Low light photography of moving objects is difficult. When you take a low light photograph typically you use a tripod and open the shutter longer than usual.
If you open the shutter for too long with a moving object then there will be trailing. For this picture I had the aperture open wide and snapped a "normal" shutter snap with as much light as possible. I think it represents the mood of the concert well.
I used a manual zoom with everything in focus.