It was inevitable that DxO, long-time benchmarkers of camera sensors, would inevitably turn its attention to the eyes in the skies. The company tested a handful of the cameras that come with popular drones -- 5 DJI models, the and the . The results aren't very surprising, though they do serve to drive home how much of a difference the extra image-processing power in a full-size camera makes, but which drone cameras lack because it requires more room and battery power than you can fit into their relatively small designs.
Basically, they all displayed far worse low-light sensitivity than current cameras with the equivalent size sensors. However, in some cases they fared pretty comparably to last-generation models. For example, the Four Thirds size sensor in the DJI Zenmuse X5S showed poor low-light sensitivity compared to Olympus' current flagship(an ISO sensitivity rating of 956 for the DJI vs. ISO 1312 for the Olympus), but it outperformed the original , which tested out at ISO 757.
And it's no surprise that the smaller the sensor, the worse it gets. I did find it interesting that the Hero5 Black performed so poorly, but that's because it captures only 10 bits of color per pixel compared with most other camera's 12- or 14 bpp.