JPH06258568A - Camera provided with servo af function - Google Patents

Abstract

PURPOSE:To realize photographing in focus without missing photographing timing for a moving object by reducing a time lag concerning a stroboscope at the time of servo AF. CONSTITUTION:A strobe light emission level setting means 1 for setting a strobe light emission level in a discrimination means 1 comparing a photometry level obtained by a photometry means (AE device) 5 with the set strobe light emission level to a lower value than that in other AF mode in the case a servo AF mode is selected by an AF selection means 15 is provided, and, in the case where the servo AF mode is selected as the AF mode, the probability of the automatic charge and light emission of the stroboscope is lowered or the automatic charge and light emission are inhibited.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo A equipped with a servo AF function for always focusing on a moving subject.
The present invention relates to improvement of a camera with an F function.

[0002]

2. Description of the Related Art Conventionally, A is used for automatic focusing.
A camera equipped with an F (auto focus) function is common. As the AF function, many cameras have a servo AF function that can keep a moving subject in focus.

Further, a camera having a built-in strobe is also common, and in this type of camera, the subject brightness is measured (hereinafter referred to as AE), and it is determined that the brightness is lower than a predetermined value (brightness) (dark). If so, the sequence is such that the strobe is automatically charged and the strobe is fired at the time of shooting (hereinafter referred to as auto strobe).

[0004]

However, assuming a camera having the above-mentioned functions, even if the subject moving by the servo AF is focused, the time lag due to the strobe charging or the like will occur if the subject is dark. This may cause problems such as occurrence of a shooting timing, missing of a shooting timing, and an out-of-focus photograph because the subject has already moved at the time of shooting.

(Object of the Invention) An object of the present invention is to provide a servo A
It is an object of the present invention to provide a camera with a servo AF function that can reduce a time lag related to a strobe at F and take a focused photograph without missing a photographing timing for a moving subject.

[0006]

According to the present invention, when the servo AF mode is selected by the AF selecting means, the stroboscopic light emission is set to the photometric level obtained by the photometric means as compared with other AF modes. A strobe light emission level setting means for setting the strobe light emission level to a low value in the discriminating means for comparing with the level is provided, and when the light measurement level obtained by the light measurement means is lower than a predetermined strobe light emission level, automatic When the servo AF mode is selected by the AF selecting means in the strobe control means for urging the strobe to charge and emit light, compared to other AF modes,
The charging time setting means to shorten the strobe charging time is provided,
Further, when the photometry level obtained by the photometry means is lower than a predetermined flash emission level, the AF selection means automatically activates the servo AF mode in the flash control means for urging the flash charging up to a predetermined value and the flash emission. When is selected, charging voltage setting means for setting the strobe charging voltage to a low value is provided as compared with other AF modes, and A
When an AF mode other than the servo AF mode is selected by the F selection means, it is determined that the photometry level obtained by the photometry means is lower than a predetermined strobe light emission level to automatically charge the strobe. If the flash AF is activated and the servo AF mode is selected, even if it is determined that the photometry level is lower than a predetermined flash emission level, strobe control means for prohibiting strobe charging is provided, and the servo AF mode is set as the AF mode. When the mode is selected, the probability of automatic flash charging / flashing is reduced,
Alternatively, it is prohibited.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the illustrated embodiments.

FIG. 1 is a block diagram showing the main structure of a camera according to the first embodiment of the present invention.

In FIG. 1, reference numeral 1 is a microcomputer (hereinafter, referred to as a microcomputer) for controlling various circuits, and has a data table 1a as control information. Reference numeral 2 is an AF / AE switch for starting distance measurement and photometry, 3 is a shutter switch for starting shutter drive, and 4 is a known active distance measurement, for example, and outputs subject distance information to the microcomputer 1. AF device,
Reference numeral 5 is a known AE device that performs photometry and outputs subject brightness information to the microcomputer 1. Reference numeral 6 is an AF motor for driving a focus lens (not shown). Reference numeral 7 is an AF motor driver that drives the AF motor 6. Is a shutter driver, 9 is a shutter driver for driving the shutter 8, 10 is a feeding motor for winding and rewinding the film, and 11 is a feeding motor driver for driving the feeding motor 10. 1
Reference numeral 2 denotes a strobe circuit that emits strobe light at low brightness, and controls a capacitor 13 that charges a voltage for light emission and a xenon tube 14 for light emission.

Reference numeral 15 indicates a distance measuring mode, which is a single AF for measuring the distance only once when the AE / AF switch 2 is turned on.
This is an AF selection switch for selecting either the mode or the servo AF mode in which distance measurement is continued according to the movement of the subject while the AF / AE switch 2 is ON.

FIG. 2 is a flowchart showing the operation of the microcomputer 1 of the camera having the above-mentioned structure, which will be described below. [Step 101] Whether the single AF mode is selected or the servo AF mode is selected by the AF selection switch 15 is determined. If the single AF mode is selected, the process proceeds to step 102. If the servo AF mode is selected, the process proceeds to step 103. . [Step 102] Data for determining whether the AE data obtained later is dark enough to make the strobe emit light, that is, the strobe emission level (1) which is a threshold level is selected from the data table 1a and set. . [Step 103] Here, the determination data whether the photometric value obtained later is dark enough to make the strobe emit light, that is, the strobe emission level (2) which is the threshold level is selected from the data table 1a. , Set.

Here, assuming that the brightness information of the strobe light emission level (1) is FA1 and the brightness information of the strobe light emission level (2) is FA2, both have a relation of "FA1>FA2". As a result, the probability of strobe light emission is smaller in the servo AF mode in which the strobe light emission level (2) is set than in the single AF mode. [Step 104] It is determined whether the AF / AE switch 2 is turned on, and if it is turned on, step 1
The procedure proceeds to 05, and if not turned on, the procedure returns to step 101. [Step 105] The AE device 5 is driven to perform the AE operation, and the AE data obtained as a result is loaded. [Step 106] The stroboscopic light emission level set in step 102 or 103 is compared with the AE data captured in step 105. If the AE data has a lower brightness, the process proceeds to step 107. If the brightness is high, the process proceeds to step 108. [Step 107] Capacitor 1 to strobe circuit 12
Instructing 3 to charge the voltage for strobe light emission. [Step 108] The AF device 4 is driven to perform the AF operation, and subject distance information obtained as a result, that is, AF
Capture data. [Step 109] The amount of movement of the focus lens is calculated from the AF data fetched in step 108. [Step 110] The AF motor driver 7 outputs the signal of the focus lens movement amount calculated in the above step 108.
To the AF motor 6 to drive a focus lens (not shown). [Step 111] It is determined whether or not the shutter switch 3 is turned on, and if it is turned on, the operation proceeds to step 113, and if not, the operation proceeds to step 112. [Step 112] It is determined whether or not the AF mode determined in step 101 is the servo AF,
If so, the process returns to step 108, and if not, the process returns to step 111. [Step 113] The shutter 8 is opened and closed through the shutter driver 9 to expose a film (not shown). At this time, if it is determined in step 106 that the luminance is low, the strobe circuit 12 is simultaneously instructed to strobe. As a result, the strobe circuit 12 controls the light emission of the xenon tube 14, and stroboscopic photography is performed. [Step 114] The feeding motor 10 is driven through the feeding motor driver 11 to wind the film by one frame.

With the above, a series of operations is completed.

According to the first embodiment, since the strobe light emission level is lowered in the servo AF mode, the probability of strobe charging is reduced, and the time lag due to strobe use can be reduced.

(Second Embodiment) FIGS. 3 and 4 are diagrams according to a second embodiment of the present invention, FIG. 1 is a circuit diagram showing the details of a strobe circuit, and the same parts as in FIG. The same reference numerals are attached. Since the configuration other than the strobe circuit is the same as that in FIG. 1, it is omitted here.

In FIG. 3, reference numeral 21 is an oscillating transformer for generating a high voltage for charging the capacitor 13 on the secondary side by oscillation, and 22 is a rectifying diode. Reference numerals 23 and 24 are Zener diodes, and the respective Zener voltages ZD1 and ZD
D2 has a relationship of "ZD1>ZD2". 25 is a trigger coil for sending a trigger signal to the xenon tube 14, 26
Is a thyristor for controlling ON / OFF of the trigger coil 25 by a signal from the microcomputer 1, and 27 and 28 are resistors and capacitors for controlling the trigger coil 25.

The strobe circuit 12 in the second embodiment.
Is composed of the oscillation transformer 21 to the capacitor 28 and the like.

Next, the operation of the strobe circuit 12 will be described.

When strobe charging is performed, the oscillation transformer 2
An oscillation start signal is sent to the primary side of 1. As a result, a voltage n times the voltage applied to the primary side of the oscillating transformer 21 (primary side: winding ratio of the secondary side) is generated, and the diode 2
The capacitor 13 is charged through 2 When the charging voltage rises and exceeds the Zener voltages ZD1 and ZD2 of the Zener diodes 23 and 24, the voltage is applied to the microcomputer 1 at that time.

The microcomputer 1 sends an oscillation stop signal to the primary side of the oscillating transformer 21 to stop the charging, when the charging stop signal is sent at the time when the application of this voltage is detected.

As a charge stop signal, a Zener voltage ZD
Which signal of 1 and ZD2 is used is selected by the program.

The strobe light emission is performed by turning on the gate of the thyristor 26 while the capacitor 28 is charged through the resistor 27, and a current flows through the trigger coil 25 to cause the xenon tube 14 to emit light.

FIG. 4 is a flow chart showing the operation of the microcomputer 1 in the second embodiment, which is basically shown in FIG.
Therefore, only different parts will be described here.

In step 101, if the AF selection switch 15 selects the single AF mode, the process proceeds to step 202, and if the servo AF mode is selected, the process proceeds to step 203. [Step 202] The signal on the anode side of the Zener diode 23 (ZD1) is set to be used as the detection signal so that the charge voltage to the capacitor 13 becomes a high voltage and the charge stop signal is sent to the strobe circuit 12. [Step 203] Here, the charge voltage to the capacitor 13 becomes a low voltage and the charge stop signal is sent to the flash circuit 1
2 to send a zener diode 24 to the detection signal
The signal on the anode side of (ZD2) is set to be used. Then, the operation proceeds to the operation after step 104 described in FIG.

According to the second embodiment, since the strobe charging voltage during servo AF is lowered, the time required for strobe charging is shortened and the time lag can be reduced.

Even when the strobe charge is cut off only in the servo AF mode, the same effect as described above can be obtained.

(Third Embodiment) FIG. 5 is a flow chart showing the operation of the microcomputer 1 according to the third embodiment of the present invention. Since it is basically the same as that of FIG. Explained. Since the circuit configuration is the same as that of FIG. 1, it is omitted here. [Step 301] Which AF mode is selected by the AF selection switch 15 is detected, and the built-in R
Store in AM. Then, the AF / AE switch 2 is turned on.
The process proceeds to step 104 for making the ON / OFF determination.

In this step 104, the AF
・ Step 10 when the AE switch 2 is ON
5, the process returns to step 301 when OFF.

At the next step 105, the AE data is fetched and the routine proceeds to step 302. [Step 302] The predetermined flash emission level is compared with the AE data captured in step 105. If the AE data has a lower brightness, the process proceeds to step 303, and if the AE data has a higher brightness, the process proceeds to step 108. [Step 303] A stored in step 301
It is determined whether or not the F mode is the servo AF. In the single AF mode, the routine proceeds to step 107, where strobe charging is performed as described above. If the servo AF mode is selected, the process proceeds to step 304. [Step 304] Since the servo AF mode is selected, strobe charging is prohibited. Then, the process proceeds to the operations after step 108 described in FIG.

According to the third embodiment, since strobe charging is prohibited in the servo AF mode, the time lag due to strobe charging can be eliminated.

According to each of the above embodiments, in the camera having the servo AF function and the auto strobe function, when the servo AF mode is selected, the sequence for strobe charging is changed, that is, the strobe light emission level is lowered. Or setting the flash charge completion level to a low level or prohibiting flash charge, the time lag related to the flash in the servo AF mode can be reduced, and the shooting timing can be improved even for a moving subject. It is possible to prevent the image from being missed or becoming out of focus.

[0032]

As described above, according to the present invention,
When the servo AF mode is selected by the AF selection means, the strobe light emission level in the discrimination means for comparing the light measurement level obtained by the light measurement means with the set strobe light emission level is compared with the other AF modes. Provided with strobe emission level setting means to set a low value,
When the servo AF mode is selected by the AF selection means in the strobe control means that automatically promotes strobe charging and light emission when the photometry level obtained by the photometry means is lower than the predetermined strobe light emission level. Is equipped with a charging time setting means for shortening the strobe charging time as compared with other AF modes, and when the photometric level obtained by the photometric means is lower than the predetermined strobe light emission level, the predetermined value is automatically set. When the servo AF mode is selected by the AF selecting means in the strobe control means for urging the strobe charging up to and the emission of light, charging voltage setting means for setting the strobe charging voltage to a lower value than in other AF modes is provided. If an AF mode other than the servo AF mode is selected by the AF selecting means, the photometric level obtained by the photometric means is set. By automatically determining that the flash light emission level is lower than that of, the flash charge / flash is automatically prompted, and when the servo AF mode is selected, it is determined that the metering level is lower than the predetermined flash light emission level. Even if it does, strobe control means for prohibiting strobe charging is provided, and when the servo AF mode is selected as the AF mode, the probability of strobe automatic charging / light emission is reduced or prohibited.

Therefore, it is possible to reduce the time lag related to the strobe during the servo AF, and to take a photograph in focus without missing the photographing timing for a moving subject.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main configuration of a camera according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the microcomputer shown in FIG.

FIG. 3 is a circuit diagram showing details of a flash circuit of a camera according to a third embodiment of the present invention.

FIG. 4 is a flowchart showing an operation of a main part of the microcomputer shown in FIG.

FIG. 5 is a flowchart showing the operation of the main part of the microcomputer of the camera of the third embodiment of the present invention.

[Explanation of symbols]

 1 Microcomputer 4 AF device 5 AE device 12 Strobe circuit 15 AF selection switch

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location G03B 15/05 7139-2K

Claims (4)

[Claims] 1. An AF selecting means for selecting any one of AF modes including a servo AF mode which functions to always focus on a moving subject, a photometric means for measuring the subject brightness, and the photometric means. Comparing means for comparing the obtained photometric level with the set flash emission level,
When the photometric level is lower by the comparison means, in the servo AF function-equipped camera equipped with a strobe control means for automatically promoting strobe charging / light emission, the servo AF mode is selected by the AF selection means. The camera with a servo AF function is provided with a stroboscopic light emission level setting means for setting the stroboscopic light emission level in the discrimination means to a lower value than in other AF modes. 2. An AF selecting means for selecting one of AF modes including a servo AF mode which functions to always focus on a moving subject, a photometric means for measuring the subject brightness, and the photometric means. In a camera with a servo AF function equipped with a strobe control unit that automatically promotes strobe charging / flashing when the obtained photometry level is lower than a predetermined strobe emission level, the AF selection is made in the strobe control unit. A camera with a servo AF function characterized in that when the servo AF mode is selected by the means, a charging time setting means for shortening the strobe charging time is provided as compared with other AF modes. 3. An AF selecting means for selecting any one of AF modes including a servo AF mode which always functions to focus on a moving subject, a photometric means for measuring the subject brightness, and the photometric means. In a camera with a servo AF function equipped with a strobe control unit that automatically promotes strobe charging up to a predetermined value and strobe emission when the obtained photometric level is lower than a predetermined strobe emission level, Then, the servo A is selected by the AF selecting means.
A camera with a servo AF function characterized in that when the F mode is selected, a charging voltage setting means for setting the strobe charging voltage to a low value is provided as compared with the other AF modes. 4. A servo AF including AF selection means for selecting any one of AF modes including a servo AF mode which functions to always focus on a moving subject, and a photometric means for measuring subject brightness. In the camera with function, the AF selection means is used for A
When the F mode is selected, it is determined that the photometric level obtained by the photometric means is lower than a predetermined strobe light emission level, whereby the strobe is automatically charged.
When the servo AF mode is selected for urging light emission, a strobe control means for prohibiting strobe charging is provided even if it is determined that the photometry level is lower than a predetermined strobe light emission level. Camera with servo AF function.