JPS6353531A - Blurring preventive camera - Google Patents

Abstract

PURPOSE:To take a blurring-free photograph, by instructing a shutter holding means to cancel the shutter holding near the peak of camera-shakes in accordance with signals from a camera-shake detecting means. CONSTITUTION:A camera-shake quantity detecting means 48 starts detection by means of an acceleration sensor when the 1st stroke switch is turned on. A camera-shake peak value calculating circuit 49 starts calculation when the 2nd stroke switch is turned on and differentiates acceleration signals from the means 48. At the time when the differentiated acceleration signals become zero, the circuit 49 outputs a signal for cancelling shutter holding to a shutter holding circuit 50. The circuit 50 outputs a shutter holding signal to a shutter driving circuit 46 and causes the circuit 46 to hold a shutter in a just-before-run state and, when the shutter holding cancelling signal is inputted from the camera-shake peak value calculating circuit 49, to cancel the shutter holding. Thus the shutter is run.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an image blur prevention camera, and more particularly to an image blur prevention camera in which the shutter is driven when camera shake is at its lowest.

[Background of the invention]

Generally, when taking a picture with a handheld camera, the image may appear distorted due to camera shake.

To reduce image blur, set the shutter speed quickly,
Since it is a simple method to use a photographic lens with a short focal length, cameras have been proposed that are programmed to give priority to the high-speed shutter side.

However, since such cameras are programmed to give priority to high-speed shutter speeds and shutter speeds, they may not be able to use frequently used combinations of aperture and shutter speeds, and the photographer is also programmed to give priority to camera shake. Regardless of the photographer's ability, the photographer's intentions (such as shutter speed and aperture effects) may not be fully reflected because the camera shoots at high speeds.

[Purpose of the invention]

The present invention has been made to solve these conventional problems, and by activating the shutter when camera shake has decreased, it is possible to reflect the photographer's intention to take a picture and take a picture without image blur. The object of the present invention is to provide an image prevention camera that can take pictures.

[Summary of the invention]

The image blur prevention camera according to the present invention includes a camera shake detection means for detecting camera shake, a shutter holding means for holding the shutter just before actuation, and a shutter holding means for holding the shutter in the vicinity of the peak of camera shake based on a signal from the camera shake detection means. The invention is characterized by comprising means for instructing release of shutter holding.

[Embodiments of the invention]

The present invention will be described in detail below based on embodiments shown in the drawings.

FIG. 1 is a schematic diagram of a camera body showing an embodiment of the camera according to the present invention, and FIG. 2 is a sectional view showing a state in which a photographic lens is attached to the camera body of FIG.

In the figure, reference numeral 1 denotes a camera body, and a grip part 4 is provided on one side of the front part. In the following description, the direction parallel to the film feeding direction will be referred to as the X-axis direction, the direction perpendicular to the X-axis direction and the vertical direction will be referred to as the Y-axis direction, and the direction of the optical axis of the photographing lens will be referred to as the Z-axis direction. 2a.

2b is an acceleration sensor whose sensitivity axis coincides with the Z-axis direction, which is arranged on the grip part 4 so as to be spaced apart from each other in the Y-axis direction;
One acceleration sensor 2a is provided near the release button 4&, and the other acceleration sensor 2b is provided at the lower end of the grip 4. 3m, 3bF'l Acceleration sensors whose sensitivity axes coincide with the Z-axis direction are placed facing each other in the X-axis direction, and one acceleration sensor 3a is connected to the release button 4a.
The other acceleration sensor 3b is provided at the opposite end of the grip 4. In addition, acceleration sensor 3
&' may also be used as the acceleration sensor 2a. This release button 41 is composed of a first stroke switch that is turned on at the first stroke and a second stroke switch that is turned on at the second stroke. When the first stroke switch is turned on, photometry and distance measurement are started. , when the second stroke switch is turned on, shutter release is started.

5 is a camera contact for the ink face, such as lens focal length from the lens, subject distance, and power supply to the lens;
6 is Filmno Yatrone, 7 is Filmno Yatrone DX code 6af: DX contact point to read. 11 is a focus lens system 12 is a focus lens 1 drive unit consisting of a helicoid, a motor, etc. 13 is a zoom lens system 14 is a zoom lens drive unit 15 is a motor and a cam or a voice coil, etc. Aperture 16 is an aperture drive consisting of a step, a motor, etc. A portion 17 indicates a lens contact that can be connected to the camera contact 5.

Figure 3 shows the acceleration sensor 21°22b5 shown in Figure 1.
3+3b is a detailed diagram. Reference numeral 21 denotes an outer frame, from which a pace 24 to which a coil 23 is attached is suspended by two support springs 22 having low rigidity.

Above and below the coil 23 and pace 24, a magnetic circuit board 25 and permanent magnets 26m and 26b (26b is not shown) are arranged separately from them. The magnetic circuit board 25 is fixed to the outer frame 21, and the permanent magnet 26as26bFi
, is mounted on a magnetic circuit back plate 27 fixed to the bottom of the outer frame 21. The pace 24 is provided with a slit 28, and the magnetic circuit board 2 above the slit 28
A floodlight 29 such as an infrared light emitting diode is disposed at 5, and a PSD is placed on the magnetic circuit back plate 27 below the slit 28.
(Position 5 intensive Dlod
A photoelectric displacement measuring device 30 such as a) is arranged.

When the acceleration 1 acts on the outer frame 21 as shown by the arrow, the pendulum consisting of the coil 23 and the pace 24 tilts in the opposite direction to the acceleration a, and this swing angle is measured by the displacement measuring device of the beam from the projector 29 through the slit 28. It can be detected by the position on 30.

The magnetic flux from the permanent magnets 26a*26b is
e 26 b - A closed magnetic flux loop passing through the magnetic circuit board 25 and the magnetic circuit back plate 27 is formed, so that magnetic flux is generated in a direction perpendicular to the plane of the coil. Furthermore, the polarities of the permanent magnets 26a * 26b are reversed, and by passing current through the coil 23, the swing of the pendulum can be controlled according to Fleming's law. Therefore, it is possible to extract a feedback current corresponding to the acceleration a by flowing the electric current R rather than making the pendulum swing, and then bi-quag this current to obtain the acceleration.

FIG. 4 is a diagram showing one embodiment of the basic configuration of a camera according to the present invention.

In the figure, 41 is a photometric sensor consisting of a light receiving element such as an SPC for converting light passing through a lens into an electrical signal. 42.
TV-Av11* arithmetic circuit 4 performs temperature compensation and logarithmic compression on the signal current from the photometric sensor 41, and generates a photometric signal using a voltage signal that does not depend on temperature to determine the brightness of the subject.
In the photometry circuit that outputs to 3, the 1st stroke switch, CH SW
, photometry starts by turning on . 43 is TV
It is an AV calculation circuit, and Bvo (BY
o=Bv-Avo) and the TV and AV values ft2 for the subject brightness from the Sv from the DX code 6 of the film cartridge of DX44 and the program of the program section 45.
It is calculated when the stroke switch and chi switch are turned on. The program section 45 is programmed with, for example, a Tv-Av diagram (including Avo) shown in FIG. 46 is a shutter drive circuit, and T from the TVAV calculation circuit 43
Performs V-fold signal processing and controls shutter drive. Reference numeral 47 denotes an aperture drive circuit which controls the aperture drive of the lens based on the AV signal from the TVAV calculation circuit 43.

Reference numeral 48 denotes camera shake amount detection means, which starts detection when the first stroke switch SW1 is turned on using the aforementioned acceleration sensor 2a*2b*3a*3b. 49 is the camera shake peak value > [1ill path, and when the second stroke switch SW is turned on, calculation is started, and the time when the acceleration signal from the camera shake amount detection means 48 is differentiated and becomes O (maximum and minimum time of acceleration) ) outputs a signal to release the shutter holding circuit to the shutter holding circuit described later.

50 is a shutter holding circuit, and the shutter movement circuit 4
6, the shutter holding signal is fully output to hold the shutter just before running. Then, when a shutter hold release signal from the camera shake peak value calculation circuit 49 is input, the shutter hold is released and the shutter is caused to run.

Next, the operation of the camera configured as described above will be explained. It is assumed that the camera has an exposure program diagram set as shown in FIG. By attaching the No.Trone to this camera, the ISO signal read from the DX code 6a via the QDX contact 7 is supplied to the TVAV calculation circuit 43.Turn on the power switch (not shown) in the 0th order. This causes the next camera system, including this system, to go into standby mode. By pressing the first stroke switch, the switch SW, photometry and detection of the amount of camera shake are started. For example, Bv
If 0=2 and l5O=100, then from the program diagram TV= 6 (1/60) AV= 4 (FNO=4)
is decided. At this point, when the second stroke switch SWj is pressed, the TVAV calculation circuit 43 outputs TV=6 to the shutter drive circuit 46, and the shutter is held by the shutter holding circuit 50. At the same time, Av-Avo is output to the aperture drive circuit to drive the aperture. Also, in the camera shake peak value calculation circuit 49, the second step
After the CH SW is pressed, the signal from the acceleration sensor is first differentiated and becomes O, and at the 9th point, the shutter holding circuit 50 outputs a holding/decompressing signal to release the holding of the shutter and run the shutter at 1/60 seconds. let

Therefore, a photo without image preset is the photographer's shooting intention (in this case, the TV value and Av value determined by the program).
It will be photographed.

Incidentally, when frequency analysis is performed on camera shake when the camera is held in hand, as shown in FIG. 6, the frequency band of camera shake is 5 Hz or less, and most components have frequencies of 2 Hz or less.

In most cases of normal photography, the focal length of the lens is between 35mm and 200mm. In this case, the camera shake when shooting handheld is a concern because the shutter speed is 1/15 to 1/2 at 35 m.
It is almost impossible to hold it on hand with anything less than 60.1/8! However, if it is 1/125 or more, there is almost no problem. f at 200m
l 1/60 to 1/250 1/30 or less is almost impossible, 11500 or more is perfectly acceptable. In other words, the shutter speed is 1/155 to 1/250 (67 mm to 4
ms).

From the above, let's simplify the manual vibration to 2 Hz simple harmonic motion! As shown in Figure 10, in the case of simple harmonic motion at 1 Hz, the shutter time is 1/15 # 67 ms, if the shutter is run at the peak of the amplitude, the maximum value (2 x τ lower x 180' = 0.8) approximately 0.4 times (1-Nitobutsu x
180° = 0.33), and if the amplitude peak is in the middle of the shutter movement, it will be approximately 0.1 times the maximum value (1-* 250 x 180° = 0.08). .

Therefore, by setting the amplitude peak point to the middle of shutter travel, a photograph with even less image blur can be obtained.

Figure 7 shows a block diagram of a camera shake peak value calculation circuit that controls the start time of shutter travel so that the peak amplitude point is in the middle of shutter travel.

This camera shake peak value calculation circuit is a differential circuit (
a phase shift filter that shifts the phase of the signal from the integrating circuit 49 and the differentiating circuit 491 by half of a predetermined time according to the camera shake frequency;
49b, and a zero detection circuit 49c that determines the time when the acceleration signal from the phase shift filter 49b becomes zero and outputs a shutter holding release signal to the shutter holding circuit 50.

Phase shift filter 49bt-! As shown in FIG. 8, the phase shift angle at each shutter speed is determined depending on the frequency of the camera f.

That is, the signal from the camera shake amount detecting means 48 is calculated by the differentiating circuit 49, and the signal is applied to the phase shift filter 49.
By passing through b, a signal whose phase is shifted by half of the predetermined time according to the set shutter time in consideration of the camera shake frequency is output to the zero detection circuit 49e, and this zero detection circuit 4
Find the time when the acceleration becomes zero in 9a.

A shutter holding release signal is output to the shutter holding circuit 50 to cause the shutter to run. As a result, the signal is such that the acceleration is zero in the middle of the shutter travel time.

FIG. 9 shows a flowchart explaining the operation of a camera using a phase shift filter in the camera shake peak value calculation circuit.

By pressing the first stroke switch SW, the TV value and AV value are determined according to the program diagram of the program section, and high brightness and low brightness are determined based on the determined TV value and AV value.

Here, if the Tv value/AV value is determined to be "good", the camera shake amount detection a is started, and when the second stroke switch, CH SW, is further pressed, the diaphragm is driven by the AV value. Then, a phase shift filter is selected based on the set TV value, the shutter is held, and when the zero detection circuit of the camera blur peak value detection circuit detects a pre-peak, the shutter is driven and photographing is performed.

〔Effect of the invention〕

As explained above, according to the present invention, the shutter can be activated at a time when there is little camera shake.
Take pictures without image blur.

You can get nine benefits by being able to take photos without changing the sunset time.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the camera according to the present invention;
Figure 2 is a cross-sectional view, Figure 3 is a partially cutaway perspective view of the acceleration sensor, Figure 4 is a block diagram, and Figure 5 is 'rvw A.
Y diagram, Figure 6 is a frequency analysis diagram of camera shake, Figure 7 is a block diagram of the camera shake peak value calculation circuit, Figure 8 is a characteristic diagram of the phase shift filter, Figure 9 is a flowchart, and Figure 10 is the camera shake peak. FIG. 3 is a diagram showing the relationship between the time point and the time point at which the shutter starts running. 1: Camera body, 2m52b*3m, 3b: Acceleration sensor, 4: Grikeg, 5: Camera contact, 6: Film cartridge, 7: DX contact, 41: Photometric sensor, 42
: Photometric circuit, 43 :, 'rv-Av calculation circuit,
45 Nibragram unit, 46: Shutter drive circuit, 47: Aperture drive circuit, 482 Camera shake amount detection means, 49: Camera shake peak value calculation circuit, 50: Shutter holding circuit. Figure 1, '! I;l' change [ratio] Shift frequency (Hz)

Claims (1)

[Claims] camera shake detection means for detecting camera shake; shutter holding means for holding the shutter just before actuation; and means for instructing the shutter holding means to release shutter holding near the peak of camera shake based on a signal from the camera shake detection means. An image stabilization camera characterized by comprising: