JPS59216132A - Previewing device of single-lens reflex camera - Google Patents

Abstract

PURPOSE:To prevent an error in aperture setting in previewing operation and to prevent the manual application of unreasonable force by releasing an automatic stopping-down member even through a manual stopping-down member. CONSTITUTION:A magnet MgR operates instantaneously in response to shutter release operation, an attracting piece A1 is separated to unlock a preset lever L from a lock lever 9, and a lever U rotates with the elastic force of a spring 19 to perform stopping-down operation to a set aperture value. On the other hand, when a preview button 1 for manual stopping-down operation, a preview interlocking plate 3 moves to close a switch Swp with the slanting part 3b of the interlocking plate 3, and the magnet MgR operates to perform stop-down releasing, stopping down the lens through the same operation with automatic stoppingdown mode. This constitution prevents an error in aperture setting in preview mode and also prevents the manual application of unreasonable force to a stopping-down mechanism.

Description

[Detailed description of the invention] B. Field of invention The present invention relates to a camera equipped with a preview device.

BACKGROUND OF THE INVENTION A preview device is used in a single-lens 7-lens camera to narrow down the aperture of the photographic lens to the aperture value at which exposure is actually performed, and to check the effect of the depth of focus in the viewfinder. This is the equipment provided.

In other words, in a camera that has aperture priority and automatic shutter speed control modes, the aperture value is set in advance, the subject brightness is measured with the aperture open, and the shutter speed at the preset aperture value is calculated. The aperture is narrowed down to a predetermined aperture value by the release operation, and the exposure time is controlled based on the previously calculated shutter speed data. With such a configuration, the photographing lens aperture is open before the shutter release operation, and the fine lens aperture is in the open state.
Inside, you can only see the subject image when the aperture is wide open. In such a case, the preview device is a device that allows the user to confirm the subject image with the aperture narrowed down to a predetermined aperture value within 7 isogoos before operating the shutter release. However, such a preview device can be used not only for a series of aperture priority modes, but also for shutter speed priority shooting operation modes or program shutter operation modes, up to the automatically controlled aperture value. For example, a camera in which the field of view within the finder can be observed by narrowing down the aperture has been proposed in Japanese Patent Laid-Open No. 5O-62fJ28.

FIG. 1 shows the previously proposed preview device.

In this figure, R denotes an aperture drive ring located inside the photographic lens barrel, and the aperture is narrowed down by rotating counterclockwise in the figure. P is a pin placed on the same ring. In the figure, the mechanical parts other than R and P are on the side of the camera body, and L rotates to the right around axis X according to the aperture value automatically controlled by the aperture preset lever. 1
The pin P is in contact with the lever L, and as the lever L moves to the right, the aperture drive ring R rotates and the aperture is narrowed down to a predetermined aperture value. First, the operation of this apparatus during exposure will be described. When the shutter button B is pressed, the lever 11 and the three-pronged lever 12 are disengaged, and the three-pronged lever 12 is rotated counterclockwise about the axis X by the tension of the spring Sp. Three-pronged lever 12 and lever I! 3 is engaged with pin pl, and lever l! 3 and the aperture preset lever L are engaged by pin p2, and the three-pronged lever L! 2 and lever l! The three parts of the 3-tooth aperture preset lever L rotate integrally in the counterclockwise direction to narrow down the aperture. At this time, a gear G is protruded from the lever 13, and a pinion Z meshing with the gear G is rotated at an increased speed, and this rotational resistance is used to brake the aperture to an appropriate speed. . As the aperture is progressing, the light transmitted through a certain photographic lens is photometered, and when the amount of light reaches the proper exposure at the preset shutter speed, an aperture stop signal is output, the magnet l-M is activated, and the pinion 2 A stop claw F engages with the mold wheel W integrated with the mold wheel W, and the narrowing down is stopped. There is some time delay between when the aperture stop signal is actually output and when the aperture stops, so when compensating for this delay, the aperture stop signal must have no delay. It is now output earlier than when it was created. The time for compensating for this delay will be referred to as the pre-trigger amount. This pre-trigger amount is an important amount as the motivation for the present invention.

Next, the preview operation of the apparatus shown in FIG. 1 will be described. Since the preview is performed before the shutter release is operated, the mechanism is in the state shown in FIG. In this state, when the preview button V is manually pushed to the left, the lever l! 3 is rotated counterclockwise, and in conjunction with this, the aperture preset lever L is driven counterclockwise to perform aperture. To stop the diaphragm, the magnet (M) is activated to lock the model wheel W in the same manner as in the above-mentioned photographic exposure. In this case, the rotation of the lever 13 is braked by the gear G and the pinion 2, but since the button ■ is pressed manually, the force that drives the lever 13 depends on the person and the force of the spring Sp. Unlike tension, it varies. For this reason, the pre-trigger amount mentioned above must vary depending on the situation, but in reality the pre-trigger amount is fixed in the control circuit, so in the case of previewing, the narrowed down aperture value is The aperture value will have an error compared to the correct aperture value. In addition, since the levers 1 and 3 are manually driven, when the push force of the button V is too strong and the pawl F locks on the mold wheel W, a very strong force may be applied between the two, or the mold wheel may If you try to force the button V even after it has stopped, a strong force will be applied between the mold wheel and the pawl, and the mechanism may be damaged.

C. Purpose The present invention attempts to solve the above-mentioned problems in the previously proposed preview devices.

D. Structure The present invention is characterized in that the aperture adjustment device used during photographic exposure is also used during the preview operation, and the operation for performing the preview is simply to start the aperture adjustment device. have By doing this, the pre-trigger amount can be exactly the same both during preview and shooting exposure, and there will be no error in aperture setting during preview, and no unreasonable manual force will be applied to the mechanism. .

E. Embodiment FIG. 2 shows an embodiment of the present invention. R is the aperture drive ring, L is the preset lever, and P is the pin set on the ring R. The aperture drive ring R is given a clockwise rotational habit by a spring, and the preset lever L rotates clockwise around the axis X, so that the tip moves to the left, and the pin P moves to the left of the lever L. The aperture narrows down as you move toward the camera.

First, the structure of the apparatus will be explained, focusing on the operation when performing photographic exposure. A clockwise rotational behavior is given by the preset lever load spring 9, and the upright portion La engages with the locking lever 9 and is initially locked at the position shown in the figure. Magnet M? R is instantaneously activated and releases the suction piece A1 that was initially attracted to M'/R. The suction piece A1 is held by a preset release lever 15 that can rotate around the shaft 8, and the lever is given a counterclockwise rotational habit by a spring 17, so that the suction piece A1 is attached to the magnet MA.
When released from R, the lever 15 rotates counterclockwise, and the locking lever 9, which is coaxial with the lever 15, is pushed by the pin 15a. Therefore, the engagement between the locking lever 9 and the preset lever L is disengaged, and the preset lever is rotated clockwise by the tension of the spring 19 as described above, and the pin P follows this movement, thereby narrowing the aperture. . A sector gear G is pivotally mounted concentrically with the preset lever L, and the upright portion Ga of the gear engages with the lever L, and is pushed in the same direction by clockwise rotation of the lever L. . This sector gear G and pinion 7 mesh,
By rotating the pinion 2 at an increased speed, braking is applied to the rotation of the lever L so that the aperture narrowing speed becomes an appropriate value. A wind turbine W is provided integrally with the pinion 2, and the teeth of the same type wheel are reflective photocoupler Pct.
The rotation angle of the lever L is thus detected, and the rotation angle of the lever L is detected by counting the detection pulses of the teeth caused by the rotation of the windmill W by a counter, thereby detecting the amount of reduction of the aperture from the open aperture. an aperture value calculated from the photometric value at the maximum aperture of the photographing lens and a preset shutter speed or a program in the case of program shutter operation;
Or, in the case of aperture priority mode, when the preset aperture value matches the aperture value determined from the aperture reduction amount detected from the count on the counter, a stop signal is issued and the magnetic MPF is activated. The stop claw F engages with the heavy weight W, stopping the aperture from narrowing down, thereby setting the aperture to a predetermined value. In fact, as mentioned above, the stop signal is output earlier by a predetermined pre-trigger amount. - The sequence of the start of running of the curtain, start of timing operation, start of running of the second shutter curtain, and exposure operation progresses.

Next, the preview operation will be described. When the preview button (2) is pushed in the direction of the arrow, the preview moving plate 3 is pushed to the right in the figure. The preview linkage plate 3 has a long hole 3ai fitted with a guide pin 5, and the left and right arms act to return the mechanism to its original state after previewing. When the preview interlocking plate 3 is pushed rightward to the middle of the stroke regulated by the guide groove 3a, the right end inclined portion 3b of the interlocking plate hits the switch Swp and the switch is closed.

When this switch is closed, the magnet MPR is activated, and the various parts operate in exactly the same manner as in the photographic exposure described above, and the aperture is narrowed down to a predetermined aperture value. In this case, the mechanisms operating are the aperture adjustment mechanism and the control circuit during photographic exposure, and the pre-trigger amount is the same in either case, and the aperture adjustment is made without error even during preview.

Finally, the return operation of the mechanism after the aperture adjustment will be described. In FIG. 3, the positions of the preset lever L and the lever 29 shown by solid lines show the states after return, and the positions of the levers L and 29 shown by dotted lines show the states at the time of aperture adjustment.

When the preset interlocking plate 3 is pushed to the position indicated by the two-dot chain line in FIG. 3, the switch Swp is closed and narrowing down starts. When the preset interlocking plate is pushed to the right by the full length of the elongated hole 3a shown in FIG. 2 in FIG. , the protruding arm 3d pushes the lever 42 and rotates it one turn counterclockwise, and the same lever pushes the pin 15b set on the lever 15 to the left and moves the suction piece A1 held by the lever 15 to the magnet M51'. Press and hold on H.

Magnets) MPR is a coil wound around an iron core containing a permanent magnet, and it attracts one adsorption piece AI to the iron core in a non-energized state.
A current sufficient to cancel the magnetic flux of the permanent magnet is applied to the coil i.
This instantaneous flow releases the suction piece. In this case, the protruding arm 3d of the preset interlocking plate 3 causes the suction piece to be suctioned and held on the core of the magnet M9H. Also arm 3C
The lever 29 is pushed L1 so that the suction piece A2 held by the lever is suctioned and held on the iron core of the magnet MPF. Now, when you release the preview button 1, the preview series movement plate 3
is returned to the left by the action of the spring 7, and the entire device is returned to the state shown in solid lines in FIG. The mechanism returns after the exposure operation as follows. In FIG. 2, the engagement between the locking lever 33 and the reset lever 31 is disengaged, and the set lever is 31 rotates counterclockwise around axis X under the action of spring 32, and 1 preset lever L'
It is pushed counterclockwise by the il-pin 31a to return to its original position. Following the return of the preset lever L, the sector gear G also returns due to the action of the spring 23. The reset lever 31 itself is returned to its original position by a mechanism (not shown) in conjunction with the winding of the film. In addition, an unillustrated mechanism that is linked to the operation of the photographing mechanism after the completion of the exposure operation, such as the completion of the second curtain run, returns the end of the preset release lever and the lever 29 to their original positions, and attaches the adsorption pieces AL A2 to the respective magnets MP.
It is adsorbed and held by R and M y F.

FIG. 4 shows another embodiment of the invention. In the above-mentioned embodiment, the shutter release is performed electrically by the magnet M5'H, but in this embodiment, the shutter release is performed purely mechanically. "- Only the parts that are different from the above-mentioned embodiment are illustrated except for the parts that are common to the above embodiment. In the case of preview, when the preview button 1 is pressed and the preview movement plate 3 is displaced to the right, the screen held by the same plate is shown. The release pin 105 pushes the L-shaped bent end of the preset release lever 15 and rotates it counterclockwise to engage the upright portion La of the preset lever L with the locking end of the preset release lever 15. When the aperture is released, the preset lever L is released and the aperture starts to stop.The operation in which the aperture stops at a predetermined aperture value is the same as in the above embodiment.The mechanism returns from the preview operation as follows. The release pin 105 is slidably fitted into a long hole 3f that extends in one direction perpendicular to the moving direction i of the preview moving plate 3, and the plate spring 32 engages the long hole 3f.
is pushed towards the outer edge of the When the preview link moving plate 3 is pushed to the right end of the movable range regulated by the guide groove 3a, the part 3e pushes the preset lever L back to its original position, and the pin 105 rebels against the spring 3y and moves into the elongated hole 3f. Slide the lever, escape the end of the preset lever 15, and pass through to the right side of the same end. Therefore, the entire preset lever becomes free and engages with the clockwise rotation LLa under the action of the spring 11. After that, when the button 1 is released, the interlocking plate 3 returns to the left by the action of the spring 7, but at this time, the pin 105 also slides inside the elongated hole 3f, escapes the end of the lever 15, and passes through to the left side of the same end. . To release the shutter, when a shutter release button (not shown) is pressed, the release shaft 111 is pressed down, and the preset release lever 15 is pushed by the slope of the conical lower end of the shaft 111 and rotated counterclockwise. The preset release lever 15' is coaxial with the preset release lever 15, and has a single pin 15c, and when the preset release lever is pushed by this pin and rotated counterclockwise, the preset lever is activated. L is disengaged from the preset release lever 15, and the aperture is narrowed down.

FIG. 5 is a block diagram of the electric circuit in the embodiment shown in FIG. 203), the above 5p is connected to both input terminals.
C (zot) is connected, and its output terminal outputs an analog signal corresponding to the subject brightness via a constant current source (205) and a bias caused by a film sensitivity resistor (207). The analog signal is converted to AD by the AD conversion circuit (209), and the open photometry is applied to BV+5V-A.
V.

The data is sent to the adding circuit (213) via the data line to generate data AVo corresponding to the open value of the attached lens.
B is transmitted from the AD conversion circuit (209) in this circuit.
The data of V+5V-AVo and the data of AVo from the open l value generation circuit (211) are added to generate data of BV+5V=EV.The EV data is sent to two subtraction circuits (described later) via the data line.
241, 243).

During this time, the cent of the captured aperture value AVs is performed. Noah/7'
-) 1 (223) is further connected to the input terminal of the inverter (22
2), and as long as the preview signal T is input, the NOR gate 1 (223) is kept closed and the aperture value Avs cannot be set.

The shutter speed set value generation circuit (223) is a circuit for manually setting the shutter speed value TvS.
While the pulses of the above-mentioned pulse generator are being output, the shutter speed value Tv is taken in through the NOR gate 2 (229).
Set s. The EV value data from the addition circuit (213) and the shutter speed set value data Tvs from the shutter speed set value generation circuit (233) are input to the subtraction circuit (241) through the data line, and the EV-TVS
is subtracted, and data of the appropriate aperture value Avc is output.

Similar to the above, the EV value data from the addition circuit (213) and the aperture value data Avs from the cent value generation circuit (227) are input to the subtraction circuit (243), and EV-AVS is subtracted to obtain appropriate shutter speed data. Output Tvc.

Set value data Avs and appropriate aperture value data Avc are input to the selector circuit (245), and shutter speed set value data Tvs is input to the selector circuit (247).
This circuit receives data TvC of the appropriate shutter speed value and selects the data according to the exposure control mode of the camera. Exposure control mode selection switch (24
When 9) is closed, a pair of data a from the input data is selected and the camera is set to automatic aperture-priority control, and when the same switch (249) is opened, data b is selected and the camera is set to automatic shutter-speed control with priority. Set. The aperture value data selected by the selector circuit (245) is AV
It is transmitted to the register (253).

The data contents of the AV register (253) are transmitted to the aperture display section (255) and the aperture control section (25) via the data line.
7), and the aperture value is displayed on the display section (25B). Further, to the aperture display section (255)
It is connected so that the Q output of the 0 tube C259) is input, and the 17 lip 70 amplifier (259) is connected to the clock pulse input terminal (cp), and is configured to turn off when the lens is attached to the camera body. attached lens attachment switch (
SW-LENS) is connected, and when the lens is removed from the camera body, a clock pulse is input, the Q output is lowered to a low level, and the aperture display is turned off.

The shutter speed second selection circuit (25'l) receives the appropriate shutter speed value Tvc or shutter speed TV set value Tv selected by the selector circuit (247) as described above.
s is input, as well as the actual measured light value BV+5V-AVo which is AD-converted after photometry. Second
When the preview button (1) in the figure is operated to enter the preview state (1), the switch Swp is closed and an sp multiplied signal is given to the AV register (253) and the second shutter speed selection circuit (251).
), and the second shutter speed selection circuit (251) is configured to select actual measured light value data. At this point, the aperture blades (57) are set to the shooting aperture aperture, so the photometric value data is BV+5V-
It becomes AV, and shutter automatic control data by so-called stop-down photometry is transmitted to the TV register (261). Therefore, if there is no preview operation, the data selected by the selector circuit (247) will also be selected by the second shutter speed selection circuit (251).

The data content input to the TV register (261) is displayed on a shutter speed display section (263), and is also output to a shutter speed control section (265) and used for shutter speed control. Aperture system 1allffflH257
) energizes the aperture magnet CM9F) to stop the aperture when the above-mentioned AV value data and model car W are related. In addition, the shutter speed control section (265) controls the TV register (
It is assumed that a circuit that compares the shutter speed value data from 261) and the strength of the clopa pulse has a predetermined relationship between the two.

Effects According to the present invention, as described above, the mechanism for stopping down the aperture to a predetermined aperture value is the same for previewing and photographing exposure, and the only difference is that the means for releasing this mechanism is different. Therefore, the pre-trigger amount is naturally the same in both cases, and there is no error in the aperture adjustment during the follow-up review.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a conventional example, Fig. 2 is a perspective view of an embodiment of the present invention, Fig. 3 is a plan view illustrating the return operation of the above device, and Fig. 4 is another embodiment of the present invention. FIG. 5 is a block diagram of the turn/tread section in the embodiment of FIG. 2. R...Aperture drive ring, P =...Aperture pin, L
...Preset lever, G...Sector gear, 2...
Pinion, W...type car, ■...preview button,
3...Preview series movement plate, 15...Preset release lever-1F...Claw for stopping model car W, MyR, M
yF...Magnet.

Claims (1)

[Scope of Claims] (1) A camera equipped with an automatic aperture adjustment device that is released by shutter release operation and narrows down the aperture to a predetermined aperture value, which also includes a manual aperture adjustment member and can also be adjusted by operating the same member. A preview device for a single-lens reflex camera, characterized in that the automatic aperture adjustment device is arranged to be released. 2. An aperture preset member that is unlocked by operation of a shutter release operating member and moves to narrow down the aperture, and a blocking means that prevents movement of the aperture preset member at a position corresponding to a predetermined aperture value. In a 7-rex camera equipped with an automatic aperture adjustment device having an automatic aperture adjustment device, the aperture preset member is unlocked by operating a manual aperture member, and its movement is prevented by the blocking means to perform a preview. , a preview device which removes the aperture preset member from a preview state;