JP2911953B2 - Auto exposure camera - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an automatic exposure camera having a function of detecting film sensitivity using a DX code.

(Prior Art) As film manufacturing technology has advanced and user needs have been diversified, recently, there has been a tendency to use various types of films having different film sensitivities, numbers, and latitudes.

Therefore, recent films attach a so-called DX code that expresses film information such as film sensitivity, number of sheets, latitude, etc. in a black and white pattern on the patrone, and reads this film information on the camera side equipped with electronic circuits, By performing appropriate signal processing according to the type of the camera, the operation timing and operation time of the shutter and the strobe are controlled so that high quality or desired photographing can be performed.

As shown in FIG. 4, the DX code is composed of 12 sensing areas S1 to S12, and displays film information in a pattern formed by filling each area with white (silver) or black. Speaking of the sensitivity, compact cameras use only three sensing areas S2, S3, and S4 (S1 and S7 are common areas) for sensitivity and display in 1EV steps for reasons of camera performance and cost ( ISO
50 to 3200) on the camera side with four pins P1 to P4
Detect according to the table below.

However, as can be seen from this table, in the three sensing areas S2, S3, and S4, the ISO 25,32,4
Since 0 cannot be detected, conventional compact cameras are forced to use ISO 100, which is the most frequently used sensitivity, in this case, as in the case of films without DX code (for example, films made in Korea). You have set.

Recently, however, most films are DX-coded, and some foreign films (eg Kodak Chrome 25) have ISO 25 films. The sensitivity is now set to ISO 25. By doing so, it is possible to determine up to ISO 25 without increasing the number of contacts for detection and increasing the sensing area of the DX code, and it is possible to widen the detectable sensitivity range of film sensitivity information.

However, in the case of a film without such sensitivity information, setting the film sensitivity to around ISO 25 always adjusts the flash emission condition even if the subject brightness is relatively large, so the user needs to know the camera condition. There is a problem that the strobe light is emitted even in the case of a so-called "empty state" in which the release button is pressed with no film loaded, and wasteful power consumption is often caused, such as automatic charging thereafter.

Further, in a camera having a mode for prohibiting strobe light emission or a camera without a strobe and a release lock at low brightness is performed, in the "empty" state,
There is also a problem that the user cannot release the camera to check the function of the camera except for a very high brightness environment.

(Object and Configuration of the Invention) The present invention has been made in view of the above points, and in an automatic exposure camera having a film sensitivity detecting means using a DX code, a detectable area of the DX code has been expanded and a function check at the time of emptying has been performed. The purpose of this camera is to prevent wasteful power consumption due to flash emission and subsequent charging in cameras with flash. To achieve this purpose, film sensitivity cannot be detected when no film is loaded. The second sensitivity is set to be higher than the first sensitivity that is sometimes set.

(Example) Hereinafter, the present invention will be described with reference to the drawings.

FIG. 1 shows a portion and a main portion related to the present invention in a circuit configuration of a zoom lens camera with a strobe as an example of a camera according to the present invention.

In the figure, 10 is a power supply control unit that supplies power to each part of the circuit, 11 is a CPU that controls the shooting sequence of the camera, 12 is a liquid crystal display device that displays the number of films and the degree of battery consumption,
13 is an LED that displays in the viewfinder such as a short distance warning, 1
4 is a strobe device. Reference numeral 15 denotes a shutter drive unit that drives a shutter motor 16, reference numeral 17 denotes a focus motor that performs focusing by moving a focus lens (front lens), and reference numeral 18 denotes a lens drive unit that drives the focus motor 17. Reference numeral 19 denotes a zoom drive unit that drives a zoom motor 20 for performing zooming, and reference numeral 21 denotes a film drive unit that drives a film winding / rewinding motor 22. 23 is a film transfer amount detection switch for detecting the film transfer amount,
Reference numeral 24 denotes a position detection unit of the zoom lens. Reference numeral 25 denotes a group of key switches. The switch S1 is turned on when the release button is lightly pressed, and is turned on when the release button is pressed down once more.
Switch, a zoom switch that turns on when the zoom button is pressed, a mode switch that turns on when the mode switching button is pressed, and a rewind switch that turns on when the midway rewind button is pressed.

Furthermore, 26 is used to control two types of clocks with different frequencies from CPU1.
An oscillating circuit for supplying the signal to 1, a DX code detecting circuit 27 for reading a DX code attached to a film cartridge, and a distance measuring unit 28 for measuring a distance to a subject. This distance measuring unit 28
It consists of a light-emitting unit that irradiates the subject with infrared light from the infrared LED, and a light-receiving unit that receives reflected light from the subject with a light-receiving element such as a PSD and detects the distance from the light spot position to the subject. ing. Reference numeral 29 denotes a photometry unit that measures the luminance of a subject using CdS or the like.

In the embodiment shown in FIG. 1, the presence or absence of the film is detected by determining whether or not the auto-loading is completed based on the output of the film transport amount detection switch 23. In addition to this, a switch that is turned on by being pushed by the film in the film path inside the camera or a switch that turns on when the film cartridge is stored in the film cartridge storage room is provided, and it is detected by the ON / OFF signal of this switch. It may be.

Next, the operation of the embodiment will be described with reference to the flowcharts of FIG. 2 and FIG. FIG. 2 shows a main routine of the photographing sequence, and FIG. 3 shows a subroutine for DX code detection.

First, in FIG. 2, when a battery is loaded into the camera (F
-1), the CPU 11 is reset (F-2), and thereafter, the main oscillator is stopped and is kept in the stop state to reduce current consumption (F-3). Main switch is ON
Then (F-4), the CPU 11 executes a predetermined program (F-5), and various initializations on the mechanism of the camera (for example, returning the lens position to the initial position) are performed (F-). 6). Next, in order to judge whether or not to perform the auto load, the auto load (AL) condition is checked (F-7). If the auto load (AL) condition is satisfied, the auto load operation is executed. Based on the output of the transfer amount detection switch 23, when the film is auto-loaded normally and the auto-loading is completed, the auto-load execution information is stored in the young memory in the CPU 11. If the auto load condition is not satisfied, the CPU 11 enters standby (F-
8) The state shifts to the halt state (F-9).

Steps (F-1) to (F-7) are executed only once when the battery is loaded, and after the battery is loaded, step (F-8)
Run from

In step (F-10), the key switch group 25
Is checked, and if any one of the keys is turned on, the CPU 11 operates (F-11). If any of the keys is off, the power-off timer elapses (F-1).
2) If the predetermined time (for example, one hour) has not elapsed, the halt state is maintained, and if it has elapsed, the power is turned off (CPU is stopped) (F-32).

When any key is turned on (F-10), the CPU 11 operates (F-11), first checks the battery voltage (F-13), and the battery voltage is lower than the predetermined value and there is no battery voltage. If it is determined that the main switch is ON, the power is turned off (F-32), and the main switch is turned OFF.
If so, the process returns to step (F-8).

On the other hand, if the battery voltage is determined to be equal to or higher than the predetermined value in (F13), the autoload condition is checked (F-15) to determine whether or not to perform the autoload, and if the condition is satisfied. For example, in the same manner as described above, the auto-load operation is performed by executing the AL sequence, and based on the output of the film transport amount detection switch 23, when the film is normally auto-loaded and the auto-load is completed, the auto-load execution information Is stored in the memory in the CPU 11 (F-1
6). If the auto load condition is not satisfied, then S1
It is checked whether or not the switch is turned on (F-17). If the switch is turned on, the DX code is detected first (F-18), and the process shifts to the photographing sequence (F-19). The DX code detection operation will be described later with reference to the subroutine of FIG.

In the photographing sequence, first, distance measurement and photometry are performed, and photographing conditions such as a shutter speed and a position of a focus lens are calculated from the results. The position of the focus lens can be moved stepwise from, for example, 1 step to 24 steps, and the copy body distance 18 is adjusted according to the lens position.
Focuses from m (1 step) to 0.8m (24 steps). The obtained lens position is stored in the variable memory “lens step”.
Thereafter, it is further determined whether or not the conditions for use of the strobe are satisfied. If so, the strobe is charged. Next, the S2 switch is turned on
Is reached, the focus lens is extended according to the value of the lens step, the shutter is driven to perform exposure, and the lens is returned to the initial position.

Thereafter, the film is wound up (F-20), and it is determined whether or not the film is terminated from the tension of the film (F-20).
21) If the film ends, rewind the film (F-3
4) If not, it is determined whether or not the continuous shooting condition is satisfied (F-22). The continuous shooting condition is a snap switch
ON, and the S2 switch is ON. If this condition is satisfied, the flow returns to step (F-19) again, and photography and film winding are repeated. In other words, in the snap mode in which the depth of field is increased in consideration of the quick shooting performance and the time required for the focus adjustment is shortened, continuous shooting can be performed by keeping the release button pressed.

On the other hand, if the S1 switch is OFF (F-17), the zoom switch is checked (F-23). If the switch is ON, the zoom drive unit 19 is operated to execute a zoom sequence (F-24) to perform a zoom operation. If it is OFF, check the snap switch (F-25).

If the snap switch is ON, the SNAP sequence is executed (F-26). Since this snap sequence is not the gist of the present invention, the description is omitted.

In step (F-27), if the state of the mode switch is ON, the process proceeds to the MONO sequence if it is ON (F-2).
8) Switch the use mode of the flash or self-timer. If the mode switch is OFF, the state of the main switch is checked (F-29). If it is ON, it is determined whether or not the test condition is satisfied (F-30). Tests such as photometry and ranging are performed accordingly (F-31), and if not, power off (F-3)
2).

If the main switch is OFF (F-29), look at the rewind switch (F-33). If it is OFF, turn off the power (F-32). If it is ON, rewind the film (F-32). -34).

Here, the detection of the DX code will be described with reference to FIG.

Release button is depressed one step and S1 switch is turned on
Then, the CPU 11 reads the DX code of the film from the four pins (one of which is a common terminal) for reading the DX code provided in the patrone storage room of the camera (S-1),
DX data (DXZ) as shown in the table below in the memory in CPU11
(S-2).

Next, the CPU 11 determines whether all the DX codes read via the pins P1 to P4 are "H" (S-3). Sensitivity
It is determined that the sensitivity is indeterminate, which is either ISO25 or a film without sensitivity information. Then, the next time the autoloading execution information is
It is determined whether or not it is stored in the memory in U11 (S-
4) If the camera is in the shooting state, "0" is input to the DX data DXZ so that shooting can be performed at ISO 25 (S-5), but if the camera is in the shooting state, the DX data DXZ corresponds to ISO 100. “2”
Is input (S-6). By doing this, the camera can still use ISO 2
Since the sensitivity is set to ISO 100, which is higher than 5, the strobe emits light infrequently and is less likely to be recharged, which reduces wasteful power consumption.

Returning to step (S-3), if all the read DX codes are not "H", the DX data (DXZ) corresponding to the read DX code is read from the memory and set (S-7).

Thus, regardless of whether the DX data (DXZ) is set to “0”, set to “2”, or set to any other value, the process proceeds to the next shooting sequence with the set value (F
-19) (see FIG. 2). In the photographing sequence, an appropriate exposure is obtained by controlling the aperture diameter and the shutter opening time corresponding to the set ISO value. Since the exposure control is not the gist of the present invention, the description is omitted.

In the above embodiment, whether or not the camera is in a shooting state is determined by whether or not a film is loaded in the camera,
Therefore, it was decided whether or not the auto-loading operation of the film was completed normally based on the output of the film transfer amount detection switch.In addition, a switch that was turned on by the film was provided in the film path. Alternatively, a switch that is turned on when a film cartridge is stored in the cartridge storage chamber may be provided, and the determination may be made using an ON / OFF signal of this switch. In the embodiment, the sensitivity is set to ISO 100 when the film sensitivity information is not detected and the camera is not in the shooting state. However, it is possible to set the sensitivity to another sensitivity higher than ISO 25. Of course.

Further, in the above-described embodiment, the zoom lens camera has been described as an example. However, the present invention is not limited to this type of camera, and it is needless to say that the present invention can be applied to general cameras having a film sensitivity detection function of reading a DX code and controlling shooting conditions. is there.

(Effects of the Invention) As described above, the present invention relates to a first sensitivity set when the film sensitivity cannot be detected when no film is loaded in an automatic exposure camera having a film sensitivity detection function using a DX code. Since the second sensitivity is set to be higher, the function can be easily checked even in a so-called “empty” mode where the user often does not load a film even in a high brightness environment,
In a camera with a strobe, the strobe does not emit light meaninglessly and does not automatically charge afterwards,
Wasted power is not consumed, and the power saving effect is excellent. In addition, film sensitivity can be detected for foreign-made ISO 25 films, and when set to ISO 100, underexposure can result in underexposure and unusable films can be properly exposed, increasing the user's flexibility in film selection. did.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration of a zoom lens camera as an example of an automatic exposure camera according to the present invention.
FIG. 3 is a flowchart showing the entire operation of the camera according to the present invention shown in FIG. 1, FIG. 3 is a flowchart showing a DX code detecting operation according to the present invention, and FIG. 4 is a diagram showing a DX code detecting mechanism. 11 ... CPU, 15 ... Shutter drive unit, 18 ... Lens drive unit, 21 ... Film drive unit, 27 ... DX code detection circuit,
28: Distance measuring unit, 29: Light measuring unit

Claims (1)

(57) [Claims] 1. An automatic exposure camera having film sensitivity detecting means for detecting sensitivity information based on a DX code, wherein a detecting means for detecting the presence or absence of a film and a state in which the sensitivity detecting means detects indefinite sensitivity information. A sensitivity setting unit that sets the first sensitivity when the detection unit detects the presence of the film and sets a second sensitivity higher than the first sensitivity when the absence of the film is detected. And automatic exposure camera.