Low lighting conditions divide usually into those of daylight and those of artificial lighting. The normal maximum daylight is outdoors, in the middle of the day in clear weather.
As we’ve already seen, this is in the order of 50,000 lux or more. While it’s probably going too far to say that the manufacturers of cameras, lenses, film, and sensors assume this to be the standard, what most people would call bright daylight is the ideal condition technically. This was the “sunny 16” rule, from the days when many photographers would estimate settings, and it holds that the usual exposure on a sunny day is 1 over the film/sensor speed at ƒ/16 (thus 1/100 at ƒ/16 at ISO 100).