JP2976233B2 - Red-eye prevention device for flash photography - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a red-eye prevention device in flash photography that can be applied to a camera having a flash.

(Prior art) Conventionally, when taking a color photograph by emitting a flash,
The red-eye phenomenon in which the pupil of the human eye becomes redder may occur, and various methods have been proposed and implemented to prevent this red-eye.

For example, as disclosed in JP-B-58-48088, a subject (human) is pre-irradiated, and then a main-emission is performed.
As disclosed in Japanese Patent Publication No. 033, a flash device or the like is known which has a red-eye prevention function by performing continuous light emission at a fast cycle.

(Problems to be Solved by the Invention) However, in the above-described conventional apparatus, always operating the prevention means for preventing the red-eye effect requires a longer time for photographing than general flash photographing and is unnatural. Therefore, it is preferable that the prevention means is selectively used only in a condition where true red-eye occurs.

Also, in the case of normal light and backlight, the degree of opening of the pupil diameter of the person causing red-eye differs with the same subject brightness, and the probability of occurrence of red-eye phenomenon also changes. Did not.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a red-eye prevention device in flash photography in which red-eye prevention means is operated only under conditions in which the red-eye phenomenon is likely to occur, and appropriate flash photography is performed.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a distance measuring means for measuring a distance to a subject, a photometric means for measuring luminance of a subject, A red-eye prevention device for strobe photographing, comprising: a red-eye prevention unit for preventing a red-eye phenomenon of the above; and a control unit for controlling operation of the red-eye prevention unit based on a measurement result of the distance measuring unit and the photometric unit. In some cases, the control unit is configured to shift to an operation reference having a luminance higher than a subject luminance, which is an operation reference at the time of normal light in the red-eye prevention unit.

(Operation) According to the configuration of the present invention, it is determined by the control means whether or not the red-eye effect is likely to occur based on the distance measurement data of the distance measurement means and the luminance data of the photometry means. The means work.

In addition, even if the subject brightness is the same, there is a high probability that the red-eye phenomenon will occur when the subject is backlit. Shift the operating reference.

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

FIG. 1 is a block diagram of one embodiment of the present invention, wherein 1 is a CPU (central processing unit) as control means, and 2 is a known red-eye prevention means such as a strobe pre-emission means and a lamp irradiation means.
, 4 is a distance measuring means for measuring the distance to the subject, 5 is a backlight measuring means, and 6 is a light measuring means for measuring the luminance of the subject, and 7 is a device for driving each part of the camera. It is a motor.

In FIG. 1, a CPU 1 performs camera sequence control such as camera shutter control, motor 7 control, time measurement, arithmetic processing, and the like, and a distance measuring means 4 uses an active type or passive type distance measuring element. The distance measurement result is transmitted to the CPU 1 under the control of the control signal of the CPU 1. The photometric unit 5 includes a light receiving element (not shown) or a light receiving element and an amplifier, and has a well-known configuration as a backlight detecting unit 6 by dividing the light receiving element into two parts.
It is controlled by the control signal of U1 and the photometric result is
Send to The strobe device 2 is charged by the CPU 1,
The presence or absence of light emission and pre-light emission are controlled.

The criterion of the operation control of the CPU 1 with respect to the red-eye prevention means 3 is as shown in FIG. 2 showing the relationship between the subject distance and the red-eye occurrence probability. When it is up to the distance (it changes depending on the ISO and the aperture of the taking lens), turn on the operation,
Also, as shown in FIG. 3 showing the relationship between the subject brightness and the red-eye occurrence probability, the operation is performed when the subject brightness is less than LV12, and the relationship between the subject state and the red-eye occurrence probability at the same brightness in FIG. As shown in the explanatory diagram, in a normal light state, a human receives a large amount of light and a pupil diameter becomes small, so that red eyes are unlikely to occur. The operation is set to be turned on when the subject brightness is lower than LV13.

An embodiment of the above configuration will be described with reference to the flowchart of FIG.

When the first release is turned on, the CPU 1 performs a battery check. If there is no abnormality (YES in S-1), the CPU 1 causes the distance measuring means 4 to measure the subject distance (S-2). The luminance is measured (S-3), and the taking lens is extended according to the subject distance (S-4). Here, if the first release is turned off (NO in S-5), the taking lens returns to the original position (S-6), the first release is turned on (YES in S-5), and When the second release is turned on (YES in S-7), the subject brightness is less than LV12 (YES in S-8), and the subject distance is between 1.5 m and the strobe reach distance (S-9). YES), the CPU 1 activates the red-eye prevention means 3 to make the strobe pre-emission (S-1).
0). Thereafter, the shutter is opened and closed and the main flash is emitted (S-11).

Also, the subject brightness is less than LV12 (YES in S-8),
If the subject distance is out of the range from 1.5 m to the strobe reach distance (NO in S-9), the flow proceeds to step (S-11) without firing the preflash.

Further, the subject brightness is equal to or higher than LV12 (NO in S-8),
When there is no daylight synchro or backlighting (NO in S-12),
The shutter is opened and closed without flash emission (S
-13). Also, the subject brightness is LV12 or more (N of S-8)
O) and in the daytime synchro or backlight condition (S-1)
3; YES), when the subject brightness is less than LV13 (S-14
If (YES), the flow goes to step (S-9). If it is equal to or higher than LV13 (NO in S-14), the flow goes to step (S-13).

After the shutter is opened and closed and the main flash is fired,
The taking lens returns to the original position (S-15), and the film is wound up by one frame (S-16).

Note that the distance between the strobe device 2 provided on the camera body (not shown) and the photographing lens (the red-eye phenomenon is less likely to occur as the distance between the two becomes greater) or the focal length of the photographing lens (the longer the focal length, Since the subject at the same distance becomes larger and red-eye is conspicuous), the subject distance and the subject brightness at which the red-eye phenomenon is likely to occur change, so that the reference of the operation control of the red-eye prevention means 3 is set according to the specifications of the camera.

If the strobe reach distance is extended by the change in ISO, the CPU 1 may change the criterion of the subject distance in the step (S-9) in FIG. Considering that no image is taken, it is conceivable not to perform pre-emission when the distance is longer than a certain distance.

As described above, in this embodiment, in the flash photography,
The camera can determine the situation of the subject and control the red-eye prevention means 3 to turn on and off more appropriately without allowing the user to select a mode such as a normal mode or a red-eye prevention mode. That is, the pre-emission for preventing red-eye
This improves the problem that it takes time and involves unnaturalness, and the problem that pre-emission is performed even on a subject such as a bright subject or a distant landscape.

(Effects of the Invention) According to the present invention, it is possible to operate the red-eye prevention means only under shooting conditions in which the red-eye phenomenon is likely to occur, based on the distance measurement data and the photometry data. By operating the red-eye prevention means even at a high price, it is possible to provide a red-eye prevention device in flash photography in which proper flash photography is always performed.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of a red-eye prevention device for flash photography according to the present invention, FIG. 2, FIG. 3, and FIG.
FIG. 5 is a flowchart according to the flash control operation of the present embodiment. DESCRIPTION OF SYMBOLS 1 ... Control means, 2 ... Strobe device, 3 ... Red-eye prevention means, 4 ... Distance measuring means, 5 ... Light measuring means, 6 ... Backlight detecting means.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03B 7/00-7/28 G03B 15/04-15/05

Claims (1)

(57) [Claims] 1. A distance measuring means for measuring a distance to a subject, a photometric means for measuring luminance of a subject, a red-eye preventing means for preventing a red-eye phenomenon at the time of flash photography, and the distance measuring means. And a control means for controlling the operation of the red-eye prevention means based on the measurement result of the light-measuring means. A red-eye prevention device in strobe photography, wherein the control means is configured to shift to an operation reference having higher luminance than luminance.