Photographing a conference is a lot like street photography: you have to be unobtrusive, and you're constantly hunting for interesting expressions. Even with 400 people intently focused on a single speaker, there's plenty of subject matter to capture. My main challenge was lighting - a messy mix of fluorescent, video, and LED - and darkness (as conferences tend to be). Despite the funky colors thrown off by the projection screens, I shot the available light, with not too unpleasing results.
See more of my photos from the Gasification Technologies Council's annual conference on their site.