This is taken with a Nikon D3s (set to 3 exposures) with 85mm f/1.8 lens, four SB-900s and an SU-800 Commander
The first exposure is taken on camera left with one SB-900 in an umbrella with half the black backing removed, there is an umbrella on camera right that is also adding a little light to her back. ( Shot at f/2.8, 1/15th, using SU-800 CDR)
The second exposure is taken with 3 SB-900s going off at once (one in an LTP suspended in the middle of the frame, and one SB-900 in an umbrella to camera left and to Camera right). The flashes were set to RPT mode, I cannot remember the hertz. Kamila moved from camera left to right as they were going off.(f/4, 2.5 seconds, using SB-900 as Master)
The last exposure is done with one SB-900 in an umbrella with half the black backing removed on camera right, and one SB-900 in the same setup on camera left. (shot at f/2.8, 1/15th, using SU-800 CDR)
The triple exposure was done in camera.