JPH047530A - Camera with automatic programmed zooming function - Google Patents

Abstract

PURPOSE:To improve the feeling of the use of this camera by inhibiting automatic programmed zoom(APZ) operation when the difference between detected focal length and a specific distance is less than a specific value. CONSTITUTION:The quantities of rotation of an AF motor and a zoom motor are inputted to a CPU 2 by encoders 9 and 10, the focal length of a photographic lens is calculated from the quantities of rotation, and the AF motor 7 and zoom motor 8 are driven through a driver IC circuit 6 according to the focal length. Then when the difference between the detected focal length and specific distance is less than the specific value, an APZ means is inhibited from being activated regardless of the command output of a command means. Consequently, the stable operation feeling is obtained by the slight motion of the camera due to the blurring of a photographer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to cameras, and more particularly to cameras having an automatic program zoom function.

[Prior Art] In recent years, automatic program zoom (Auto Progr.
Cameras with am Zoom (hereinafter referred to as rAPZJ) functionality have become known.

This APZ function means that when the subject distance is determined, the photographing magnification is automatically calculated using the program line that shows the relationship between the subject distance and the photographing magnification β, and it becomes "f (focal length) - β・D". This function calculates the focal length f using the formula and drives the zoom motor so that the focal length of the zoom lens becomes the obtained focal length.

Figure 10 shows the so-called TTL (ThroughThe
(Lens) This shows the principle of distance measurement of a camera using a phase difference detection method.

In the figure, the incident light that has passed through the photographing lens 100 is passed through the relay lens 101 and then split into two by the aperture mask 104.
The light beam is divided into two light beams, and images are formed by the re-imaging lens 102 on two areas, a standard part and a reference part, set on the image sensor CCD 103. The amount of defocus is detected based on the distance between the two images formed on the CCD 103. That is, the focus state, that is, the front focus or rear focus state, is determined based on the magnitude of the distance between the images appearing on the reference portion and the reference portion of the CCD 103 with respect to a predetermined distance.

The focusing lens of a camera is normally positioned before the release operation so that it will be in focus when the subject is at an infinite position. Then, at the position of the focusing lens, the defocus amount is detected based on the image interval of the actual object appearing on the image sensor CCD 103, and the object distance can be calculated based on this defocus amount.

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) shows the position of the zoom lens group when the focal length of the zoom lens is small (wide state). It shows the position of the zoom lens group when the lens group moves to a long distance state (telephoto state).

That is, in the wide-angle state, the first lens group 111, the second lens group 113, and the third lens group 115 are on the film surface 11.
They are arranged on the optical axis in a state where they are brought to the 7 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 a subject image corresponding to the zooming operation can be observed in the finder.

Incidentally, in many cases, the focusing motor is configured such that it is activated only when the reset button is pressed one step.

Figure 13 shows the relationship between the subject distance and the focal length of the zoom lens used in cameras with APZ function.
FIG. 3 is a diagram showing the contents of a Z program line.

The horizontal axis represents the subject distance, and the vertical axis represents the focal length f of the zoom lens. Depending on this program line, the focal length f of the zoom lens is determined based on the formula: f=SXD+45 for a subject whose distance is between 1 and 11.4 m. In this way, a camera having an APZ function automatically determines the photographing magnification regardless of the subject distance, so there is no need to manually zoom each time a photograph is taken, which is convenient depending on the purpose of photographing.

[Problems to be Solved by the Invention] FIG. 12 is a diagram showing the relationship between the actual shooting distance of a subject and the shooting distance detected by a camera using the TTL phase difference method.

As can be seen from the figure, measurement errors vary depending on the focal length of the zoom lens.

That is, as is clear from the figure, as the focal length of the zoom lens increases, the accuracy of detecting the distance measurement error increases proportionally. Specifically, as is clear from the distance measurement principle of the TTL phase difference detection method shown in FIG. 10, the accuracy improves in proportion to the square of the focal length of the zoom lens. This means that when the photographic lens is in the wide-angle state, the distance measurement error is larger than when it is in the telephoto state.

By the way, in a conventional camera having an APZ function as described above, when a subject is close to the camera, the error range of odofocus is at a level that has almost no effect on zooming. Nevertheless, since zooming is performed even when the camera moves due to slight changes in framing, such as camera shake by the photographer, a stable sense of operation cannot be obtained.

This invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a camera that provides a stable operational feeling even when the camera moves slightly due to camera shake or the like by the photographer.

[Means for Solving the Problems] A camera having an automatic program zoom function according to the present invention includes a zoom means for changing the focal length of a photographing lens, a distance measuring means for measuring the photographing distance of a subject, and a camera having an automatic program zoom function according to the present invention. an APZ means for automatically changing the focal length of the photographing lens to a predetermined distance using a zoom means according to the measured photographing distance; a command means for instructing the use of the APZ means; and control means for prohibiting activation of the AP2 means, regardless of the command output of the command means, when the difference from the distance is less than a predetermined value.

[Operation] In this invention, when the difference between the detected focal length and the predetermined distance is less than a predetermined value, the APZ means is not activated.

[Embodiment] FIG. 1 is a diagram showing the overall configuration of a circuit related to a photographing mechanism of a camera according to an embodiment of the present invention.

In the figure, a CPU 2 that controls the entire shooting operation, an image sensor 1 for distance measurement, an eyepiece detection unit 11 that detects when the user looks into the finder, and an AF momo that drives the focusing lens. -7, an encoder 9 that encodes the amount of rotation of the motor 7, a zoom motor 8 that drives the zoom lens, an encoder 10 that encodes the amount of rotation of the motor 8, and an AF momo-7.
and a driver IC circuit 6 for driving the zoom motor 8 and a switch So for detecting power-on of the camera.
, a switch S1 that is turned on when the camera's release button is pressed in the first step, a switch S2 that is turned on when the release button is pressed in the second step, and a zoom switch SZ for instructing zoom to the telephoto side. The circuit includes a zoom switch S22 for instructing zooming to the wide side.

The eyepiece detection unit has a configuration in which, for example, a light emitting element and a light receiving element are provided near the viewfinder, and when the photographer looks into the viewfinder, the light emitted from the light emitting element is reflected by the photographer, and the reflected light 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 encoders 9 and 10, and the focal length of the photographing lens is calculated in degrees based on the amount of rotation. Based on the focal length, the AF mode 7 and zoom motor 8 are driven via the driver C circuit 6. This allows focusing and zooming operations to be performed.

FIGS. 2A and 2B show an A according to an embodiment of the present invention.
3 is a flowchart showing contents at the initial start of PZ operation.

First, in step S1, it is determined whether the camera is powered on. In this case, the lens is often located at the W end so that the camera can be stored compactly. Next step S
3, it is detected whether the photographer looked through the camera's finder. When the switch So is on and the photographer's eye contact is detected, it is determined that the APZ operation can be started, and the light receiving operation by the image sensor CCD is controlled in step S5. That is, the amount of light received within the image sensor CCD is integrated over a predetermined period of time, and the analog data of the amount of light is converted into digital data in step S7. Then, in step S9, the image sensor C
It is determined whether distance measurement is possible or not based on digital data based on the output data of the CD. 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), the current focal length of the photographic lens (fo) is read in step Sll. Note that this focal length is calculated based on the output signal from the encoder 1o for the zoom motor.

In step 813, the subject distance is calculated based on the distance measurement result and the focal length of the photographic lens.

In other words, if the subject distance S is the defocus amount DF, 5=fo2/DF It is calculated by

In step S15, AP2 line (first
(see Figure 3), the focal length f of the photographic lens is calculated.

Next, in step S17, it is determined whether the focal length f is close to the current focal length fO of the photographing lens. The shooting distance f is the focal length f. If the focal length f1 is closer to the predetermined value, the lens is driven to zoom to the focal length f1 in step S39, and the transition is made to continuous APZ operation that enables continuous APZ operation.

On the other hand, the focal length f is the current focal length f.

If the distance is greater than 1 by a predetermined amount (step S1
7 is NO), and the shooting lens is changed from the wide side (W) to the telephoto side (
Zooming is started at T) (S19). Step S
At step 21, the focal length f at the start of movement of the photographing lens is read.

Next, in step S2B, the light receiving operation of the image sensor CCD is controlled, and the light receiving operation of the subject image is started. In step S25, the focal length fE of the photographic lens at the time when a predetermined period of time has elapsed from the start of movement of the photographic lens is read. Then, the analog data output from the image sensor CCD is converted into digital data, and it is determined in step S29 whether distance measuring operation is possible.

If the contrast of the subject image has decreased, distance measuring operation is impossible, so the zooming operation of the photographing lens is stopped in step S41, and the continuous APZ
to move to.

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

S= ((fs + ft)/2) 2/DF Next, in step 833, based on the calculated subject distance S, the focal length f1 at which the photographing lens should be driven is set to AP.
Calculated based on the Z line. In step S35, the current focal length f of the photographing lens is read.

Next, in step S37, the driving focal length f is determined.

and the current focal length f. It is determined whether or not the difference between the predetermined value and the predetermined value is 2 or less. If it is less than the predetermined value, step 8
At step 43, the photographing lens is driven to zoom to the focal length f, and the process shifts to continuous APZ operation.

When the difference between the driving focal length f and the current focal length fO is larger than the predetermined value of 2 (No in step S37), the process returns to step S19, further zooms to the telephoto side, and the operations from step S19 to step 837 are repeated. .

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

Here, the continuous APZ operation is an operation that performs smooth continuous zooming in accordance with the movement of the subject or when changing the photographic subject.

In step 851, it is determined whether or not there is an action of looking into the finder by the photographer, that is, whether or not eye contact has been detected.

If close eye detection is recognized, it is determined in step 853 whether the zoom switch has been turned on. When the zoom switch is turned on, the zoom operation begins. The zoom operation will be described later.

When the zoom switch is not pressed (step 853)
(NO), the light receiving operation of the image sensor CCD is controlled in step S55, and a digitally converted CCD output is obtained (S57).

In step S59, it is determined whether distance measurement based on the CCD output is possible. When distance measurement is not possible, step 35
Return to step 1 and repeat the above operation. When distance measurement is possible (YES in step S59), the current focal length f is read in step S61.

Then, the subject distance is calculated based on the focal length f (563). The driving focal length f1 is calculated based on the APZ line so that an ideal imaging magnification is obtained for the subject distance.

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

If the zooming determination is YES in step S67, the zoom direction is set to the current focal length fo in step S69.
The determination is made based on the values of and driving focal length f. Then, in step S71, the absolute value of the difference in focal lengths is determined as follows.Next, in step 873, a zoom speed is set according to the absolute value of the difference in focal lengths. shown in the table.

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 CPU 2
At , timer TO is reset. When the zoom direction is the wide direction, a timer To is set and activated in step S81. Thereafter, the photographing lens is driven to zoom based on the zoom speed and zoom direction determined above (S79). Then, the process returns to step S51 and repeats the above operation.

FIG. 4 shows the zooming determination step S6 in FIG. 3B.
7 is a flowchart showing the specific contents of step 7.

In order to explain this zooming determination flow, the positional relationship with respect to movement of the subject in the telephoto direction and the wide direction will be explained with reference to FIG.

In the figure, S indicates the original position of the subject, and α indicates a position moved from the subject position S by a distance α in the wide direction. -α indicates a position where the subject has moved by a distance α in the telephoto direction, and -β indicates a position where the subject has moved by a distance β in the telephoto direction.

And fC is the focal length of the photographic lens based on the APZ line when the subject is at position α, and f and f
Similarly to -ρ, this shows the focal length when the subject is at the 1α and 1β positions.

In step S81, it is determined whether the value of the timer To set in FIG. 3B is less than a predetermined value of 3 or not. When timer To is smaller than the predetermined value, in step 383
The value of I is determined by the following formula.

1/xc, t=1/S+1/α Next, in step S85, the value of X-c is determined using the following equation.

1/x-bi-1/S-1/α Then, based on the above-determined X7, the corresponding focal length f is calculated from the APZ line (S87).

Similarly, the focal length f is calculated using the APZ line based on X-,% (S89).

Next, in S91, it is determined whether the current focal length f, is between fC, and f- distances. If it is between them, in step 893, the absolute value of the difference between the driving focal length f and the current focal length f is calculated, and it is determined whether the value is smaller than a predetermined value of 4 (S 95 ). value t
is smaller than the predetermined value of 4, the zooming determination is returned as "YES".

As shown above, the processing in steps 383 to S91 is
This figure shows a process of performing zooming when it is detected that the subject has moved more than a predetermined distance α in the telephoto direction and wide-angle direction.

When timer To is greater than 3 to a predetermined value (step S8
1 (No), the process advances to step S97. This means that when zooming is performed in the wide direction, the next zooming operation is not performed until a predetermined period of time has elapsed. Then, in step S97, the value X[% is calculated using the following formula.

1 /

1/x/3-1/S1/β Then, in step 5101, the focal length fcI is calculated by the APZ line based on the value xCI determined above. X−ρ obtained above in step 8103
The focal length f−ρ is calculated based on the APZ line. In step 105, the current focal length f,
It is determined whether or not the focal length is between fC% and f-ρ. If the value is between that range, the process proceeds to step 893, but if the value is not between that range, the zooming determination returns as "No. 1".

As shown above, steps 397-510
The processing in step 5 is performed when it is detected that the subject has moved more than the distance α in the wide direction and the distance β in the tele direction.
This is the first time you are trying to perform a zooming operation.

Note that since the distance α is less than the distance β, the timer T.

The process does not proceed to step 883 and subsequent steps until a predetermined period of time based on has elapsed, and zooming is not performed until it is detected that the subject has moved significantly.

FIG. 6 is a flowchart showing what is done when switch S is turned on.

When the switch S is turned on, that is, when the release button is pressed to the first position, an interrupt is generated in the cPU, and the routine shown in the figure is entered.

In step 5101, the light receiving operation of the image sensor CCD is controlled and the distance measuring operation begins. and step 5103
Then, the output of the image sensor CCD is converted from analog data to digital data. Then, in step 5105, it is determined whether distance measurement is possible. When distance measurement is possible, the defocus amount DF is calculated in step 8107, but when distance measurement is not possible, the process returns to step 5101 and the distance measurement operation is repeated. In step 5109, it is determined whether the calculated DF amount is less than the focusing width. When the amount of defocus is equal to or greater than the focusing width, the amount of movement of the focusing lens is calculated from the amount of defocus in step 5111. Then, a focusing operation is performed in step 8113, and the process returns to step 5101 to repeat the same operation until the DF amount becomes less than the focusing width.

When the defocus amount is less than the focusing width (step 51
(YES in step 09), the process proceeds to step 5115, where it is determined whether or not Si continues to be on. If this state does not continue, it is assumed that there is no release operation and the process returns to the main routine.

On the other hand, when the on state of step S continues, it is determined in step 5117 whether or not the switch S2, that is, the release button has been pressed to the second position. When it is determined that the switch S2 is turned on, the process proceeds to the release operation, but if not, the process proceeds to step 511.
Return to step 5 and maintain that state.

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

In step 5121, it is determined whether the zoom direction is on the telephoto side. If the zoom direction is the telephoto side, a flag T is set as the zoom direction in step 8123, and if the zoom direction is not the telephoto side, a flag W is set in the zoom direction in step 5125, and zooming starts (S125). In step 5127, it is determined whether the zoom switch (switch SKI or switch 5Z2) is on, and if the zoom switch is pressed, the zooming operation continues.

Step 5129 when zoom button is not turned on
Zooming is stopped at step 8131, and it is determined whether switch S is turned on. If the switch S1 is on, the flow returns to the switch S on operation flow, but if not, it is determined in step 8133 whether the zoom switch is on. Step 5121 if the zoom switch is on
Return to step 8131 and repeat the above operation, but if the zoom switch is not turned on, return to step 8131 and turn on the switch S.
The subsequent operation is performed depending on the ON state of 1.

In principle, the camera control does not enter continuous APZ operation once the zoom button is operated, but continuous APZ operation becomes possible after the power is turned off or an exposure operation is performed. However, in this actual routine, if the switch S is on, the flow returns to the on state of the switch S, so if the switch S is then turned off, the APZ operation will begin.

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

In this flow, it is determined in step 5141 whether the power switch So of the camera is on or not, and when it is on, the focal length is set to fK in step 3143. Then, in step 5145, it is determined whether or not eye proximity has been detected, and only when eye proximity has been detected, the process moves to continuous APZ operation.

FIG. 9 is a flowchart of APZ operation according to yet another embodiment of the invention.

In this flow, it is determined in step 5151 whether or not the power switch So of the camera is turned on. Then, only when an eye proximity is detected while the switch is on (YES in step 8153), f is set as the focal length (step 5157), and then the continuous APZ operation is started.

[Effects of the Invention] As described above, according to the present invention, when the difference between the detected focal length and the predetermined distance is less than or equal to the predetermined value, the APZ operation is prohibited, so that the operational feeling of the camera is improved.

[Brief explanation of 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 APZ according to an embodiment of the present invention, and FIG. 3A is a diagram showing the entire circuit configuration of a camera according to an embodiment of the present invention. 3B is a flowchart showing the content of the continuous APZ operation shown in FIG. 2B, FIG. 4 is a flowchart showing the specific processing content of the zooming determination shown in FIG. 3B, and FIG. is the fourth
FIG. 6 is a schematic diagram showing the position of the subject related to the explanation of the figures, FIG. 6 is a diagram showing the specific contents of the interrupt routine by turning on the switch S1 according to an embodiment of the present invention, and FIG. 7 is the diagram shown in FIG. 3A. FIG. 8 is a flowchart showing the specific details of the zoom operation being carried out, and FIG.
Flowchart diagram showing specific details of initial operation, No. 9
10 is a flowchart showing specific details of the initial operation of APZ according to yet another embodiment of the present invention, FIG. 10 is a diagram showing the distance measurement principle of the conventional TTL phase difference detection method, and FIG.
12 is a diagram showing the arrangement of various lens groups in a general photographing optical system, FIG. 12 is a diagram showing the arrangement of lenses in a general finder optical system, FIG. 13 is a diagram showing an example of a conventional APZ line, The figure is a diagram showing the relationship between the actual subject distance and the detection distance of the subject by the camera, which varies depending on the focal length of a general photographic lens. In the figure, 1 is an image sensor, 2 is a CPU, 6 is a driver IC circuit, 7 is an AF motor, 8 is a zoom motor, 9 is an encoder, 1o is an encoder, and 11 is an eyepiece detection unit. Note that the same reference numerals in each figure indicate the same or corresponding parts. Figure Figure

Claims (1)

[Claims] A camera having an automatic program zoom function, comprising: a zoom means for changing the focal length of a photographing lens; a distance measuring means for measuring a photographing distance of a subject; and a photographing distance measured by the distance measuring means. APZ means for automatically changing the focal length of the photographing lens to a predetermined distance using the zoom means according to the distance; command means for commanding the use of the APZ means; When the difference from the predetermined distance is less than or equal to the predetermined value, the APZ
and control means for inhibiting activation of the means.