You blinked

Han of Hong Kong is traveling with his parents, Li and Law.

...

Han: Mom, you blinked. We’ll take it again.

Ms Li: I always flinch when the flash goes off.

Mr Law: You blink before the flash goes off.

Han: Anyway, focus on your eyes. Keep them wide open, like a gwailo.

Ms Li: No way, I'm Chinese.

Han: I’m serious. The big-name movie actors have this charisma because they blink less often than ordinary people. They train themselves not to blink. Chinese or not, makes no difference.

...