Traditional Culture Encyclopedia - Photography major - Why does the flash of a digital camera sometimes flash once and sometimes twice?

Why does the flash of a digital camera sometimes flash once and sometimes twice?

When the flash lamp shines directly on the human eye, because of its fast speed, the pupil of the human eye has no time to contract, and the reflection of the lamp light will form a red eye. So today's flash has anti-red-eye technology, that is, first flash to narrow the pupil of human eyes, and then flash to shoot.

All you have to do is turn off the red-eye flash, and it will only flash.