Once the sun went down, the obvious challenge was photographing in low light. I opened up the aperture all the way to f/4, using a Canon 5D Mark IV and Canon 24-105mm II lens.
In post processing with Lightroom, and Aurora and Noiseless from MacPhun, some of the shots were simply too grainy. That happens when shooting at around 25,000 ISO! I had to shoot without a tripod because most of these kinds of venues do not allow tripods. That is a good policy in this case as it was nearly pitch black out and the Christmas crowd was fairly large.