@franxter wrote:
not precisely
Then you should ask more precise questions...
No flash will allow you to use non-HSS flash at greater than your sync speed, since there is a physical limitation of your shutter curtain partially obsuring the sensor at shutter speeds higher than sync. So your answer is, ANY HSS-capable flash will allow you to shoot at faster than sync speed, with the disadvantage of the flash power being reduced (it's just the nature of how HSS works).
Think of it this way... imagine your flash is a container with a certain amount of light inside it.
When you take a photo at less than sync speed, the shutter curtain is completely open (sensor completely exposed) and the flash fires all of it's light at once, covering the entire sensor with one burst. Therefore the sensor gets 100% of the light emitted by the flash.
When you take a photo at greater than sync speed, your sensor is never completely exposed all at once, since the second shutter curtain begins to close before the first curtain is completely open. Therefore, HSS works by emitting multiple pulses of light over that time span to evenly light the sensor as the open area between the two shutter curtains moves across in front of it. You lose power because much of the light emitted by the flash lands on the shutter curtains, and is blocked from reaching the sensor and increasing the exposure, therefore there is no way for 100% of the light emitted from the flash to reach your sensor.
Some of the advantages of using HSS is to be able to reduce ambient light for creative effect while selectively lighting what you want to emphasize, or to be able to use large apertures in bright conditions (sunny day) for shallow depth of field when shooting something like portraits at 2pm in bright sunlight with fill flash.
