David -- What an interesting dialog you precipitated here! You brought the following to the discussion: extremely high ISO; extremely low level lighting and problems introduced by stage lighting, which can be a whole world of weirdness; walls of an unknown color; all of which created a challenge we would not even have been able to begin to examine in the days of film. That's my take-away here.
We are able to do things today which we were unable to accomplish in "the old days" and it's fun. The ensuing discussion has been very interesting and thought provoking. Thanks!