JPH0882826A - camera - Google Patents

Abstract

(57) [Abstract] [Purpose] With a conventional single-lens reflex camera, the time for stopping down the aperture to a predetermined aperture value immediately before shooting may be longer than the mirror-up time, and as a result, in continuous shooting mode. At the time of shooting, there is a drawback that the number of shooting frames per unit time is limited by the aperture driving time. The present invention provides an improved camera. According to the camera of the present invention, the time for narrowing down to an arbitrary aperture value is stored in advance in the storage means, and the time for narrowing down to the aperture value determined based on the photometric value is compared with the narrowing down time in the storage means. However, for example, in the continuous shooting mode, the aperture value is changed so that the aperture time does not exceed the mirror-up time, and the shutter operation time is also changed according to the shooting mode (step 4 of the flowchart).
10).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera, and more particularly to a camera having a diaphragm and a shutter as separate bodies and having a continuous shooting function, and for performing field photometry through a shooting optical system. Regarding the camera that is configured.

[0002]

2. Description of the Related Art A camera (for example, a single-lens reflex camera) in which an aperture and a shutter are configured as separate devices and which is configured to perform field photometry through a photographic optical system, is disclosed in Sho 63-17225
As disclosed in Japanese Patent Publication No. 5, the following operation is performed in the camera during shooting.

That is, whether or not the diaphragm is fully opened is detected immediately before photographing, and when the diaphragm is not fully opened, the diaphragm is driven so as to be fully opened. At this time, if the diaphragm does not fully open, a warning is displayed on the display device as an abnormality such as "insufficient power supply". Then, after the aperture is fully opened without any abnormality as described above, photometry is performed, and the aperture of the aperture and shutter operation time (shutter speed) are determined according to the photometric result of the photometry. After determining the aperture and shutter speed,
In parallel with the mirror-up operation of the camera, the diaphragm device is driven to narrow down the diaphragm to a predetermined diaphragm opening, and then the shutter operates to finish photographing one frame of film.
Immediately after the shooting, the diaphragm is driven to the fully open position in parallel with the mirror down operation, and the standby state is set for the next shooting.

[0004]

The known camera described above has the following drawbacks.

Since the above-described full-opening operation of the diaphragm and the operation of narrowing the diaphragm to a predetermined diaphragm opening are performed for each frame of film, if the time required for diaphragm driving is longer than the time required for mirror up and mirror down, diaphragm driving is performed. The time required to shoot one frame of film is limited depending on the time, and the number of frames to be shot per unit time is reduced in the case of continuous shooting. Therefore, the operating time of the diaphragm device becomes an obstacle to the improvement of the continuous shooting performance of the camera.

This tendency becomes greater in a camera having a large aperture lens. This is because, in a camera having a large-diameter lens, the diaphragm device also has a large diameter, and therefore the diaphragm blade has a large diameter, so that the moment of inertia of the blade is large and therefore the driving time becomes long.

Conventionally, as one method for correcting the above-mentioned drawbacks, for example, a technique disclosed in Japanese Patent Application Laid-Open No. 2-97925 is known, but this technique has another drawback that the viewfinder screen becomes dark. was there.

On the other hand, in order to reduce the time required for the operation of fully opening the diaphragm and the operation of narrowing down the diaphragm, the operating speed of the diaphragm blade is increased by increasing the rotation speed of the step motor which is the drive source of the diaphragm blade. For example, the number of continuous frames per unit time can be increased, but as is well known, the frequency of the drive pulse that can be applied to the motor is limited, and an excessively high frequency pulse signal is applied to the motor. If applied, it will cause step out of the motor, making it impossible to perform accurate rotational drive.Therefore, unless a stepper motor is used as the drive source for the diaphragm blades, this method cannot shorten the operating time of the diaphragm device. Is.

[0009]

OBJECT OF THE INVENTION It is an object of the present invention to provide an improved camera which does not have the disadvantages of the prior art. Specifically, the present invention provides a camera that automatically selects an exposure condition that requires a narrowing drive time shorter than the exposure condition determined in the non-continuous shooting mode when the continuous shooting mode is selected. The purpose is to provide.

More specifically, the object of the present invention is to provide a diaphragm device, a shutter device, a photometric device, a photographing mode selecting operation means, and an aperture value and a shutter operation time according to the photometric result of the photometric device. And an exposure condition determining means for determining the exposure condition determining means for determining a field of view through a photographing optical system, and narrowing down the diaphragm device from an open state to an arbitrary diaphragm value before photographing. The exposure condition determining means has a storage means in which a narrowing time required for driving is stored in advance, and the exposure condition determining means uses the photometry when the shooting mode different from the normal single frame shooting is selected by the shooting mode selection operating means. By comparing the aperture required time up to the aperture value determined according to the result with the aperture time in the storage means, the aperture value and shutter operation time based on the photometric result are compared to the photographing mode. It is to provide a camera which is characterized in having a function of changing the aperture value and the shutter operation of seconds when suitable shooting mode selected by the mode selection operation means.

[0011]

In order to solve the above problems, the present invention provides a diaphragm device, a shutter device, and
A photometric device, a shooting mode selection operation means, and an exposure condition determination means for determining an aperture value and a shutter operation time according to a photometric result by the photometric device, and subject field photometry through a shooting optical system. In the camera configured to perform the above, the exposure condition determining means includes a storage means that stores in advance a narrowing time required to drive the diaphragm device from the open state to a desired aperture value before shooting. However, when a shooting mode different from the normal single frame shooting is selected by the shooting mode selection operation means, an aperture required time up to an aperture value determined according to the photometric result and a stop time in the storage means are displayed. By comparing the aperture value and shutter operation time based on the photometric result with the aperture value and shutter operation time suitable for the shooting mode selected by the shooting mode selection operation means. To provide a camera which is characterized in that it has a function to change.

In the camera of the present invention, for example, when the shooting mode of the camera is the continuous shooting mode, the pre-stored narrowing down time is compared with the narrowing down time up to the aperture value based on the photometric value for continuous shooting. Since the exposure condition determining means newly sets a suitable aperture value and shutter operation time, the number of frames to be photographed per unit time in continuous shooting can be increased as compared with the conventional camera.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a schematic view of the main structure and control system of a single-lens reflex camera constructed by applying the present invention.
In the figure, 1 is a camera body, and 2 is a lens barrel detachably attached to the camera body 1.

The lens barrel 2 is equipped with the following devices.

Reference numeral 3 is a focusing lens, 4 is a zoom lens, 34 is a diaphragm device, 35 is a diaphragm open detection switch,
Reference numeral 31 is a focusing lens drive mechanism, 32 is a drive circuit that drives a focusing lens motor, and 36 is a drive circuit that drives a step motor that is a drive source of the diaphragm device.
Reference numeral 33 denotes a microcomputer (hereinafter abbreviated as lens microcomputer) capable of controlling the circuits 32 and 36 and capable of communicating information with the microcomputer 10 (hereinafter abbreviated as camera microcomputer) on the camera body side. On the other hand, the camera body 1 is equipped with the following devices.

Reference numeral 5 is a well-known vertically movable mirror, 6 is a well-known pentaprism, 7 is a viewfinder eyepiece lens, 8 is a well-known photometric element such as SPC (silicon photodiode), and 9 is an output signal of the element 8. A photometric circuit for calculating the field brightness on the basis of 10 is a camera microcomputer connected to the lens microcomputer 33 by a serial transmission line via electrical contacts 1b and 2b provided on the mount 2a, and 11 is a C
A known distance measuring element including a CD line sensor or the like, 12 is a focus detection circuit that detects the focal length of the object from the output of the element 11, 13 is a mirror drive motor for moving up and down the mirror 5, and 14 is the motor. A mirror drive circuit for driving 13, a focal plane shutter (hereinafter referred to as a shutter) 15, a shutter drive circuit for controlling a drive source of the shutter, 17 for pressing a first stroke of a shutter release button (not shown) A switch (SW1) which is turned on in association with the operation, 18 is a switch which is turned on in association with the pushing operation of the second stroke of the release button (hereinafter referred to as a release switch), 19 is a power source (battery) A power supply voltage detection circuit for detecting the voltage of 20, a display device 21 including a known liquid crystal device, and 22 a camera. A mode selection first switch that is linked to a first shooting mode selection operation means (not shown) for selecting the shooting mode (OFF when the shooting mode is discontinuous shooting, ON when the shooting mode is continuous shooting), Two
Reference numeral 3 denotes a mode selection second switch which is turned on when the release time lag priority is selected by the second photographing mode selection operation means (not shown) and is turned off when the release time lag priority is not selected.

The lens microcomputer 33 stores in advance peculiar data relating to the lens barrel 2, and when the lens barrel 2 is attached to the camera body 1, the peculiar data in the lens microcomputer 33 is transmitted to the camera microcomputer 10 immediately. The camera microcomputer rewrites the lens barrel related data in its own memory circuit. In the camera of the present embodiment, the time required to stop the aperture from the fully opened state to an arbitrary aperture value is also written in advance in the storage device in the lens microcomputer 33 as one of the unique data, and the lens barrel 2 is attached to the camera body 1. When the camera is attached to the camera microcomputer 1
0 is transmitted.

The camera microcomputer 10 has a function of determining an exposure condition (aperture opening, shutter operation time) based on an input from the photometric calculation circuit 9, and a necessary aperture time and an input signal from the switch 22 or 23. It has a function of determining the exposure condition according to the above.

FIGS. 1A and 1B are flowcharts of the control operation performed in the camera microcomputer 10 (that is, the function of the camera microcomputer as the control means of the camera of this embodiment). 2 and FIG. 1, the function of the camera of this embodiment and the operation of each unit will be described.

<Step 1> When a release button (not shown) of the camera body 1 is half pressed, the switch 17 shown in FIG.
Is turned on, and the microcomputer 10 proceeds to step 2 when detecting that the switch 17 is turned on.

<Step 2> Whether or not the aperture is open is determined by the input from the aperture open detection switch 35. If it is determined that the diaphragm device 34 is open, the process proceeds to step 3. If it is not open, the process proceeds to step 101, and the lens microcomputer 33 drives the diaphragm device 34 via the diaphragm drive circuit 36 to fully open the diaphragm.

<Step 101> Lens Microcomputer 33
The step motor of the diaphragm device 34 is driven via the diaphragm driving circuit 36, and the process proceeds to step 102.

<Step 102> The diaphragm is fully opened (open)
If it is opened, the process proceeds to step 3, and if it is not opened, the process proceeds to step 103.

<Step 103> It is checked whether or not a fixed time has passed. If the fixed time has passed, the control operation is ended, and if not passed, the process returns to step 101.

<Step 3> The focus detection circuit 12 performs focus detection (defocus amount detection) based on the output of the distance measuring element 11, and the camera microcomputer 10 performs focusing (focusing operation) according to the detection result. To do so, the lens microcomputer 33 drives the focusing lens drive circuit 32 to move the focusing lens 3 in the optical axis direction via the focusing mechanism 31, and then proceeds to step 4.

<Step 4> The photometric calculation circuit 9 performs photometric calculation according to the output of the photometric element 8 to calculate the field brightness. Go to step 5.

<Step 5> Exposure conditions (shutter speed, aperture value) based on input from the photometry calculation circuit 9
To calculate. Go to step 6.

<Step 6> It is detected whether the mode selection first switch 22 is turned on (in the continuous shooting mode), and if the switch 22 is turned on (continuous shooting mode), the process proceeds to step 7. If the switch 22 is off, the process proceeds to step 111.

<Step 111> Whether or not the release time lag priority is selected is checked. If the release time lag priority is given, the process proceeds to step 112, and if the release time lag priority is not given, the process proceeds to step 113.

<Step 112> Aperture time lag OK
If yes, the process proceeds to step 10. If NO, the process proceeds to step 113.

<Step 113> The shutter speed is changed to the high speed side and the aperture value is changed to the open side, and the process returns to step 112.

<Step 7> Whether or not "piece speed priority" is selected by the photographing condition selection means (not shown), and if "piece speed priority" is selected, the operation proceeds to step 8 and is selected. If not, proceed to Step 10.

<Step 8> It is checked whether or not the shutter speed determined in Step 5 is a value suitable for "frame speed priority". If yes (Y), the process proceeds to Step 9, n
If o (N), the process proceeds to step 121.

<Step 9> By comparing the required time (throttle time lag) for narrowing down to the aperture value determined in step 5 and the aperture time lag corresponding to "frame speed priority", it is determined whether or not it is less than a certain value. If it is less than a certain value, the process proceeds to step 10. If it is more than the certain value, the process proceeds to step 121.

<Step 121> The shutter speed is changed to the high speed side and the aperture value is changed to the open side, and the process returns to step 8.

<Step 10> As a result of steps 6 to 9, the shutter speed and the aperture value are determined. Go to step 11.

<Step 11> The shutter speed and aperture value determined in step 10 are stored in the camera microcomputer, and the process proceeds to step 12.

<Step 12> The shutter speed and aperture value are displayed on the display 21.

<Step 13> Release switch 18
Is turned on, and if the switch is on, the process proceeds to step 14, and if not, the process returns to step 3.

<Step 14> The motor 13 is driven through the mirror drive circuit 14 to raise the mirror, and the process proceeds to step 15.

<Step 15> If it is necessary to narrow down the aperture, the process proceeds to step 16, and if the aperture may remain open, the process proceeds to step 19.

<Step 16> Power supply voltage detection circuit 19
The voltage of the power source 20 is checked via the, and if the voltage is equal to or higher than a predetermined value, the process proceeds to step 17, and if it is equal to or lower than the predetermined value, the process proceeds to step 131.

<Step 131> Waiting for a certain period of time to pass, and the process proceeds to step 17.

<Step 17> The diaphragm device 34 is driven through the lens microcomputer 33 and the diaphragm drive circuit 36 to narrow down the diaphragm to a predetermined value, and the routine proceeds to step 18.

<Step 18> Whether the diaphragm drive is completed is confirmed via the lens microcomputer 33. If it is completed, the process proceeds to step 19, and if it is not completed, the process branches to step 141.

<Step 141> It is checked whether the throttle opening has reached a predetermined value, and if it has reached a predetermined value, step 142
If not, the process returns to step 18.

<Step 142> It is checked whether or not the mirror up is completed, and if it is completed, the operation proceeds to stop, and if not completed, the operation proceeds to step 201.

<Step 201> It is checked whether or not a predetermined time has elapsed, and if it has elapsed, the process proceeds to stop, and if not, the process returns to step 142.

<Step 19> It is checked through the mirror drive circuit 14 whether or not the mirror up is completed. If it is completed, the process proceeds to step 20, and if not completed, the process branches to step 151.

<Step 151> It is checked whether or not a predetermined time has elapsed, and if it has elapsed, the process proceeds to stop, and if not, the process returns to step 19.

<Step 20> Shutter drive circuit 1
The shutter is driven via 6, and the process proceeds to step 21.

<Step 21> It is checked whether or not the shutter drive is completed, and if it is completed, step 22
If not, the process branches to step 161.

<Step 161> It is checked whether or not a fixed time has passed, and if it has passed, the operation proceeds to stop, and if it has not passed, the operation returns to step 21.

<Step 22> The motor 13 is driven through the mirror drive circuit 14 to cause the mirror down, and the process goes to step 23.

<Step 23> It is confirmed whether the aperture value is the aperture value or any other aperture value. If the aperture value is open, the process proceeds to step 26. If not, the process proceeds to step 24.

<Step 24> The power supply voltage is checked. If the power supply voltage is a predetermined value, the process proceeds to step 25, and if it is less than the predetermined value, the process branches to step 171.

<Step 171> Wait until a fixed time has passed, and proceed to step 25.

<Step 25> The diaphragm is driven, and the process goes to step 26.

<Step 26> Aperture opening switch 35
Whether or not the aperture is open is checked according to the output state of 1., and if the aperture is open, the process proceeds to step 27, and if not, the process branches to step 181.

<Step 181> It is checked whether or not a fixed time has passed. If the fixed time has passed, the process proceeds to stop, and if the fixed time has not passed, the process returns to step 26.

<Step 27> The driving of the diaphragm device 34 is stopped through the lens microcomputer 33 and the diaphragm drive circuit 36, and the process proceeds to step 28.

<Step 28> It is checked whether or not the mirror drive circuit 14 has completed the mirror down. If the mirror down is completed, the process returns to the start. If the mirror down is not completed, the process branches to step 191.

<Step 191> It is checked whether or not a fixed time has passed, and if the fixed time has passed, the process proceeds to stop, and if the fixed time has not passed, the process returns to step 28.

<Correspondence between Invention and Embodiment> The “exposure condition determining means” described in the claims is the camera microcomputer in the embodiment, and the “storage means” in the claims is the lens microcomputer in the embodiment. is there. Further, the "imaging mode selection operation means" in the claims is an operation button (not shown) that is interlocked with the switches 22 and 23 of the embodiment.

[0066]

As described above, according to the present invention, when the shooting mode is set to the non-normal shooting mode other than the normal single frame shooting, the aperture and shutter operation time determined by the photometry result Are automatically changed at different aperture values (suitable for the non-normal shooting mode) and shutter seconds (for example, when the continuous shooting is selected, the aperture operation time of the aperture device does not exceed the mirror-up time). A camera capable of increasing the number of frames per unit time as compared to a conventional camera without requiring an increase in a film feeding motor and an increase in speed of a diaphragm device driving motor is provided. It

[Brief description of drawings]

FIG. 1 is a diagram showing a first half portion of a flow chart showing a control operation of a camera of one embodiment of the present invention and a function of an exposure condition determining means mounted on the camera.

FIG. 2 is a diagram showing the latter half of the flowchart of FIG.

FIG. 3 is a diagram showing a schematic configuration of a single-lens reflex camera as one embodiment of the present invention.

[Explanation of symbols]

1 ... Camera body 2 ... Lens barrel 3 ... Focusing lens 4 ... Magnification changing lens 5 ... Mirror 6 ... Penta prism 7 ... Viewfinder eyepiece lens 8 ... Photometric element 9 ... Photometric calculation circuit 10 ... Camera microcomputer (microcomputer) 11 ... Distance measuring element 12 ... Focus detection circuit 13 ... Mirror drive motor 14 ... Mirror drive circuit 15 ... Shutter device 16 ... Shutter drive circuit 17 ... Switch (switch interlocked with first pressing operation of release button) 18 ... Release switch (the button) 19: Voltage detection circuit 20 ... Power supply 31 ... Focusing mechanism 32 ... Focusing lens drive circuit 33 ... Lens microcomputer 34 ... Aperture device 35 ... Aperture fully open detection switch 36 ... Aperture drive circuit 1a, 2a ... Mount 1b, 2b ... electrical contacts

Claims (1)

[Claims] 1. A diaphragm device, a shutter device, a photometric device, a photographing mode selecting operation means, and an exposure condition determining means for deciding an aperture value and a shutter operation time according to a photometric result by the photometric device. In a camera that is configured to perform field photometry through a photographic optical system, the necessary aperture time required to drive the aperture device from the open state to an arbitrary aperture value is stored in advance before shooting. The exposure condition determining means determines the aperture value determined according to the photometric result when a shooting mode different from the normal single frame shooting is selected by the shooting mode selection operating means. The aperture value and shutter operation time based on the photometric result are selected by the photographing mode selection operation means by comparing the aperture time up to Camera, characterized in that it has a function of changing the aperture value and the shutter operation of seconds when appropriate to the imaging mode.