In recent years, a flash device has been widely employed to an optical apparatus such as, for example, a camera. Particularly when the flash device is employed in the photographing, the light is the important component. In an automatic light adjusting device which is employed in the photographing, the flashlight is ceased when the reflecting light from an object to be photographed attains to a predetermined value.
The reflected light from the object to be photographed is, however, few in case that color of the object is black or in case that distance from the object to be photographed to the flash device is long, and an automatic light adjusting device was inactivated, and therefore a photographer could not judge easily how to the distance between the object and the flash device or to adjust the diaphragm. To contrary, the object to be photographed is white, the quantity of the reflected light becomes much, and the quantity of the reflecting light becomes much when the distance from the object to the flash device is very short. Accordingly, the automatic light adjusting device does not activate correctly. It is also impossible for the photographer to alternate the distance or to adjust the diaphragm.
A flash device which can produce multiple flashlight during a predetermined time interval is so called a multi-flashing device. Thus multi-flashing device can produce the multiple flashlight momentarily and periodically. By using the multi-flashing device, it is possible to photograph a rotating substance or a moving substance at the stationary state by means of the flashlight which is repeated momentarily and periodically. In this kind of prior art multi-flashing device, the quantity of the flashlight in short distance photographing was same value with that of the flashlight in long distance photographing in spite that the few quantity of the flashlight is adequate in short distance photographing, since the multi-flashing device has not been provided with a light quantity control device which can automatically control the quantity of light. It was, accordingly, impossible to increase the flashing times and to make repetition of the flashing of the flash device particularly employing a battery as a power source faster in short distance photographing, and, therefore, it was impossible to obtain the suitable exposure.