As can be seen in these photos, with a slight tweaking, it can be saved, even if the lighting is less than perfect. I begin the evening with my ISO set to at least 400 or 800. If the lighting is really dim, I might even bump it up to 1600. Modern Digital DSLR's handle ISO settings up to 1600 with little, or no, noise introduced. You may notice slight noise artifacts in the very black areas of the photo, but that can usually be dealt with effectively. These photos were taken with a Canon 60D, a Tamron 28-300mm IS Zoom lens, and a hot shoe mounted Canon 580EX flash. I am shooting the event in Shutter priority, set at 1/250 of a second, which is the sync setting of my flash when using the ETTL setting.
The top photo appears too dark, lacking details. With just a slight levels adjustment I can increase the light, without introducing a lot of noise. And the photo is saved, and more interesting to view.
This photo of Maine Governor Paul LePage was taken during his keynote speech. Close proximity to the stage is key to these types of captures. Depending on the venue, and your association with the organizers, you can put yourself in a good position, or not. I like to arrive early and check out the room arrangements and stage lighting, if I can.
Part of the fun in event photography is grabbing candid shots of the people in attendance. Everyone knows you are there to take photos, but the more you mingle and talk to folks the more at ease they will become. My goal is to be as unobtrusive as possible.
This photo of Bethel Shields, Dr. Tom Shields, and Governor Paul LePage shows how I captured a conversation in progress, without intruding on their space. A good zoom lens can capture a lot of interaction, without intruding on private conversations, and being in their face.
A couple of thoughts, from my perspective, to close this topic. It is all about the photography. I do not care what your political affiliations are, or your personal feelings. If you have agreed to photograph the event, (I will repeat) it is all about the photography. It is my job to take images that show folks in their best moments, and make them look as good as possible. No open mouths, no chewing food, no ugly facial expressions. And people do make the weirdest faces when engaged in conversation and especially eating. And, above all, Have Fun....