Blink-free Photo Calculator
Find the chance everyone has their eyes open in a group photo.
The more people in a photo, the more likely someone blinks.
The math behind it
Chance all eyes are open = (1 - blink probability)^people. Take a few shots to be safe.
Worked example
10 people at 4% blink chance gives about 66% per shot.
FAQ
How many photos should I take?
Roughly 1 / (chance per shot) to be reasonably sure of one good frame.