The Lux ratings for the HERO3 and HERO3+ cameras are not something that we have available.  We feel that the Lux rating does not provide an accurate picture of the light sensitivity capabilities of the camera, since this is only a rating for the camera sensor, and does not take into account the actual processing of the image by the camera.  The best thing you can do to get a better idea of the camera's low-light performance is to take a look at our customers' videos on websites like Youtube or Vimeo.  Try searching for "HERO3 low-light", and you'll get a great mix of both amateur and pro videos that show how our cameras perform in low-light settings.