value is smaller than a predetermined comparison value;
A change unit that changes the comparison value according to the focal length to be set, and a control unit that prohibits the operation of the photographing magnification change unit when the difference is determined to be smaller than the comparison value by the determination unit. Features.

Preferably, the camera having the automatic zoom function is characterized in that when the focal length to be set is a change in a direction in which the focal length becomes larger than the current focal length, the changing means changes the comparison value to a larger value.

Further, a camera having an auto-zoom function according to the present invention is a camera having a function of automatically changing a photographing magnification to a predetermined photographing magnification, wherein a distance measuring means for detecting a distance to a subject, and a detection by the distance measuring means. A photographing magnification changing unit that changes the photographing magnification according to the result; and whether a difference between the distance obtained by the previous detection and the distance obtained by the current detection by the distance measuring unit is smaller than a predetermined comparison value. Determining means for determining the comparison value, changing means for changing the comparison value, and control means for inhibiting the operation of the photographing magnification changing means when the difference is determined to be smaller than the comparison value. And

[Operation] According to the above configuration, it is determined whether the difference between the previously obtained subject distance and the presently obtained subject distance is smaller than a predetermined comparison value, and the comparison value used at that time depends on the subject distance. To an appropriate size. If the difference is smaller than the comparison value, the operation of the magnification changing means is not performed. If the subject distance obtained this time is longer than the last time, the comparison value is changed to a larger value.

In addition, it is determined whether or not the difference between the current focal length and the focal length to be set next is smaller than a predetermined comparison value, and the comparison value used at that time has an appropriate value in accordance with the focal length to be set. It is changed to. If the focal length to be set is larger than the current value, the comparison value is changed to a larger value.

In addition, it is determined whether or not the difference between the previously obtained subject distance and the presently obtained subject distance is smaller than a predetermined comparison value, and the comparison value used at that time can be changed.

Embodiment FIG. 1 is a diagram showing an entire configuration of a circuit relating to a photographing mechanism of a camera according to an embodiment of the present invention.

In the figure, a CPU 2 for controlling the entire photographing operation, an image sensor 1 for distance measurement, an eyepiece detection unit 11 for detecting that a user has looked into a finder, and an AF motor for driving a focusing lens 7, an encoder 9 for encoding the amount of rotation of the motor 7, a zoom motor 8 for driving a zoom lens, an encoder 10 for encoding the amount of rotation of the motor 8, an AF motor 7 and a zoom motor 8. a driver IC circuit 6 for driving, a switch S ₀ for detecting the power-on of the camera, the switch S to be turned on by pushing one stage of the release button of the camera
Circuit _1, a switch S ₂ which is turned on by the second stage of depression of the relay's button, the Zumusuichi S _Z1 to direct zoom telephoto side, the zoom switch S _Z2 Prefecture for to direct the zoom to the wide side Is configured.

The eyepiece detection unit has a configuration in which a light-emitting element and a light-receiving element are provided, for example, in the vicinity of a finder. When a photographer looks into the finder, light emitted from the light-emitting element is reflected by the photographer. The light is detected by the light receiving element, and the presence or absence of the eyepiece can be detected.

The amount of rotation of the AF motor and the zoom motor is input to the CPU 2 by the encoders 9 and 10, and the focal length of the photographing lens is calculated based on the amount of rotation. The AF motor 7 and the zoom motor 8 are driven via the driver IC circuit 6 based on the focal length. As a result, a focusing operation and a zooming operation are performed.

2A and 2B show an APZ according to one embodiment of the present invention.
It is a flowchart which shows the content at the time of the initial start of an operation.

First, in step S1, the power-on state of the camera is determined. In this case, the lens is often located at the W end for housing the camera small. Next, step S3
, It is detected whether or not the photographer has looked into the viewfinder of the camera. If the switch S ₀ is the eyepiece of the photographer on-sensed, it is determined that the may enter the APZ operation, the light receiving operation by the image pickup device CCD is controlled in step S5. That is, the amount of light received in the image sensor CCD is integrated in a predetermined time, and in step S7, the analog data of the amount of light is converted into digital data. Then, in step S9, it is determined whether or not distance measurement is possible based on digital data based on output data of the image sensor CCD. When the amount of light received by the image sensor CCD is small, the light receiving operation of the image sensor CCD is repeated until distance measurement becomes possible.

If distance measurement is possible (YES in step S9), step S
In step 11, the current focal length of the photographing lens (f ₀ ) is read. This focal length is determined by the encoder 10 for the zoom motor.
Is calculated based on the output signal.

In step S13, the subject distance is calculated based on the distance measurement result and the focal length of the photographing lens.

That is, the subject distance S is calculated by S = f ₀ ² / DF where the defocus amount is DF.

In step S15, to the ideal imaging magnification with respect to the calculated subject distance, the focal length f ₁ of the photographing lens based on the APZ line (see FIG. 13) is calculated.

Next, in step S17, whether the focal distance f ₁ is close to the focal length f ₀ of the photographing lens at the present time is determined. If the focal length f ₁ is closer than a predetermined value K ₁ with the focal length f _0,
Lens so as to zoom to the focal length f ₁ in the step S39 is driven, the process proceeds to Continuous APZ operation which enables continuous APZ operation.

On the other hand, the zooming when (NO at step S17), the imaging lens is telephoto side from the wide side (W) (T) the focal length f ₁ apart than the predetermined amount K ₁ with respect to the focal length f ₀ at the present time It is started (S19). In step S21, the focal length f _s at the start movement of the taking lens is read. Next, in step S23, the light receiving operation of the image sensor CCD is controlled, and the light receiving operation of the subject image is started. The focal length f _E of the imaging lens at the time when the predetermined time has elapsed from the start of the movement of the photographing lens is read in step S25. Then, analog data as an output from the image sensor CCD is converted into digital data, and it is determined in step S29 whether or not a distance measurement operation is possible.

If the contrast of the subject image is low, the distance measurement operation is impossible, so the zooming operation of the photographing lens is stopped in step S41, and the process shifts to continuous APZ.

If it is determined in step S29 that distance measurement is possible, a subject distance is calculated in step S31. The subject distance S at this time is calculated by the following equation.

_{S = {(f s + f} E) / 2} 2 / DF next step based on the calculated subject distance S S3
The focal length f ₁ at which the photographing lens should be driven at 3 is APZ
It is calculated based on the line. The focal length f ₀ of the current taking lens at step S35 is read.

Then the difference between the drive focal length f ₁ and the focal length f ₀ of the current in step S37 is equal to or less than a predetermined value K ₂ is determined. If it is equal to or less than the predetermined value, the focal length f ₁ is determined in step S43.
The photographing lens is driven in order to perform zooming, and the operation shifts to the continuous APZ operation.

The difference between the drive focal length f ₁ and the focal length f ₀ of the current exceeds a predetermined value
When K ₂ greater (NO in step S37), the process returns to step S19, further repeats the operation of step S19 to step S37 and zooming toward the telephoto side.

FIGS. 3A and 3B are flowcharts showing the specific contents of the continuous APZ operation shown in FIG. 2B.

Here, the continuous APZ operation is an operation for performing smooth continuous zooming in accordance with the movement of the subject or when the photographing subject is changed.

In step S51, it is determined whether the photographer has performed an operation of looking through the viewfinder, that is, whether or not an eyepiece has been detected.
When the eyepiece detection is recognized, it is determined in a step S53 whether or not the zoom switch is turned on. When the zoom switch is turned on, the operation shifts to a zoom operation. The zoom operation will be described later.

When the zoom switch is not pressed (step S53
In step S55, the light receiving operation of the image sensor CCD is controlled, and a digitally converted CCD output is obtained (S5).
7).

In step S59, it is determined whether or not distance measurement based on the CCD output is possible. When the distance measurement is not possible, the process returns to step 51 and the above operation is repeated. When ranging is possible (step S59
In YES), the focal length f ₀ of the current in step S61 is read. Then, the subject distance is calculated based on the focal length f ₀ (S63). To the ideal imaging magnification for the object distance is calculated on the basis of driving the focal length f ₁ in APZ line.

Next, a zooming determination operation is performed in step S67, the contents of which will be described later with reference to FIG.

If the zooming determination is YES in step S67, the the zoom direction in step S69 is determined based on the value of the drive focal length f ₁ and current focal length f _0. And step S7
In step 1, the absolute value of the difference between the focal lengths is obtained.
Next, in step S73, a zoom speed is set according to the absolute value of the difference between the focal lengths, and the correspondence is shown in the table below.

In step S75, it is determined whether the zoom direction determined in step S69 is the telephoto direction. When the zoom direction is the telephoto direction, in step S77, the timer T ₀ is reset in CPU 2. When the zoom direction is the wide-angle direction, at step S81, the timer T ₀ is set in the timer is activated. After that, the photographing lens is zoom-driven based on the zoom speed and the zoom direction obtained above (S79). Then, the process returns to step S51 to repeat the above operation.

FIG. 4 shows a zooming determination step S67 in FIG. 3B.
3 is a flowchart showing the specific contents of FIG.

With reference to FIG. 5, a description will be given of the positional relationship regarding the movement of the subject in the direction in which the subject moves away and the direction in which the subject approaches.

In the figure, S indicates the initial position of the subject, and α indicates the position moved by the distance α in the direction approaching the camera from the position S of the subject. -Α indicates a position at which the position of the subject moves by a distance α in a direction away from the camera, and -β indicates a position at which the subject moves by a distance β in a direction away from the camera.

F _α is the focal length of the photographing lens based on the APZ line when the subject is at the position α, and is the focal length when the subject is at the positions −α and −β, like f− _α and f− _β. It is shown.

The set value of the timer T ₀ in Figure 3B at step S81 is, whether it is less than the predetermined value K ₃ is determined. Timer T ₀
There is smaller than a predetermined value, the value of x _alpha is calculated by the following equation at step S83.

1 / _xα = 1 / S + 1 / α Next, in step S85, the value of x− _α is obtained by the following equation.

_{1 / x -α = 1 / S} -1 / α and on the basis of the x _alpha obtained above, the focal length f _alpha corresponding than APZ line is calculated (S87). Similarly, the focal length f− _α is calculated by the APZ line based on x− _α (S89).

Next, in S91, the current focal length f ₀ is f _α and f
It is determined whether it is between _-α . If not in the meantime, at step S93, driving the absolute value of the difference of the focal length f ₁ and the focal length f ₀ of the current is calculated, the value is whether or not a predetermined value K ₄ smaller is determined (S95). If the value is less than the predetermined value K _4, as the zooming determination returns as "YES".

As described above, the processing of steps S83 to S91 indicates the processing of performing zooming when it is detected that the subject has moved more than the predetermined distance α in the direction moving away from and approaching the camera.

When timer T ₀ is larger than the predetermined value K ₃ (N in step S81
O), and proceed to step S97. This means that when zooming is performed in the wide direction, the next zooming operation is not performed until a predetermined time has elapsed. Then, the value x _alpha is calculated by the following equation at step S97.

In _{1 / x α = 1 / S} + 1 / α then step S99 the value x _beta is obtained by the following equation.

1 / x _β = 1 / S−1 / β and the value x _α obtained above in step S101
Is used to calculate the focal length f _α by the APZ line. In step S103, the focal length f- _β is calculated by the APZ line based on x- _β obtained above. The focal length f ₀ of the current in step 105 whether there is between the focal length f _alpha and _f-beta is determined. If not, the process proceeds to step S93, but if it is during that time, the zooming determination returns as "NO".

As described above, the processing in steps S97 to S105 performs the zooming operation only when it is detected that the subject has moved more than the distance α in the direction approaching the camera and greater than the distance β in the direction away from the camera. That's what we are trying to do.

The distance α are the <distance beta, until a predetermined time has elapsed based on the timer T ₀ is not Utsura in after step S83, the until it detects that the subject has moved largely will be zooming is not performed.

6 is a flowchart showing the contents to be performed when the switch S ₁ is turned on.

When the switch S ₁ is turned on, i.e., when the release button is pushed to the first stage, it takes interrupt the CPU, it is intended to fall to the routine shown in the figure.

In step S101, the light receiving operation of the image sensor CCD is controlled, and the distance measuring operation starts. Then, in step S103, the output of the image sensor CCD is converted from analog data to digital data. Then, it is determined in step S105 whether or not distance measurement is possible. When the distance measurement is possible, the defocus amount DF is calculated in step S107. When the distance measurement is not possible, the process returns to step S101 to repeat the distance measurement operation. In step S109,
It is determined whether or not the calculated DF amount is smaller than the focusing width. If the defocus amount is equal to or larger than the in-focus width, the extension amount of the focusing lens is calculated from the defocus amount in step S111. Then, a focusing operation is performed in step S113, the process returns to step S101, and the same operation is repeated until the DF amount becomes smaller than the focusing width.

When the defocus amount is less than the focus width (step S1
(YES in 09), the process proceeds to step S115, and it is determined whether or not the Si ON state continues. If the state is not continued, it is determined that there is no release operation, and the process returns to the main routine.

On the other hand, when followed by the on-state step S _1, the switch S ₂ in step S117, the namely whether or not made pushing up to the second step of the release button is determined. When the switch S ₂ is determined to have been turned on, but moves to a release operation, otherwise the process returns to step S115, the state is maintained.

FIG. 7 is a flowchart showing specific contents of the zoom operation shown in FIG. 3A.

In step S121, it is determined whether the zoom direction is on the telephoto side. If the zoom direction is telephoto, step S1
If the flag T is set as the zoom direction in 23 and the zoom direction is not the telephoto side, the flag W is set in the zoom direction in step S125 and zooming starts (S12).
Five). In step S127, it is determined whether or not the zoom switch (the switch _SZ1 or the switch _SZ2 ) is turned on. When the zoom switch is pressed, the zooming operation is continuously performed. If the zoom button is not turned on, zooming is stopped in step S129, and
Whether the switch S ₁ is turned on is determined in S131. If switch S ₁ is being turned back to the flow of the switch S ₁ on operation, but if not, whether the zoom switch is turned on is determined in step S133.
While repeating the above operation returns to step S121 when the zoom switch is turned on, when the zoom switch is not turned on returns to step S131, the subsequent operation by the on-state switch S ₁ is being operated.

Note that, in principle, the control of the camera does not enter the continuous PAZ operation once the zoom button is operated, and the continuous APZ operation becomes possible after the power is turned off or the exposure operation is performed. However, this practice routine, the switch S ₁ is the display returns to the flow of the on switch S ₁ If the ON state, where will enter the APZ operation if the switch S ₁ off and.

FIG. 8 is a flowchart of an initial operation of the APZ according to one embodiment of the present invention.

In this flow, the power switch S ₀ of the camera at step S141 it is discriminated whether or not in the ON, the focal length in step S143 when it is turned on is set to f _K. Then, in step S145, it is determined whether or not the eye detection has been performed.
Move on to APZ operation.

FIG. 9 is a flowchart of an APZ operation according to still another embodiment of the present invention.

In this flow, whether the power switch S ₀ of the camera is turned on is determined in step S151. Only when the eyepiece is detected while the switch is on (YES in step S153), the focal length is set to f
_{After K} is set (step S157), continuous APZ
Move to operation.

[Effects of the Invention] As described above, the present invention does not operate the magnification changing means when the change in the subject distance or the focal length is smaller than the predetermined comparison value. At that time, since the comparison value is appropriately changed according to the subject distance or the focal length, the comparison value is appropriately changed even if the magnitude of the error included in the distance measurement changes. Therefore, the determination as to whether or not to operate the magnification changing unit is appropriately performed, the operation of the magnification changing unit is stabilized, and the operation in the magnification change does not give a user a sense of incongruity.

[Brief description of the drawings]

FIG. 1 is a diagram showing the overall circuit configuration of a camera according to an embodiment of the present invention. FIGS. 2A and 2B are flowchart diagrams showing the contents of the initial operation of the APZ according to an embodiment of the present invention. And FIG. 3B is a flowchart showing the contents of the continuous APZ operation shown in FIG. 2B.
FIG. 3 is a flowchart showing the specific processing contents of the zooming judgment shown in FIG. 3B, FIG. 5 is a schematic diagram showing the position of the subject related to the description of FIG. 4, and FIG. 6 is an embodiment of the present invention. shows specific contents of the interrupt routine by the on switch S ₁ according to the example, FIG. 7 is a flowchart showing specific contents of the zoom operations shown in figures 3A, FIG. 8 is another of the invention FIG. 9 is a flowchart showing the specific contents of the initial operation of the APZ according to the embodiment of FIG. 9, FIG. 9 is a flowchart showing the specific contents of the initial operation of the APZ according to still another embodiment of the present invention, and FIG. FIG. 11 is a diagram showing a principle of distance measurement of a phase difference detection method, FIG. 11 is a diagram showing an arrangement state of various lens groups of a general photographing optical system, FIG. 12 is a diagram showing an arrangement of lenses of a general finder optical system, FIG. The figure shows an example of a conventional APZ line, and FIG. It varies depending on the focal length of the photographing lens is a diagram showing the relationship between detection distance of an object by the actual object distance and the camera. In the figure, 1 is an image sensor, 2 is a CPU, 6 is a driver IC
The circuit, 7 is an AF motor, 8 is a zoom motor, 9 is an encoder, 10 is an encoder, and 11 is an eyepiece detection unit. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (5)

(57) [Claims] 1. A camera having a function of automatically changing a photographing magnification to a predetermined photographing magnification, a distance measuring means for detecting a distance to a subject, and a photographing magnification according to a detection result by the distance measuring means. A photographing magnification changing means for changing the distance, and a judging means for judging whether or not the difference between the distance obtained by the previous detection by the distance measuring means and the distance obtained by the current detection is smaller than a predetermined comparison value. Changing means for changing the comparison value in accordance with the detection result of the distance measuring means; and when the determination means determines that the difference is smaller than the comparison value, prohibits operation of the photographing magnification changing means. A camera having an auto-zoom function, comprising: a control unit. 2. The method according to claim 1, wherein, as a result of the detection by said distance measuring means, when it is detected that the distance is longer than the previous time, said changing means changes said comparison value to a larger value. 2. The camera having the autosome function according to 1. 3. A camera having a function of automatically changing a photographing magnification to a predetermined photographing magnification, a distance measuring means for detecting a distance to a subject, and a photographing magnification according to a detection result by the distance measuring means. A photographing magnification changing means for changing; a difference between the focal length and a focal length to be set obtained from a detection result of the distance measuring means; and a judging means for judging whether or not the difference is smaller than a predetermined comparison value. Changing means for changing the comparison value according to the focal length to be set; andcontrol means for prohibiting the operation of the photographing magnification changing means when the determination means determines that the difference is smaller than the comparison value. A camera having an auto-zoom function. 4. If the focal length to be set is a change in a direction in which the focal length becomes larger than the current focal length, the changing means changes the comparison value to a larger value. A camera having an auto zoom function according to item 1. 5. A camera having a function of automatically changing a photographing magnification to a predetermined photographing magnification, a distance measuring means for detecting a distance to a subject, and a photographing magnification according to a detection result by the distance measuring means. A photographing magnification changing means for changing the distance, and a judging means for judging whether or not the difference between the distance obtained by the previous detection by the distance measuring means and the distance obtained by the current detection is smaller than a predetermined comparison value. Changing means for changing the comparison value; and control means for prohibiting the operation of the photographing magnification changing means when the difference is determined to be smaller than the comparison value. , A camera with an auto zoom function.