JPH04116537A - Prewinding system camera using film with magnetic storage part - Google Patents

Abstract

PURPOSE:To execute high-density recording within a prescribed range while avoiding expensive and complicated constitution by providing a storage means and a prediction and calculation means which predicts and calculates the film feeding speed of a frame after photographing based on the information on a present photographing frame number and information from the storage means corresponding to it. CONSTITUTION:The storage means which stores the winding time of an interval between the respective frames detected by a frame position detection means 102 by making it correspond to a frame number at a prewinding time is provided. Besides, the prediction and calculation means 101A which predicts and calculates the film feeding speed of the frame after the photographing based on the information of the present frame number obtained by the detection means 102 and the information from the storage means 103 corresponding to it is provided. Then, the film feeding speed of the respective frames after the photographing is predicted based on the winding time of the respective frames at the prewinding time. Thus, the high-density recording is executed within the prescribed range while the constitution is prevented from becoming expensive and complicated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention comprises a magnetic head for writing information into a magnetic storage section provided on a film, and a frame position detection means for detecting a frame position from the amount of film feeding. The present invention relates to an improvement of a prewind type camera using a film with a magnetic storage section.

Note that the above-mentioned prewind method refers to a method in which once a film cartridge is loaded into the camera, all the film is wound, and then rewound by one frame each time a photograph is taken.

(Background of the Invention) Conventional devices that magnetically record information can record at appropriate density by feeding the magnetic recording medium at a constant speed or by detecting the speed of the magnetic recording medium with an encoder. It is l/A as possible.

On the other hand, in the case of cameras, as described in U.S. Pat. No. 4,864,332, etc., there are cameras that use a magnetic head to record photographic information such as shutter speed and aperture value in a magnetic storage section provided on the film. Proposed.

However, in cameras such as those proposed above, the length of information that can be recorded per frame of film is finite, and although it is necessary to ensure that the information per frame does not exceed this length, constant speed feed is almost impossible. However, in order to realize the above-mentioned functions, the camera must be equipped with an encoder having an expensive and complicated configuration.

There is also a method that detects the power supply voltage of the camera and uses duty drive to feed the film based on this, trying to keep the feeding speed as constant as possible, but even if this method is adopted, many This was insufficient when attempting to record information at high density.

(Objective of the Invention) The object of the present invention is to solve the above-mentioned problems, and to prevent the structure from becoming expensive and complicated, and to enable high-density recording within a predetermined range. It is an object of the present invention to provide a prewind type camera using attached film.

(Features of the Invention) In order to achieve the above object, the present invention provides a storage means for storing the winding time between each frame detected by a frame position detection means in association with a frame number during prewinding, and a frame position Predictive calculating means for predicting and calculating the film feeding speed of the frame after photographing based on the current photographing frame number information obtained from the detecting means and the corresponding information from the storage means;
The present invention is characterized in that the film feeding speed of each frame after shooting is predicted from the winding time of each frame during prewinding.

(Embodiments of the Invention) Hereinafter, the present invention will be described in detail based on illustrated embodiments.

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of the present invention, and its operation will be explained below using the flowchart shown in FIG.

The control means 101 first determines whether or not the back cover is closed in step 201, and when it determines that the back cover is closed, the control means 101 proceeds to step 202, assuming that the film cartridge is loaded in the camera, and drives the film feeding means 104. Then, winding of the film provided with the magnetic storage section is started. Next, in steps 203 and 204, the current frame number and the time required to wind up one frame are detected from the information from the frame position detection means 102 and the timer 10IB, and these pieces of information are stored in the storage means 103 in association with each other. In the next step 205, all films (total number)
It is determined whether or not winding has been completed, that is, whether or not the prewind has been completed, and if it has not been completed, the same operation is repeated thereafter. After that, the process proceeds to step 206 by confirming the completion.

In step 206, the state of the switch SW1, which is turned on by the first stroke of the release button, is determined, and when it is determined that it has been turned on, the process proceeds to step 207208, where a photometering means and a distance measuring means (not shown) are respectively operated to perform photometry. Then, in step 209, the switch S is turned on by the second stroke of the release button.
The state of W2 is determined. Then, the switch SW2 is turned on.
If it is determined that this has been done, the process proceeds to step 210, where known lens control and shutter control, that is, focus adjustment and exposure operations on the film surface are performed.

In the next step 211, the calculation means 101A in the control means 101 detects the current shooting frame number obtained from the information from the frame position detection means 102, and the film feeding speed suitable for this shooting frame number is detected. A predictive calculation is performed.

In the next step 212, the control means 101 instructs the film feeding means 104 to feed the film according to the predicted feeding speed. In step 213, the magnetic head 105 is driven, and the shutter speed, aperture value, shooting date, etc. Write various shooting information such as comments.

In the next step 214, it is determined whether or not the feeding of the photographic frame has been completed, and upon determining that it has been completed, the process proceeds to step 215, in which the film feeding means 104 is commanded to stop the film feeding.

Next, in step 216, it is determined whether the film has finished, that is, whether all frames have been photographed,
If the process has not been completed, the process returns to step 206 and the same operation is repeated. Furthermore, when all the frames have been photographed, as is well known, the operation of winding all the films into the film cartridge is started.

As described above, since the feeding speed after shooting is predicted and calculated from the winding time information of each frame stored in the storage means 1.3 when the film is wound, an encoder with an expensive and complicated structure is used. This makes it possible to record high-density information within a predetermined range.

FIG. 3 is a view of the camera that makes it possible to implement the above embodiment, viewed from the back with the back cover removed.

In Figure 3, 1 is the camera body, 2 is the viewfinder, and 3
4 is a film cartridge chamber, and 4 is a fork for driving a spool in the film cartridge to rewind the film. 5 is a film aperture, 6 is a magnetic head, and 7 is a film winding spool, which is driven when winding the film.

FIG. 4 is a block diagram showing a schematic configuration of the camera.

In FIG. 4, 51 is a photometry circuit that measures the brightness of an object to be photographed, and 52 is a distance measurement circuit that measures the distance to the object. A microcomputer (hereinafter referred to as microcomputer) 53 controls various circuits, and has a timer, ROM, RAM, etc. inside. Reference numeral 54 denotes a switch (hereinafter referred to as SWI) for starting photometry/distance measurement which is turned ON by the first stroke of the release button of the camera (not shown), and 55 is turned ON by the second stroke of the release button to start the release operation. (hereinafter referred to as SW2). 56 is a camera back cover switch (not shown), which is turned on in conjunction with opening and closing of the back cover.

Turn off. 57 is a switch (not shown) for detecting the presence or absence of a film cartridge. 58 reads the number of films and film type (for example, manufacturer, universal/negative, film sensitivity, etc. (this determines the type of film base and emulsion and predicts the film pulling and winding force) from the DX code provided on the film cartridge. This is a DX code reading circuit.

Reference numeral 59 denotes a motor control circuit for controlling a film feeding motor (not shown), and the film is wound up by forward rotation of the motor and rewound by reverse rotation of the motor. 60 is a shutter control circuit for controlling exposure to the film; 61 is a lens control circuit for controlling the position of the photographing lens so that the subject is in focus; 62 is a circuit for controlling the magnetic head 6 shown in FIG. This is a head control circuit that records and reads various information into and from the provided magnetic storage section. Reference numeral 63 denotes a frame position detection circuit for detecting each frame (one frame) on the film, and there is a method for detecting perforations or a method for detecting the amount of film travel.

Reference numeral 64 denotes a temperature detection circuit, which is configured independently in this embodiment, but can also be used as the photometry circuit 51. 65 is a voltage detection circuit that detects the battery voltage, performs A/D conversion, and transmits the information to the microcomputer 53.

FIG. 5(a) is a graph showing changes in film winding time (i.e., changes in feeding speed) during prewinding.

The film is wound by the film take-up spool 7, and the winding time per frame increases as the spool diameter apparently increases as the film is wound onto the film take-up spool 7. As shown in FIG. 5(a), the winding time t is shortened. On the other hand, as the spool diameter increases, the load increases, so
Speed does not simply depend on the ratio of the spool diameter (part B).

If the prewind method is used as in this example, it is better to record the winding time for all the pieces during prewind.
This information is useful when feeding (rewinding) the film. just,
It is possible to predict and correct load fluctuations due to the number of turns.

FIG. 5(b) is a diagram in which the time between photographed frames during rewinding is predicted using the information in FIG. 5(a).

In the rewinding direction, the film is wound around the spool in the film cartridge, so initially the rewinding time t
' takes time, and as the photographic frame (frame number) advances, the winding diameter increases and the rewinding time t' becomes shorter. On the other hand, since the load increases as in the case of winding, the unwinding time t' does not decrease monotonically (part B').

Therefore, it becomes possible to perform correction using the information shown in FIG. 5(a) stored at the time of prewinding. That is, Fig. 5(a)
The prediction in FIG. 5(b) is that the film take-up spool 7
This is possible by determining the ratio between the rotation speed and diameter of the spool and the rotation speed and diameter of the spool in the film cartridge. First, find the initial velocity at the beginning of winding on each spool, then use the ratio of each spool diameter to find the rate of change in the apparent spool diameter due to film thickness to find the slope. Finally, the portion where the linear change does not occur (portion B) is corrected using the raw data shown in FIG. 5(a). Note that the slope of the portion B can also be predicted by predicting and correcting the load fluctuation based on the remaining amount of film and the amount of winding.

An example of the calculation formula according to the above explanation is shown below.

In FIG. 5(a), N: total number of sheets, M: frame number of the part (A-B) where the winding time does not change linearly,
to: first winding time, A: slope between (NM),
B is the slope between (M and 1). Further, n in the following formula means the frame being fed.

tn:to -A (N-n),',(N232M
)tn=t(, -A (N-M)-B (M-n),'
, (M≧n≧1) Next, let the diameter of the film take-up spool 7 be Dl, its rotation speed when no load is Vl, the spool diameter of the film cartridge be Dl, and the rotation speed when no load is v2. .

In FIG. 5(b), t6 "Dl /DI XV2 /Vt X t6A
'=AXD1 /D2 B' =BXD1 /D2, tn ==jOA' (n 1), ', (M≧n
≧1) It is expected that tn :=jO-A' (M-1) -B' (n-M) ,', (N232M).

It is quite conceivable that the correction term for the above approximate formula will increase by taking into account the film type, temperature, and power supply voltage state, and this will enable appropriate information to be recorded. As described below, these factors are taken into account when predicting the feeding speed.

Furthermore, it is also effective to create a predictive formula that takes into account actual data such as the characteristics of the film feed motor used in the camera and the gear train.

6(a) and 6(b) are operational flowcharts of the microcomputer 53 shown in FIG. 4, which has the function of performing the above-mentioned predictive calculation.

"Step 1" It is determined whether the back cover is closed based on the state of the back cover switch 56. If it is not closed, step 1 is repeated, and if it is closed, the process proceeds to step 2.

"Step 2" It is determined whether the film cartridge is loaded in the film cartridge chamber 3 based on the state of the switch 57. If the film cartridge is not loaded, the process returns to step 1, and if it is loaded, the process proceeds to step 3.

"Step 3" A film feeding motor (not shown) is rotated normally via the motor control circuit 59 to start winding the film.

Step 4J The DX code reading circuit 58 is driven to read the number of films (total number) and film type from the DX code provided in the film cartridge.As a reading method, reading from the film by the magnetic head 6 may be considered. This embodiment assumes a method of reading the DX code on the surface of the film cartridge as described above.

"Step 5" Here, the number of films read in step 4 (total number) is set.

"Step 6" Here, set the film type (manufacturer reversal/negative, film sensitivity) read in step 4.

"Step 7" It is determined whether one frame has been detected by the frame position detection circuit 63 which detects the position of a frame from perforations or the like. If not detected, step 7 is repeated, and if detected, the process proceeds to step 8.

"Step 8" The winding time required to wind one frame is read from the timing of the frame position detected in step 7 above using an internal timer, and is stored in the RAM in the microcomputer 53.

"Step 9" In order to know which frame the above winding time information corresponds to, a frame number is also stored in the RAM in correspondence with the above information.

"Step 10" The temperature inside the camera is detected by the temperature detection circuit 64.
The temperature information is inputted and stored in the RAM.

"Step 11" The voltage detection circuit 65 is operated to measure the power supply voltage, and this power supply voltage information is input and stored in the RAM.

"Step 12" It is determined whether or not prewinding has been performed up to the number of films set in step 5. If the prewinding has not been completed, the process returns to step 7, and if the prewinding has been completed, the process proceeds to step 13.

"Step 13" Switch SWI enters standby state.

Then, when the switch SW1 is turned on, the process proceeds to step 14.

"Step 14" The photometric circuit 51 is operated and the subject brightness information obtained here is input.

"Step 15" The distance measuring circuit 52 is operated and the object distance information obtained here is manually input.

"Step 16" Determine the state of switch SW2 and turn O
If NL/, proceed to step 18 in FIG. 6(b), and O
If it remains FF, the process advances to step 17.

"Step 17" Here, the state of the switch SW1 is determined again, and if it remains ON, the process returns to step 16 and the switch SW1 is turned on.
If it is FF, the process returns to step 13.

"Step 18" The lens control circuit 61 is controlled based on the object distance information (distance measurement information) obtained in step 15, and the photographic lens is focused.

"Step 19" The shutter control circuit 60 is controlled based on the subject brightness information (photometry information) obtained in step 14, and an exposure operation is performed on the film surface.

"Step 20" In order to know the temperature inside the camera at this point, the temperature detection circuit 64 is operated, and the obtained temperature information is input.

"Step 21" In order to know the state of the power supply voltage at this point, the voltage detection circuit 65 is operated, and the obtained power supply voltage information is input.

"Step 22" The winding time between one frame in step 8 and the winding time for one frame in step 9 are used to know the inclination that appeared in the prediction formula explained using FIG. 5(b) and the first winding time. In addition to the frame number, we also consider the number of films in step 5, the type of film in step 6, the temperature in step 10, the power supply voltage in step 11, the temperature in step 20, and the power supply voltage in step 21. Predicting the feeding speed of the frame after shooting is performed.

"Step 23" Based on the result of step 22 above, the write frequency f for recording information to the magnetic storage section is determined.

"Step 24" The film feeding motor is reversely rotated via the motor control circuit 59 at the feeding speed determined by the above-mentioned predictive calculation, and rewinding of the film is started.

"Step 25" The magnetic head 6 is actually driven via the head control circuit 62 to write the various types of photographic information described above onto the magnetic memory provided in the film being fed.

"Step 26" It is determined whether or not the frame position has been detected by the frame position detection circuit 63. If detected, the process proceeds to step 27.

"Step 27" The drive of the film feeding motor is prohibited via the motor control circuit 59, and rewinding of the film is stopped.

"Step 28" Current frame number and step 5
It is determined from the number of films at , whether all the frames have been photographed, and if not, the process returns to step 13 and the same operation is repeated, and if it has been completed, the process proceeds to step 29.

"Step 29" The film feeding motor is reversed via the motor control circuit 59, and all the film is wound into the film cartridge.

"Step 30" It is determined whether or not there is a film cartridge in the film cartridge chamber 3 based on the state of the switch 57, and when there is no film cartridge, the process returns to step 1 in FIG. 6(a).

FIG. 7 shows an example of changes in the winding time t due to temperature changes.

As the temperature rises, the winding time tends to become faster due to a reduction in the film winding load, a reduction in the friction of the gear train, and an increase in the efficiency of the power source battery, while at a lower temperature, the winding time tends to become slower. Therefore, in the step 22, the feeding speed obtained under other conditions is predicted by the temperature based on the ratio when the normal temperature is set to "1".

FIG. 8 shows changes in the winding time t due to changes in the power supply voltage.

It is well known that the higher the power supply voltage, the faster the rotation of the film feeding motor becomes, and the shorter the winding time t becomes. In step 22, in addition to the correction for this, since the camera in this embodiment is a prewind system, power is continuously consumed during winding, and a voltage drop occurs as the winding progresses. When shooting a single frame, the power must be restored, so we take this into consideration when making corrections.

FIG. 9 is a plot of the difference in the average winding time depending on the number of films (total number of films).

If all information is stored during prewinding as shown in Figure 5(a), the impact will be small, but if no information is stored during prewinding or if the no-prewind method is used, the load will increase as the amount of winding increases. By using this number of films as one of the correction factors in step 22, it is possible to predict the feeding speed more accurately because of the increase in the drawer force when the film cartridge is tightly packed. becomes. Furthermore, when the diameter of the spool in the film cartridge changes depending on the number of films, such as when taking 12 or 24 films, this information is essential for predicting the feeding speed.

In addition, in this embodiment, the load fluctuation caused by the winding amount and the remaining amount is included as a correction factor, but since these relationships depend on the total number of films, from this point of view, the number of films is important information. It would be one.

FIG. 10 is a plot of the difference in the average winding time t when the film type, for example, manufacturer reversal/negative, film sensitivity, etc., is classified into A-H.

If the camera has information about the average film type in this way, it becomes possible to predict the feeding speed corresponding to various types of film, but in step 22, this information is taken into account. I am using it.

Furthermore, it is also possible to correct the fact that changes due to temperature differ depending on the type of film. In other words, it is possible to handle corrections other than changes in the apparent spool diameter.

FIG. 11 is a flow chart showing the operation of the main parts in another embodiment of the present invention, and
Steps 2o to 25 in Figure (b) are partially modified. Note that the same step number indicates a part that performs the same operation, so the details are omitted here.

After step 20, the process proceeds to step 24, where the film starts to rewind, and then proceeds to step 21, where the power supply voltage is measured, and in the next step 31, the change in the power supply voltage measured in step 21 is approximately It is determined whether the voltage has become constant (stable) or not, and if it is not constant, the process returns to step 21 and the power supply voltage is measured again. Further, if it is determined in step 31 that the power supply voltage is constant, the process proceeds to step 22, where a prediction calculation of the feeding speed is performed as described above, and in the next step 23, information from the magnetic head 6 is calculated based on the above information. Writing frequency f for recording
is determined, and in step 25 the magnetic head 6 is actually driven to start writing information.

FIG. 12 is a diagram explaining the reason for performing the determination as described in step 31 of FIG. 11 above.

A necessary condition for recording information in step 25 in FIG. 6(a) is that the motor current is at a time after time t2 in FIG. 12. Time t1 to t2 in FIG. 12 is the start-up time of the film feeding motor, and at this time, a large amount of current is flowing through the motor, so the power supply voltage is extremely low, so information is written at time t2. The subsequent steps are appropriate, and in order to achieve this, the determination flow of step 31 is provided.

FIG. 13 is a flowchart showing the operation of the main parts in another embodiment of the present invention. In this embodiment, the time and temperature actually required for feeding against the expected feeding time,
The power supply voltage and frame number are stored to correct the feeding time (feeding speed) of the next photographic frame, and steps 27 and 28 in FIG. 6(b) in the above embodiment are used. Some parts of the space have been changed. Note that the same step numbers as in FIG. 6(b) are portions that perform the same operations, so the details thereof will be omitted here.

After stopping the rewinding of the film in step 27, the process proceeds to step 27-1, where the time actually required for rewinding is memorized, and in the next step 27-2, the power supply voltage at this time,
The temperature and frame number are memorized, and in step 27-3, the feeding time predicted in step 22 and the step 27 are stored.
After analyzing the difference between the feeding time and the feeding time stored in step 27-1, and writing down the information stored in step 27-2, the correction value of the feeding speed predicted in step 22 is calculated for the next photographic frame. and store this correction value.

According to this embodiment, the film feeding speed of the frame after shooting is determined from the winding time of each frame during prewinding and the spool diameters of the film winding spool and the spool in the film cartridge that are stored in advance. Prediction calculation (Figure 5 (a) → Figure 5 (b)),
Since the film is fed based on this,
Information can be written to the magnetic storage part of the film with high density within a predetermined range, and because of this, an encoder for detecting the amount of film movement can be omitted, reducing the cost of the camera. It is possible to achieve simplification of structure and structure.

In addition, since the feeding speed determined by predictive calculation is corrected based on the number of films, film type, temperature, power supply voltage, etc., not only changes in the apparent spool diameter but also load fluctuations in the film pull-out force are applied. etc. can be predicted with even higher accuracy.

(Effects of the Invention) As explained above, according to the present invention, there is provided a storage means for storing the winding time between each frame detected by the frame position detection means in association with a frame number during prewinding, and a frame position Predictive calculating means for predicting and calculating the film feeding speed of the frame after photographing based on the current photographing frame number information obtained from the detecting means and the corresponding information from the storage means;
Since the film feeding speed of each frame after shooting is predicted from the winding time of each frame during prewinding, it is possible to prevent high-density recording within a predetermined range while preventing an expensive and complicated configuration. It becomes possible to do this.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a schematic configuration of an embodiment of the present invention, Fig. 2 is a flowchart showing its operation, and Fig. 3 is a rear view of a camera for realizing the embodiment of Figs. 1 and 2. , FIG. 4 is a block diagram showing the same configuration, and FIG. 5 (
Figure 5 (a) is a diagram showing the feeding speed that fluctuates with the apparent change in the spool when winding the film, and Figure 5 (b)
) is a diagram showing the feeding speed that fluctuates with the apparent change in spool during film rewinding, which can be predicted from Figure 5(a), and Figures 6(a) and (b) are the operations of the microcomputer shown in Figure 4. 7 is a diagram showing the relationship between temperature change and winding time, Figure 8 is a diagram showing the relationship between power supply voltage status and winding time, and Figure 9 is a diagram showing the number of various films and their average number. FIG. 10 is a diagram showing the relationship between film type and winding time. FIG. 11 is a flow chart showing the operation of the main parts in another embodiment of the present invention. FIG. FIG. 13, which is a diagram to help explain the operation, is a flowchart showing the operation of the main parts in another embodiment of the present invention. 1...Camera body, 6...Magnetic head, 7...Film winding spool, 53...
... Microcomputer, 59 ... Motor control circuit, 6
3... Frame position detection circuit, 101...
... Control means, 101A ... Calculation means, l0I
B...Timer, 102...Frame position detection means, 103...Storage means, 104...
. . . Film feeding means, 105 . . . Magnetic head.

Claims (1)

[Claims] (1) A film with a magnetic memory unit that is equipped with a magnetic head that writes information to a magnetic memory unit included in the film while the film is being fed, and a frame position detection means that detects the frame position from the amount of film feed. In a prewind camera using a prewind system, a storage means stores a winding time between each frame detected by the frame position detection means in association with a frame number during prewind;
Predictive calculating means for predicting the film feeding speed of the frame after photographing based on the current photographing frame number information obtained from the frame position detecting means and the corresponding information from the storing means. A pre-wind camera that uses film with a magnetic storage area.