Harold Edgerton invented the electronic flash

Edgerton’s iconic images would be difficult enough to create today, even with computers on hand to open and close the shutter and fire the flash. But Edgerton took his pictures in the days of analogue, recording them on a motion picture camera converted to shoot at previously impossible speeds, and lighting them with an electric flash he invented himself.

Amazing photographs and great article to read. 
I think he’s most know for this photograph: the bullet through the apple.