Phase One has a video on their home page where Frederico Martins is putting the high speed flash sync of the phase one to good use.http://youtu.be/WjIAd1KcT4E
However he claims that it is impossible
to do the same thing (flash with high shutter speed) with a 35mm DSLR. This is not true.
The video even shows him showing that it is not possible with a Nikon.
Well it is possible and it is possible to go even faster than a DF with leaf shutter lenses.
All he needed to do is use the Pocket Wizard Flex TT5 flash sync radio slaves with the hypersync function.
No problem with this setup, direct flash and an aperture of 5.6 (he said he was shooting at 1/1600th at 5.6).
Here is an example of hypersync used with strobe and a 35mm DSLR.
shot at 1/2500, F7.1, ISO 100
Nikon D300s, 24-70mm, ISO 200, 1/8000 at F5.
See the photographers article here http://tombolphoto.com/blog/more-rangerhypersync-news/
Here is another interesting example too though the image was used in a composite, it was still shot outside over poweing the sun.http://www.youtube.com/watch?feature=endscreen&NR=1&v=jYKoNm0cxoY
Aslo here is a method without using a Flex TT5 and getting high speed sync with broncolor strobes.http://www.prophotonut.com/2010/05/23/18000th-flash-sync-with-broncolor-mobil-and-canon-5d-mk2/
Now that said it would be interesting to see if it were possible to use hypersync to go even faster using the
focal plane shutter of the DF. It may be a bit of a problem as the duration of the shutter swipe of the DF might be too long due to the flash sync without hypersync and the focal plane shutter is 1/125. Might be possible with a relatively long duration strobe like an Elinchrom 6,000 classic pack or the older 404.
Hypersync does take a bit of callibration. I am getting clean full frame exposure at a 1/4000th of a second using the elinchrom 6,000 pack.
However the 6,000 pack has to use a dual head to use all 6,000 so the duration is not quite as good as the 404 that can discharge in a single tube 4000 head.
I should be able to get a clean 1/800th using a 404 head with the 6,000 pack set to 4,000.
This may sound confusing, but here is how it works.
This is how the shutter works on the D800 for examnple.
At the fastest flash sync, 1/320th the first curtain opens fully. The flash goes off and then the second curtain closes.
For faster shutter speeds the second curtain stats to shut before the first shutter finishes opening.
At 1/8000th of a second this is what happens. The first curtain opens, but 1/8000th of a second after it starts to move the second curtain starts to close.
So there only a crack open between the two curtains. This crack scans over the sensor exposing each pixel for 1/8000th of a second.
To make this work the flash has to be illuminating for the duration of the scan. That is just under 1/320th of a second.
The Flex TT5 is calibrated so as to have the flash illuminating at the right time.
At the very highest speeds there may be a bit of underexposes area at the bottom of the frame. Depends on the flash/camera combination.
While the Phase One leaf shutter systems fastest flash sync speed with the most recent backs is 1/1600th it is simpler to use
and can be used with ultra fast flash.