Leaf shutters have their own issues. People that think they give true sync at high speeds don't understand how they work. They are not a panacea they are an effective second aperture.
Huh? Ignoring the stupid strobist videos that are diluted at best...I think you need to learn and actually use a leaf shutter. A 1/1000s leaf is completely open and exposes the entire frame 'sync'ronously for the flash exposure to fire. The 'second aperture' comment only applies on cameras where a shutter is augmented by the sensor for capture. Look at the original 1Ds - 1/500 because the CCD could start and stop listening to data faster than the focal plane shutter.
Before you give ME a "I own and use 3 leaf shutter lenses"...maybe you should try shooting medium and large format - all my Hasselblads and Schneider lenses (many more than 3) say that you're not truly comprehending why a leaf is important when balancing ambient and flash. Go push some real power on the flash side (not some strobist < 50w/s) and see why you need a leaf.
Maybe you should get some facts straight too. The 1Ds has a CMOS sensor, the 1D has a CCD, I know, I have one.
Second, that is not how leaf shutters work, they open sequentially (basically but not entirely) from the center out, and then close in the reverse order, from outside to center, the second aperture is totally relevant, the Fuji halves this effect because it has an electronic first curtain, it doesn't start exposing the sensor until the shutter is completely open, if the senor does not have an electronic first and/or second curtain then it is reacting to light as the shutter opens and/or closes.
My three lenses are medium format!
As for flash power, tell me your t1 times. You might realise there is no difference between the light on the subject at full power and quarter power over 1/750 sec sync speed or so. PCB Einsteins are very fast but look at the graph, and comparison, here, under the Comparison Data tab. http://www.paulcbuff.com/e640.php
YET AGAIN, there are good reasons for leaf shutters, but the way they are talked about in threads like these makes them sound like panaceas for flash use, as I keep saying, they are not, they have their limitations, and it is surprising how close to focal plane shutter sync speeds those limitations start kicking in.
1. That's not a 1Ds I'm talking about - it's in reference to PLURAL 1D cameras
2. Ever rebuilt a leaf shutter? From the sounds of it, not. When you've rebuilt a few dozen leaf shutters, then we'll talk. Try rebuilding a few Prontor Hasselblad lens shutters from a CF or newer. And then, give a few LF Copal #3's a working.
3. Yup, a leaf shutter opens from the center and closes to the center - EXPOSING THE FRAME EQUALLY at high speed. Whereas, a FP would form a slit because the second curtain is already moving before the first curtain is completely open. Congratulations, you pass a basic physics lesson.
4. Get some real lights - we'll talk when you start to use Broncolor and have some really high speed flash with ultra short durations that can keep up with high FPS. The pulsing of HS sync reduces your distance, hence coverage and for motion, it isn't consistent. Therefore, firing ONE burst of light at a subject will freeze ONE frame of the motion. On top of it all, you would actually be able to get some light > 50ft.
You can keep arguing your (lack of) point. Those of us out here who actually get out and use our equipment will just keep on going using our (to you obviously useless) leaf shutters in daylight with great results, just like the example above.
BTW, let's see you HS sync a H5D Hasselblad if it had a FP shutter. Good luck. Your sync speed would be something like 1/30s. The larger the sensor/film, the longer it takes to get the shutter curtains moving. So, yes, there is a reason for LS in modern application.
Anyways, have fun with your theories and spewing of internet-obtained info. The rest of us will now go shoot some actual pics with our gear...