“The effect of seeing human faces and bodies in crystalline extreme slow motion has been revelatory, to dancers and nondancers alike. Until now, David Michalek said, this technology — still in the prototype phase — has been used primarily for applications like military ballistics tests and car-crash simulations. Now, in ‘Slow Dancing,’ slow-motion high definition is being harnessed to show things as minute as the trajectory of a flyaway strand of hair or the progression of a gesture through a hand, finger by finger.”