I can't load that page, which I'm curious to read because my understanding of the z-buffer is that the ratio of near to far is the important thing (thus both ranges are important.) That the z-buffer works logarythmically is irrelevant, because the greater density nearer the camera is still being spread out when the ratio is higher. That is, the z-buffer is finer near the camera than far no matter what the ratio is, but the z-buffer near the camera is more fine when the ratio is lower.