Yeah, I think it is normal that people cannot help blinking eyes when exposed to bright light suddenly. Last week, I went to watch a movie with my friends in a cinema, when I walked outside from the dark cinema after the movie was over, I also blinked more than usual. After a while, I adjusted to the bright light. Therefore, I do not think it abnormal. But if you blink frequently even when you are not exposed to the bright light in a sudden, you should check out whether you are catching a cold or suffering from a sinus infection. Even a bit of dirty things can stimulate our ocular nerve and result in the pain in the eye, hence blinking more. In this case, you should go to hospital and consult an experienced eye doctor so that you can receive a prompt treatment.