Nikons have a way of cheating the sync, it's pretty clever, and works some of the time, depending on your situation. I've used it many times in a fix.
Details here: http://nikonclspracticalguide.blogspot.co.uk/2008/03/10-auto-fp-high-speed-sync-explained.html
@photoben started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
Nikons have a way of cheating the sync, it's pretty clever, and works some of the time, depending on your situation. I've used it many times in a fix.
Details here:
http://nikonclspracticalguide.blogspot.co.uk/2008/03/10-auto-fp-high-speed-sync-explained.html