Cavern Expedition with the E-M5
This was the toughest lighting situation I've ever dealt with. The E-M5 did fairly well. For the most part, I was able to push the shadows around to get usable images. In some scenes, the extreme dynamic range was just too much, and there was no way to get usable highlights and shadows in the same scene. A D800 probably would have done better. All taken handheld, and with the ZD 12-60mm.