JPS63138317A - Focus adjusting device for automatic focusing type single lens reflex camera - Google Patents

Abstract

PURPOSE:To maintain the stable holding state of a camera at the time of photography while the operability and quick shooting performance are superior by providing a switch for focus adjustment which is operated manually and connected to a driving motor by a switching means for switching from an automatic mode to a manual mode when the distance of an object can not be measured so that it is exposed outside a camera body. CONSTITUTION:The switch 40 for focus adjustment which is operated manually and connected to the driving motor 7 for driving the photographic lens system in a lens system for automatic focusing by the switching means 4 for the switching from the automatic mode to the manual mode when the distance of the object can not be mea sured and automatic focusing is impossible is provided so that it is exposed partially outside the camera body 1 which includes the driving motor 7. Consequently, when the distance measurement is impossible, a photographer operates the switch 40 for focus adjustment provided outside the camera body 1 manually to drive the driving motor 7, and then the photographic lens system is moved into a necessary state through a focusing driving mechanism to easily perform focusing body the manual operation at a high speed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to manual focusing in an autofocus single-lens reflex camera when the subject cannot be measured and automatic focusing cannot be performed. (
The present invention relates to an improvement in a focus adjustment device that allows easy and quick manual focusing.

[Conventional technology]

Recent single-lens reflex cameras have become extremely multi-functional, and by automating each mechanism as much as possible, it is necessary to greatly improve quick shooting performance and operability. Initially, an automatic focus adjustment mechanism called autofocus, which performs automatic focusing, and furthermore, a motor drive mechanism, which performs film winding, rewinding, etc., have been appropriately adopted. In particular, the automatic focus adjustment mechanism that performs autofocus allows you to easily and appropriately take pictures by simply pointing the camera at the subject, and does not require the troublesome focusing (focusing) of conventional methods, which improves quick shooting and operability. It is one of the technologies that is currently attracting attention because it is highly effective in improving

By the way, the above-mentioned autofocus (automatic focusing) is subject to restrictions depending on the subject conditions.
For example, when photographing a dimly lit subject with poor contrast, the distance sensor installed inside the camera body cannot measure the distance to the subject and automatic focusing cannot be performed. It is necessary to switch to manual mode and perform focusing manually. Conventionally, such manual focusing has generally been performed by rotating a distance measuring ring provided on the outer periphery of the lens barrel.

[Problem that the invention seeks to solve]

However, manual rotation of the distance measurement ring on the outer periphery of the lens barrel not only poses problems in terms of operability and quick shooting performance, but also makes it difficult to maintain a stable hold of the camera. It was problematic. In other words, the above-mentioned distance measurement ring is gear-coupled via a focusing drive mechanism to a drive motor that drives the lens by autofocus, and because the drive mechanism has a particularly large reduction ratio, manual operation on the distance measurement ring side is not necessary. The force becomes heavy, which not only poses a problem in terms of operability, but also makes it impossible to operate quickly and reliably, which poses a problem in terms of quick shooting performance. Furthermore, with such a distance measuring ring, the photographer must perform complicated operations such as moving his/her hand toward the lens barrel.
This also causes problems such as the ability to hold the camera during photographing. In other words, in the conventional configuration in which the distance measuring ring is provided on the outer periphery of the lens barrel, this distance measuring ring also rotates during automatic focusing by autofocus.
If the photographer holds this distance-measuring ring, there is a risk that it will become a burden and prevent the lens system from moving to the desired focusing position, so great care must be taken.

It is necessary to take some measures that can eliminate the problems mentioned above, including the problems caused by exposing such a rotating member (m-distance ring) to the outer circumference of the lens barrel.

[Means for solving problems]

In order to meet such demands, the focus adjustment device of an autofocus single-lens reflex camera according to an uninvented invention switches from automatic mode to manual mode when it is impossible to measure the distance to the subject and automatic focusing cannot be performed. A manually operated focus adjustment switch connected to a drive motor for driving the photographing lens system in the lens barrel and automatically focusing the lens system is installed inside the drive motor. It is provided so as to be exposed on a part of the outside of the camera body.

[Effect]

According to the present invention, when automatic focus adjustment is not possible and distance measurement is not possible, the photographer manually operates the focus adjustment switch provided on the outside of the camera body, thereby driving the drive motor. By moving the photographic lens system to a desired state via the focusing drive mechanism, manual focusing can be performed easily and quickly.

〔Example〕

Hereinafter, the present invention will be explained in detail using embodiments shown in the drawings.

1 to 3 show an embodiment of a focus adjustment device for an autofocus single-lens reflex camera according to the present invention. First, what is indicated by the symbol l in FIG. 1 is an autofocus single-lens reflex camera. As shown in the figure, the camera body 1 has a substantially rectangular parallelepiped shape with a thin depth similar to a well-known single-lens reflex camera, and has a pentaprism installed in the center of its upper end. A warship section 2 with a finder section (both not shown) is protruded from the blue side, and on both sides there are a release button 3 and an AF (autofocus) mode switch necessary for taking photographs. A display panel 5 is provided to display various operation push buttons such as the switch button 4 and their setting conditions. Further, a lens mount section 6 is provided at the center of the front surface of the camera body 1, to which a photographic lens 10 having a structure as shown in FIGS. Although not shown, various mechanical parts required for this type of autofocus single-lens reflex camera are internally installed.

On the other hand, as shown in FIGS. 2 and 3, the photographic lens 10 is mounted at the rear end of the lens mount section 6 (indicated by imaginary lines in FIG. 2) at the center of the front surface of the camera body l. The lens barrel 11 includes a lens barrel 11 to which the portion 11a is engaged and mounted, and within the lens barrel 11, lens systems 12 and 13 of a plurality of groups (front and rear two groups in this embodiment) are arranged in the axial direction. It is arranged so that it can be moved freely. Here, this embodiment shows a case where the front and rear lens systems 4 and 5 described above can be selectively driven by focusing by an automatic focus adjustment mechanism or zooming by an automatic zoom mechanism. The configuration is such that one drive motor 7 disposed within the camera body 2 is also used as a drive source for focusing and zooming. In addition, 8 in the figure is a driving force transmission mechanism including a deceleration mechanism that decelerates the rotation of the drive motor 7 and transmits it to the output shaft 9.
A control circuit (see FIG. 7), a battery (not shown), etc., which drive and control the motor 7 by operating the switches of the automatic focus adjustment mechanism and automatic zoom mechanism described above, are also arranged at appropriate positions within the camera body 1. ing.

Furthermore, to briefly explain the driving mechanism for driving the focusing and zooming of the front and rear lens systems 12 and 13 mentioned above with reference to FIGS. straight forward cam y414a,
A first cam cylinder 14 having a first cam cylinder 14b, and rotating cam grooves 15a and 15b (see Fig. 4) that are rotatably fitted to the outer circumference of the first cam cylinder 14 and inclined in the circumferential direction. A second cam cylinder 15 is installed in the second cam cylinder 15 in a loosely fitted state,
The rear end of the first cam barrel 14 is integrally fixed to the lens barrel 11. And these first
and the cam groove 14a on the front side of the cam cylinder 14.15 of w42,
a helical gear part 1 having an engaging pin 16 that engages in the interior of the lens system 15a and for moving the front lens system 12 back and forth inward;
A sleeve member 17 having a sleeve 7a formed thereon is slidably held on the inner periphery of the distal end portion of the first cam cylinder 14. As shown in FIG.

Further, in the rear cam grooves 14b and 15b, an outer peripheral portion of a lens frame 18 that holds the rear lens system 13 and is slidably supported in the axial direction within the first cam cylinder 14 is provided. A protruding retaining bottle 19 is engaged.

Further, a zoom ring 20 is rotatably fitted on the outer periphery of the rear end side of the lens barrel 11, and an engagement tube having a long groove 21a elongated in the axial direction is formed in a part of the inner periphery of the zoom ring 20. A portion 21 is provided in a protruding manner.

The tip of this engagement cylinder portion 21 is connected to the second cam cylinder 1.
An engaging pin 22 protruding from the second cam cylinder 15 side facing the outer periphery of the zoom ring 20 is engaged in the long groove 21a, and by rotating the zoom ring 20, the second cam The cylinder 15 rotates, and as a result, the rotating cam grooves 15a, 15b
The sleeve member 17 having the engaging pin 16.19 engaged therein and the lens frame 18 holding the rear lens system 13 move forward and backward along the linear cam grooves 14a and 14b on the first cam cylinder 14 side. It is configured to slide in the direction.

It goes without saying that a long groove is formed along the circumferential direction in a portion of the lens barrel 11 that corresponds to the engaging cylinder portion 21 of the zoom ring 20.

On the other hand, the front lens system 12 is a lens frame member formed at the front end side of the lens barrel 11 so as to sandwich the first and second cam barrels 14 and 15 from the front side, with a backward U-shaped cross section. A helical gear portion 24a that engages with the helical gear portion 1'7a of the sleeve member 17 is formed on the outer periphery of the inner cylindrical portion 24 of the bracket. Further, the outer cylindrical portion 25 of the lens frame member 23 has an engaging protrusion 25 protruding from a part of its outer periphery.
a is engaged with a keyway 26a formed in the axial direction on the inner peripheral part of a distance ring 26 which is rotatably held inside the front end of the lens barrel 11, whereby this front lens system The lens frame member 23 holding the lens frame member 12 is configured to rotate integrally as the distance ring 26 rotates, and to move back and forth by the meshing of the helical gear portions 24a and 17a.

As mentioned above, there is a zoom ring 20 that moves the front and rear lens systems 12 and 13 back and forth simultaneously, and a
The distance ring 26 that moves only the camera body 1 back and forth is appropriately switched by the latch mechanism 30 as follows.
It is driven by a motor 7 on the side. That is, inside the lens barrel 11, there is a coupling portion 31 exposed between the output shaft 9 on the motor 7 side and a part of the rear end of the lens barrel 11.
A rotation transmission shaft 32 connected to the rotation transmission shaft 32 is rotatably supported along the axial direction, and the rotation transmission shaft 32 has clutch gears 33a at both ends.

A sleeve 33 having a diameter of 33b is connected in one rotation direction by a keyway or the like and is fitted in such a manner that it can move only in the axial direction. The outer periphery of this sleeve 33 is provided with a zoom lens that is slidable in the axial direction outside the lens barrel 11.
The extending end 34a portion of the AF switching lever 34 is fitted,
A pair of springs 35a and 35b are fitted on both sides thereof. Therefore, when the switching lever 34 is slid, the spring 35a in the operating direction.

35b is compressed, and its elastic force presses the clutch gears 33a, 33b of the sleeve 33 to move them in a desired switching direction.

Further, the sleeve 33 is connected to a part of the inner circumference of the zoom ring 20 through a long groove formed in the lens barrel 11.
A gear portion 36 is provided to selectively engage one clutch gear 33a. On the other hand, the rotation transmission shaft 3
2, a rotation transmission shaft 37 for focusing is connected to the lens barrel 11 (in this embodiment, the first cam barrel 1, which is the fixed side)
4), and a gear 37b is provided at the rear end thereof facing with an interval larger than the length of the gear portion 36 and sleeve 33 on the zoom ring 20 side. 37b is configured to selectively mesh with the other clutch gear 33b of the sleeve 33. Further, a gear 37a is provided at the front end of the rotation transmission shaft 37 and meshes with a gear portion 38 formed at the rear end of the distance ring 26 rotatably supported on the front end side of the lens barrel 11. , so that rotation can be transmitted to the distance ring 26. Note that a portion 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, by switching the switching lever 34, the clutch gears 33a at both ends of the sleeve 33,
33b is connected to the gear section 36 of the zoom ring 20 or the gear section 38. By selectively meshing with one of the gears 37b of the rotation transmission shaft 37 connected via the gear 37a, the zoom ring 20 or the distance ring 26 is rotationally driven, thereby enabling zooming drive or focusing drive. It is. That is, during zooming, the rotation of the zoom ring 20 causes the second cam barrel 15 to rotate, and the front and rear lens systems 12, 13
is the rotating cam groove 15a.

The distance ring 26 is moved back and forth according to the movement ratio determined by the distance ring 26b.
The lens frame member 23, which rotates integrally with the front lens system, is helically coupled to the sleeve member 17, which is relatively stationary, so that only the front lens system 12 can be moved back and forth while rotating. Of course, by switching the switching lever 34, a switching switch (not shown) is created.
The configuration is such that a control circuit on the camera body 1 side performs zoom/AF switching.

According to the configuration of this embodiment, focusing drive and zooming drive can be easily and reliably performed with one drive motor 7 by switching the switching lever 34, and the operability is excellent. This has the advantage that the number of mechanical parts built into the main body 1 can be reduced, and the overall size of the camera can be made smaller.

Now, according to the present invention, as described above, the drive motor 7 provided in the camera body l is connected to the distance sensor (not shown) (the seventh
The control circuit (see figure)
(consisting of a central processing unit 1cPU and a lens drive circuit, etc.) moves the lens systems 12 and 13 (in this embodiment, only the front lens system 12) in the lens barrel 11 and automatically performs focusing. In a focus adjustment device using an automatic focus adjustment mechanism, the focus adjustment device is connected to the drive motor 7 that performs focusing by switching the device from automatic mode to manual mode when distance measurement of a subject is impossible due to lack of contrast or the like. manual (
A feature is that a manually operated focus adjustment switch 40 is exposed and provided on the outside of the camera body l (on the back side of the release button 3 on the side of the upper end thereof).

Here, the above-mentioned manually operated focus adjustment switch 40 is exemplified as having a push button structure that can be suppressed in two directions (the focal length changes to a longer direction or a shorter direction). However, it is not limited to this,
For example, it is easy to understand that it may have a slide lever structure, or it may have a two-stage structure that allows fine adjustment and coarse adjustment.

Further, as the means for switching from the automatic mode to the manual mode described above, it is preferable to use, for example, an AF mode changeover switch button 4 provided at the upper end of the camera body l and operated to suppress the operation. It may be configured such that the pressing operation is performed by confirming the distance measurement failure state displayed on the display panel 5 or a display section in the finder section (not shown), etc.; however, the present invention is not limited to this, and Does the central processing switch to manual mode occur when the distance measurement is unbalanced? A configuration may be adopted in which automatic switching is performed using cficPtJ or the like, and in this case as well, the necessity thereof may be displayed on the display panel 5, a display section in the viewfinder section, or the like. In addition, the AF/MF mode switching display (displayed by lighting) on the display panel 5 mentioned above, its focal length setting value, and a mark (indicated by a dotted circle in the figure) indicating that distance measurement is not possible are displayed. The state is illustrated in FIG.

According to such a configuration, when automatic focusing cannot be performed and distance measurement is not possible, the photographer manually operates the focus adjustment switch 40 provided on the upper end of the camera body 1, and the drive motor is activated. By moving the lens system 12 within the lens barrel 11 to a desired state using the arrow 7, focusing can be easily and quickly performed manually. Then, as is clear from the flowchart shown in FIG. 6, by displaying the focused state by this manual operation on the display panel 5, the display section in the finder section, etc. in the same manner as described above,
If the photographer presses the release button 3, an appropriate photograph can be taken. Therefore, according to the configuration of the present invention, even when automatic focusing cannot be performed, the display of this state is sensed and the automatic mode is switched to the manual mode, In addition, by manually operating the focus adjustment switch 40 exposed on the outside of the camera body l to the desired state, focus adjustment can be easily and easily made by skillfully utilizing the drive motor 7 that performs focusing by autofocus. It can definitely be done.

To take a picture when distance measurement is possible and the focus can be adjusted using autofocus, the photographer must perform the release operation (first step) and the central processing unit, as shown in Figures 6 and 7. Distance measurement is performed by calculating the output signal from the distance sensor that is input together with the film sensitivity and various lens information in the ACPU, and the lens drive circuit drives the drive motor 7 accordingly, and the lens system 12 It is well known and easily understood that a photograph is taken by moving to a required position and performing a release operation (second step) in this state.

Note that the present invention is not limited to the structure of the embodiment described above, and the shape, structure, etc. of each part may be modified and changed as appropriate. For example, the shape and structure of each part of the camera body 1, the number of groups of the lens system disposed in the lens barrel 11 of the photographic lens 10, etc.
The number of sheets, as well as the driving conditions during focusing and zooming.

Furthermore, the clutch mechanism 30 and the like for switching between the focusing drive mechanism and the zooming drive mechanism are not limited to the above-mentioned embodiments, and can be selected as appropriate, and the respective drive mechanisms can be changed accordingly. All you have to do is do it.

Further, the manually operated focus adjustment switch 40, which characterizes the present invention, may be provided at a location outside the camera body l where it can be easily operated, and various modifications are possible. Furthermore, it is easily understood that the release button 3 may be set in the non-suppressable state as a means for notifying the photographer of the state in which distance measurement is not possible.

In addition, in the embodiment described above, 1 manually operated switch 4
0 is used only for adjusting the focus jl, but for example, if the photographing lens lO is configured to perform autofocus and zooming as in the above-mentioned embodiment, and the same drive motor 7 selectively switches the It will be readily understood that when configured to be driven, this manually operated switch 40 may also be configured to perform zooming using an automatic zoom mechanism.

〔Effect of the invention〕

As explained above, according to the focus adjustment device for an autofocus single-lens reflex camera according to the present invention, when it is impossible to measure the distance to the subject and automatic focusing cannot be performed, the automatic mode is switched to the manual mode. A focus adjustment switch for manual operation is connected to a drive motor for driving the photographing lens system in the lens barrel and automatically focusing the lens system by means of a switching means, and the drive motor is provided with a focus adjustment switch for manual operation. Although the structure is simple and inexpensive, manual focus adjustment is not possible with conventional distance measuring rings, which tend to require heavy operating force. This method is extremely easy, appropriate, and quick compared to using a camera, and is superior in terms of operability and quick-shooting performance.Furthermore, there is no exposure of the distance measuring ring on the outer periphery of the lens barrel, making it easier to use the camera during shooting. It has various excellent effects such as being able to maintain a stable hold state.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of the camera body seen from the front, showing an embodiment of the focus adjustment vtllF in an autofocus single-lens reflex camera according to the present invention, and FIG. 2 is a schematic perspective view of the entire photographic lens attached to the camera body. A schematic side sectional view, Fig. 3 is a schematic perspective view showing its external appearance, Fig. 4 is an exploded view of the rotating cam ring that drives each lens system during zooming and focusing, and Fig. 5 shows the 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 diagram showing the configuration of the device. l...Camera body, 311・φ・Release button, 4・
φ...AF mode changeover switch button, 5...Display panel, 6...Lens mount section, 7...Drive motor, 9...Output shaft, 10...Fist/Photographing lens, 1
1φφ...Lens barrel, 12.13...Front and rear two group lens systems, 14.15...First and second cam cylinders, 14a, 14b...Linear cam grooves, 15a, 15
b... Rotating cam groove, 18.19... Engaging pin,
17...Sleeve, 17a-0/helical gear part,
18... Lens frame, 20... Zoom ring, 2
4... Lens frame member, 24a11... Helical gear part, 26... Distance ring, 30... Clutch mechanism, 31 ◆... Coupling part, 40... Manual (manual) Switch for focus adjustment by operation.

Claims (1)

[Claims] An autofocus single-lens reflex camera equipped with a focus adjustment device that moves the photographic lens system inside the lens barrel and automatically adjusts the focus by driving the drive motor installed inside the camera body according to the distance measurement information of the subject. In the camera, a manually operated focus adjustment switch connected to the drive motor by a switching means for switching from automatic mode to manual mode when distance measurement of the object is impossible is provided on the outside of the camera body. A focus adjustment device for an autofocus single-lens reflex camera, characterized by: