JPH0610706B2 - Single lens reflex camera preview device - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a camera provided with a preview device.

(B) Background of the Invention The preview device is a single-lens reflex camera for confirming the effect of the depth of focus in the field of view within the finder by narrowing down the aperture of the taking lens to the aperture value at which the actual exposure is performed. Is a device provided in.
That is, in a camera having an operation mode of aperture priority and automatic shutter speed control, 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 terminating operation is performed to narrow down the aperture value to the planned aperture value, and the exposure time is controlled based on the previously calculated shutter speed data. With such a configuration, the photographic lens aperture is in the open state before the shutter release operation, and only the subject image at the open aperture can be seen in the finder. In such a case, the preview device is a device for enabling the subject image in a state in which the aperture value is narrowed down to the predetermined aperture value before the shutter release operation to be confirmed in the finder. By the way, such a pre-view device preliminarily narrows down to the automatically controlled aperture value not only in the aperture priority mode as described above but also in the shooting speed priority shooting mode or the program shutter operation mode. A camera capable of observing the field of view inside the finder is proposed in, for example, Japanese Patent Laid-Open No. 62028/50.

FIG. 1 shows the previously proposed preview device. In this figure, R is a diaphragm drive ring located in the lens barrel of the taking lens, and the diaphragm is narrowed by rotating counterclockwise in the figure. P is a pin set up on the ring. In the figure, there are mechanical parts other than R and P on the camera body side, and L is pivotally moved to the right around the axis X according to the aperture value automatically controlled by the aperture preset lever. Pin P on the lever
Are in contact with each other, and follow the movement of the lever L to the right, and the diaphragm drive ring R rotates and the diaphragm can be narrowed down to a predetermined diaphragm value. First, the operation of this apparatus during exposure will be described.
When the shutter button B is pushed, the engagement between the lever 11 and the three-pronged lever 12 is disengaged, and the three-pronged lever 12 pivots about the shaft center X in the counterclockwise direction by the tension of the spring Sp. The three-pronged lever 12 and the lever 13 are engaged by the pin p1,
The lever l3 and the aperture presetting lever L are engaged with each other by the pin p2, and the three-piece lever l2, the lever l3 and the aperture presetting lever L rotate integrally in the counterclockwise direction to narrow down the aperture. . At this time, a gear G protrudes from the lever 13 and the pinion g meshing with the gear G is rotated at an increased speed, and braking is applied by this rotation resistance so that the throttle speed of the diaphragm becomes appropriate. ing. The light that has passed through the photographic lens is being metered, and when the amount of light reaches the proper exposure at the preset shutter speed, the diaphragm stop signal is output and the magnet M is activated to activate the pinion g. The stop claw F of the integrated ratchet wheel W is engaged, and the narrowing is stopped. Since there is a certain time delay between when the stop signal is actually output and when the stop is stopped, there is no delay in the stop signal for the time to compensate for this delay. It is supposed to be output earlier than. The time for this delay compensation will be called the pre-trigger amount. This pre-trigger amount is an important amount as a motive of the present invention.

Next, the pre-view operation of the apparatus shown in FIG. 1 will be described. Since the preview is performed before the shutter release operation, the mechanism is in the state shown in FIG. When the preview button V is manually pushed to the left in this state, the lever l3 is rotated counterclockwise independently of the three-pronged lever l2, and along with this, the aperture preset lever L is driven counterclockwise. It is narrowed down. The stop of the narrowing down is performed in the same manner as in the above-described photographing exposure, and the magnet M is operated to lock the ratchet wheel W. In this case, the rotation of the lever 13 is braking by the gear G and the pinion g. However, since the button V is manually pushed, the force for driving the lever 13 by a person may be a spring. It is also different, unlike the tension of Sp. For this reason, the above-mentioned pre-trigger amount must be different depending on the case, but in reality, the pre-trigger amount is fixed in the control circuit. It has an error with respect to the correct aperture value. Also, since the manual lever 13 is driven, the button V
When the force of pushing is too strong and the claw F is locked to the ratchet wheel W, a very strong force acts between them, or the button V is forcibly pushed even after the ratchet wheel is stopped. A strong force acts between the ratchet wheel and the claw, which may damage the mechanism.

(C) Object The present invention is intended to solve the above-mentioned problems in the proposed preview device.

D. Configuration The present invention utilizes the aperture adjustment device during photographing exposure as it is during the preview operation. The aperture value is calculated on the camera body side, and the aperture value is calculated based on the start signal on the camera body side. A pre-view device applied to a camera equipped with an automatic aperture adjustment mechanism in which a lens aperture device is narrowed down by a corresponding amount, having a starting means for activating a manual aperture operation, and for activating the activation means. In particular, it is characterized in that the automatic diaphragm adjusting mechanism operates. By doing so, the pre-trigger amount can be exactly the same during pre-view and during shooting exposure, and no error occurs in aperture setting during pre-view, and no manual force is applied to the mechanism.

E, Embodiment FIG. 2 shows an embodiment of the present invention. R is an aperture driving ring, L is a preset lever, and P is a pin which is erected on the ring R. The iris driving ring R is given a habit of clockwise rotation by a spring, and the preset lever L has an axis X.
The center of the pin rotates clockwise to move the tip to the left, and the pin P follows the movement of the lever L to the left, and the aperture is narrowed.

First, the structure of the apparatus will be described, focusing on the operation when performing photographing exposure. The preset lever L is given a habit of clockwise rotation by a spring 19, and the upright portion La is engaged with the locking lever 9 and locked at the position shown in the figure.
First, the magnet Mg is released by the shutter release operation.
R is momentarily activated to release the adsorbing piece A1 that was initially adsorbed on MgR. The suction piece A1 is held by a presets release lever 15 which can be rotated around the shaft 8, and the lever 17 is given a turning tendency in the counterclockwise direction by a spring 17, so that the suction piece A1 is Magnet Mg
When released from R, the lever 15 rotates counterclockwise, and the locking lever 9 that is concentric with the lever 15 is pushed by the pin 15a. For this reason, the engagement between the locking lever 9 and the preset lever L is released, the preset lever is rotated clockwise by the tension of the spring 19 as described above, and the pin P follows this and is narrowed down.
A fan gear G is pivotally mounted coaxially with the preset lever L, and a rising portion Ga of the gear is engaged with the lever L, and the lever L is rotated in the clockwise direction to be pushed in the same direction. Be moved. The fan-shaped gear G and the pinion g mesh with each other, and the pinion g is rotated at an increased speed, whereby braking is applied to the rotation of the lever L so that the throttle speed of the diaphragm becomes an appropriate value. The ratchet wheel W is provided integrally with the pinion g, the teeth of the ratchet wheel are detected by the reflection type photocoupler PC, and the detection pulse of the tooth due to the rotation of the ratchet wheel W is counted by the counter. , The rotation angle of the lever L, and accordingly the amount of narrowing of the aperture from the open aperture is detected. Aperture value calculated by the measurement value at the open aperture of the taking lens and preset shutter speed or program in case of program shutter operation, or preset aperture in case of aperture priority mode When the value and the aperture value obtained from the aperture reduction amount detected from the count of the counter coincide with each other, a stop signal is issued, the magnet MgF is operated, and the stop claw F is engaged with the ratchet wheel W, By stopping the narrowing of the diaphragm, the diaphragm is set to a predetermined value. In this case, actually, as described above, the stop signal is output earlier by the predetermined pre-trigger amount. When the aperture adjustment is completed as described above, the sequence of raising the single-lens reflex mirror, starting the movement of the first shutter shutter, starting the timing operation, starting the movement of the second shutter shutter, and the exposure operation proceeds.

Next, the preview operation will be described. When 1 is a preview button and is pushed in the direction of the arrow, the preview interlocking plate 3 is pushed to the right in the figure. The pre-view interlocking plate 3 has a long hole 3a in which a guide pin 5 is fitted and is guided in the left-right direction, and has two protruding arms 3d and 3e in an F shape and an arm 3c on which a spring 7 is applied.
These arms have the function of returning the mechanism to the original state after performing preview. Preview link board 3
Is pushed rightward up to the middle of the stroke regulated by the guide groove 3a, the right end inclined portion 3b of the interlocking plate is switched to the switch Sw.
Upon hitting p, the switch is closed. When the switch is closed, the magnet MgR is operated, and each part is operated in exactly the same manner as in the above-described photographing exposure, and the aperture is stopped down to a predetermined aperture value. In this case, the mechanism that operates is a diaphragm adjusting mechanism and a control circuit at the time of exposure for photographing, so that the pre-trigger amount is the same in both cases, and diaphragm adjustment is performed without error even in the preview.

Finally, the return operation of the mechanism after the aperture adjustment has been performed will be described. The positions of the preset lever L and the lever 29 shown by the solid lines in FIG. 3 show the state after returning, and the positions of the two levers L and 29 shown by the chain double-dashed line show the state during aperture adjustment. In FIG. 3, when the preset interlocking plate 3 is pushed to the position of the chain double-dashed line, the switch Swp is closed and the narrowing is started. In FIG. 3, when the preset interlocking plate is pushed rightward to the full length of the long hole 3a shown in FIG. 2, the preset lever L is pushed by the projecting arm 3e and the third
Returning to the original position shown by the solid line in the figure, the protruding arm 3d pushes the lever 42 to rotate it counterclockwise, and the lever 15 pushes the pin 15b standing on the lever 15 to the left and is held by the lever 15. The adsorption piece A1 is pressed against and held by the magnet MgR. Magnet MgR is a coil wound around an iron core containing a permanent magnet. In a non-energized state, the attracting piece A1 is attracted to the iron core, and a current sufficient to cancel the magnetic flux of the permanent magnet is momentarily applied to the coil. Therefore, the adsorption piece is released.
In this case, the attracting piece is attracted and held by the iron core of the magnet MgR by the action of the protruding arm 3d of the preset interlocking plate 3. Further, the arm 3c pushes the lever 29 so that the attraction piece A2 held by the lever is attracted and held by the iron core of the magnet MgF. When the preview button 1 is released, the preview interlock plate 3 returns to the left by the action of the spring 7, and the entire apparatus returns to the state shown by the solid line in FIG. The mechanism is restored after the exposure operation as follows. In FIG. 2, the engagement between the locking lever 33 and the reset lever 31 is disengaged in association with the operation of the completion of the second curtain of the shutter or the subsequent return of the single-lens reflex mirror. Action causes it to rotate counterclockwise about axis X and move the preset lever L
Is pushed counterclockwise by the pin 31a to return it to its original position. Following the return of the preset lever L, the sector gear G also returns by the action of the spring 23. Reset and lever 3
1 itself is returned by a mechanism (not shown) in conjunction with the winding of the film. A mechanism (not shown) interlocked with the operation of the photographing mechanism after the exposure operation such as the completion of running of the second curtain returns the presets release lever 15 and the lever 29 to their original positions, and the suction pieces A1 and A2 are respectively magnetized to the magnet Mg.
It is adsorbed and held on R and MgF.

FIG. 4 shows another embodiment of the present invention. In the above-mentioned embodiment, the release of the narrowing operation is performed electrically by the magnet MgR, but in this embodiment, the narrowing release is performed purely mechanically. Only the different parts except the parts common to the above-mentioned embodiment are shown. In the case of pre-view, when the pre-view button 1 is pressed to displace the pre-view interlocking plate 3 to the right, the release pin 105 held by the plate pushes the end of the presets release lever 15 bent in an L shape, Is rotated counterclockwise to disengage the rising portion La of the preset lever L and the locking end of the preset release lever 15 and release the preset lever L to start the operation of narrowing the aperture. . The operation of stopping the aperture at the predetermined aperture value is the same as in the above-described embodiment. The return from the pre-view operation of the mechanism is performed as follows. The release pin 105 is slidably fitted in an elongated hole 3f extending in a direction orthogonal to the moving direction of the pre-view interlocking plate 3, and is pushed by a plate spring 3g toward the outer end of the elongated hole 3f. When the pre-view interlocking plate 3 is pushed to the right end of the movable range regulated by the guide groove 3a, the portion 3e pushes the preset lever L back to its original position, and the pin 105 repels the spring 3g to move it within the long hole 3f. Escape the end of the sliding preset lever 15 and pass through to the right of the end. Therefore, the preset lever 15 is free to rotate clockwise by the action of the spring 11 and engages with La. 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 also, the pin 105 slides in the elongated hole 3f to escape the end of the lever 15 and pass through to the left of the end. When the shutter release button (not shown) is pressed to release the shutter, the release shaft 111 is pushed down, and the preset release lever 15 is pushed by the inclined surface of the lower cone of the shaft 111 to rotate counterclockwise. Be punished. The presets release lever 15 'is coaxial with the presets release lever 15, the pin 15c is upright, and the presets release lever 15 is pushed by this pin to rotate in the counterclockwise direction. The engagement between L and the presets release lever 15 is released, and the diaphragm is narrowed down.

FIG. 5 is a block diagram of the electric circuit in the embodiment of FIG. 2 described above. The photovoltaic element (hereinafter referred to as Spc) (201) is provided at a position where the subject light passing through the photographing lens is measured, and an operational amplifier (203) is provided. ) Both input terminals of the Spc (20
1) is connected, and its output terminal is a constant current source (20
An analog signal corresponding to the brightness of the subject is output via the bias of 5) and the film sensitivity resistor (207). The analog signal is AD-converted by the AD conversion circuit (209), and the data of BV + SV-AVo by the light on the open side is transmitted to the addition circuit (213) and the shutter speed second selection circuit (251) through the data line. It The open F value data generation circuit (211) is a circuit for generating data AVo according to the open F value of the mounted lens, and the output data AVo is transmitted to the adder circuit (213), and the AD conversion circuit (209) is generated in the circuit. Data of BV + SV-AVo and the data of AVo from the open F value generation circuit (211) are added to generate data of BV + SV = EV. The EV data is transmitted via the data line to two subtraction circuits (24
1, 243). Aperture set value generation circuit (2
27) is a circuit for manually setting the aperture value.
Via the NOR gate 1 (223), the pulse generator (22
While the set switch (225) is closing the pulse 1), the aperture value AVs is set. An inverter (222) is further provided at the input terminal of NOR gate 1 (223).
A pre-view signal () described later is input via the, and as long as the pre-view signal is input, the NOR gate 1 (223) is kept closed and the setting of the aperture value Avs becomes impossible. The shutter speed set value generation circuit (233) is a circuit for manually setting the shutter speed value Tvs, and is a NOR gate 2 (229) while the shutter speed set switch (231) is closing the pulse of the pulse generator. Capture shutter speed value Tvs is set via. 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 E
V-TVS is subtracted, and the data of the proper aperture value Avc is output. Similarly to the above, the subtraction circuit (243) includes the EV value data from the addition circuit (213) and the set value generation circuit (2).
Aperture value data Avs from 27) is input and EV-A
Data of appropriate shutter speed Tvc is obtained by subtracting VS.
Is output. The set value data Avs and the proper aperture value data Avc are input to the selector circuit (245), and the shutter speed and set value data Tvs and the proper shutter speed value data Tv are input to the selector circuit (247).
This is a circuit for inputting each c and selecting data according to the exposure control mode of the camera. When the exposure control mode switch (249) is closed, a pair of data a is selected from the input data for the aperture priority shutter speed automatic control.
Then, when the switch (249) is opened, the data b is selected and the camera is set to the shutter speed priority diaphragm automatic control. The aperture value data selected by the selector circuit (245) is transmitted to the AV register (253). And A
The data content of the V register (253) is transmitted to the aperture display section (255) and the aperture control section (257) via the data line, and the display section (255) displays the aperture value. The Q-output of the D-flip flop (259) is further connected to the iris display section (255) so that the D-flip flop (259) has a clock pulse input terminal (cp) and a lens attached to the camera body. Lens device switch (S
(W-LENS) is connected, and when the lens is detached from the camera body, a clock pulse is input, the Q output is lowered to a low level, and the aperture display is erased.

In the second shutter speed selection circuit (251), the proper shutter speed value Tvc or the shutter speed TV set value Tvs selected by the selector circuit (247) as described above.
Is input, and the measured light value BV + SV-AVo, which has been AD-converted after photometry, is also input. When the pre-view button (1) shown in FIG. 2 is operated to enter the pre-view state, the switch Swp is closed so that the AV register (253) and the shutter speed second selection circuit (25).
1) is supplied with the sp signal and holds the data in the AV register (253), and the shutter speed second selection circuit (251) selects the measured light value data. At this point, the diaphragm blade (57) is set to the photographic diaphragm aperture, so the photometric value data is BV + SV-AV.
Then, the automatic shutter control data by so-called aperture metering is transmitted to the TV register (261). Therefore, if there is no pre-view operation, the data selected by the selector circuit (247) is the same as the shutter speed second selection circuit (2).
51) will also be selected. TV register (26
The data content entered in 1) is the shutter speed display section (2
63) and is output to the shutter speed control unit (265) and used for the shutter time control. The aperture control unit (257) is a circuit for comparing the above-mentioned AV value data with the output (FP) of the photocoupler (PC) which monitors the rotation of the ratchet wheel W, and when both inputs have a predetermined relation, the aperture magnet (MgF) is urged to stop the narrowing. In addition, the shutter speed control unit (265)
A circuit for comparing the shutter speed value data from the V register (261) with the clock pulse count and when the two have a predetermined relationship, the shutter magnet (Mg-S) is energized to close the shutter and close the desired shutter. Control in seconds.

F. Effect According to the present invention, as described above, the mechanism for narrowing the aperture to a predetermined aperture value is common in both pre-view and shooting exposure, and only means for releasing this mechanism is provided separately. , In both cases, the pre-trigger amount is of course the same, so there is no error in the aperture adjustment during pre-view.

[Brief description 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 for explaining the returning operation of the above apparatus, and FIG. 4 is another embodiment of the present invention. FIG. 5 is a perspective view of the main part of FIG. 5, and FIG. 5 is a block diagram of the circuit part in the embodiment of FIG. R: diaphragm drive ring, P: diaphragm pin, L: preset lever, G: fan gear, g: pinion, W
…… Claw wheel, 1 …… Preview button, 3 …… Preview interlocking plate, 15 …… Presets release lever, F …… Claw wheel W Stopping claw, MgR, MgF …… Magnet.

Continuation of the front page (56) Reference JP-A 52-91426 (JP, A) JP-A 55-46727 (JP, A) JP-A 52-132825 (JP, A) JP-A 50-62028 (JP , A) Actual development Sho 47-36146 (JP, U)

Claims (1)

[Claims] 1. An automatic aperture adjustment mechanism is provided, in which an aperture value is calculated on the camera body side, and based on a start signal on the camera body side, a lens aperture device is narrowed down by an amount corresponding to the aperture value. A preview device applied to a camera, having start-up means for starting a manual aperture operation, the automatic aperture adjustment mechanism is also activated by activation of the start-up means, and an amount of lens corresponding to the aperture value is set. A preview device for a single-lens reflex camera, wherein the narrowing device is configured to narrow down.