A diagonal fish-eye lens was used in this 2012 shot. Despite using a sturdy tripod, some shake were still visible at 100 percent view. This was probably due to shutter shock which thing the older Panasonic cameras, such as the GX1 used here, were quite prone to. Thankfully, things looked fine at this size.
This was captured with the Handheld Night Shot mode in which multiple images were recorded at high speed and then merged together for less noise. It was a jpeg-only mode and operated totally in automatic with no option for manual input.
The original capture actually had flares around the lights. This was fixed in post by selecting the affected areas and toning down the mid-tones, after which the shadows were brightened a little for the whole image.
Helluva Times 