Thanks. That was actually a pretty substantial crop.
Yes, that was ambient light. The exif tags are intact. 50mm prime, f/2.0, 1/60th of a second, ISO 3200. I'm sure ISO 3200 looks grainy enough on my camera that many people would never use it, without exception. But I'd rather push ISO 3200 (under-expose the photo, and increase the exposure in post-processing (which would be even more grainy)) than not even try.