Thanks for the compliments!
Yes, I think the IS was mandatory here, and even more so, the f/2.8. Having shot an f/4 lens in this same venue, you're going to have a hard time. Typically, I shoot the 50mm f/1.4 for these concerts, but I wanted to try something different. I was concerned about losing a few stops due to the aperture, but it wasn't a concern, at all. The only thing I can accredit that to is the IS, since every other variable was the same (except focal length, which would have only compounded the problem, being longer). You can see all the settings in the EXIF info, since that's all been preserved in the images above.
Here are a couple wider shots of the venue, to give you a better grasp of the conditions. It's pretty dark, but the performers are lit up with spotlights. In the second shot, with the blonde singing, you can see the exposure difference between someone in the spotlight, and someone not (the guitarist in the background).
As for settings, I am forced into ISO 1600. That's just the way it goes. Typically, I keep the camera on aperture priority, and make sure it's wide open. I also normally underexpose a couple clicks, like -2/3 EV. Another option that's worked well is spot metering, because you want the performers faces and skin tones properly exposed, even at the cost of losing the shadows.
What amazes me is how evenly and smoothly this L lens pulled light out of the shadows. In the 4th shot, the singer with the vest and the blue and red lights... the fact that I can see into the area around his throat, and especially his back arm.... I've never had that before. Typically, those are sacrificed into the mud for the rest of the shot.
Here's one more of those shadow-to-spotlight photos.
