I never really paid that much attention to the length of time a flash goes off for until I started doing droplet photography! It never occurred to me that lower power settings (i.e. typically by setting the flash power manually) results in a shorter flash duration. Too much power and the duration's too long and you get movement in the shot. So to get better shots I need to turn *off* all the auto-wizz-bangery of my flash units! I'm now doin' it "Old Skool"
Thanks This is one heck of a learning curve. I've never had to think about how many milliseconds of lag my camera's shutter has, or how that lag changes depending on what functions you've got enabled at the time! All part of the fun.