that's okay
I'm well aware of what the differences between front and rear (or first and second curtain) sync are. My experiences tell me that in dance situations, rear sync is preferred because dancers who know the moves ask why dancers are doing the steps backwards if I shoot with first curtain sync. What i'm trying to say is i also know that the length of the trails in the photos can be controlled, but i dont' know how or what controls that.
The lens was fully open as well that night. It had to be.
The ISO on the camera was 640 but don't let that fool you, the automated PP means these photos are currently at between ISO900 to 1250. Any more then that and we'd all be looking at grain (see out background areas with not much illumination). A 50 f/1.8 is certainly in the works, but other people tell me for this sort of stuff a 50 f1/8 can be rather limiting as shooters like us don't get much room to move backwards and forwards, only side to side.
Anything slower than 1/25 means bad pictures for me and it isn't VR's fault. The subjects move so fast that their faces ended up becoming blurred smears.
It seems like i'm reaching the limits of my equipment.