Originally Posted by David A. Goldfarb
I'm glad you are so busy. I have done a huge amount of work in dim light for music performances and ballet and can attest to the challenge. I find that under-exposing 1-2 stops at ISO 1600 and then recovering the highlights works well with my Can 5DII. Stage lighting that appears great to the stage production folk, is often very harsh and over contrasty for photography with rapid gradient from over-exposure to horrible shadows. With digital workflow using Capture One, very good results can be had shooting at f4.0-5.6. Only rarely do I use f 2.8 as the DOF tends to be too limited for more than a few people moving on stage.
So I don't think that f2.0 is needed. The 70-200 2.8 L works so well and has the advantage of allowing zoom to cover more of the cast if need be. I use a sound blimp, and I cannot imagine having two blimped bodies, one with a 200 f1.8 and another with a 70-200 2.8L which is needed anyway in most cases, unless a 50mm is needed for the entire stage.