THIS IS NOT A COMPOSITE. It's a single shot. You can read the exif below but here are the rest of the details

I used the Sigma EF-500 DG Super mounted on the camera
the sigma was set to Multi-flash
set at 20 flash/80hz/1/64 power with a stofen diffuser and one sheet (1 ply) toilet paper over that.
the camera had a ND8 neutral density mounted
there was also a 100 watt light blub on the right to help with shadows