I'll guess with a digicam in motor drive/rapid exposure mode, Hmmmm... at least 4 frames a second? Less frames a sec will allow u to catch less of the moment thats all... Then, with the camera on tripod with locked focus and exposure, catch all the frames then overlay in photoshop with the appropriate level adjustment... I'll try out in a moment and post my results.
I tried, but my snoopy drop faster than my fps... so I used movie mode, shoot then break up the movie using Radtools, combine the image with photoshop.