Canon announces that it was able to capture a video of Yaeyama-hime fireflies flying in darkness on the high-sensitivity 35 mm full-frame CMOS sensor with 19um pixels developed by the company for video capture and announced in March 2013. No artificial lighting was used during shooting, which took place after sunset amid the island's mountains. Despite an exceptionally dark shooting environment of less than 0.01 lux, a level in which the naked eye would have difficulty discerning surrounding objects, the CMOS sensor at 30fps was able to capture not only the color of the light emitted by the fireflies, each of which measures only a few millimeters in length, and their movements, but also the surrounding vegetation in which the species lives.
Yaeyama-hime fireflies amid jungle vegetation
(Photomontage created from video footage)
A Youtube copy of the video from Canon site shows the footage: