Einstein is a good choice for water drop photography. Even at half power, you can get 1/2000s flash durations. At 5 feet, and with an 8.5" reflector, you should be able to achieve f/32 at ISO 100 at this setting. Again, as power is reduced, flash duration get shorter.
As for shooting dirt bikes, there are many variables. Is it indoor or outdoor. Bright sun or shade, day or night (predominantly, how bright is the ambient). If the ambient is bright, and you get motion blur from it, the flash duration of the flash is somewhat irrelevant, especially on a clean background (like the sky). If flash is your only/dominant light source, then the flash durations will be relevant.
The 640Ws power level, you will find little that is significantly faster, so regardless of which light you choose, the flash duration will be similar. It is at reduced durations that the type of light will really start to make a difference.
|