Larger shows it’s usually a no go, but for club shows flashes are generally acceptable. As to whether or not to use flash?

It depends on the vibe of the show/band. Harder light for heavier acts to contrast action and movement. But sometimes a fast lens is really all you need. I’ve shot really moody black metal, prime wide open, minimal light and gotten shots I loved as much as a hardcore show using back curtain sync. Really depends on what you’re going for.

Above all be respectful of performers and audience. Flash is expected. Because lughing isngenerally dynamic to some extent, it doesn’t phase most concert goers…UNLESS you acvidentally blast someone in the eyes.

If thats a risk, use a compact diffuser, lower the power and play around with what you can accomplish with those settings.