JPH09197534A - Method and device for counting film for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize counter display preventing the taking-out time of a film cartridge from being mistaken. SOLUTION: By this method, the number of photographed frames is displayed on a display means when the rewinding action of a film is started and a display number obtained by subtracting one by one from the number of photographed frames during the rewinding action of the film is successively displayed on the display means. The subtraction on the display number displayed on the display means is operated late in comparison with a case that the subtraction is operated one by one by detecting the winding-up of one frame when the film is rewound. Thus, the time that the film cartridge can be taken out from a camera and the time that the display number becomes zero or 'E' resulting from that the display number displayed on the display means is successively subtracted can be made to match each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film counting method and device for a camera, and more particularly, after film rewinding is completed, the shooting condition of the film such as whether the film has been taken or is being taken is set in a film or a film cartridge. The present invention relates to a camera film counting method and apparatus applied to a camera.

[0002]

2. Description of the Related Art In general photography of a 135 film, film rewinding is automatically started when the filming of all frames of the film is completed or a film rewinding command is issued during the filming. In the rewinding process of the film, the film counting device sequentially counts down and displays the number of films as one frame is rewound, and when the rewinding to the first frame is completed, the pre-winding part of the film is about several seconds. After rewinding with, the symbols such as "E" (empty symbols) are displayed.

On the other hand, recently, a new standard film cartridge as shown in FIG. 6 has been proposed. The film cartridge 10 has a single spool 12 as shown in FIG. 6, and a film 14 is wound around the spool 12. The film 14 is provided with perforations 14A indicating the positions of the frames, and
A magnetic recording layer 14B is formed on the entire surface of the film or on the edge of the film, and information relating to each frame can be recorded on this magnetic recording layer 14B.

Further, in this film cartridge, any film such as an unexposed film, a film before or after development during filming or a film after development, can be wound up in the cartridge. There is. Although not shown in FIG. 6, the film cartridge 10 is provided with a light-shielding lid so that the film in the cartridge is not exposed.

[0005]

By the way, in the camera using the film cartridge 10, when the filming of all frames of the film is completed or the film rewinding is instructed during the filming, the film rewinding is started, When all the films have been rewound into the cartridge, the light-shielding lid of the film cartridge is closed, and information indicating the film shooting state such as whether the film has been shot or in the middle of shooting is recorded on the magnetic recording layer of the film, or The film cartridge can be set (recorded) on the identification means provided on the film cartridge, and then the film cartridge can be taken out from the camera.

Therefore, as shown in FIG. 7, it takes a time T ₂ required to set the above information from when the counter display is "1" to when "E" is displayed. During this set time T ₂ , "-" is displayed as a counter display.
- Although progress display is made of ", set time T ₂ is, 1
Since it is as long as 0 seconds, the photographer (user) judges that the rewinding has been completed during this set period (the film cartridge can be taken out), and as a result, the film room is opened carelessly for shooting. There was a risk that the film would be exposed to outside light.

The present invention has been made in view of the above circumstances. Even when the film cartridge takes a long time to set the photographing information and the like after the rewinding of the film is completed, the time for taking out the film cartridge can be improved. An object of the present invention is to provide a film counting method and device for a camera, which can display a counter without causing misidentification.

[0008]

In order to achieve the above object, the present invention displays the number of photographed frames at that time on the display means at the start of rewinding of the film, and the rewinding of the film causes In the film counting method of the camera in which the number of images displayed on the display means is sequentially reduced, the time required for the number of images displayed on the display means during the rewinding is reduced by the number of frames actually rewound. Is characterized by delaying and reducing. Then, even after all the films have been wound into the film cartridge, the display number is kept decreasing until the film cartridge can be taken out. When the film cartridge can be taken out, the display number is reduced. Is stopped, and the display at this time is set to, for example, "0" or "E".

According to the present invention, a relatively long time until the displayed number of sheets is switched to a symbol such as "E" at the time of rewinding the film is simulated as the time required for rewinding the number of photographed films. Allocation (that is, the time for switching the number of displayed images is set to be longer than the time interval required to actually rewind one frame), whereby the time interval for sequentially counting down the number of displayed images and the number of displayed images from "1" to " The time interval until switching to a symbol such as "E" is made the same or substantially the same so that the photographer does not give time to open the film chamber carelessly.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a camera film counting method and apparatus according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a block diagram of essential parts of a camera provided with a film counting device according to the present invention. In the figure, 10 is a film cartridge loaded in the film chamber, 20 is a winding shaft for winding the film 14 supplied from the film cartridge 10, and 22 is a photographing optical system including a photographing lens, a shutter and the like. still,
16 is a light-shielding lid of the film cartridge 10,
Is a lid opening / closing member that is rotated when the light shielding lid is opened / closed.

This camera has an automatic film winding and rewinding function, and one frame is wound on the basis of a frame detection signal from the perforation sensor 24 during photographing. That is, the perforation sensor 24 is
Perforation 14A of the film 14 (see FIG. 6)
A frame detection signal is output each time the image is detected, and the film feeding control means (not shown) makes a 1 based on the frame detection signal.
Controls the feeding / stopping of the film when winding frames.

The frame detection signal from the perforation sensor 24 is added to the counter 26. The counter 26 is an up / down counter, which counts up each time a frame detection signal is added from the perforation sensor 24 during shooting, and outputs the count value to a display 30 such as an LCD via a display control circuit 28. As a result, the number of shots is displayed on the display 30.

On the other hand, the filming of all frames of the film is completed,
Alternatively, when the film rewinding operation is performed during the shooting and a rewinding command is output, the automatic film rewinding is started. When the film is automatically rewound, the counter 26 counts down each time a frame detection signal is applied from the perforation sensor 24, and the display control circuit 28
Executes display control according to the present invention described later.

Next, the display control during film rewinding according to the present invention will be described in principle. Assuming that the rewinding command is output when the number of shots is 25, the shortest time t for taking out the film cartridge 10 is t.
Is the time t required to rewind 25 frames as shown in FIG.
_1, film is the total time between the time t ₂ required to set the information indicating the photographing state of the film, such as one way already shot or captured.

In the present invention, the time t ₂ required to set the above information is pseudo-allocated to the time t ₁ required to rewind the film. That is, as shown in FIG. 2, rather than the timing at which the number of shots is counted down with the actual rewinding of one frame,

[0016]

[ _Formula 9] t ₂ / n _exp = t _dly n _exp : Number of shots at the start of rewinding t ₂ : Delay shown in maximum time from rewinding to the first frame until film cartridge can be taken out The timing of switching the display of the number of shots is delayed by the time t _dly .

As a result, the time required to rewind each frame is displayed as if the time t _{dly is} long, but after the number of shots "1" is displayed, "E" is displayed at the same display switching timing. You can switch to the display of ". FIG. 3 is a block diagram showing an example of the display control circuit 28 shown in FIG. As shown in the figure, the display control circuit 28 includes a selector 40, a driver 41, and a memory 4.
2, arithmetic circuit 43, timer 44 and down counter 4
It is composed of 5.

The selector 40 has an A input for inputting the count value from the counter 26 (FIG. 1) and a down counter 45.
B input to input the count value from
The input is selected and the count value is output to the display device 30 via the driver 41. As a result, the number of shots counted by the counter 26 is displayed on the display unit 30.

On the other hand, when the film rewind command is input, the selector 40 selectively outputs the count value added to the B input. Further, the memory 42 stores the count value (the number of photographed frames) n _exp at the time of inputting the rewind command,
The timer 44 starts a predetermined timing operation at the time of inputting the rewind command, and the down counter 45 is set to the count value n _exp at the time of input of the rewind command.

The arithmetic circuit 43 executes the arithmetic operation of the equation (9) based on the count value n _exp stored in the memory 42, and calculates the delay time t _dly . The arithmetic circuit 43
Is preset with time t ₂ which is a unique value according to the camera. The timer 44 outputs a pulse signal for switching the display, and is added from the arithmetic circuit 43 to a predetermined time C required for the actual rewinding of one frame (a constant determined by the rewinding speed of the film). The time t _dly is added, and a pulse signal is output to the down counter 45 each time the added time (C + t _dly ) elapses from the input of the rewind command. The down counter 45
Count value n _exp set at the time of inputting the rewind command
Every time a pulse signal is applied from the timer 44, the count value is counted down by B of the selector 40.
Output to input.

Since the selector 40 selectively outputs the count value added to the B input when the film is rewound, the count value of the down counter 45, that is, the count value of the down counter 45 is displayed on the display 30.
Every time the time (C + t _dly ) elapses from the input of the rewind command, a value obtained by sequentially counting down the number of captured images n _exp is displayed. As a result, when the film is rewound, a value different from the count value of the counter 26 is displayed as shown in FIG. 2, the number of shots "1" is displayed, and then "E" is displayed immediately.

In this embodiment, the number of photographed images is down-counted at a time interval in which the delay time t _dly is added to the constant C required for rewinding one frame, but the time interval t _int defined by the following equation is used.

[0023]

T _int = (t ₁ + t ₂ ) / n _exp t ₁ : time required to rewind all the frames of the film after starting rewinding the film t ₂ : rewind all the frames of the film It is also possible to down-count the number of shots until the time when the film cartridge can be taken out.

Further, in the above embodiment, when the film is rewound, the number of shot images is down-counted and displayed regardless of the frame detection signal from the perforation sensor 24, but the present invention is not limited to this. The number of shots may be displayed in association with the signal. That is,
As shown in FIG. 4, the conventional pulse signal for switching the display is
Although it coincides with the frame detection signal in time, in another embodiment of the present invention, the frame detection signal is t _dly , 2t _dly , 3
The signal sequentially delayed by t _dly ... _Is used as a pulse signal for display switching.

FIG. 5 is a block diagram showing another example of the display control circuit 28 shown in FIG. Note that parts common to those in FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted. As is clear from a comparison between FIG. 3 and FIG. 5, in FIG. 5 a subtractor 46 is added, and instead of the timer 44, a delay circuit 47 for delaying the frame detection signal is provided. The subtractor 46 subtracts the count value k output from the counter 26 (FIG. 1) from the count value n _exp at the time of inputting the rewind command stored in the memory 42, and the subtracted value (n _exp −k ) Is output to the delay circuit 47. The value (n _exp -k) is 0 at the time of inputting the rewinding command, but increases by 1 every time one frame is rewound.

The delay circuit 47 appropriately delays the frame detection signal output from the perforation sensor 24 and outputs it as a pulse signal for display switching. The delay time is the time t added by the arithmetic circuit 43.
_dly (see the equation (9)) is multiplied by the value (n _exp −k) added from the subtraction circuit 46, and the time {(n _exp −k) × t _dly } obtained by the multiplication is input. The frame detection signal to be output is delayed and output. That is, each time the delay circuit 47 inputs a frame detection signal, the frame detection signal is sequentially delayed by t _dly , 2t _dly , 3t _dly ... And this is output to the down counter 45 as a pulse signal for display switching.

The down counter 45 counts down the count value n _{ex p} set at the time of inputting the rewinding command each time the pulse signal is applied from the delay circuit 47, and the count value is input to the B input of the selector 40. Output to. Since the selector 40 selectively outputs the count value added to the B input when the film is rewound, the display 30
Indicates the count value of the down counter 45.

In this embodiment, the time required to wind one frame and the time t ₂ from the time the film is rewound to the first frame to the time when the film cartridge can be taken out are shown at the start of rewinding. The count value n _exp is down-counted at a time interval obtained by adding the delay time divided by the number of shots n _exp , but the present invention is not limited to this, and for example, when the remaining 10 frames are reached during rewinding,
The count value 10 may be down-counted at a time interval obtained by adding the time required to wind up one frame and the delay time obtained by dividing the time t ₂ by 10. In this case, the time interval for counting down the count value becomes longer from the middle of the rewinding (10th frame), and it seems that the film rewinding speed becomes slower, but even in this case, the purpose can be achieved. .

The time interval for counting down the count value is not limited to a fixed time interval. For example, the time interval may be shortened or lengthened as the film is rewound, and when the film cartridge becomes ready to be taken out, it is displayed as zero or E. It may be. In addition, it takes time for the 35 mm size film to be rewound into the film cartridge after the film is rewound to the first frame. May be delayed.

Furthermore, in this embodiment, the number of images displayed during shooting is the number of shots (the number of shot frames).
However, the number of images that can be captured (the number of unexposed frames) may be displayed. In this case, when an unused film cartridge is loaded in the camera, film information such as the number of film frames and ISO sensitivity is read from the film cartridge, and the number of read frames (total number of unexposed frames) is displayed in the counter. After setting, the number of unexposed frames is counted down for each shooting. On the other hand, at the time of rewinding, the display of the current number of unexposed frames is switched to the display of the number of photographed frames, and the number of photographed frames is counted down by one in the above-described manner.

Further, in the present embodiment, the number of photographed frames is counted down by one, but it is not limited to this, and may be counted down by two, for example. However, when counting down by 2,
It is necessary to make the countdown cycle twice as long as when counting down by one.

[0032]

As described above, according to the camera film counting method and device of the present invention, the time from the rewinding to the first frame until the film cartridge can be taken out is taken. By allocating a pseudo time to the rewinding of the number of films, and displaying the number of displayed films later than the number of films corresponding to the position where the film is actually rewound, the number of displayed films "1" to "E" etc. You can shorten the time to switch to the symbol
As a result, it is possible to eliminate an erroneous operation in which the photographer carelessly opens the film chamber.

[Brief description of drawings]

FIG. 1 is a block diagram of a main part of a camera including a film counting device according to the present invention.

FIG. 2 is a diagram used for explaining a counter display according to the present invention.

3 is a block diagram showing an example of the display control circuit shown in FIG.

FIG. 4 is a diagram used for explaining a counter display according to the present invention.

5 is a block diagram showing another example of the display control circuit shown in FIG.

FIG. 6 is a view showing an example of a film cartridge applied to the camera according to the present invention.

FIG. 7 is a view showing a counter display at the time of rewinding the film in the related art.

[Explanation of symbols]

 10 ... Film cartridge 24 ... Perforation sensor 26 ... Counter 28 ... Display control circuit 30 ... Indicator

Claims (16)

[Claims] 1. A camera in which the number of frames taken at that point in time is displayed on the display means at the start of film rewinding, and the number of images displayed on the display means is sequentially reduced as the film is rewound. In the film counting method, the number of images displayed on the display means during the rewinding is
A film count method for a camera, which is characterized by delaying the time as compared with the case where the number of frames actually rewound is reduced. 2. The film counting method for a camera according to claim 1, wherein the number of displayed images is reduced until the film cartridge can be taken out even after all the films have been wound into the film cartridge. . 3. The film cartridge has a light-shielding lid that is closed after all the films have been wound into the film cartridge, and the operation of reducing the number of displayed images is
3. The film counting method for a camera according to claim 2, wherein the light shielding lid is closed and then stopped. 4. At the time of starting rewinding of the film
Number of frames taken n_{ex p}Is displayed on the display means,
The number of frames already taken n during the film rewind _expFrom 1
The number of displayed images, which is subtracted by one, is sequentially displayed on the display means.
In the film counting method for melah, at the start of rewinding, a delay time t defined by the following equation_dly [Equation 1] t_dly= T_Two/ N_exp t_Two: Film after all frames of film are rewound
The time until it becomes possible to remove the cartridge is calculated, and the number of images displayed on the display means during the rewinding is calculated as
The delay time t is equal to the time required to rewind one frame._dlyTo
It is characterized by subtracting one by one at the added time interval and displaying it.
How to count the film on the camera. 5. At the time of starting the film rewinding,
Number of frames taken n_{ex p}Is displayed on the display means,
The number of frames already taken n during the film rewind _expFrom 1
The number of displayed images, which is subtracted by one, is sequentially displayed on the display means.
In the film counting method for melah, at the start of rewinding, a delay time t defined by the following equation_dly [Equation 2] t_dly= T_Two/ N_exp t_Two: Film after all frames of film are rewound
The time until it becomes possible to take out the cartridge is calculated, and it is rewound by the rewinding operation during the rewinding.
Number of tops n_rwdAnd the number of frames already taken
n_expFrom the number of frames counted above_rwdDisplayed sheet after subtracting
Time T, which is defined by the following equation_dsp [Formula 3] T_dsp= T_rwd+ N_rwd× t_dly T_rwd: Number of frames rewound n_rwdWhen was counted
The camera frame is characterized by displaying on the display means every moment.
Illumin count method. 6. The number of photographed frames n _{ex p} at that time at the start of film rewinding is displayed on the display means, and
In a film counting method for a camera, which sequentially displays the number of displayed images subtracted from n _exp by 1 during the film rewinding, at the start of the rewinding, a time interval t _int defined by the following equation: t _int = (t ₁ + t ₂ ) / n _exp t ₁ : the time required to rewind all the frames of the film after starting the rewinding of the film t ₂ : the film cartridge after all the frames of the film have been rewound Of the number of images to be displayed on the display means during the rewinding,
A film counting method of a camera, wherein the time interval t _int is subtracted by 1 and displayed. 7. The camera according to claim 1, wherein either one of the number of photographed frames and the number of unexposed frames is displayed on the display means during photographing. Film counting method. 8. The film cartridge has a light-shielding lid and setting means for setting a filming state of the film which has been photographed or is in the middle of photographing, and at the time t ₂ , the closing operation of the light-shielding lid and 7. The camera film counting method according to claim 4, including a time required for setting the photographing state. 9. The film counting method for a camera according to claim 7, wherein when the film cartridge can be taken out, the fact is displayed on the display means. 10. The film counting method for a camera according to claim 9, wherein the symbol "E" is displayed on the display means when the film cartridge can be taken out. 11. At the time of starting the film rewinding
Number of frames shot in n _expIs displayed on the display means
The number of frames already taken during film rewinding is n_expOr
The display number obtained by subtracting 1 from each is sequentially displayed on the display means.
In a film counting device for a camera, the delay time t defined by_dly [Formula 5] t_dly= T_Two/ N_exp t_Two: Film after all frames of film are rewound
Calculating means for calculating the time until it becomes possible to take out the cartridge,_expDisplayed number subtracted by 1 from
Is the delay time t in the time required to rewind one frame.
_dlyAre sequentially displayed on the display means at time intervals including
A camera film counting device, characterized by comprising:
Place. 12. At the time when the film rewinding is started
Number of frames shot in n _expIs displayed on the display means
The number of frames already taken during film rewinding is n_expOr
The display number obtained by subtracting 1 from each is sequentially displayed on the display means.
In a film counting device for a camera, the delay time t defined by_dly [Equation 6] t_dly= T_Two/ N_exp t_Two: Film after all frames of film are rewound
Calculating means for calculating the time until the cartridge can be taken out, and the rewinding operation during the rewinding
Number of tops n_rwdAnd the number of frames already taken
n_expFrom the number of frames counted above_rwdDisplayed sheet after subtracting
Time T, which is defined by the following equation_dsp [Equation 7] T_dsp= T_rwd+ N_rwd× t_dly T_rwd: Number of frames rewound n_rwdWhen was counted
A film count device for a camera, characterized by comprising:
Place. 13. The time when the film rewinding is started
Number of frames shot in n _expIs displayed on the display means
The number of frames already taken during film rewinding is n_expOr
The display number obtained by subtracting 1 from each is sequentially displayed on the display means.
In the film counting device of the camera, the time interval t defined by_int [Equation 8] t_int= (T₁+ T_Two) / N_exp t₁: Everything from film to film rewind
Time required to rewind the frame_Two: Film after all frames of film are rewound
Calculating means for calculating the time until it becomes possible to take out the cartridge,_expDisplayed number subtracted by 1 from
Is the time interval t_intTo display on the display means
Means for controlling the film count of the camera.
Place. 14. The camera according to claim 11, wherein the display means displays either one of the number of photographed frames and the number of unexposed frames during photographing. Film counting device. 15. The film counting device for a camera according to claim 14, wherein said display means displays a message indicating that the film cartridge can be taken out. 16. The film counting device for a camera according to claim 15, wherein said display means displays a symbol "E" when the film cartridge can be taken out.