That’s a problem I need to solve for the next funpark shots in December. Of course, the most easiest way would be to use Nikon’s built in iTTL sync, however, iTTL always severely downregulated the power of my speedlights. Furthermore iTTL frequently delayed my camera trigger (still communicating between devices?) missing my fast moving objects.

I found a Phase One 645DF body could sync at 1/1600 with theP40+ back but that costs me an unacceptable 280 Euros per day…. I tried also a Canon G11 but found it also difficult to handle in the bright sunlight.

As others already found high speed sync working Nikon DSLRs using a SB-800, I wanted to get my old SB-20s at work. So I decided to go for a setting that I found at Tony Donaldson’s site

You will need a DSLR that is capable of this high-speed sync, and the dedicated flash from that manufacturer … I usually set mine on manual to 1/128th power (the lowest it will go) … All that’s doing is tricking the camera to fire the flash right as the second curtain starts moving. Not the same thing as setting second-curtain sync… Attach your strobes via a sync cord or using a wireless trigger. I know Pocketwizard says it works to 1/500, but I’ve had it work fine at 1/5,000th just as well… Optical slaves also work.

Upon request Nikon Germany Support says this is NOT possible. I was also sceptical but but found the following setup working:

The SB-600 may sit directly on the hot shoe while I prefer to have it in the camera bag where it emits no light on the subject only flashing a 15 Euro optical Hama transmitter that is connected to a 50 Euro Yongnuo wireless sender.

The Yongnuo triggers several remote SB-20s that came all from Ebay at 20-30 Euro each. So not really a big deal… At 1/1 power the the flash duration time of the distant SB-20s is already greater than 1/1000s to get a perfect sync even at 1/2000s or less.

For the heck of it, how is it working?

Here is an action diagram: The curtain movements overlap at 1/1000s – this is the critical time window where we need our light. A sync exactly to the second curtain comes too late, a sync exactly to first curtain too early while sync to FP seems to be the best choice (FP=focal plane).

Speedlights seem to have only at full power such a long flashing time. So that’s the downside as this setup will not work at lower power of the speedlights. But if you need less light, move the flashes away from the subject or put them in a softbox.

Addendum 22-11-2010

Two more blogs following the same lines: blog1 and blog2. Great idea to put also the optical trigger into a stofen!