JPH07119871B2 - Focus adjusting device for auto-focus single-lens reflex camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a manual focusing operation in an autofocus type single-lens reflex camera when the subject cannot be distance-measured and automatic focusing (autofocus) cannot be performed. The present invention relates to an improvement of a focus adjustment device that enables (manual focus) to be performed easily and quickly.

[Conventional technology]

The recent single-lens reflex cameras are extremely multifunctional, and it is necessary to greatly improve the quick-shooting property and the operability by automating each mechanism part as much as possible. Initially, an automatic focus adjustment mechanism called automatic focus for performing automatic focusing, and a motor drive mechanism for winding and rewinding a film have been appropriately adopted. In particular, the auto-focus adjustment mechanism that performs auto-focusing makes it easy and appropriate to shoot simply by pointing the camera at the subject and does not require the troublesome focusing (focusing) that is required in the past. It is one of the technologies that is currently attracting attention because it has a great effect on improving the above.

By the way, the above-mentioned autofocus (automatic focusing) is restricted by subject conditions,
For example, when shooting a subject that is dim and has no contrast, it is impossible to measure the distance of the subject with the distance sensor provided in the camera body, and automatic focusing cannot be performed. It is necessary to switch to manual mode and focus manually (manually). That is, in general, as disclosed in JP-A-56-162726, etc.,
The camera body is provided with a switching knob for AF (auto focus) and MF (manual focus) switching that can be operated externally. By operating this, manual focusing is performed, and the ranging ring is provided on the outer circumference of the lens barrel. It was configured to be operated by rotating.

[Problems to be solved by the invention]

However, such a manual rotation operation of the distance measuring ring on the outer peripheral portion of the lens barrel not only poses a problem in terms of operability and quick shooting characteristics, but also in obtaining a stable hold state of the camera. It had a problem. That is, the above-described distance measuring ring is gear-coupled to the drive motor for driving the lens by auto focus through the focusing driving mechanism. Especially, since the reduction ratio of the driving mechanism is large, the manual operation on the distance measuring ring side is performed. Not only was the force increased and there was a problem in terms of operability, but also it was not possible to perform a quick and reliable operation, and there was also a problem in terms of rapidity. Furthermore, according to such a distance measuring ring, the photographer needs to perform a complicated operation such as moving his or her hand toward the lens barrel side when operating the ring.
Further, this causes a problem that the holding property of the camera at the time of shooting is impaired. That is, in the structure in which the distance measuring ring is provided on the outer peripheral portion of the lens barrel as in the conventional case, the distance measuring ring also rotates during automatic focusing by the auto focus, so that the photographer can measure the distance. If the ring part is held, it may become a load and the lens system may not be moved to a desired focusing position. Therefore, it is necessary to pay sufficient attention to such a rotating member (distance measuring ring). It is necessary to take some measures capable of eliminating the above-mentioned problems, including a problem caused by exposing the above) to the outer peripheral portion of the lens barrel.

[Means for solving problems]

In order to meet such a demand, the focus adjusting device in the autofocus single-lens reflex camera according to the present invention is an automatic mode for performing automatic focusing when the distance measurement of a subject is impossible and automatic focusing cannot be performed. Switching means for automatically switching to the manual mode for performing the focusing by the manual operation, and the camera body for performing the focusing by moving the photographing lens system when the switching to the manual mode is performed by the switching means. A focus adjustment switch for manual (manual) operation connected to a drive motor provided in the drive motor, the focus adjustment switch being exposed to a part of the outside of the camera body in which the drive motor is provided. Is.

Further, the focus adjusting device in the autofocus single-lens reflex camera according to the present invention includes a focus adjusting device for focusing by moving the taking lens system in the lens barrel, and an automatic zoom mechanism for zooming, This automatic zoom mechanism is configured to be driven by a focus adjustment drive motor provided inside the camera body, and a manual adjustment focus adjustment switch provided on a part of the outside of the camera body allows the automatic zoom mechanism to operate. It is configured so that it can also be zoomed.

[Action]

According to the present invention, the focus adjustment device is automatically switched from the automatic mode to the manual mode when the distance cannot be measured because the automatic focusing as the auto focus cannot be performed, and the photographer is provided outside the camera body. By operating the focus adjustment switch manually (manually), the drive motor is driven to move the photographic lens system to the required state via the focusing drive mechanism, which allows easy and quick manual focus adjustment. It

Further, according to the present invention, when an automatic zoom mechanism for zooming is provided in parallel, the drive motor can be driven by the manual operation of the focus adjustment switch to perform the required zooming drive of the taking lens system. .

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings.

1 to 3 show an embodiment of a focus adjusting device in an autofocus type single-lens reflex camera according to the present invention. First, the reference numeral 1 in FIG. 1 denotes an autofocus type single-lens reflex camera. As shown in the figure, the camera body 1 has a substantially rectangular parallelepiped shape with a thin depth as in the well-known single-lens reflex camera, and a pentaprism is provided in the center of its upper end. A warship section 2 having a finder section (both not shown) is provided on the rear side, and a release button 3 and an AF (autofocus) mode changeover switch button 4 etc. which are necessary for taking a picture are further provided on both sides of the warship section 2. There are provided various operation push buttons such as, and a display panel 5 for displaying the setting conditions and the like. Further, in the center of the front surface of the camera body 1, there is provided a lens mount portion 6 on which a taking lens 10 having a structure as shown in FIGS. 2 and 3 is mounted, and further inside the camera body 1. Although not shown, various mechanical parts and the like required for this type of autofocus single-lens reflex camera are internally provided.

On the other hand, as shown in FIGS. 2 and 3, the taking lens 10 is mounted at the rear end with respect to the lens mount portion 6 (shown by an imaginary line in FIG. 2) at the center of the front surface of the camera body 1. A lens barrel 11 to which the portion 11a is fitted and attached,
In addition, in this lens barrel 11, a plurality of groups (in this embodiment, front and rear two groups) of lens systems 12 and 13 are arranged so as to be movable in the axial direction. Here, in the present embodiment, before the above,
The figure shows the case where the rear lens systems 12 and 13 can be selectively driven by focusing by an automatic focus adjustment mechanism or zooming by an automatic zoom mechanism, and as a driving source for performing focusing and zooming, a camera is used. The configuration is such that one drive motor 7 disposed in the main body 1 is also used. Reference numeral 8 in the drawing denotes a driving force transmission mechanism including a speed reduction mechanism that decelerates the rotation of the drive motor 7 and transmits it to the output shaft 9. Further, the motor 7 is driven by the switch operation of the automatic focus adjustment mechanism and the automatic zoom mechanism described above. Control circuit for drive control (see FIG. 7)
A battery, a battery (not shown), and the like are also provided at appropriate positions in the camera body 1.

Further, the driving mechanism for focusing and zooming the front and rear lens systems 12 and 13 will be briefly described with reference to FIGS. 2 to 4.
A first cam barrel 14 having straight cam grooves 14a, 14b along the axial direction is provided therein, and an outer peripheral portion of the first cam barrel 14 is rotatably fitted and inclined in the circumferential direction. Rotating cam groove 15a,
A second cam barrel 15 having a portion 15b (see FIG. 4) formed therein is provided in a loosely fitted state, and the rear end of the first cam barrel 14 is integrated with the lens barrel 11 side. It is fixed to.
The first and second cam barrels 14 and 15 have an engagement pin 16 engaged in the front cam grooves 14a and 15a, and a helical gear portion for moving the front lens system 12 back and forth inside.
A sleeve member 17 on which 17a is formed is slidably held on the inner circumference of the tip end portion of the first cam barrel 14. Further, the rear lens system 13 is provided in the rear side cam grooves 14b and 15b.
And an engaging pin 19 projectingly provided on the outer peripheral portion of a lens frame 18 that holds the lens barrel and is slidably supported in the first cam barrel 14 in the axial direction.

Further, a zoom ring 20 is rotatably fitted to the outer periphery of the lens barrel 11 on the rear end side, and an engagement cylinder having a long groove 21a axially elongated in a part of its inner peripheral portion. The part 21 is projected. The tip of the engagement cylinder portion 21 faces the outer peripheral portion of the second cam cylinder 15, and an engagement pin 22 projecting from the second cam cylinder 15 is engaged in the long groove 21a. And by rotating this zoom ring 20, the second
The cam barrel 15 rotates, and as a result, the sleeve member 17 having the engaging pins 16 and 19 engaged in the rotating cam grooves 15a and 15b and the lens frame 18 holding the rear lens system 13 are Cam tube
It is configured to slide in the front-rear direction along the straight cam grooves 14a, 14b on the 14th side. Incidentally, the lens barrel 11
Of course, a long groove is formed along the circumferential direction in the portion of the zoom ring 20 corresponding to the engaging cylinder portion 21.

On the other hand, the front lens system 12 is a lens frame member having a rearward U-shaped cross section that sandwiches the first and second cam barrels 14 and 15 from the front side on the front end side of the lens barrel 11.
Held by the inner cylindrical portion 24 of 23, and at the outer peripheral portion of the inner cylindrical portion 24, the helical gear portion 17 to the sleeve member 17 is provided.
A helical gear portion 24a that meshes with a is formed. Further, the outer tubular portion 25 of the lens frame member 23 is rotatably held in a state in which the engaging projection 25a projecting on a part of the outer periphery thereof is not exposed to the outside inside the front end portion of the lens barrel 11. The distance ring 26 is engaged with a key groove 26a formed in the inner peripheral portion of the distance ring 26 in the axial direction.
The lens frame member 23 for holding is configured to rotate integrally with the rotation of the distance ring 26, and to move back and forth due to the meshing of the helical gear portions 24a and 17a.

Further, as described above, the zoom ring 20 that moves the front and rear lens systems 12 and 13 back and forth simultaneously and the distance ring 26 that moves only the front lens system 12 back and forth include the following clutch mechanism 30.
The motor 7 on the camera body 1 side is appropriately switched by
Driven by. That is, inside the lens barrel 11, a rotation transmission shaft 32, which is connected to the output shaft 9 on the side of the motor 7 and a coupling portion 31 exposed at a part of the rear end of the lens barrel 11, is connected in the axial direction. It is rotatably supported along
Moreover, the rotation transmission shaft 32 has clutch gears 33a at both ends,
A sleeve 33 having 33b is fitted in a state in which it is connected by a keyway or the like in the rotational direction and is movable only in the axial direction. The lens barrel is attached to the outer periphery of the sleeve 33.
11. An extended end 34a portion of a zoom / AF switching lever 34, which is slidably operated outside in the axial direction, is fitted, and a pair of springs 35a, 35b are fitted on both sides thereof. Therefore,
When the switching lever 34 is slid, the springs 35a and 35b in the operating direction are compressed, and the elastic force of the springs 35a and 35b causes the sleeve 33 to move.
The clutch gears 33a, 33b are pressed and moved in the required switching direction.

In addition, a part of the inner peripheral portion of the zoom ring 20 is provided with a gear portion 36 so that one clutch gear 33a of the sleeve 33 is selectively meshed with a long groove formed in the lens barrel 11.
Is provided. On the other hand, a rotation transmission shaft 37 for focusing is rotatably supported by the lens barrel 11 (between the first cam barrel 14 which is the fixed side in this embodiment) in parallel with the rotation transmission shaft 32, and thereafter. A gear 37b is provided at the end portion on the end side and faces the gear portion 36 on the zoom ring 20 side and the sleeve 33 at an interval larger than the length of the sleeve 33, and the gear 37b is selected from the other clutch gear 33b of the sleeve 33. Are configured to be meshed with each other. Further, a gear 37a meshing with a gear 38 formed at the rear end of the distance ring 26 rotatably supported on the front end side of the lens barrel 11 is provided at the front end of the rotation transmission shaft 37. Thus, the rotation of the distance ring 26 can be transmitted. In addition,
A part of the zoom ring 20 in the circumferential direction is formed with a notch so as not to interfere with the switching lever 34 when rotated during zooming.

In such a configuration, one of the clutch gears 33a and 33b at both ends of the sleeve 33 is connected to the gear portion 36 of the zoom ring 20 or the distance ring 26 side via the gear portion 38 and the gear 37a by the switching operation of the switching lever 34. By selectively meshing with any of the gears 37b of the rotation transmission shaft 37,
By rotating the zoom ring 20 or the distance ring 26, zooming drive or focusing drive can be performed. That is, during zooming, the second cam barrel 15 is rotated by the rotation of the zoom ring 20, and the front and rear lens systems 12 and 13 are moved back and forth according to the movement ratio determined by the rotating cam grooves 15a and 15b. On the other hand, at the time of focusing, the lens frame member 23 that rotates integrally with the distance ring 26 is helically coupled to the sleeve member 17 that is relatively fixed, so that only the front lens system 12 rotates. While moving back and forth. Of course, a changeover switch (not shown) is operated by the changeover operation of the changeover lever 34, and the zoom of the control circuit or the like on the camera body 1 side is performed.
It is configured to switch / AF.

Further, according to the configuration of this embodiment, the focusing drive and the zooming drive can be easily and reliably performed by the single drive motor 7 by the switching operation of the switching lever 34.
It has advantages such as excellent operability, reduction of the taking lens 10 and built-in mechanical parts in the camera body 1, and reduction in size of the entire camera.

Now, according to the present invention, as described above, the drive motor 7 provided in the camera body 1 is provided with a distance sensor (not shown).
The lens system 12, 1 in the lens barrel 11 is driven by a control circuit (consisting of a central processing unit CPU and a lens drive circuit etc.) according to the distance measurement information of the subject from the figure reference.
The focus adjusting device having an automatic focus adjusting mechanism for automatically adjusting the focus by moving 3 (only the front lens system 12 in this embodiment) is characterized by adopting the following configuration. That is, when the distance measurement of the subject is impossible due to the lack of contrast, etc., the focus adjustment device is automatically switched from the automatic mode for automatically focusing to the manual mode for manually performing the focusing. The switching means to be performed is composed of a control circuit such as a central processing unit CPU, and when the switching to the manual mode is performed by this switching means, the lens systems 12 and 13 are moved to perform focusing. A focus adjustment switch 40 for manual operation, which is connected to a drive motor 7 provided in the camera, is exposed outside the camera body 1 (on the rear side of the release button 3 on one side of the upper end). Is.

Here, as the focus adjustment switch 40 by the manual operation described above, a case where it has a push button structure that can be pressed in two directions (the focal length changes to a longer direction or a shorter direction) is illustrated. However, the present invention is not limited to this, and may have, for example, a slide lever structure, or may have a two-step structure that enables fine adjustment and coarse adjustment.

Further, as the means for switching from the automatic mode to the manual mode described above, when the distance measurement is impossible, for example, the state in which the distance measurement is impossible is displayed on the display panel 5 or a display unit in the finder unit (not shown), and at the same time, The central processing unit CPU or the like which constitutes the control circuit may be automatically switched. In addition, AF / MF to the display panel 5 described above
FIG. 5 exemplifies display states such as a mode switching display (displayed by lighting), its focal length set value, and a mark (indicated by a broken line circle in the drawing) indicating a state in which distance measurement is impossible.

With such a configuration, when distance measurement is impossible because automatic focusing cannot be performed by autofocus, the state is detected by the central processing unit CPU, etc., and the focus adjustment device automatically switches from automatic mode to manual mode. Can be switched. When the photographer manually operates the focus adjustment switch 40 provided on the upper end side of the camera body 1 in this state (manual operation), the drive motor 7 causes the lens system 12 in the lens barrel 11 to move to a desired state. It can be moved, and focusing can be performed easily and quickly by manual operation. Then, as is apparent from the flowchart shown in FIG. 6, the state of being focused by this manual (manual) operation is displayed on the display panel 5 or the display section in the finder section in the same manner as described above, and the photographing is performed accordingly. Release button 3
By pressing, you can take a proper photo.

Therefore, according to such a configuration of the present invention, even when the automatic focusing as the auto focus cannot be performed, the state is displayed and this is sensed to automatically switch from the automatic mode to the manual mode. The focus adjustment switch 40 exposed to the outside of the camera body 1 to a desired state manually, and skillfully using the drive motor 7 for focusing by auto focus. The adjustment is easy and reliable.

Here, in the case where the distance can be measured and the focus can be adjusted by the autofocus, the photographer performs a release operation (first stage) as shown in FIG. 6 and FIG. Distance measurement is performed by calculating an output signal from the distance sensor which is input together with film sensitivity and various lens information in the CPU, and the lens drive circuit drives the drive motor 7 in accordance with the distance measurement. Move to the required position and release operation in this state (second step)
It is well known that the shooting is performed by performing the, and it can be easily understood.

It should be noted that the present invention is not limited to the structure of the embodiment described above, and the shape, structure, etc. of each portion can be freely modified or changed. For example, the shape and structure of each part of the camera body 1, the number and number of groups of lens systems arranged in the lens barrel 11 of the taking lens 10, the driving state during focusing and zooming, and the focusing driving mechanism and the zooming driving mechanism. The clutch mechanism 30 and the like for switching between and are not limited to the above-described embodiment, and can be appropriately selected, and the respective drive mechanisms and the like can be appropriately changed accordingly.

Further, the attached position of the focus adjustment switch 40 which is a feature of the present invention may be any position on the outside of the camera body 1 where it can be easily operated, and various modifications can be considered. Further, it can be easily understood as a means for notifying the photographer of the state in which the distance cannot be measured or a state in which the release button 3 cannot be pressed.

Further, in the above-described embodiment, the switch 40 operated manually is used.
I explained the case of using only for focus adjustment,
For example, when the taking lens 10 is configured to perform auto-focusing and zooming as in the above-described embodiment and is selectively switched and driven by the same drive motor 7, this manually operated switch is used.
It will be readily appreciated that the 40 may be configured for automatic zooming.

〔The invention's effect〕

As described above, according to the focus adjustment device in the autofocus type single-lens reflex camera according to the present invention, when the distance measurement of the subject is impossible and the automatic focusing cannot be performed, the automatic mode is automatically switched to the manual mode. And a drive provided in the camera body for automatically focusing by moving the photographing lens system in the lens barrel when the manual mode is switched by the switching means. A focus adjustment switch for manual (manual) operation connected to the motor is provided, and this focus adjustment switch is exposed on a part of the outside of the camera body. The following excellent effects are obtained.

That is, according to the present invention, the control circuit automatically detects a state in which distance measurement is impossible in which automatic focusing cannot be performed as auto focus, and the focus adjusting device automatically switches from the automatic mode to the manual mode. To be Then, in this state, the photographer manually operates the focus adjustment switch provided on the outside of the camera body,
Focus adjustment by manual (manual) operation can be performed extremely easily, properly, and quickly compared to the case of using a range-finding ring that tends to be heavy in operation force, and is superior in terms of operability and quick-shooting. There is.

Further, according to the present invention, the distance measuring ring for focusing etc. is not exposed on the outer peripheral portion of the lens barrel, and the stable hold state of the camera at the time of photographing can be maintained.

Further, according to the present invention, an automatic zoom mechanism for zooming is provided together with a focus adjusting device for focusing by moving the taking lens system in the lens barrel, and the automatic zoom mechanism is provided in the camera body. It is configured so that it can be driven by the focus adjustment drive motor, and the focus adjustment switch for manual operation exposed on the outside of the camera body allows zooming by the automatic zoom mechanism. Not only (focusing) but also the zooming function can be performed in a desired state by a simple operation, and the configuration is simplified and the operability can be improved.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a camera main body showing an embodiment of a focus adjusting device in an autofocus type single-lens reflex camera according to the present invention, and FIG. 2 shows an entire photographing lens mounted on the camera main body. Fig. 3 is a schematic side sectional view, Fig. 3 is a schematic perspective view showing the appearance, Fig. 4 is a development view of a rotary cam ring that drives each lens system during zooming and focusing, and Fig. 5 is AF (autofocus) on the display panel. ), MF (manual focus; manual operation) switching display state, FIG. 6 is a flowchart of the focus adjustment device according to the present invention, and FIG. 7 is a block configuration diagram showing the same device configuration. 1 ... Camera body, 3 ... Release button, 4 ... AF mode switch button, 5 ... Display panel, 6 ... Lens mount, 7 ... Drive motor, 9 ... Output shaft, 10 ... Shooting Lens, 11 ... Lens barrel, 12,13 ... Lens system of front and rear two groups, 14,15 ... First and second cam barrels, 14a, 14b
…… Straight cam groove, 15a, 15b …… Rotating cam groove, 16,19 …… Engaging pin, 17 …… Sleeve, 17a …… Helical gear, 18
...... Lens frame, 20 ...... Zoom ring, 24 ...... Lens frame member, 24a ...... Helical gear part, 26 ...... Distance ring, 30 ...
… Clutch mechanism, 31 …… Coupling section, 40 …… Focus adjustment switch for manual operation, CPU …… Central processing unit that constitutes the control circuit.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G03B 13/34 G03B 3/10

Claims (2)

[Claims] 1. A focus adjustment device for automatically focusing by moving a photographing lens system in a lens barrel by driving a drive motor provided in a camera body according to distance measurement information of a subject. In an autofocus single-lens reflex camera, switching means for automatically switching from an automatic mode for automatically focusing when the object cannot be measured to a manual mode for manually focusing, and the switching means. A focus adjustment switch for manual operation, which is connected to a drive motor for moving the taking lens system in the lens barrel to perform focusing when the mode is switched to the manual mode, In the autofocus single-lens reflex camera, the focus adjustment switch is provided by being exposed outside the camera body. Focus adjustment device. 2. A focus adjusting device for automatically focusing by moving a photographing lens system in a lens barrel by driving a drive motor provided in a camera body according to distance measurement information of a subject. In an auto-focus type single-lens reflex camera, switching means for automatically switching from an automatic mode to a manual mode when distance measurement of the subject is impossible, and the lens when the manual mode is switched by the switching means. And a focus adjustment switch for manual operation, which is provided outside the camera body so as to be connected to a drive motor for focusing by moving a taking lens system in the lens barrel, and the lens mirror An automatic zoom mechanism that performs zooming by moving the taking lens system inside the body is provided with a drive for focus adjustment provided in the camera body. Drivable constituted by chromatography data, and focusing apparatus in autofocus single-lens reflex camera, characterized by being configured for performed by the focus adjusting switch zooming by the automatic zooming mechanism for the manual operation.