JPS5852206B2 - Automatic aperture-setting single-lens flex camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention allows the driving member for unlatching the mirror to be released from the locking state by the shirt release operation and is driven by the driving force, and the aperture preset system is operated by the driving force for stopping the mirror from the interchangeable lens. , relates to an automatic aperture-determining single-lens reflex camera in which the mirror is unlatched and a photographing operation is performed by running the first driving member after an automatic stop by an electromagnet in an aperture control system. .

A single-lens reflex camera with automatic aperture determination as described above was previously proposed by the present applicant in, for example, Japanese Patent Laid-Open No. 5099133.

In this camera, a slow-speed member is arranged in relation to the above-mentioned drive member, and the traveling speed of the mirror is slowed down so that the mirror starts to rise after the aperture is set, no matter what aperture the aperture is set to. has been done.

In such a case, after the aperture preset system is automatically stopped by the electromagnet, only the driving force for that purpose is applied to the driving member, but while the aperture preset system is in motion, the aperture driving force for the interchangeable lens is also applied via it. Since it is applied to the driving member, the traveling speed of the driving member becomes faster.

As a result, for example, depending on whether the aperture presetting system stops moving early or late, in other words, depending on the size of the aperture aperture that should be automatically determined, the actual exposure after the release of the driving member, that is, the camera release and the mirror rises, is determined. There will be a difference in the time it takes to start (hereinafter referred to as body lag).

By the way, if this body lag is set unnecessarily long, it will not be possible to expose at the correct timing when shooting moving objects, so it is desirable to set it as short as possible, but in order to shorten it, the movement speed of the aperture preset system can be adjusted If it is set too fast, the electromagnet in the aperture presetting system automatically stops, or in other words, errors tend to occur in the aperture determination.

Also, in order to shorten the body lag, if the traveling speed of the drive member is made too fast, the aperture preset system will automatically stop when the aperture should be set to the minimum aperture value, that is, the aperture value to be controlled will be reduced. The mirror begins to rise before the decision is made, making it impossible to perform correct automatic aperture control.

As mentioned above, if there is a difference in body lag depending on the aperture value that should be controlled, the photographer will not only have to guess the actual exposure start time when operating the release button, but also have sensory anxiety about the photo opportunity. When a motor is used to continuously photograph several frames per second, there will be a difference in the planned frame speed.

In view of the above-mentioned circumstances, the present invention provides an automatic aperture-determining single-lens camera of the above-mentioned type in which the body lag is as short as possible within the range where automatic aperture control is possible and is constant regardless of the aperture value to be controlled. It was created for the purpose of providing a reflex camera, and was published in
In the above-mentioned configuration of No. Q-99133, a slow speed member is also arranged for the aperture preset system to slow down the movement of the aperture preset system, so that the aperture driving force of the interchangeable lens is substantially transferred to the mirror via the aperture preset system. In addition to not affecting the drive of the drive member for unlocking, the slow speed member placed relative to the drive member should be moved from the position where the aperture preset system corresponds to the open aperture value to the position corresponding to the minimum aperture value. The degree of the slow speed is set so that the drive member always releases the lock of the mirror at a constant timing immediately after the time required for the mirror to move at a slow speed until the end of the time period has elapsed.

To describe the present invention in detail with reference to the drawings, Fig. 1 shows the mechanical configuration of an embodiment in which the present invention is applied to a so-called instantaneous automatic aperture determination type single-lens reflex camera. The interchangeable lens L is attached to the flange 4 of the lens barrel of the mirror box 30 in the camera body.

In the interchangeable lens L, an aperture ring 2 that opens and closes the aperture blades 1 is given a narrowing habit by a spring 2b, as is known in the art.

By aligning the scale 3b of the aperture preset ring 3 with the index 3a, the protrusion 3c rotates to a position corresponding to the preset aperture value, and the rotation of the aperture ring 2 by the spring 2b causes the protrusion 2c to move to the position corresponding to the preset aperture value. When it collides with the protrusion 3c, the aperture is actually set at the preset aperture aperture.

The aperture operating pin 2a protruding from the aperture ring 2 toward the camera body is connected to the aperture preset lever 5 inside the camera body when the interchangeable lens L is attached to the camera.
, and is biased against the spring 2b to maintain the aperture blade 1 in an open state.

When the aperture preset lever 5 operates, the aperture ring 2 follows and rotates to narrow down the aperture.

Therefore, when the aperture is to be automatically controlled as in the present invention, the aperture preset ring 3 is set to the minimum aperture as shown in the figure.

In this embodiment, the diaphragm determining mechanism that determines the operating position of the diaphragm preset lever 5 is disposed at the bottom of the mirror box 30. Slow down the movement of the stop lever I and the aperture preset lever 5,
It consists of a first slow-speed member that ensures the locking of the locking lever I by the ratchet pawl, and a mechanism that increases the rotational displacement of the ratchet pawl with respect to the tip stroke of the aperture preset lever 5.

The aperture preset lever 5 has a fan-shaped gear 5h on the rotating shaft 5a.
A lever 5d is pivotally supported along with the lever 5d and is pivotally supported on a separately provided shaft 5b, an intermediary lever 5c is linked to one end of the lever 5d, and a spring 5f is applied to the other end of the lever 5d and the aperture preset lever 5. , together with the pin 5e of the lever 5 which makes partial contact with the concave groove of the lever 5c by this spring 5f, constitutes an aperture preset system consisting of a loop-shaped moving body, and the intermediate lever 5c and the fan-shaped gear 5h make partial contact by the spring 5g. They are arranged in an interlocking relationship.

The fan-shaped gear 5h is configured to rotate a ratchet wheel 6 coaxially integrated therewith via a pinion 6a, and magnifies the rotational displacement of the claw portion of the ratchet wheel with respect to the operating stroke of the throttle operation pin 2a.

The pallet 6c that opposes the escape wheel 6b, which is coaxial with the ratchet wheel 6, constitutes the first slow speed member, and allows the lever 5 to slowly move and the locking lever 7 that opposes the ratchet wheel 6 to move the lever 5 slowly.
The structure is such that the locking to the ratchet wheel 6 is performed reliably.

Next, in order to operate the mechanism for driving the mirror after operating the aperture determining mechanism, a drive lever 8 is rotatably provided on the shaft 5b of the lever 5d.

The drive lever 8 has a bent piece 8b that engages with one end of the lever 5c, and is given dextrorotation about the shaft 5b by a spring 8a, and the other end 8c is pivoted on the side wall of the mirror box with a shaft 9a. It is engaged with the good luck lever 9.

An air damper 11 as a second slow-speed member is connected to the good-luck lever 9, and it slows down the movement of the drive lever 8 and the good-luck lever 9 to an extent sufficient to determine the aperture of the interchangeable lens L. The pin 9b is configured to quickly engage with the mirror locking lever 10 to release the lock and operate the mirror drive lever 12 after a certain period of time has elapsed.

Further, the good luck lever 9 is locked by a release lever 23 which is operated via an intermediary lever 22 when a release button 21 of the camera is pressed.

When the release button 21 is pressed, the release lever 23 releases the locking of the speed control lever 90, so the drive lever 8 moves clockwise around the shaft 5b, releasing the inhibition of the aperture preset system including the aperture preset lever 5. , the aperture operating pin 2a of the lens pushes the aperture preset lever 5 by a spring 2b.

Therefore, the lever 5 rotates to the right around the shaft 5a, and the fan-shaped gear 5h connected to it by the spring also rotates to the right around the shaft 5a.
The ratchet wheel 6 is rotated to the left via the pinion 6a.

At this time, the rotation of the ratchet wheel is slowed down by the pallet wheel 6c and the escape wheel 6b, which constitute the first slow speed member.

Therefore, the aperture is opened and narrowed down, and the subject light that passes through this is relayed by optical components such as the mirror 13, condenser lens 19, and pentaprism 20, and changes the illuminance of the light-receiving surface of the photovoltaic element D1 according to the aperture. .

When the aperture is stopped down to the appropriate aperture, the photovoltaic element D1
An exposure control circuit (not shown) receiving the output turns the magnet (Ml) from on to off, and the suction force of the adsorption piece 7a of the locking lever 7 is released, so the locking lever 7 is moved by the spring 7.
b rotates clockwise and connects to the pawl of the ratchet wheel 6.

This engagement stops the rotation of the ratchet wheel 6 and the sector gear 5h, and the aperture preset system 5° 5c, 5d, 5f
, 5e stop their movements and stop the diaphragm operation pin 2a, so that the decision to stop the interchangeable lens L is made.

Subsequently, the drive lever 8 and the opening lever 9 are rotated clockwise while being rotated by the air damper 11, which is a second slow speed member, and the locking lever 10 is operated to release the locking of the mirror drive lever 12.

Then, the lever 12 is rotated by the spring 12a to raise the movable mirror 13, and in the final stroke of the mirror raising, the front curtain locking lever 15 is actuated via the lever 14, and the shutter front curtain gear 16 is unlocked. .

After the leading curtain has traveled, the magnet M2 is turned off after an exposure time corresponding to the narrowed aperture aperture, and the trailing curtain locking lever 18 with magnet suction disengages the trailing curtain gear 17 to stop the trailing curtain from traveling. Allow.

When the blocking lever 24 rotates counterclockwise at the time when the rear curtain finishes traveling, the return lever 25 for determining the aperture and returning the mirror drive mechanism to its initial state is released from the lock by the lever 24 and becomes free. The spring 25a pushes the bent piece 8b of the drive lever 8, so the loop-shaped moving body including the aperture preset lever 5, the ratchet wheel 6, the sector gear 5h, the good luck lever 9 and the mirror 1 drive lever 12 are assembled as shown in FIG. Return to state.

Note that the return lever 25 is charged via the levers 28, 27, and 26 by the winding lever 290 being operated.

Next, the above structure of the present invention, especially the first slow speed members 6b, 6.
Before describing the effects of c. The diaphragm is stopped by the diaphragm aperture, and the rays passing through the diaphragm aperture, which changes from moment to moment, are photometered. When the aperture reaches the appropriate aperture, the diaphragm presetting member is stopped and the aperture is determined. From then on, only the driving member is used. Let's consider a single-lens reflex camera that simply moves and rotates a movable mirror with instantaneous automatic aperture determination.

In such a camera, if the drive member is made to correspond to the levers 8 and 9 of the above embodiment, the driving force for moving it forward is provided by the drive spring 8a, but until the aperture is determined, the drive spring 8a is used. In addition to the driving force caused by this, a force by the spring 2b of the automatic aperture mechanism in the interchangeable lens L is applied to the drive lever 8.

Figure 2 shows the relationship between the displacement of the drive member and the load in a single-lens reflex camera with instantaneous automatic aperture determination, in the upper left diagram, and the diagram in the upper right, which shows the relationship between the displacement of the drive member and time. , the relationship between the illuminance of the light-receiving surface of the light-receiving element and time is shown in the chart below.

1. All lines in the diagrams are shown as straight lines for ease of understanding.

However, in reality, it will be curved because of inertia in the movement of each member and pounding generated when stopping, but in order to show the nature of these movements, this can be replaced with a straight line.

Now, considering the above, the load of the drive spring 8a applied to the drive member is Y, and the load applied by the spring 2b is Z.
Then, the load until the aperture is determined is Y+Z, and the load after the aperture is determined is Y.

That is, (a) if the aperture is determined at the intermediate aperture value when the displacement of one driving member reaches an intermediate displacement amount X between the displacement amount X1 corresponding to the open aperture and the displacement amount X2 corresponding to the minimum aperture aperture, The load changes as shown by the solid line in the upper left diagram, and in response to this change, the displacement of the driving member changes over time as shown in the solid line in the upper right diagram, and a bending point occurs at point QX (tX, X), and from this bending point The slope becomes gentler ahead.

(b) When the aperture is determined to be fully open, the change in load changes as shown by the broken line in the upper left chart, and the temporal change in the displacement of the drive member in response to this change becomes as shown in the broken line in the upper right chart, and QXl ( An inflection point occurs at the point (tX, xt).

(c) When the aperture is determined at the minimum aperture diameter, the change in load will be as shown by the chain line in the upper left diagram, and the temporal change in the displacement of the drive member in response to this change will be as shown in the chain line in the upper right diagram, QX2(tX2 , resulting in an inflection point at point X2).

In either case, the displacements of the driving members before the aperture is determined have the same slope and overlap each other, and the straight lines of the displacements after the aperture is determined are straight lines that are gentler than the above slope and are parallel to each other.

Taking the above embodiment as an example, the above means that the good luck lever 9 is interlocked with the drive lever 8, and the good luck lever 9 is interlocked with the drive lever 8.
The same applies when only the damper 11, which is the second slow speed member, is attached to the
(in the case of the above-mentioned structure of the issue).

As a result of the above, the time when the displacement of the drive member reaches the displacement amount X3 that releases the mirror drive lever is tX in case (a), tXl in case (b), and tXl in case (c). pear, and the time is different for each, and the time when the 7-year-old is released by the rotation of the mirror, that is, the body lag is TX in case (a) and TX in case (b).
1, (.

), it will be TX2, and it will take the longest time if the aperture is determined to be wide open.

In order to keep the body lag constant regardless of the aperture aperture determined, the present invention provides a first slow speed member in addition to the second slow speed member disposed on the opening lever 9 that constitutes a part of the drive member. A slow speed member is provided in conjunction with the aperture preset member 5 of the camera body that controls the aperture operating pin 2a of the lens. The pinion 6a with which the pinion 5h meshes, the escape wheel 6b that rotates coaxially with the pallet wheel 6c, and the pallet wheel 6c constitute a first slow speed member.

In the present invention, the first slow speed member is actuated at the same time as the stop-down starts so that the stop-down driving force on the interchangeable lens side does not substantially act on the drive member of the movable mirror, while the drive member of the movable mirror is driven by itself. The body lag TX is made substantially constant regardless of the determined aperture aperture by being driven while being slowed down by the second slow speed member based only on the originally applied driving force, This is shown in Figure 3. δ in Figure 2 above
This problem is solved by making the slope of up to four prongs coincide with the slope of the line segment beyond point QX.

In FIG. 3, the load applied to the drive member changes from the position X where the aperture is determined, as in FIG. 2, and decreases from Y+Z to Y.
Since the first slow speed member, which was controlling the speed of the aperture in conjunction with the first slow speed member, also loses its braking function, the drive members 8 and 9 are substantially driven by the drive spring 8a both before and after the aperture is determined. becomes the same, and its temporal displacement is the aperture determination time tX
Since the mirror is displaced and unlocked without any speed change before or after, the body lag TX remains approximately constant no matter what aperture is determined at any point in time.

Therefore, after the body lug TX is released and the aperture aperture is properly set, the movable mirror is unlocked.
The drive spring 8b, the lens aperture operating spring 2b, and the first slow speed member and the second slow speed member are designed to provide the minimum time required for the mirror to rotate to the photographing position and the shutter to be released. As a result, no matter what aperture is determined, the body lag of the camera can be kept constant and minimized.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the mechanical structure of the main part of the present invention;
The figure is an operation diagram of a single-lens reflex camera with automatic instantaneous aperture determination that is not according to the present invention, and FIG. 3 is an operation diagram according to the present invention. In the figure, 1...Aperture blade, 2a...
・Aperture operation pin, 2b...Aperture operation spring, 3.
...Aperture preset ring, 5, sa, 5.
c, 5b, 5e--Aperture preset system, 6...
...Ratchet wheel, 6b. 6c...First slow speed member, 7...Aperture locking lever 8.9...Driving member, 8a...
... Drive spring, 10 ... Mirror locking lever, 1
DESCRIPTION OF SYMBOLS 1... Second slow speed member, 12... Mirror drive lever, 13... Movable mirror 15...
...Front curtain locking lever 16...Front curtain gear, 1
7... Rear curtain gear, 18... Rear curtain locking lever 21... Shirt release button, 23...
...Release lever 126...Return lever 2
9... Winding lever, 30... Mirror box, Dl... Photovoltaic element, Ml...
・First magnet for aperture, M2... Second magnet for shutter, X... Displacement amount of drive lever,
Xl...displacement when opening the aperture, X...
Amount of displacement when determining the intermediate aperture, X2...Amount of displacement when stopping down to the minimum aperture, X3...Amount of displacement to release the locking of the mirror locking lever, Y... ...Load of drive spring, Z...Load of throttle operation spring, T
······Time axis.

Claims (1)

[Claims] 1 By the shirt release operation, the drive member for unlatching the mirror is released from the lock and is driven by the driving force, and the aperture preset system is caused to follow the driving member by the aperture driving force of the interchangeable lens. In the automatic aperture-determining single-lens reflex camera, the mirror is unlocked by running the drive member after the aperture presetting system is automatically stopped by an electromagnet in the exposure control circuit, and the mirror is raised and the shirt is released. A first slow speed member that slows down the movement of the aperture preset system and a second slow speed member that slows down the travel of the drive member are provided, and the aperture driving force is reduced by the action of the first slow speed member. substantially does not act on the drive member through the aperture preset system, and the second slow speed member moves the aperture preset system from a position corresponding to the open aperture value to a position corresponding to the minimum aperture value. The degree of slow speed is set so that the drive member unlocks the mirror at a fixed timing immediately after the time required for the first slow speed member to move while being slowed until A single-lens reflex camera with automatic aperture determination.