I have a question, probably dumb, about the way that flash output is characterized. It is more of a curiousity than anything. The output for any kind of photo lighting is given in W.s (watt-seconds). Since power (watts) is energy per unit time the implication is that the output is given in energy. Does this mean that for each firing of a 1000 W.s flash (set on max) a 1000W.s 1kJoule of energy will be given off? If so, what soes it imply for continuous sources? I guess what I am wondering about is how do you characterize a device in units of energy.