The number of levels in each f/stop has been misunderstood by those advocating expose to the right and others. In a 14 bit capture, the brightest f/stop contains 8192 potential levels, but those are dithered by noise and the actual raw file contains far fewer effective levels. Furthermore, the human visual system (Weber-Fechner law) is sensitive only to a 1% change in luminance (see Norman Koren
). He also has an expanded explanation of levels and the effect of gamma on the distribution of levels in each stop. If one needs to tease out highlight detail with editing, it is useful to have more than the required number of levels but there is no way to use 8192 levels even if they were attainable.
DXO measures the tonal range, which is the number of bits necessary to encode the range of a sensor. The Nikon D800e has 14 bit files but the tonal range is only 9.83 bits at ISO 100, and this is a highly rated camera.