Composition: In this first shot, I chose a position where the sponsor logo was clearly displayed. I thought this would be a good context clue, but after taking several shots, decided that I should try to include the projection screen in the background instead. So I changed my position as soon as the next speaker took the podium.
The nice thing about shooting in the manual mode is that as long as the main lights remain constant, the background can be under or over-exposed and you will still have a consistently exposed subject. When they turned out the house lights to lend drama to the background PowerPoint presentation, the subject was still properly exposed, save the shadow areas that were no receiving any fill light.