JPH07117678B2 - camera - Google Patents

Description

The present invention relates to an improvement in a camera having a built-in flash device or a camera to which the flash device can be attached.

Generally, the depth of field at the time of taking a picture becomes deeper as the subject distance becomes longer and the aperture becomes smaller.
In other words, the depth of field is shallow when shooting at close range or when the aperture of the diaphragm is large (generally when shooting in a dark place).
Defocus is likely to occur.

As for short-distance photography, for example, in an autofocus type camera, a large number of sawtooth portions are formed on the lens control plate that operates at the time of release, and it operates when the distance to the subject is measured by the distance measuring device. It is customary for an engaging portion such as a lever to engage with the sawtooth portion. This saw-tooth portion needs to be formed particularly finely on the short distance side in order to move the lens in small steps, but it is technically and costly to form such a highly accurate saw-tooth portion. Instead, the lever engagement part did not engage the sawtooth part well and the focus was not properly achieved.

It should be noted that in the conventional example, there is only known one that uses an aperture control device to switch between AE and flashmatic according to the luminance signal of the subject.

The present invention eliminates the above-mentioned drawbacks of the prior art,
That is, the object of the present invention is to provide a camera that does not cause out-of-focus when an autofocus type camera performs short-distance shooting. Therefore, a flash device is used in the present invention. That is,
The present invention relates to a photometric device 44 that measures subject brightness and outputs a brightness signal corresponding to the brightness, a distance measuring device 18 that measures a subject distance and outputs a distance signal corresponding to the distance, and the brightness signal. And a flash control device 41 that controls the operation of the flash device in response to the distance signal, and an aperture control device 43 that controls the aperture in response to the brightness signal and the distance signal. Become.

In such a camera, firstly, when the brightness signal indicates a brightness lower than a first predetermined value, the flash control device sets the flash device to a state of emitting light upon photographing, and the aperture control device sets The diaphragm is controlled based on the distance signal. That is, the flashmatic method is used.

Secondly, when the luminance signal indicates a luminance higher than the first predetermined value and higher than the second predetermined value, the flash control device sets the flash device to a state in which the flash device does not emit light upon shooting, and The control device controls the diaphragm based on the luminance signal. That is, the flash does not emit light, and the aperture is controlled according to the brightness of the subject.

Thirdly, when the brightness signal indicates a brightness between the first predetermined value and the second predetermined value, and the distance signal indicates a distance farther than the predetermined value, the flash control device causes the flash device to operate. Is set to a state in which no light is emitted in association with photographing, and the aperture control device controls the aperture based on the luminance signal.
That is, the same control as in the second case is performed.

Fourthly, when the brightness signal indicates a brightness between the first predetermined value and the second predetermined value, and the distance signal indicates a distance shorter than a predetermined value, the flash control device causes the flash device to operate. Is set to emit light upon shooting, and the aperture control device controls the aperture based on the distance signal. That is, the same control as in the first case is performed.

Hereinafter, the present invention will be described in more detail with reference to the drawings showing an embodiment in which the present invention is applied to an autofocus type camera.

In FIG. 1, a lens barrel 2 holding a taking lens 1 is connected to a guide rod 3 at a protruding portion 2a thereof. Lens barrel 2
A diaphragm 4 is provided inside, and a roller portion 2b is formed outside the lens barrel 2. The guide rod 3 is movable in the optical axis direction (left-right direction in FIG. 1) by a part 6 of the camera body, and is biased leftward by a spring 7.

The lens limiting plate 11 includes a tooth portion 11a, a cam portion 11b, and a protrusion portion 11d.
And is guided by the pin 12 and the long hole 11e, and is movable in the vertical direction (in FIG. 1). The roller portion 2b can contact the cam portion 11b or 11c. The limiting plate 11
Moves up in conjunction with the release operation and moves the lens barrel 2 from the long distance side to the short distance side (to the right in the figure) through the contact between the cam portions 11b and 11c and the roller portion 2b. The limiting plate 11 returns to the lower end position after the exposure is completed. A lever 14 is rotatably mounted around a pin 15 in the vicinity of the limiting plate 11, and is biased by a spring 16 in the right-handed direction. The lever 14 is provided with an engaging portion 14a capable of engaging with the tooth portion 11a, and a magnet 17
It is designed to be adsorbed by. A distance measuring circuit 18 is connected to the magnet 17.

A contact piece 21 is provided at a position where it can contact the protrusion 11d of the limiting plate 11.
A first switch 21 including a and 21b is provided.
In the closed circuit including 21, a second switch (normally closed switch) 41, a first switch 21 and a second switch 21, which are in series with the first switch 21,
A third switch (normally open switch) 42 and a magnet 24 are arranged in parallel with 41.

A lever 28, which is rotatably mounted around a pin 26 in the vicinity of the magnet 24 and biased in a clockwise direction by a spring 27, attracts the end portion where the engaging portion is formed to the magnet 24. It has become. The guide plate 32 having the strobe 31 at the upper end is biased upward by the spring 33,
The pins 36 and 37 and the long holes 32a and 32b are guided so that they can move up and down.

The diaphragm 4 and the second switch 41 are controlled by a diaphragm control circuit 43, which controls the photometric circuit 44 and the distance measuring circuit 18.
It is controlled by. The third switch 42 is controlled by the photometric circuit 44.

Next, the operation of this embodiment will be described.

First, when the subject brightness is very dark, that is measured by the photometry circuit 44, and the output signal from the photometry circuit causes the third switch 42.
Turns on. As a result, the magnet 24 is excited and the lever 28 rotates counterclockwise against the action of the spring 27.
The guide plate 32 is disengaged by the spring, and the guide plate 32 is lifted by the action of the spring 33, and the strobe 31 pops up. In the pop-up state, the strobe 31 can emit light, that is, it can emit light in synchronization with opening of the shutter. Also the control circuit
The signal from the distance measuring circuit 18 is input to 43, and the signal from the control circuit 43 is also output to the diaphragm 4.
Therefore, after the pop-up, the aperture 4 is set according to the shooting distance.
Changes. It will be switched to the so-called flash system.

That is, the magnet 17 is demagnetized at a predetermined time in accordance with the output signal from the distance measuring circuit 18, the lever 14 is rotated right by the action of the spring 16, and the engaging portion 14a thereof is raised in association with the release operation. It engages with the sawtooth portion 11a of the limiting plate 11. When the lens limiting plate 11 is raised (released), the lens barrel 2, that is, the lens 1 is moved and focused. At the same time, the output signal from the distance measuring circuit 18 is input to the control circuit 43, and the aperture of the diaphragm 4 is adjusted according to the signal so that proper exposure can be obtained (a small diaphragm is provided on the short distance side). ).

Next, the brightness of the subject is medium (brightness set to an aperture value that makes the depth of field shallow when shooting at close range)
However, at this time, different operations are performed depending on whether the shooting distance is long or short. First, when the aperture value is set so that the depth of field becomes shallow during short-distance shooting, the control circuit 43 operates based on the output of the photometric circuit 44 and the second switch 41 is turned on. The first switch 21 is turned off when the subject distance is equal to or greater than a predetermined value (for example, 1 m or more).
As it is, the magnet 24 is not excited, and therefore the strobe 31 does not pop up.

On the other hand, when the subject distance is equal to or less than a predetermined value (for example, 1 m or less), the first switch 21 is turned on.

That is, at this time, the lens limiting plate 11 rises considerably, so that the contact portions 21a and 21b are brought into contact with each other by the protrusion 11d and the first switch 21 is turned on. When the first switch 21 is turned on, the second switch 41 is also turned on. Therefore, the magnet 24 is excited as described above, the lever 28 is rotated counterclockwise, and the strobe 31 is popped up. Thereafter, photographing by the flash-matic method is performed, and the diaphragm 4 is narrowed down according to the object distance, so that a sufficient depth of field can be obtained. It should be noted that the third
Switch 42 is off.

Furthermore, when the subject brightness is very bright,
The third switch 42 is kept off by the signal from
Since the second switch 41 is also off, the strobe 31 does not up. This is because the diaphragm 4 is considerably narrowed down, and the depth of field is deep regardless of the distance of the shooting distance.

The advantages of the above embodiment will be described in detail with reference to FIGS. 2 and 3 in comparison with the conventional example.

FIG. 2 shows an automatic focus detection type camera having a built-in flash device, in which the subject distance is plotted on the horizontal axis and the lens stop position is plotted on the vertical axis.
Here, suppose that the focal length of the shooting lens is 38 mm and the brightness is F2.8.
Curves 51 and 52 show the depth of field when. When the depths of field before and after the adjacent lens stop positions are connected so as to be in contact with each other, the lens stop positions become stepwise as shown in FIG. For example, if the focal position of the lens is 1.7 m, the depth of field will be 1.5-1.9 m, and if it is 2.2 m, it will be 1.9-
With a depth of 2.6m, the depth range is connected back and forth.

Now, focusing only on the number of steps, the subject distance is 1 m.
There are 8 steps for ~ ∞ and 8 steps for 0.5m ~ 1m.

FIG. 3 is a graph corresponding to FIG. 2 in the above embodiment. When the subject distance is 1 m to ∞, the step does not change as compared with the conventional technology. However, when the shooting distance is 1 m to 0.5 m, a diaphragm based on flash sensitivity is selected, the diaphragm value is different depending on the subject distance (closer as the distance is closer), and the depth of field increases. The range is shown between the straight lines 53 and 54. If you take a step between these straight lines, as shown in the figure
With 0.5 to 1 m, 2 steps is good. The reduction in the number of steps means that it is not necessary to form fine steps, thereby achieving a reduction in manufacturing cost.

It should be noted that the above description is merely one embodiment of the present invention, and the present invention should not be limited to this.

As described above, according to the present invention, in the auto-focus type camera, when the subject brightness is lower than the first predetermined value, the flash device is caused to emit light according to the shooting, and the aperture is adjusted according to the subject distance (flash). On the other hand, when the subject brightness is higher than the second predetermined value higher than the first predetermined value, the flash device does not emit light,
Adjust the aperture according to the magnitude of the luminance signal.

Next, when the subject brightness is between the first predetermined value and the second predetermined value, the subject distance is larger (far) than the predetermined value.
The operation differs depending on whether it is small or close. That is,
When the subject is farther than the predetermined value, the same control as when the subject brightness is higher than the first predetermined value is performed.
On the other hand, when the subject is closer than the predetermined value, the flashmatic method is used.

As a result, when the subject is extremely dark, the flash device is caused to emit light, and the aperture is adjusted according to the subject distance, so that the depth of field during short-distance photography can be improved. If the subject is bright enough,
Even when taking a close-up shot, the flash device is not caused to emit light, and the aperture is adjusted according to the brightness of the subject, so the power of the flash device battery can be saved.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment in which the present invention is applied to an autofocus system camera, and FIG. 2 is a graph showing a relationship between a subject distance and a lens stop position in a conventional autofocus system camera. FIG. 3 is a graph corresponding to FIG. 2 in the above embodiment. [Explanation of symbols of main parts] 1 ... Lens 4 ... Aperture 18 ... Distance measuring device 31 ... Flash device 41 ... Flash control device 43 ... Aperture control device 44 ... Photometric device

Continuation of front page (56) References JP-A-52-50228 (JP, A) JP-A-50-1724 (JP, A) JP-A-54-128731 (JP, A) JP-A-49-133027 (JP , A) JP 50-115033 (JP, A) JP 58-118626 (JP, A) Actual opening 54-55836 (JP, U) Actual opening 57-201526 (JP, U) Actual opening 48-14428 (JP, Y1)

Claims (1)

[Claims] 1. A photometric device that measures subject brightness and outputs a brightness signal corresponding to the brightness, a distance measuring device that measures a subject distance and outputs a distance signal corresponding to the distance, and the brightness signal. A camera including: a flash control device that controls the operation of a flash device in response to the distance signal; and an aperture control device that controls an aperture in response to the luminance signal and the distance signal. When the brightness signal shows a brightness lower than the first predetermined value, the flash control device sets the flash device to a state in which the flash device emits light upon photographing, and the aperture control device controls the aperture based on the distance signal. (B) When the brightness signal indicates a brightness higher than a second predetermined value indicating a brightness higher than the first predetermined value, the flash control device sets the flash device to a state in which the flash device does not emit light during photographing, The aperture control device is A diaphragm is controlled based on the brightness signal, and (c) the brightness signal indicates a brightness between the first predetermined value and the second predetermined value, and the distance signal indicates a distance farther than the predetermined value. The flash control device sets the flash device so that it does not emit light upon shooting, the aperture control device controls the aperture based on the brightness signal, and (d) the brightness signal is the first When the brightness between the predetermined value and the second predetermined value is shown and the distance signal shows a distance shorter than the predetermined value, the flash control device sets the flash device to a state of emitting light in association with photographing. The camera, wherein the aperture control device controls the aperture based on the distance signal.