I'm a professional corporate event shooter. Also do occasional Mitzvahs and weddings. Two years ago I switched back to 35mm format from Micro Four Thirds after shooting the latter format exclusively for 7 years, simply because of the bat-cave lighting conditions I sometimes encounter. Now that I don't need to use flash as much, I often find myself shooting at ISO 12,800-25,600 and f1.4-2.0. (Thank you, DxO for making this possible!). The Edison Ballroom in NYC is probably the dimmest venue in which I work. It's one of the reasons why I shoot bright primes on three cameras rather than using something more convenient but less bright, such as Tamron's or Samyang's 35-150/2.0-2.8.
How about you? What are the most challenging lighting conditions you encounter at events, and how do you deal with them?
Let's get some practical problem-solving conversations started on this forum. New wedding/event shooters welcome.