Is an electronic flash fast enough to stop the a7R shutter slap motion? It depends: All equipment the same as the last post unless noted. Camera shutter release mode: 2 second self-timer, shutter speed: 1/160 second, first curtain synch: 90mm Leica f/2 APO Summicron, f/5.6 with ND filter at minimum absorption, flash duration 1/8000 second… [Read More]