JPS5848088B2 - Akameboushihouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing red eye in flash photography.

When a color photograph is taken using flash light when the illuminance around the subject is insufficient, a phenomenon often occurs in which the pupil of the human eye turns red.

The reason for this is thought to be as follows. That is, the pupils of the human eye in the above-mentioned situation are considerably dilated.

Therefore, when a high-intensity flash light is irradiated in such a case, the flash light is extremely reflected on the retina inside the eye.
It is believed that this causes the eye area to be overexposed.

An object of the present invention is to provide a method for preventing the occurrence of the above-mentioned red eye phenomenon, and its features include:
Prior to flash photography, the subject is pre-illuminated to reduce the aperture of the human pupil, and then the flash light for flash photography is generated and the subject is illuminated. At this time, the camera's shirt is opened. The problem lies in the fact that red-eye in flash photography is prevented by performing flash photography.

The present invention will be described in detail below with reference to the drawings, but prior to explaining the present invention, the movement of the human pupil will be described.

FIG. 1 is a diagram illustrating the movement of the pupil of the human eye, with the horizontal axis representing time and the vertical axis representing the degree of pupil aperture.

FIG. 2 is a diagram showing the luminance distribution of preliminary irradiation, in which the horizontal axis represents time and the vertical axis represents luminance.

When the surroundings are extremely dark, the diameter of the pupil of the human eye is
As shown at point A in the figure, it is approximately 7.8(x).

However, at this time, when the eye is irradiated with light as shown in Figure 2, the pupil starts to become smaller after about 0.3 (seconds) (see point B in Figure 1), and about 1.3 seconds after the irradiation. ), the pupil becomes minimal and stops moving.

If irradiation is stopped at this point, approximately 0.
Maintain that opening degree for 3 seconds, then approximately 2.4 (seconds)
The pupil returns to its original aperture.

The present invention actively utilizes this pupil movement to prevent red eye that occurs during flash photography.

In the present invention, first, prior to flash photography, preliminary irradiation as shown in FIG. 2 is performed for about 1.6 seconds (the time required for the pupil to close during the preliminary irradiation).

Then, as mentioned above, the pupil of the human eye becomes almost the smallest.

Therefore, at this point, the flash photography is completed by emitting light for photographing and simultaneously opening and closing the shutter of the camera.

In this way, even if the subject is in a dark place, flash photography will be performed when the pupil has almost reached its minimum size, thereby eliminating the occurrence of red eye phenomenon.

Next, a flash photographing device to which the present invention is applied will be explained with reference to FIGS. 3 and 4.

FIG. 3 is a structural diagram of essential parts of an embodiment of a flash photographing device to which the present invention is applied, in which 101 is a Franche device, a normally open power switch connected in series to a power supply battery 1, and a known step-up circuit. It also has a known control circuit 3 including a known trigger circuit for triggering the discharge tube 8, the discharge tube 8, and the like.

Reference numeral 102 denotes a camera, and this camera 102 is a normally open switch 6 that is opened in conjunction with the first press of a shirt release button (not shown), and is opened in conjunction with the second press of the release button. a normally closed switch 5, a normally open switch 9 that is closed when the shutter is fully open, a lamp 7 for generating preliminary irradiation light, a photographing lens optical system 13, and an aperture 1.
2. It has a shirt shirt 11.

10 is a film, 103 is a subject, and in order to make the explanation easier to understand, only the human eye is shown.

Next, the operation of the apparatus according to the above configuration will be explained with reference to FIG. 4 showing waveforms of each part shown in FIG. 3.

In addition, in FIG. 4, 2 indicates the operation of the power switch 2,
6 indicates the operation of the switch 6, 7 indicates the operation of the lamp 7, 5 indicates the operation of the switch 5, and 8 indicates the operation of the discharge tube 8.

First, prior to flash photography, the power switch 2 of the flash device 1 is closed.

This causes the control circuit 3 to start operating and - emitted energy is stored in its capacitor (not shown).

Next, when the shirt release button is pressed to close the switch 6, the lamp 7 lights up and illuminates the subject 103.

When the illuminance around the person increases due to the light emitted from the lamp T,
The size of the pupil of the human eye gradually decreases as described above, and approximately 1.6 seconds have passed after the lamp 7 is turned on.
The pupil aperture is at its minimum.

The photographer then presses the shirt release button further.

By pressing the second stage of the release button, the switch 5 is opened as shown at 5 in FIG. 4, so the lamp 7 is turned off.

At the same time, the front curtain (not shown) of the camera's shirt shutter moves in conjunction with the second press of the shirt shutter release button, and the shirt shutter opens.

When the leading curtain of the shirt starter travels to the final end and the shirt starter is fully opened, the switch 9 forming the X contact is closed and the discharge tube 8 is triggered.Flash light for photographing the card is generated from the discharge tube 8, The object 103 is irradiated with the light and flash photography is performed.

The switch 9 is closed within 1/60 (second) after the lamp 7 stops emitting light (within the time period during which the pupil remains closed), as shown at 8 in Fig. 4. Because there is
Flash light for photographing is generated when the pupil is at its minimum diameter.

Therefore, no red eye phenomenon occurs. In the above embodiment, the timing of opening the switch 5 is left to the experience of the photographer. If the switch 5 is configured to start the operation and open the switch 5 by the delay means after about 1.6 seconds, it becomes possible to automatically control the light emission and extinguishment of the lamp.

Further, in the above embodiment, an example is shown in which the flash device and the camera body are separate bodies, but the same effects as described above can be obtained even if the flash device 101 is built into the camera body.

Furthermore, even if an auto-adjustable flash device is used as the flash device 101, if the same effect as described above can be obtained and the risk of overexposure is ignored, flash photography can be carried out with the lamp 7 on. It's okay.

Note that even in this case, it is possible to prevent the red eye phenomenon.

[Brief explanation of the drawing]

Figures 1 and 2 are diagrams explaining the movement of the human pupil, Figure 3
The figure shows the structure of the main parts of an embodiment of the present invention, and FIG. 4 shows the waveform diagram of each part shown in FIG. 3. In the figure, 7... lamp, 8... discharge tube, and 103... subject are shown, respectively.

Claims (1)

[Claims] 1. Before irradiating flash light for photography, preliminary irradiation is carried out for a time necessary for the human pupil to close, and the irradiation for photography with the flash light is performed with the pupil closed. A method for preventing red-eye in flash photography, characterized by what has been done.