JPH046932B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a focal length switching type camera that allows focal length switching even during initial release operation.

(Prior art) Conventionally, interchangeable lens cameras, in which a standard lens is replaced with a telephoto lens with a longer focal length, have been widely used to take close-up shots of distant objects. Recently, cameras have been developed that can switch between two different focal lengths with a simple operation.

This type of bifocal camera has two optical systems with different focal lengths built into the camera, and switches to one of the optical systems manually when taking a picture, but compared to conventional lenses, it is less troublesome to change lenses. Although switching the optical system has become easier, it still takes a certain amount of time, so if the subject is moving, you will miss the shot, and it is also difficult to switch the focal length while framing.

Therefore, the present inventors have proposed a bifocal camera in which the focal length can be changed by starting a motor and moving a lens unit by operating a button.

In conventional focal length switching cameras, the F value of the photographing lens is often darker on the long focal length side than on the short focal length side. Therefore, even if there is no warning when metering on the short focal length side, if you switch to the long focal length side, a low brightness warning indicating insufficient brightness will be issued due to the dark F value, or a slow shutter speed that may cause camera shake. was selected, so after switching the focal length, it was necessary to perform photometry again to confirm whether photography was possible.

However, in the past, there was no configuration in which the focal length could be changed by operating the focal length switching button or lever during the initial release operation. This is to ensure that if you change the focal length after metering with the first release operation, the information measured before switching will be retained even after switching, so that necessary warnings will not be given or false warnings will not be given. This was due to consideration. Therefore, conventionally, in order to switch the focal length, it was necessary to once release the release, switch the focal length, and then press the release again to perform photometry again.

(Object and Structure of the Invention) The present invention has been made in view of the above points, and an object of the present invention is to improve the usability when switching the focal length in a camera capable of switching between two types of focal length. In order to achieve this, the lens is configured so that the focal length can be changed even during the first step of pressing the release button.

(Example) The present invention will be explained below based on the drawings.

FIG. 1 is a front view of an embodiment of a bifocal camera according to the present invention, and FIGS. 2A and 2B are side views of the same camera when the same camera has two different focal lengths. The main body, 2 is a lens barrel that is movable back and forth in the center of the front of the camera body 1, 3 is a viewfinder window, 4 and 5 are distance measuring windows, and 6 is a lens barrel that is movable back and forth.
A light-receiving element such as a CdS, 7 is a release button that can be operated in two steps.The first step performs distance measurement, photometry, battery check, and position check and position correction of the lens unit, which will be described later. Operation allows you to move the lens unit, drive the shutter, etc. 8 is an automatic return type focal length switching button. When this button 8 is pressed in the direction of the arrow, when the lens barrel is in the retracted state, it will be extended from the state shown in Fig. 2 A to the state shown in Fig. 2 B, and then returned to the extended state. At some point, it is stored as shown in FIG. 2B from the state shown in FIG. 2B.

FIG. 3 shows a lens barrel moving mechanism of a camera according to the present invention.

A lens unit is built into the lens barrel 2, and protrusions 2a, 2b,
2c is engaged with and supported by three guide shafts 10 installed in the camera body, so that it can move in the direction of arrow A while maintaining its axial center position.

A bifocal photographic optical system is built into the lens barrel 2, and by moving straight in the direction of arrow A relative to the camera body, the configuration of the optical system is rearranged and the focal length is automatically switched. It's getting old.

The lens barrel 2 has a concave portion 11 formed by a flat partition wall 11a on the circumferential surface of the bottom thereof, and accommodates each member of a driving force transmission system for moving the lens barrel 2.

That is, a plate 12 having symmetrical rising parts 12a and 12b is fixed and integrated with the upper surface of the partition wall 11a by screws or the like.
Further, a crankshaft 13 is rotatably mounted through the plate 12 and the partition wall 11a.

The crankshaft 13 is in a state in which its axial movement is restrained by a regulating member (not shown), and the crank lever 1 has symmetrical falling portions 14a and 14b at a height separated by a slight distance from the plate 12.
4 is fixed and provided.

A strong torsion spring 1 is installed between the plate 12 and the crank lever 14 as a stroke absorbing member.
5 is assembled into the crankshaft 13 in a loosely fitted state, and both ends thereof are connected to the rising portion 12 of the plate 12.
a, 12b and the falling portions 14a, 14b of the crank lever 14, so that the left and right sides are biased equally. Therefore, the crank lever 14 is elastically integrated with the plate 12, that is, the lens barrel 2, and is configured not to rotate in either the left or right direction due to a slight external force. . All of these members are housed within the space of the recess 11 and are mounted so as not to interfere with the optical system within the lens barrel 2.

On the other hand, a crank lever 1 is attached to the lower end of the crankshaft 13 that protrudes to the outside of the partition wall 11a of the recess 11.
A crank arm 16 is fixed at a substantially right angle to the crank arm 4, and a drive pin 18, which is a drive member for the lens barrel 2, is engaged in the elongated hole 16a, which is operated by a planetary gear mechanism 17 provided inside the camera body. It matches.

This planetary gear mechanism 17 includes a large gear 20 that is rotated by a drive gear 19 around a shaft 20a in a fixed position, and a small gear 21 that is pivotally attached to this large gear 20.
It further comprises a fixed internal gear 22 that meshes with the pinion 21, and a drive pin 18 is implanted on a plate 21a fixed to the pinion 21.

In this configuration, the internal gear 22 has a knurl diameter twice that of the small gear 21, and since the drive pin 18 is located on the knurled circumference, the large gear 20 rotates one-half of a revolution. The pinion 21 revolves around the circumference of the internal gear 22 by half a revolution, and at the same time, the pin 21 itself rotates half a rotation, so the pin 18 moves linearly in the direction of arrow B and rotates around the internal gear 22. The stroke is set to be long enough to cover the amount of movement of the lens barrel 2.

In the lens barrel moving mechanism having such a configuration, the operation for switching the focal length of the lens barrel 2 is performed as follows.

The drive gear 1 is driven by the power of a motor (not shown).
When gear 9 rotates, for example, clockwise, it is decelerated and the large gear 20 starts rotating counterclockwise. At this time, the small gear 21 also rotates together with the large gear 20 to rotate the drive pin 18 counterclockwise on an arc, but due to the engagement with the internal gear 22, it is simultaneously rotated clockwise. As a result, the drive pin 18 starts to move linearly in the direction of arrow B.

Therefore, the drive pin 18 applies a clockwise rotational force to the crank arm 16, but since the crank lever 14 is integrated with the lens barrel 2 by the action of a strong torsion spring 15, the drive pin 18 applies a clockwise rotational force to the crank arm 16. The drive pin 18 ends up moving the lens barrel 2 from a predetermined one end position (retracted position) in parallel in the direction of arrow A through the crankshaft 13.

Even after this action continues and the large gear 20 reaches nearly half a turn and the lens barrel 2 moves to the other end position (extended position) and stops, the driving force continues to be applied to the drive pin 18. Working crank lever 14
is rotated against the elastic action of the torsion spring 15, and this operation enables the drive pin 18 to complete its full stroke and move on to the next return operation.

On the other hand, due to the continued rotation, the drive pin 18 moves to arrow B
Even when moving in the opposite direction, the strong torsion spring 15 acts on the crank lever 14 in the opposite direction as well as in the case described above, so the lens barrel 2 is moved in parallel. It becomes possible to move it to a predetermined one end position.

Even after the lens barrel 2 is moved to its predetermined one end position and stopped in this way, the planetary gear mechanism 17 continues to operate as in the case described above, and the torsion spring 15
Since the crank lever 14 is rotated counterclockwise against the elasticity of the drive pin 18, the drive pin 18 is stopped after completing its entire return stroke and accurately reaching the collapsing position.

Therefore, when the operation of the planetary gear mechanism 17 is stopped, the drive pin 18 biases the crank lever 14 either clockwise or counterclockwise against the torsion spring 15, so that the crank lever 14 is slightly rotated. I'm keeping it.

FIG. 4 shows only the parts related to the driving of the lens barrel moving mechanism of the camera according to the present invention, and the circuit parts related to normal distance measurement, photometry, shutter, and lens driving are omitted.

In the figure, 30 is the battery, S ₁ is the first-stage release switch that is turned on when the release button 7 (see Figure 1) is pressed one step, and is off otherwise, and S ₂ is the first-stage release switch that is turned off when the release button 7 is pressed further. The two-stage release switch that turns on, S ₃ , is normally connected to contact a, but the focal length switch button 8 (first
31 is a transistor that becomes conductive when either the first-stage release switch _S1 or the focal length switch _S3 is turned on; 32;
33 is a microcomputer-configured controller that outputs operation commands to the camera load based on distance measurement and photometry data; 34 is a controller for moving the lens barrel 2 according to commands from the controller 34; A motor driver _S4 that drives the motor 35 cooperates with a part of the movement mechanism of the lens barrel,
This is a state detection switch that is turned off when the lens barrel 2 is at the normal position on the short focal length side or the long focal length side, and turned on at other times. Reference numeral 36 is a transistor that holds the controller 33 by itself when the switch _S3 is set to the contact b side.

Next, the focal length switching operation of the camera according to the present invention will be explained using FIGS. 5 and 6.

This camera starts by turning on the first stage release switch _S1 and turning on the focal length changeover switch _S3 (connection to the contact b side).

First, the operation when switching the focal length will be explained.

When the switch _S3 is connected to the contact b side, the controller 33 determines that the focal length has been changed, that is, the switch _S3 is on (step F-1), and proceeds to the lens movement subroutine (F-2). In F-2, the motor is driven to move the lens, and the signal from switch _S4 determines whether the lens barrel 2 has reached the normal extended or retracted position. Sometimes steps for stopping the motor and stopping the lens are included, but these steps are omitted in the figure.

On the other hand, when the first stage release switch _S1 is turned on, the switch _S3 is off, so the process proceeds to a photometry step F-3 and a distance measurement step F-4. That is, photometry (F-3) is performed at the timing shown in FIG. 6B, followed by distance measurement (F-4) at the timing shown in FIG. 6C. Then release button 8 (see Figure 1)
It is determined whether or not a two-step release operation has been performed by further pressing (F-5). the result,
When the two-step release operation is performed, a series of shooting sequences such as driving the lens and shutter and winding the film are performed (F-6); otherwise, metering continues (F-7), and the focal length is changed again. It is determined whether or not the process has been performed (F-8).
After that, if the focal length switch _S3 is turned on at the timing shown in Fig. 6D, the step (F
Proceeding to step -2), the motor 35 is driven at the timing shown in FIG. 6E, and the lens barrel 2 moves to reach the extended position or retracted position. As shown in FIG. 6, the state detection switch _S4 is turned on while the lens barrel 2 is moving, but turned off when the lens barrel 2 reaches the normal extended position or retracted position. Then, when the second stage release switch is turned on again after the photometry (F-3) and distance measurement (F-4) steps, the shutter drive film is wound,
Ends the shooting operation. Thereafter, the process returns to F-1 and distance measurement and photometry are repeated.

(Effects of the Invention) As explained above, the present invention provides a camera in which two types of focal lengths can be switched, and the focal length can be switched while performing the initial shutter release operation.
Since light metering is performed again in a switchable manner, camera operation becomes easier and quick shooting performance is improved.

[Brief explanation of drawings]

Fig. 1 is a front view of a focal length switching camera according to the present invention, Fig. 2 A is a side view showing the lens barrel of the same camera in a retracted state, and Fig. 2 B is a side view showing the lens barrel of the same camera in a protruding state. , FIG. 3 is a perspective view of the main part of the lens barrel moving mechanism of the focal length switching type camera according to the invention, FIG. 4 is a main part of the electric circuit of the camera according to the invention, and FIG. 5 is a focus diagram of the camera according to the invention. A flowchart of the distance switching operation, and FIG. 6 is a time chart illustrating the focal length switching operation of the camera according to the present invention. 1... Camera body, 2... Lens barrel, 7...
Release button, 8... Focal length switching button, 3
0... Battery, 32... DC/DC converter, 33... Controller, 34... Motor driver, 35... Motor, S ₁ ... 1-stage release switch, S ₂ ... 2-stage release switch, S ₃ ... ...Focal length selection switch, S ₄ ...Status detection switch.

Claims (1)

[Claims] 1. In a focal length switchable camera in which the first-step operation of the release measures light and gives a warning to the photographer based on the result, the first-step operation of the release is a first detecting means for detecting whether or not the release is being performed and outputting a detection signal; a photometering means for performing photometry when the first detecting means inputs a detection signal indicating that the first release operation is being performed; a second detection means for detecting whether an operation for switching the distance has been performed and outputting a detection signal; a moving means for moving the lens unit in order to switch the focal length; and the first detection means and the first detection means. and control means for controlling the photometric means based on the detection signal from the second detection means and controlling the moving means based on the detection signal from the second detection means, and the control means controls the first shutter release operation. When a detection signal indicating that an operation for switching the focal length has been performed is input from the second detection means while a detection signal indicating that an operation for switching the focal length has been input from the first detection means, the moving means The focal length switching type camera is characterized in that the lens unit is moved by activating the lens unit to switch the focal length, and after the movement of the lens unit is completed, the photometry is performed again by the photometry means.