K-x/Sigma do high school theatre

I decided to try my K-x and Sigma 50-150 combo at our local high school's theatre production. I was sitting at floor level and shooting between spectators' heads, so no wide shots and certainly no composition to speak of. The lighting was difficult as some of the actors were in the shadows when they should have been more in the spotlights and the intensity of the lighting varied. All pics were shot at f2.8 and at high ISO.

Pics are in the reply (6 large files) and are pretty well untouched, including the big heads in front of me!