The information provided here was given to us by Sean.
The following image of a graph represents the lag time in a not fully saturated high quality NEO. The graph shows the lag time to be around 100-120 micro seconds. The initial flat portion on the bottom left of the graph is the lag of the equipment. The time from where the purple line starts to rise to where it levels out (reaches full power) may be considered the lag time. ie from about where x is 25us to where x is 140us.
(Click image to enlarge)