JPH05130478A - Electronic camera - Google Patents

Abstract

PURPOSE:To obtain smooth zooming by using a zoom lens and an electronic telescopic controller. CONSTITUTION:A CPU 108 uses at first a drive circuit 114 and a step motor 112 to magnify a zoom lens 100 in response to a zoom switch 110. When the focus of the zoom lens 100 reaches a prescribed value, the CPU 108 makes the charge read range of an image pickup element 102 narrow by using a drive circuit 104 thereby magnifying its output to a usual value. Simultaneously, the CPU 108 drives the zoom lens 100 in the reverse direction to restore it to a position thereby cancelling the magnification. Then the CPU 108 drives the zoom lens 100 in the original direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic camera having an image pickup means for converting an optical image into an electric signal, and more particularly to an optical zoom device and an electronic camera having a zoom function by the electronic zoom device. ..

[0002]

2. Description of the Related Art Photographing lenses with variable focal lengths, so-called zoom lenses, are well known, and not only still cameras such as silver halide film cameras and electronic still cameras,
It is also widely used in movie cameras such as video cameras and TV cameras.

An optical system as an example of a zoom lens is shown in FIG. Along the optical axis, in order from the object side, the front lens 10,
The variator 12, the compensator 14, the diaphragm 16, and the imaging lens 18 are provided, and the imaging element 20 is arranged on the focal plane on the rear side of the imaging lens 18.

The front lens 10 is actually composed of about three lenses. By moving the front lens 10 in the optical axis direction, the focusing distance (focusing distance) can be changed. The lens in which the front lens 10 functions as a focusing lens in this way is called a front lens.

The variator 12 is a second group lens composed of a plurality of lenses and functions as a zooming lens for changing the focal length (that is, magnification). The compensator 14 is a correction lens that is interlocked with the variator 12 and maintains the focusing distance even when the magnification is changed by the movement of the variator 12 in the optical axis direction. The imaging lens 18 is the lens 1
Optical images of 0, 12, and 14 are formed on the photoelectric conversion surface of the image sensor 20.

FIG. 3 is a diagram showing the interlocking relationship between the variator 12 and the compensator 14. The vertical axis represents the focal length (9 mm to 54 mm in this example), and the horizontal axis represents the lens position. The image sensor 20 is located in the direction of the arrow on the horizontal axis. The characteristic of the variator 12 is indicated by reference numeral 22, and the compensator 1
The position of 4 is indicated by reference numeral 24.

FIG. 4 is a vertical sectional view showing an interlocking mechanism of the variator 12 and the compensator 14. Variator 12
And the compensator 14 are circular frames 26, 2 respectively.
The frame 26 and 28 are held by the outer peripheral portion of the frame 8, and the frames 26 and 28 are movably held in the optical axis direction by two bars 30 and 32 extending parallel to the optical axis. Protrusions 34 and 36 are provided on the outer sides of the frames 26 and 28, respectively, and are fitted into the cam grooves 40 and 42 of the cam ring 38, respectively. The cam grooves 40 and 42 are formed on the inner surface of the cam ring 38 so as to satisfy the relationship shown in FIG. That is, when the cam ring 38 is rotated about the optical axis, the variator 12 and the compensator 14 move in accordance with the cam grooves 40 and 42 while maintaining the positional relationship shown in FIG.

Reference numeral 44 denotes a fixed lens barrel, and the outer peripheral surface of the cam ring 38 is in close contact with the inner surface of the lens barrel 44. Although not shown in FIG. 4, the front lens 10, the diaphragm 16, the imaging lens 18, and the like are fixed to the lens barrel 44.

A zoom ring 46 is provided outside the lens barrel 44, and the zoom ring 46 is connected to the cam ring 38 via a connecting member 48. The gear 50 is formed on a part of the surface of the zoom ring 46, and the output gear 54 of the zoom motor 52 is the gear 50.
Meshes with. When the zoom motor 52 is rotated, the gears 50 and 54 rotate the zoom ring 46 about the optical axis. The zoom ring 46 and the cam ring 3 are connected by the connecting member 48.
Since 8 moves integrally, the cam ring 38 also rotates around the optical axis, and as described above, the variator 12 and the compensator 1
4 moves together in the optical axis direction.

As a driving mechanism for the variator 12 and the compensator 14, there is also a mechanism in which the bar 28 is rotated by a zoom motor so that the variator 12 and the compensator 14 are moved in the optical axis direction by the rotation of the bar 28.

The above is a front-lens focus type zoom lens, but in recent years, a so-called inner focus type zoom lens in which a focusing lens is arranged after the variator (on the side of the image pickup device) is also used. It was This inner focus type zoom lens has advantages that it is easy to miniaturize and the object side lens surface does not move. This zoom lens has a configuration in which the positional relationship between the variator and the compensator is stored as data, and the motors that move each are individually driven by a microcomputer.

Next, the electronic zoom will be briefly described. A part of the image signal from the image sensor is enlarged and output. This makes it possible to obtain an image enlarged at an arbitrary magnification. For example, in FIG. 5A, reference numeral 56 denotes a photographing screen by the image pickup device, and the image signal of the shaded portion 58 therein is enlarged to the same size as the photographing screen 56 as shown in FIG. 5B. This is called electronic zoom because an enlarged image is obtained by electronic processing. With the electronic zoom, you can select any magnification and it is easy to change the magnification continuously.
Switching to a small number (1 type or 2 types) of a fixed enlargement ratio is particularly called an electronic teleconverter.

As an electronic zoom capable of continuously selecting the enlargement ratio, there is the 1989 National Conference of the Television Society of Japan, 8-1 "Consideration of electronic zoom of arbitrary magnification by controlling image sensor".
FIG. 6 shows a schematic block diagram thereof. Reference numeral 60 is a taking lens, 62 is a CCD type image pickup element, and 64 is a CCD drive circuit capable of controlling vertical transfer. The output of the image sensor 62 is processed by the process circuit 66 and delayed by the line memory 68 for three lines. The vertical interpolation circuit 70 interpolates the output of the line memory 68 in the vertical direction under predetermined weighting to form a scanning line signal according to the enlargement ratio. The horizontal interpolation circuit 72 interpolates the output of the vertical interpolation circuit 70 in the horizontal direction under predetermined weighting to form a pixel signal according to the enlargement ratio. The CPU 74 transfers the drive circuit 64 vertically,
The weighting of the vertical interpolation circuit 70 and the weighting of the horizontal interpolation circuit 72 are controlled.

At an arbitrary enlargement ratio, the scanning line of the output will be located in the middle of the scanning line obtained from the output of the image pickup device 62, so that the ratio of the mutual distances and the predetermined weighting are set. Interpolate the upper and lower signals. As a result, the image quality deterioration due to enlargement can be suppressed to some extent.
It is difficult to realize a general zoom ratio such as double. Therefore, at present, the optical zoom and the electronic zoom are used together.

[0015]

When the electronic teleconverter described above is used in combination with the optical zoom, it is conventionally impossible to obtain smooth zooming from the widest state to the state where the both are used in the widest state. There was a problem. For example, when the zoom ratio of the optical zoom is 6 times and the magnification of the electronic teleconverter is 1.5 times, theoretically, the maximum is 9 times (=
6 × 1.5) magnified image can be obtained, but when the electronic teleconverter is turned on from off, the image instantly becomes 1.5 times, so if you want to obtain an intermediate magnification, further optical zoom There is no choice but to operate to reduce the enlargement ratio. This is very troublesome in operation.

On the other hand, the electronic zoom capable of continuously changing the enlargement ratio may be used together with the optical zoom, but the electronic zoom requires a complicated and high-speed circuit, which causes a significant increase in cost. , It is difficult to install in inexpensive consumer equipment.

This is because, even when both the optical zoom and the electronic zoom are used, if they are operated at the same time, the following problems occur. That is, firstly, if there is a difference between the time required from the wide end of the optical zoom to the tele end and the time required for the electronic zoom, only the magnification change speed during the electronic zoom function becomes faster, and the view angle change is not smooth. Secondly, the optical zoom generally makes the moving speed of the variator constant, but in this case, as shown in FIG. 7, the variator position (horizontal axis) and the focal point hometown (vertical axis) are not in a linear relationship. Therefore, depending on the condition in which the electronic zoom functioned during the optical zoom,
There is a difference in the magnification change speed itself.

An object of the present invention is to provide an electronic camera that solves such problems.

[0019]

An electronic camera according to a first aspect of the present invention provides an optical zoom device, an image pickup device for converting an optical image formed by the optical zoom device into an electric signal, and an image taken by the image pickup device. An electronic camera provided with an electronic teleconverter for enlarging a magnification, wherein an adjusting means is provided for adjusting the optical zoom device so as to cancel a change in magnification of the electronic teleconverter when the enlargement ratio is switched by the electronic teleconverter. It is characterized by

An electronic camera according to a second aspect of the present invention is an optical zoom device, an image pickup means for converting an optical image by the optical zoom device into an electric signal, and an electronic zoom device for electronically zooming a photographed image by the image pickup means. And an optical zoom device and control means for interlocking the electronic zoom device in a predetermined relationship.

[0021]

When the optical zoom device and the electronic tele-converter device are used together, the change in magnification due to the electronic tele-converter device is offset by adjusting the magnification of the optical zoom device. Therefore, regardless of whether the electronic tele-converter device is turned on or off or the magnification is changed, Smooth zooming can be obtained over a wide range of magnification.

When both the optical zoom device and the electronic zoom device are used together, by gradually zooming the two under a fixed relationship, it is possible to obtain smooth zooming over a wide magnification range as a whole.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. Reference numeral 100 denotes a photographing zoom lens having the lens configuration shown in FIG. The same elements as those in FIG. 2 are denoted by the same reference numerals. Reference numeral 102 is an image sensor, 104 is a drive circuit for driving the image sensor 102, and 106 is an image sensor 10.
The frame memory 108 temporarily stores the photographed image signal of No. 2 and outputs the enlarged image signal of the same size or a predetermined enlargement ratio, and 108 is a CPU for controlling the whole. A zoom switch 110 indicates zooming and its direction.

A step motor 112 moves the variator 12 and the compensator 14 in the optical axis direction, and corresponds to the zoom motor 52 in FIG. Reference numeral 114 is a drive circuit that drives the step motor 112, and 116 is a counter that counts the number of drive pulses that the drive circuit 114 applies to the step motor 112. Counter 11
The count value of 6 is returned to the CPU 108 as focal length information. In order to know the focal length from the count value of the counter 116, it is necessary to load the counter 116 with a predetermined initial value while the variator 12 is in the initial position.

Reference numeral 118 is a power source, and 120 is a power-on reset circuit.

The operation of FIG. 1 will be described. It is assumed that the zoom switch 110 instructs zooming from wide to tele while the photographing zoom lens 100 is at the wide end (actually, a focal length shorter than a threshold event point distance described later). The CPU 108 drives the step motor (zoom motor) 112 by the drive circuit 114 to zoom the zoom lens 100. The counter 116 counts the drive pulse of the step motor 112, and
Return to U108. As a result, the CPU 108 knows the focal length of the zoom lens 100.

When the focal length of the zoom lens 100 reaches a predetermined threshold value, the CPU 108 causes the frame memory 10 to operate.
The image reading range of 6 is narrowed to make the electronic teleconverter function, and the step motor 112 is reversely rotated at a high speed to reduce the magnification of the zoom lens 100 by a magnification corresponding to the magnification of the electronic teleconverter. After that, the zoom lens 100 is driven in the tele direction again by the step motor 112.

FIG. 8 shows the change in magnification of this embodiment. Time t
The electronic teleconverter actually operates in step 1 and
It is assumed that the motor 112 rotates in the reverse direction and the step motor 112 rotates in the forward direction again at the time t2. As can be seen from the above description, the total magnification momentarily becomes (magnification of the zoom lens 100) × (magnification of the electronic teleconverter) at time t1,
From the time t1 to t due to the reverse rotation of the step motor 112
Within a short time of 2, it will return to the magnification just before the operation of the electronic teleconverter. After time t2, the total magnification again smoothly increases due to the positive line of the step motor 112.

For comparison, FIG. 9 shows a characteristic diagram of a conventional example in which the electronic telephoto is turned on when the zoom lens reaches the telephoto end. In this case, the total magnification is the magnification of the zoom lens 100 immediately before reaching the tele end,
At the moment of reaching the tele end, the magnification changes to (magnification of zoom lens 100) × (magnification of electronic teleconverter). In the example described above, the magnification is instantaneously increased from 6 times to 9 times, and it is difficult to use an intermediate magnification.

In this embodiment, the time from the time t1 to the time t2 is short, but the magnification rapidly changes during that time, which gives a very strange impression. To prevent this,
For example, an image immediately before the electronic teleconverter is activated is displayed at time t2.
Up to the frame memory 106. In this way, the change in magnification disappears from time t1 to time t2. FIG. 10 shows an operation flowchart of the CPU 108 that realizes this operation.

FIG. 10 will be described in detail. It should be noted that the focal length of the zoom lens 100 that inverts the electronic teleconverter (from ON to OFF or from ON to OFF) is f1, and the focal length at which the magnification adjustment of the zoom lens 100 that cancels the magnification change due to the inversion of the electronic teleconverter is finished is f2. And The ratio of f1 to f2 is equal to the magnification of the electronic teleconverter or its reciprocal. f1 and f2 differ depending on the zooming direction. For example, if the electronic teleconverter has a magnification of 1.5
Assuming that f1 = 45 mm and f2 = 30 mm, FIG.
As shown in FIG. 1, f1 = 3 when the distance is from tele to wide
0 mm and f2 = 45 mm.

First, the flag Z is initialized to L (S
1). When the flag Z is determined (S2), the zoom operation of the zoom switch 110 is checked (S3). If the zoom switch 110 is off (S3), the step motor 112 is stopped and the process returns to S2 (S4). If the zoom switch 110 is on (S3), the step motor 1
The rotation direction and speed of 12 are determined and driven by the drive circuit 114 (S5, 6, 7).

In case of movement from wide to tele direction (S
8) If the electronic teleconverter is operating, the process returns to S2 (S9), and if the electronic teleconverter is not operating, the focal length of the zoom lens is checked (S11). Conversely, in the case of movement from the telephoto to the wide direction (S8), when the electronic teleconverter is not operating, the process returns to S2 (S8).
9) If the electronic teleconverter is operating, the focal length f of the zoom lens is checked (S11). Time t1 in FIG.
This is because there is a possibility of passing through the area at time t2 from.

Current focal length f of the zoom lens 100
Is not equal to the above-mentioned threshold f1 (S11), the process returns to S2, and if f = f1 (S11), the electronic teleconverter is inverted (S12), the flag Z is set to H (S13), and the frame memory 106 is stored. The frozen image is output in the frozen state (S14), and the variable T for counting the time from time t1 to time t2 in FIG. 8 is decremented (S1).
5). For example, the flow shown in FIG. 10 has one vertical period (1/6
(0 seconds) If it turns around like a feeling, the initial value To of T is
A value larger than (t2−t1) × 60 may be set.

Until T becomes 0 (S16), step.
The motor 112 is rotationally driven in the opposite direction to the original (S2
0), when the focal length f2 of the return operation is reached, the step motor 112 is stopped (S21, 22). Needless to say, the rotation speed of the step motor 112 at this time is preferably the maximum speed. Then, the freeze image is output (S14) and T is decremented (S15).

When T becomes 0 (S16), the flag Z is set to L (S17), freeze output is stopped (S18),
Substitute the initial value To for the counter variable T (S19), S2
Return to. After that, the magnification is changed only by the zoom lens 100.

In FIG. 10, the output time of the frozen image is To.
However, the freeze image output may be stopped when f = f2 and the captured image of the image sensor 102 may be output. In addition, the reverse drive of the step motor 112 (S
In 20), it is explained that the process is performed again at high speed, but it goes without saying that it is better to decelerate when f approaches f2. Figure 1
At 0, the focal length is detected once every 1/60 seconds, but since the focal length is actually detected at a higher speed, it is easy to decelerate at an appropriate timing.

Although the front lens focus type zoom lens has been described as an example, the present invention can be applied to an inner focus type zoom lens. FIG. 12 shows an optical system of an inner focus type zoom lens. Reference numeral 200 denotes a front lens group, which is fixed to the lens frame. Reference numeral 202 denotes a variator, where the solid line indicates the wide end position and the broken line indicates the tele end position. Reference numeral 204 denotes an aperture, 206 denotes a fixed lens group, 20
Reference numeral 8 is a focusing lens for focus adjustment, which also functions as a compensator. 210 is the focal plane.
A lens in which the focusing lens is located behind the variator lens is called an inner focus lens.

FIG. 13 shows a variator 20 for the lens of FIG.
It is a longitudinal cross-sectional view showing a drive mechanism of No. 2. The output shaft 214 of the step motor 212 is connected to the bearing 218 of the frame plate 216,
It is rotatably held by 220, and the output shaft 214 is
A groove 222 having a predetermined length of lead for feeding a ball is formed. The tip of the output shaft 214 has a ball bearing 22.
It is 4. A frame 226 for holding the variator 202
A leaf spring 230 is fixed to the leaf spring 23 with a screw 228.
The ball 232 is pressed against the groove 222 of the output shaft 214 by 0. This structure allows the step motor 212
When rotates, the variator 202 moves in the optical axis direction.

A variator 2 with a 6 × zoom lens of a video camera using a 1/3 inch CCD image pickup device.
The total movement amount of 02 is about 11 mm, and the position difference between f1 and f2 is 3 mm.
Assuming that the lead of the groove 222 of the output shaft 214 is 2 mm and the maximum speed of the step motor 212 is 480 pps with 36 pulses at one point, the time required to move between f1 and f2 is about 0. 11 seconds (= 3/2 x 36/4
80). Therefore, the above-mentioned To may be set to 7.

In such an inner focus type,
When changing the focal length, the focusing state cannot be maintained unless the focusing lens is moved at the same time. FIG. 14 shows the positional relationship between the variator 202 and the focusing lens 208 for maintaining the focused state. The horizontal axis represents the position of the variator 202 (that is, the focal length),
The vertical axis represents the position of the focusing lens 208. Two
40, 242 and 244 are infinity, 3m and 1 respectively
This is the characteristic when the subject of m is focused.

Now, zooming from wide to tele,
It is assumed that the electronic teleconverter is turned on at f1. f1 to f2
When the variator 202 is moved to A, it is necessary to move the focusing lens 208 in accordance with the focusing distance, such as A at infinity, B at 3 m, and C at 1 m. To this end, the characteristics 240, 242, 2
44 (and finer characteristics) are stored as data so that the position of the focusing lens 208 at the time of f2 can be instantly determined from the position of the focusing lens 208 at the time when the variator 202 reaches f1. You can leave it. Then, the focusing lens 208 may be moved to the determined position at high speed.

Further, the above-mentioned To is determined by the longer time of the time required to move the variator 202 and the time required to move the focusing lens 208.

At the time of zooming from the wide side to the tele direction, the points 250, 258 and 260 in FIG.
It is easy to determine 252 and 254, but conversely, when zooming from the telephoto to the wide direction, the focusing lens position of f2 (f1 in FIG. 14) is accurately determined from the stop point of f1 (f2 in FIG. 14). It is difficult in depth. As a countermeasure against this, for example, the focusing lens position of f2 (f1 in FIG. 14) is stored at the time of zooming from the tele side to the wide direction, and when returning from f1 to f2, the focusing lens is returned to the storage position. You can do it like this.

Further, even if the freeze image is output until the in-focus state is determined by the automatic focus adjustment device, the difficulty of adjusting the position of the focusing lens can be solved. For example,
If the in-focus determination is made before the To time has elapsed, the freeze image is output until the To elapses, and if the in-focus is not reached at the To time, the freeze image output may be continued until the in-focus determination is made.

In the above description, only one type of electronic teleconverter (that is, 1.5 times) has been described.
It goes without saying that the present invention can be extended and applied even when a plurality of types of magnifications such as 1.2 times and 1.5 times can be selected. In this case, the zoom lens needs to be returned twice, but the amount of return is small each time, so the time required for that is short, and smoother zooming is obtained as a whole.

As the driving means for the variator of the zoom lens, a DC motor may be used instead of the step motor. In that case, an encoder (for example, a volume encoder) for detecting the focal length is separately provided.

If the time between t1 and t2 in FIG. 8 is within the vertical blanking period, the freeze operation of the frame memory 106 can be eliminated.

According to the above embodiment, even when the optical zoom device and the electronic teleconverter are used together, the magnification can be smoothly changed even in the vicinity of the switching of the electronic teleconverter. In particular, there is an advantage that the total magnification can be smoothly changed near the maximum magnification of the optical zoom device.

Next, an embodiment of the present invention in which an optical zoom device and an electronic zoom device are used together will be described. FIG. 15 is a block diagram showing the configuration of the embodiment. Reference numeral 300 denotes a photographing zoom lens having the lens structure shown in FIG.
CD type image sensor, 304 is a CC capable of controlling vertical transfer
D drive circuit, 306 is a process circuit, 308 is a line memory for three lines, 310 is a vertical interpolation circuit, 312 is a horizontal interpolation circuit, 314 is a CPU for controlling the whole, 316
Is a zoom switch, and 318 is a zoom motor for moving the variator 12 and the compensator 14 of the zoom lens 300. In this embodiment, the zoom motor 3
A DC motor is used as 18.

Circuits 302, 304, 306, 308, 3
The individual functions of the circuits 10 and 312 are equivalent to the circuit 6 of FIG.
2, 64, 66, 68, 70, 72, and therefore the flow of the image signal by the image pickup element 302 is the same as that of the conventional example.

When the user inputs zooming from the wide to tele direction or from the tele to wide direction with the zoom switch 316, the CPU 314 causes the zoom motor 318 to operate.
Is driven to rotate in the specified direction. In this embodiment, the drive voltage of the zoom motor 318 is constant, and speed control such as pulse width modulation is not performed. On this premise, the zoom time tz required from the tele end to the wide end or from the wide end to the tele end is constant. Of course, there are some errors due to variations in the T-N characteristics of the motor 318 and variations in the torque required to rotate the cam ring.

The CPU 314 also drives the electronic zoom in the same direction at the same time as the optical zoom is driven. For example, if the maximum magnification of the electronic zoom of this embodiment is 1.5 times,
The electronic zoom is multiplied by 1 (that is, within a predetermined constant time tze).
The electronic zoom is continuously changed from the off state) to 1.5 times.

This controls, for example, the vertical transfer of the image pickup device 302 by the drive circuit 304, and the charges in the portions of the periods T1 and T3 of FIG. Then, the electric charge in the portion of the period T2 is read out. T1 + T2 + T3 is the vertical blanking period, and T1 = T3. If the periods T1 and T3 are made longer (or shorter) for each field, the angle of view becomes gradually smaller (or larger). The zoom time tze of the electronic zoom is determined by the change amount for each field.

FIG. 16 shows the zooming characteristics of the electronic zoom. The horizontal axis represents time and the vertical axis represents magnification. As mentioned above,
If the amount of change in T1 and T3 per field is constant, the higher the magnification, the greater the change in magnification per time.

FIG. 17 shows a change in magnification when the zooming of the zoom lens 300 and the electronic zooming are simultaneously performed. tz = tze, the horizontal axis is time,
The vertical axis represents the total magnification by the zoom lens 300 and the electronic zoom. The maximum electronic zoom is 1.5x,
The characteristics are shown when the maximum magnification of the zoom lens 300 is set to 6 times. As can be seen from FIG. 17, the magnification can be smoothly and continuously changed up to 9 times.

In the above embodiment, the zoom speed of the optical zoom is assumed to be constant and the zoom time tz of the optical zoom and the zoom time tze of the electronic zoom are matched, but normally, the zoom motor changes the applied voltage. Alternatively, the rotation speed may be changed by pulse-width modulating the applied voltage. In such a case, the rotational speed of the zoom motor 318 (or the moving speed of the variator 12) is detected, the zoom speed of the electronic zoom is adjusted according to the expected zoom time tz of the optical zoom, and finally, The control may be performed so that tz = tze.

FIG. 18 is a configuration block diagram of the modified embodiment.
Shown in. The same circuit elements as those in FIG. 15 are designated by the same reference numerals. The speed detection circuit 320 detects the rotation speed of the zoom motor 318 and supplies the rotation speed information to the CPU 322. The CPU 322 takes in the rotation speed information from the rotation detection circuit 320, and adjusts the zoom speed of the electronic zoom so that tz = tz finally.

FIG. 19 is a perspective view showing one structural example of the speed detection circuit 320. The zoom motor 318 includes a motor body 324, a reduction mechanism 326 that reduces the output of the motor body 324, an output shaft 328, and an output gear 330.
As the speed detection circuit 320, a rotary disk 332 having a black-and-white pattern for rotation detection printed on its surface is attached to the output shaft 328 coaxially with the output gear 330, and the photosensor 334 detects the rotation of the rotary disk 332. Photo sensor 33
The output of No. 4 is a pulse signal corresponding to the rotation of the rotating disk 332, and the rotation cycle thereof represents the rotation speed of the motor main body 324.

In FIGS. 18 and 19, the zoom motor 3 is
Although the rotational speed of 18 is detected, the electronic zoom magnification may be determined according to the variator position (or focal length). FIG. 20 shows a configuration for detecting the variator position. The brush 338 is attached to the holding frame 336 of the variator 12. The substrate 34 having a variable resistance or a gray code pattern on its surface so that the brush 338 is in sliding contact.
Place 0. The output of the substrate 340 is applied to the variator 12
The position of the A / D converter 342 is reflected on the substrate 34.
The output of 0 is converted into a digital signal and output to the CPU 314.

The CPU 314 in this modified example has a correspondence table between the zoom position (variator position) of the zoom lens 300 and the electronic zoom magnification as shown in FIG. 21, and the position of the variator 12 of the zoom lens 300 is provided. The electronic zoom is controlled to a magnification corresponding to. In FIG. 21, the zoom position "0" corresponds to the wide end and "n" corresponds to the tele end.
FIG. 22 shows an operation flowchart of the CPU 314 at this time.
Shown in. The zoom position is fetched (S30), and the electronic zoom magnification is determined with reference to the ROM storing the correspondence of FIG. 21 (S31). Check the current electronic zoom magnification (S3
2) If it is different from the determined magnification, the electronic zoom is adjusted to the determined magnification (S33).

The modified example of FIG. 20 requires a means for detecting the variator position, so that the cost of FIG. 15 or FIG.
Although it is more disadvantageous than the embodiment shown in (1), there are advantages that the zoom times of the optical zoom and the electronic zoom can be easily matched, and that the correlation between the focal length of the optical zoom and the electronic zoom magnification becomes accurate.

Various zooming effects can be obtained by preparing a plurality of correspondence tables of variator positions and electronic zoom magnifications for different combinations. The user can select which correspondence table to use by using a mode switch or the like.

FIG. 23 shows an example of characteristics when the zooming characteristics are selectable in this way. The vertical axis represents the magnification and the horizontal axis represents the variator position. Reference numeral 350 denotes a zooming characteristic as a whole, 352 denotes a characteristic in which the optical focal length determined by the variator position is shown as a change in image magnification with reference to the wide end, and 354 shows a change in magnification of the electronic zoom. Considering that the change in the focal length due to the movement of the variator is small at the wide end of the optical zoom, the electronic zoom is activated earlier when the optical zoom is located on the wide side.

If the electronic zoom is set to the maximum magnification before the optical zoom reaches the telephoto end, a sudden change appears in the total magnification at that time. Therefore, it is preferable to gradually change the electronic zoom magnification.

In the above embodiment, the product of the product of the optical zoom and the electronic zoom is obtained, but a special effect as described below can be obtained. That is, for example, a 2x optical zoom and a 2x electronic zoom are prepared, and both are controlled so as to be 1x (no zoom) as a whole. The characteristic diagram is shown in FIG. The vertical axis represents the magnification and the horizontal axis represents the variator position. Reference numeral 360 represents the overall magnification, 362 represents the optical zoom magnification, and 364 represents the electronic zoom magnification. By controlling in this way, the size of the image is the same and the amount of background blur can be controlled.

A circle of confusion generated at an arbitrary object distance outside the in-focus distance changes with the square of the distance. Therefore, in the case of double optical zoom, the blur amount changes four times at the wide end and the tele end. On the other hand, when the image is magnified with the electronic zoom, the blur is doubled with the double electronic zoom. Therefore, when the optical zoom is set to tele, the so-called depth becomes twice as large as when the electronic zoom is set to tele.

[0069]

As can be easily understood from the above description, according to the present invention, smooth zooming as a whole can be obtained even when the optical zoom and the electronic zoom or the electronic teleconverter are used together.

[Brief description of drawings]

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

FIG. 2 is a lens configuration of a front lens focus type zoom lens.

FIG. 3 is a positional relationship diagram of a variator and a compensator of a front lens focus type zoom lens.

FIG. 4 is a vertical cross-sectional view of an interlocking drive system for a variator and a compensator.

FIG. 5 is a conceptual explanatory diagram of electronic zoom.

FIG. 6 is a basic configuration block diagram of a camera having an electronic zoom function.

FIG. 7 is a relationship diagram between a variator and a focal length.

FIG. 8 is a characteristic diagram of magnification change according to the embodiment of FIG.

FIG. 9 is a characteristic diagram of magnification change of a conventional example.

FIG. 10 is a flowchart of a change operation of the embodiment of FIG.

11 is an example of a relationship between threshold values f1 and f2 in the embodiment of FIG.

FIG. 12 is a lens configuration of an inner focus type zoom lens.

13 is a vertical sectional view showing a drive system of the variator 202 of FIG.

FIG. 14 is a diagram showing the relationship between the focal length and the focusing lens position of the inner focus type zoom lens.

FIG. 15 is a configuration block diagram of a position embodiment of the present invention that uses both optical zoom and electronic zoom.

FIG. 16 is a characteristic diagram of electronic zoom.

FIG. 17 shows a combination of optical zoom and electronic zoom,
FIG. 16 is a characteristic diagram of FIG. 15.

FIG. 18 is a configuration block diagram of a modification of FIG.

FIG. 19 is a perspective view of a rotation speed detection mechanism of a zoom motor.

FIG. 20 is a vertical sectional view showing a variator position detection mechanism.

FIG. 21 is a correspondence table of variator positions and electronic zoom magnifications.

FIG. 22 is an operation flowchart for adjusting the electronic zoom magnification according to the variator position.

FIG. 23 is another characteristic diagram in which optical zoom and electronic zoom are used together.

FIG. 24 is a characteristic diagram in which the optical zoom and the electronic zoom are used together to increase the overall magnification by 1.

[Explanation of symbols]

10: Front lens 12: Variator 14: Compensator 16: Aperture 18: Imaging lens 20: Image sensor 26, 28: Frame 30, 32: Bar 34, 36:
Protrusion 38: Cam ring 40, 42: Cam groove 44: Fixed lens barrel 46: Zoom ring 48: Connecting member 50: Gear
52: Zoom motor 54: Output gear 60: Photographing lens 62: Imaging device 64: CCD drive circuit 66: Process circuit 68: Line memory 7
0: Vertical interpolation circuit 72: Horizontal interpolation circuit 74: CPU
100: Zoom lens for shooting 102: Image sensor
104: drive circuit 106: frame memory 108: CPU 110:
Zoom switch 112: Step motor 11
4: Drive circuit 116: Counter 118: Power supply 120: Power-on / reset circuit 200: Front lens group 202: Variator 204: Aperture 206: Fixed lens group 208: Focusing lens 210: Focal plane 212: Step motor 214:
Output shaft 216: Frame plates 218, 220: Bearing 222: Groove 224: Ball bearing 226: Frame 228: Screw 230: Leaf spring
232: Ball 300: Zoom lens 30 for shooting
2: Image sensor 304: CCD drive circuit 306: Process circuit 308: Line memory 310: Vertical interpolation circuit 312: Horizontal interpolation circuit 314: CPU 31
6: Zoom switch 318: Zoom motor 32
0: Speed detection circuit 322: CPU 324: Motor main body 326: Reduction mechanism 328: Output shaft 330: Output gear 332: Rotating disk 334: Photo sensor 33
6: holding frame 338: brush 340: substrate 342:
A / D converter

Claims (3)

[Claims] 1. An electronic camera comprising an optical zoom device, an image pickup means for converting an optical image obtained by the optical zoom device into an electric signal, and an electronic teleconverter device for enlarging an image picked up by the image pickup means to a predetermined magnification. An electronic camera is provided with an adjusting means for adjusting the optical zoom device so as to offset a change in magnification of the electronic teleconverter when the enlargement ratio is switched by the electronic teleconverter. 2. The electronic camera according to claim 1, further comprising storage means for freezing and outputting an output image of the electronic teleconverter during adjustment of the adjusting means. 3. An optical zoom device, an image pickup means for converting an optical image by the optical zoom device into an electric signal, an electronic zoom device for electronically zooming a photographed image by the image pickup means, the optical zoom device, and An electronic camera, comprising: a control means for interlockingly controlling an electronic zoom device under a predetermined relationship.