I had this idea too but... This article uses 20 seconds exposure, so it wouldnt be helped by PWMing the lights. Also, you'd have to do it much faster than 100

I had this idea too but... This article uses 20 seconds exposure, so it wouldnt be helped by PWMing the lights. Also, you'd have to do it much faster than 100Hz. Wave Christmas LED lights around and you'll see a strobe effect. People claim to feel (not see) 100-120 Hz flicker (I wouldn't dismiss them off hand). Finally, you'd have to have a powerful, lighting, LED able to toggle on/off at fast enough speeds. That isn't obviously available, if for no other reason large internal capacitances. As for synchronizing it, that's not too bad. I don't think you'd need a GPS clock. Use an accurate crystal clock and the mains as a 60*3 = 180 Hz reference. Turn the light off every 0, 120 and 240 degrees to cover all three phases.