JPH0545559A - Camera - Google Patents

Abstract

PURPOSE:To enable zooming while maintaining an in-focus state by tracing the stored position of a focus lens back when zooming from a wide-angle side to a telephoto side is performed in manual focus mode. CONSTITUTION:A track storage means F is stored with the movement track of a focus adjusting means B during 1st power varying operation and when 2nd power varying operation is performed, a moving speed determining means G determines the moving speed of the focus adjusting means B according to the track stored in the track storage means F and the previously set movement time of the focus adjusting means B. Namely, the moving speed of a focus lens 105 is determined in power varying operation to the telephoto side in the manual focus mode according to the stored position of the focus lens 105 and the previously set movement time and this speed focus lens 105 is moved to accurately trace the stored position back.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera, and more particularly to a lens drive control device for the camera.

[0002]

2. Description of the Related Art Looking at recent trends in camera development, a so-called inner focus lens of a type in which a rear lens group is moved to perform focus adjustment is widely used for the purpose of size reduction and weight reduction.

FIG. 5 is a diagram showing a structure of an inner focus type lens of a conventional example, FIG. 6 is a diagram showing a positional relationship between a zoom lens and a focus lens of the conventional example using a subject distance as a parameter, and FIG. It is a figure which shows the state which set the typical speed of the focus lens for every divided area.

In FIG. 5, 101 is a fixed first lens group, 102 is a second lens group (zoom lens) for zooming, 103 is a diaphragm, 104 is a fixed third lens group, and 105. Is a fourth lens group (focus lens) having a function of adjusting the focus and correcting the movement of the focal plane associated with the zooming operation of the second lens group, and 106 is an imaging surface.

Next, the operation of this conventional example will be described with reference to FIGS. In FIG. 5, when zooming is performed by moving the zoom lens 102, as described above,
The fourth lens group 105 has a function of correcting the movement of the focal plane that accompanies the zooming operation and also functions as a focus adjustment. FIG. 6 shows this state.

FIG. 6 shows the positional relationship between the zoom lens and the focus lens for maintaining focus with the subject distance as a parameter, with the horizontal axis representing the zoom lens position and the vertical axis representing the focus lens position. As can be seen in Figure 6,
During the zoom operation, if the focus lens moves along a unique trajectory for each subject distance, it is possible to perform the zoom operation in focus without causing so-called "blurring". Blurring occurs.

As described above, as a method of moving the focus lens according to the peculiar locus (FIG. 6) according to the object distance during the zoom operation, for example, Japanese Patent Application Laid-Open No. 1-28 is known.
No. 0709, etc.

This method divides the locus of FIG. 6 into regions as shown in FIG. 7 in regions having substantially equal inclinations, and drives the focus lens to take each of these regions while the zoom lens passes through that region. The velocity is calculated from the inclination of the locus passing through the region, given as a representative velocity, and during the zoom operation, it is determined from the positional relationship between the zoom lens and the focus lens to which region the region belongs, and the representative velocity of the region is determined. The speed of the focus lens is determined and moved in consideration of the correction from the AF (automatic focus adjustment device). This enables zooming while maintaining focus.

[0009]

As described above, in the above-mentioned conventional example, when the AF system is turned off (OFF), that is, in the manual focus mode, zooming from the wide (W) side to the tele (T) direction is performed. If this is done, there is a problem in that the correct trajectory for maintaining the focus cannot be selected and blurring occurs due to the following reasons. The reason for this will be described below.

In FIG. 6, the trajectories for maintaining the focus at the respective subject distances are dispersed on the T side, and W
On the side, it can be seen that objects from infinity to several meters are concentrated within the depth of field.

Therefore, when zooming from the W side to the T direction in the manual focus mode with the AF (autofocus) system off (OFF), the loci are concentrated on the wide side. On the other hand, even when the photographer determines that the subject is in focus, the actual position of the focus lens is, for example, the in-focus position of the subject of 3 m.

When zooming is performed in the tele direction as it is, the focus lens moves on a locus of 3 m, and eventually, when blurring occurs out of the depth, if the AF mode is set, information from the AF system is output. However, in the manual focus mode as in this case, since there is no information as in the case of the AF described above, the focus lens moves on the trajectory of 3 m as it is. However, there was a problem that the blur would expand.

In the above case, the zooming is from the W side to the T side. On the contrary, in the zooming from the T side to the W direction, the loci are dispersed on the T side, and the characteristic of the correct locus is easy. On the W side, these trajectories are concentrated, so that a large blur does not occur.

The present invention has been made in order to solve the above problems, and while the zooming is performed from the tele side to the wide direction, the locus traced by the focus lens is stored, and conversely, the manual operation is performed. When performing zooming from the wide side to the tele direction in the focus mode, the purpose is to trace the position of the stored focus lens in the reverse direction and enable zooming in the tele direction while maintaining the focus in the manual focus mode. And

[0015]

For this reason, in the present invention, the positions of the zooming means for zooming, the focus adjusting means for focus adjustment, and the zooming and focus adjusting means are detected. Position detecting means, driving means for driving each of the zooming and focus adjusting means, control means for controlling each of the zooming and focus adjusting means, and the focus adjustment during the first zooming operation. A camera having a locus storage means for storing a movement locus of the means, and a storage locus of the locus storage means and a preset movement time of the focus adjusting means when performing the second zooming operation. Therefore, it is an object of the present invention to achieve the above object by a camera including a moving speed determining unit that determines the moving speed of the focus adjusting unit.

[0016]

In the camera of the present invention, the locus storage means stores the movement locus of the focus adjusting means during the first magnification changing operation, and when the second magnification changing operation is performed, the movement speed determining means causes the locus storage. The moving speed of the focus adjusting means is determined from the memory locus of the means and the preset moving time of the focus adjusting means.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a camera which is an embodiment of the present invention, FIG. 2 is a flow chart for controlling the operation of this embodiment, and FIG. 3 is a zooming operation in the wide direction of this embodiment.
FIG. 4 is a diagram showing the trajectory of the focus lens and the stored position of the focus lens. FIG. 4 is a diagram showing how to trace the stored position of the focus lens when zooming in the tele direction in the manual focus mode of this embodiment.

In the figure, the same reference numerals as those used in the conventional example indicate the same or corresponding components, and the duplicated description thereof will be omitted. In FIG. 1, A is a zooming unit, which is composed of the zoom lens 102 and is a unit for zooming. Reference numeral B denotes a focus adjusting means, which is composed of the focus lens 105 and is a means for performing focus adjustment. Reference numeral C denotes a position detecting means, which is composed of the position encoders 112 and 113, and is a means for detecting the respective positions of the magnification varying means A and the focus adjusting means B.

Reference numeral D denotes a drive means, which is composed of actuators 106 and 108 such as motors, and drives each of the zooming means A and the focus adjusting means B.
Reference numeral E is a control means, which is composed of drivers 109 and 111 for driving and controlling the actuators 106 and 108, respectively, and is means for controlling the zooming means A and the focus adjusting means B, respectively.

Reference numeral F denotes a locus storage means, which is composed of a drive control circuit (microcomputer) 117 and stores the movement locus of the focus adjusting means B during the first zooming operation. G is a moving speed determining means, which is also composed of a drive control circuit (microcomputer) 117. When performing the second variable magnification operation,
It is a means for determining the moving speed of the focus adjusting means B from the stored locus of the locus storing means F and the preset moving time of the focus adjusting means B.

In FIG. 1, 114 is an image pickup device such as a CCD for converting an image formed by a lens into a video signal and outputting the image signal, 115 is an amplifier for amplifying the output signal of the image pickup device 114, and 116 is an amplifier. A bandpass filter 117 for extracting only the high-frequency component effective for detecting the focus state of the output signal of 115, 117 moves the focus lens 105 in the direction in which the high-frequency component is increased by the output signal of the bandpass filter 116. A drive control circuit (microcomputer) for performing focusing, a zoom operation by simultaneously moving the zoom lens 102 and the focus lens 105 as described in the conventional example, and 118 is a luminance of an output signal of the amplifier 116. The aperture control device keeps the brightness of the subject constant depending on the level.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG. FIG. 2 shows a lens drive control circuit 1 for operating the lens control device according to this embodiment.
17 shows a control flow chart of a program for operation control stored in 17;

In FIG. 2, when the execution of the program is started in step 201, it is determined in step 202 whether or not the zoom is performed in the wide direction. In step 202, the zoom is performed in the wide direction. If it is determined, the process proceeds to step 203.

In step 203, the zoom lens 10 is detected from the output result of the position encoder 112 (FIG. 1) for detecting the position of the zoom lens 102, as described in the conventional example.
Where in the multiple areas set in the movement range of 2 now,
If it is determined that the zoom lens 102 has moved to the next region due to zooming, it is determined whether the region to which the zoom lens 102 belongs is different from the region to which the zoom lens 102 previously belongs. ..

In step 204, the zoom lens 102
Is moved, and the position of the focus lens 104 at the time when the area to which it belongs is changed is detected from the output result of the position encoder 113, and the drive control circuit is used as the position of the focus lens 104 when the zoom lens 102 is at the changed position of the area. It is stored in the (microcomputer) 117.

While zooming in the wide direction, each processing from step 201 to step 204 is repeated. For example, when the focus lens 105 and the zoom lens 102 are zoomed in the wide (W) direction and moved in the relationship shown by the curve A in FIG. 3, the focus lens 1 as shown by a black dot in FIG.
The position 05 is stored in the drive control circuit (microcomputer) 117 as the position of the focus lens 105 when the zoom lens 102 is at the change position of the area (trajectory storage means).

If it is determined in step 202 of FIG. 2 that the zooming is not in the wide direction, the process proceeds to step 205, and it is determined whether or not the zooming is in the tele direction. When it is determined in step 205 that zooming in the tele direction is performed, the process proceeds to step 206, and when zooming in the tele direction is not executed, the process returns to step 202.

In step 206, it is determined whether the AF mode is set, that is, the AF mode or the manual focus mode is set. If it is determined in step 206 that the focus mode is the manual focus mode,
Proceeding to step 207, in step 207, the time T for moving the focus lens 105 while the zoom lens 102 passes through one area is set to a certain time in advance, and whether the set moving time T has passed Determine whether or not. Focus lens 1 in step 207
If it is determined that the travel time T set in 05 has passed, the process proceeds to step 208, and if it is determined that the travel time T has not passed, the process proceeds to step 211.

In step 208, as in step 203, it is determined whether or not there is a change in the area to which the zoom lens 102 belongs. If there is a change, step 2
If there is no change, go to step 209.

In step 210, based on the position of the focus lens 105 stored in the drive control circuit (microcomputer) 117 in step 204 and the moving time T of the focus lens 105 preset to a fixed time, the focus lens 105 Calculates the moving speed of (moving speed determining means).

FIG. 4 illustrates a method of calculating the moving speed of the focus lens 105. In FIG. 4, a black dot indicates a drive control circuit (microcomputer) 1 in step 204 of FIG.
17 shows the position of the focus lens 105 at each area change position of the zoom lens 102 stored in the table 17. The zoom lens 102 moves to the telephoto side due to the magnification change in the telephoto direction,
At the change position of a certain area, the focus lens 10
5 is at the position indicated by point A in FIG. 4, from the position of this point A, the storage position B at the next area change position of the zoom lens 102, and the preset moving time T of the focus lens. Focus lens 1 at this time
The moving speed V _A of No. 05 is calculated by V _A = (B−A) / T (Equation 1).

The focus lens 105 is moved for the set moving time T at the moving speed V _A thus calculated.

As a result, when the focus lens 105 reaches the position B1 after the movement time T, the focus lens 105 is stopped until the next change of the area. Then, when there is a change in the next area, this time the focus lens 10 at B1 and the next area change position is detected.
5 calculates a moving speed V _B of the focus lens 105 from the storage position C and the movement time T set, so as gradually moved by moving time T set the focus lens 105 at the moving speed V _B.

As described above, after the moving speed of the focus lens 105 is calculated in step 210 of FIG. 2, the process proceeds to step 211, the movement of the focus lens 105 is started, and the process returns to step 202.

When it is determined in step 207 that the moving time of the focus lens 105 has not passed, the process proceeds to step 211, the focus lens 105 continues to move, and the process returns to step 201.

If it is determined in step 208 that the area has not changed, the focus lens 105 is stopped and the process returns to step 202.

Thus, in the manual focus mode, during the zooming operation in the tele direction, these processes are repeated, so that the moving speed of the focus lens 105 can be calculated from the stored position of the focus lens 105 and the preset moving time. Is determined and the focus lens 105 is moved at this speed, so that the stored position is accurately traced.

[0038]

As described above, in the camera according to the present invention, the locus traced by the focus adjusting means is stored during zooming from the tele side to the wide side, and, conversely, in the manual focus mode, the locus is wide. When performing zooming from the side in the tele direction, by tracing the stored position of the focus lens in reverse, in the inner focus type video camera system, etc., zooming in the tele direction while maintaining focus in the manual focus mode is performed. Can be possible.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a camera that is an embodiment of the present invention.

FIG. 2 is a flowchart for controlling the operation of this embodiment.

FIG. 3 is a diagram illustrating a zooming operation in a wide direction according to this embodiment,
The figure which shows the locus | trajectory of a focus lens, and the position of the memorized focus lens.

FIG. 4 is a diagram showing how to trace the stored position of the focus lens when zooming in the tele direction in the manual focus mode of this embodiment.

FIG. 5 is a diagram showing a conventional inner focus lens structure.

FIG. 6 is a diagram showing a positional relationship between a zoom lens and a focus lens of a conventional example with a subject distance as a parameter.

7 is a diagram showing a state in which a representative speed of the focus lens is set for each of the divided areas in FIG.

[Explanation of symbols]

 A zooming means B focus adjusting means C position detecting means D driving means E control means F trajectory storage means G moving speed determining means

Claims (1)

[Claims] 1. A zooming means for zooming, a focus adjusting means for focus adjustment, a position detecting means for detecting the position of each of the zooming and focus adjusting means, and a zooming means for zooming and focusing. Drive means for driving the respective means, control means for controlling the respective means for the magnification change and focus adjustment, and a trajectory storage means for storing a movement trajectory of the focus adjustment means during the first magnification change operation, When performing the second zooming operation, the camera having the above-mentioned means determines the moving speed of the focus adjusting means from the stored locus of the locus storing means and the preset moving time of the focus adjusting means. A camera comprising moving speed determining means.