JPH0356612B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a device used in a wide-angle/telephoto switching camera in which a convergence lens is inserted behind a master lens during telephoto shooting, and the focus is adjusted by moving the convergence lens only during telephoto shooting. It is. In compact cameras, focus is usually adjusted by extending the master lens in the direction of the optical axis. When extending this master lens, for example, a focusing rod that moves in the optical axis direction of the master lens in conjunction with a distance measuring device is provided, and the lens holder holding the master lens is moved by this focusing rod. has been proposed. However, since a shutter device is arranged behind the master lens, the focusing rod passes through the shutter device. If the focusing rod passes through the shutter device in this way, assembly becomes troublesome, so it is necessary to avoid this.As a result, the layout of the shutter device becomes difficult, or the external dimensions of the shutter device become difficult. This causes the inconvenience of growing larger. In addition, the wide-angle lens is designed so that the conversion lens goes behind the master lens during telephoto shooting.
Telephoto switching cameras are known. In this wide-angle/telephoto switching camera, the master lens moves forward greatly during telephoto shooting, so the position of the master lens changes significantly between wide-angle shooting and telephoto shooting. In both wide-angle and telephoto shooting, when the master lens is moved to adjust the focus, there is a problem in that the mechanism for interlocking the distance measuring device and the master lens becomes extremely complicated. Based on the above background, it is an object of the present invention to provide a focus adjustment device for a wide-angle/telephoto switching camera that can be made simple and compact. The present invention enables a clear image to be obtained with the depth of field without moving the master lens during wide-angle shooting, and allows the conversion lens to be inserted behind the master lens during telephoto shooting. The focus is adjusted by moving the . In the present invention, wide-angle photography and telephoto photography only refer to the relative relationship between the two, and may be combinations of so-called telephoto photography and standard photography, standard photography and wide-angle photography, and the like. Embodiments of the present invention will be described in detail below with reference to the drawings. In FIG. 1, a movable lens barrel 1 holds a master lens 2 and moves along an optical axis 3 between a wide-angle position and a telephoto position (see FIG. 2). A groove 1a is formed in the movable lens barrel 1, and is fitted into protrusions 5a and 5b provided on the fixed lens barrel 4. Further, a pin 6 is implanted on the outer periphery of the movable lens barrel 1, and this pin 6 is fitted into a cam groove 7a of the cam barrel 7. The cam barrel 7 is rotatably housed within the fixed lens barrel 4. An annular groove 4a is formed in the fixed lens barrel 4, and a pin 9 implanted in the cam barrel 7 passes through the groove 4a. A wide-angle/telephoto switching ring 10 is rotatably fitted to the outer periphery of the fixed lens barrel 4, and a hole 10a provided in the wide-angle/telephoto switching ring 10 is provided with a wide-angle/telephoto switching ring 10.
A pin 9 implanted in the cam cylinder 7 is fitted. A cam 12 is formed at the rear end of the wide-angle/telephoto switching ring 10, and a pin 13 is attached to this cam 12.
are coming into contact with each other. This pin 13 passes through an elongated hole 4b formed in the fixed lens barrel 4 and is fixed to the lens holder 14. This lens holder 14 holds a conversion lens 15 (see FIG. 2) and is fixed to a slidably provided focusing rod 16. The focusing rod 16 is connected to the hole 4c of the fixed lens barrel 4 and the plate 18.
The cam plate 20 is supported in the hole 18a, is biased rightward by a spring 19, and comes into contact with the cam plate 20.
This cam plate 20 has a tapered portion 20a for positioning the focusing rod 16, and the plate 18 has a tapered portion 20a for positioning the focusing rod 16.
It is rotatably supported on a shaft 21 attached to.
Note that the reference numeral 22 is a shutter blade, which is attached to the movable lens barrel 1.
A shutter blade drive mechanism (not shown) is housed within the gap 16 of the movable lens barrel 1. code 2
4 is the front plate of the camera. In the state shown in FIG. 1, the wide-angle/telephoto switching ring 10 is set at the wide-angle position. At this time, the master lens 2 is retracted, and the conversion lens 15 is in a position retracted from the optical axis of the master lens 2. During this wide-angle shooting, the master lens 2 does not move even if the shooting distance changes, and the film (not shown) captures a clear image using only the depth of field.
tie it to FIG. 2 shows a telephoto shooting state. If the wide-angle/telephoto switching ring 10 is rotated and set to the telephoto position, the hole 10a of the wide-angle/telephoto switching ring 10
The cam cylinder 7 rotates due to its connection with the pin 9. The cam barrel 7 moves the movable lens barrel 1 forward along the optical axis 3 by coupling the cam groove 7a with the pin 6 and coupling the groove 1a with the protrusions 5a and 5b. At the same time, the lens holder 14 is rotated about the focusing rod 16 by the cam 12, so that the conversion lens 15 is placed on the optical axis 3. Therefore, the light from the subject passes through the master lens 2 and the conversion lens 15 and enters the film. During this telephoto shooting, the conversion lens 1
5 along the optical axis 3 to adjust the focus. That is, since the cam plate 20 rotates according to the distance zone and moves the focusing rod 16 with its tapered portion 20a, the lens holder 14 holding the conversion lens 15 is aligned with the focusing rod 16 on the optical axis 3. move along. FIG. 3 shows the setting mechanism of the conversion lens. The cam 12 has a recess 12a.
is formed, and the convergence lens 15 is separated from the master lens 2 during wide-angle photography when the mark "W" coincides with the index 25. During telephoto shooting when the mark "T" matches the index 25, the pin 13 enters the recess 12a, so the lens holder 14, which is biased by the spring 26, rotates counterclockwise and enters behind the master lens 2. . FIG. 4 shows the position control mechanism of the conversion lens. The cam plate 20 is returned counterclockwise by the film winding operation and is locked by the foot lever 30. This foot lever 30
is rotatably supported by a shaft 31, and is supported by a spring 32.
is biased counterclockwise. An armature 33 is fixed to the lever 31 and is attracted and held by a combination magnet 36 composed of a permanent magnet 34 and a coil 35. The approximately L-shaped positioning lever 38 controls the amount of rotation of the cam plate 20 by receiving one of the shoulders of the step teeth 20b formed on the outer periphery of the cam plate 20 at one end thereof. This positioning lever 38 is rotatably supported by a shaft 39, and is biased to a neutral position by a spring 40. Further, a bar magnet 41 is fixed to the positioning lever 38, and one magnetic pole of the bar magnet 41 is inserted into a notch 44 of an iron core 43 that is magnetized by a coil 42. Note that numerals 45 and 46 are springs 4
This is a pin that accepts 0. Combination magnet 36 and coil 35
When not energized, the cam plate 20 does not rotate. In this case, since the focusing rod 16 for moving the convergence lens 15 is in contact with the highest point of the tapered portion 20a, the convergence lens 15 is at the most advanced position, for example, 1 to 1.3 m. The subject in the distance zone will be in focus. When a forward current flows through the coil 42, the iron core 4
3 is magnetized to the south pole, the positioning lever 38 rotates counterclockwise about the shaft 39. At the same time or after a delay using a delay circuit, when the coil 35 of the combination magnet 36 is energized, the stick lever 30 is released from its attraction and is rotated counterclockwise by the spring 32. Since the hook lever 30 releases the latching of the cam plate 20, the cam plate 20 rotates due to the stored force of the spring 47, collides with the first shoulder of the step tooth 20b, and stops. As shown in FIG. 6, since the tapered portion 20a is inclined, the focusing rod 16 biased by the spring 19 moves along this tapered portion 20a. At this time, objects in the distance zone of 1.3 to 2 meters are in focus. When coil 42 is not energized, positioning lever 38 is in a neutral position, as shown in FIG. Then, the coil 35 of the combination magnet 36 is energized, and the foot lever 30 is connected to the cam plate 2.
When the cam plate 20 is released from the lock, the cam plate 20 rotates to a position where it collides with the second shoulder of the step tooth 20b.
At this time, the subject located at a distance of 2 to 4 meters is in focus. When the coil 42 is energized in the opposite direction, the iron core 43
Since the end 43b becomes the south pole, the positioning lever 38 rotates clockwise. When the coil 35 of the combination magnet 36 is energized, the cam plate 20 rotates clockwise and the step tooth 20b
The vehicle collides with the third shoulder of the vehicle and stops. At this time, the focusing rod 16 for positioning the conversion lens 15 is attached to the tapered portion 20.
As a result, objects in the distance zone of 4 m to ∽ are brought into focus. FIG. 7 shows a coil drive circuit.
The distance measuring device 50 detects the shooting distance by receiving light from a subject existing within a distance of 1 to 4 m, and when a subject exists in a distance zone of 1 to 1.3 m, the output terminal D1 is output. becomes “H”,
When the subject exists in the distance zone of 1.3 to 2 m, the output terminal D2 becomes "H", and when the subject exists in the distance zone of 2 to 4 m, the output terminal D becomes "H".
3 becomes "H". Further, in the distance measuring device 50, when distance measurement is completed, the output terminal D4 becomes "H". Therefore, if the subject is present at a distance exceeding 4 meters, only the output terminal D4 becomes "H". The signal output from the output terminal D1 is inverted by an inverter 51 and then input to an AND circuit 52. Furthermore, since the signal output from the output terminal D4 is also input to this AND circuit 52, a signal obtained by logical product of the two signals is output.
A transistor 53 is connected to the output terminal of the AND circuit 52.
is connected, and the output of the AND circuit 52 is "H"
When this happens, the transistor 53 becomes conductive and the coil 35 of the combination magnet 36 is energized. The signals output from output terminals D2 and D4 are
It is input to the AND circuit 54. This AND circuit 54
A relay 55 is connected to the output terminal of
When the output of the AND circuit 54 is "H", the relay 55
is activated to switch the relay switch 56 from contact a to contact b. Output terminals D1, D2, and D3 are OR circuit 5
7, and the obtained AND signal is inverted by an inverter 58. This inverter 58
The output terminal of and the output terminal D4 of the distance measuring device 50 are
It is connected to an AND circuit 59, and the obtained logical product signal is sent to a relay 60. This relay 6
0 operates when the output of the AND circuit 59 is "H" and switches the relay switch 61 from contact a to contact b. This contact a is grounded, and contact b
is at a positive potential. The operation of the circuit shown in FIG. 7 is as shown in the following table.

[Table] In the present invention having the above configuration, the master lens becomes a fixed focal point during wide-angle shooting, and a conversion lens enters behind the master lens during telephoto shooting, and the conversion lens is moved in the optical axis direction to adjust the focus. This eliminates the need for a focus adjustment mechanism for the master lens.Therefore, there is no need to provide a focusing rod to penetrate the shutter device installed behind the master lens, which improves the layout of the shutter device. This makes it easier and requires less space. Furthermore, since focus adjustment is performed by a master lens and a conversion lens inserted behind the shutter device during telephoto shooting, the interlocking mechanism with the distance measuring device is extremely simple.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the present invention, and is a sectional view during wide-angle photography. FIG. 2 is a sectional view during telephoto shooting. FIG. 3 is an explanatory diagram showing a conversion lens setting mechanism. FIG. 4 is a front view showing the positioning mechanism of the conversion lens. Fifth
The figure is a front view of main parts showing a state in which the positioning lever shown in FIG. 4 is in a neutral position. Figure 6 is the 4th
It is an AA sectional view of the figure. FIG. 7 is a wiring diagram showing a coil drive circuit. 1...Movable lens barrel, 2...Master lens, 4...
...Fixed lens barrel, 7...Cam barrel, 10...Wide-angle/telephoto switching ring, 12...Cam, 13...Pin, 14
... Lens holder, 15 ... Conversion lens, 16 ... Focusing rod, 20 ...
Cam plate, 20a... Tapered portion, 22... Shutter blade, 34... Permanent magnet, 35, 42... Coil, 41... Bar magnet.

Claims (1)

[Claims] 1. In a wide-angle/telephoto switching camera having a master lens and a convergence lens, with the convergence lens going behind the master lens during telephoto shooting, the master lens is moved during wide-angle shooting. A clear image is formed on the film by adjusting the depth of field, and during telephoto shooting, the convergence lens, which has entered the optical path of the master lens, is moved along the optical axis in conjunction with the distance measuring device. A focusing device characterized in that a clear image is formed on a film. 2. The focus adjustment device according to claim 1, wherein the master lens is displaced forward during telephoto shooting. 3. A cam plate that is displaced according to the distance zone detected by the distance measuring device and a lens holder holding the conversion lens are fixed to each other, and the cam plate moves in the optical axis direction of the conversion lens by the cam plate. 3. A focusing device according to claim 1, further comprising a focusing rod.