I have been looking over different hot shoe Flash units and it seems confusing as to how they rate these units output power, Could someone explain which of these two units is either more powerful or approx the same power. The first is rated at GN 45m at 85mm zoom position #2 is GN 38m/125ft at ISO100 and head zoomed to 35mm position) However the first does not say if it's...100 ISO? ...and the flash heads are rated at two different MM positions, how do you make a comparison with these varied zoom position specs, and in many cases missing data!
