Remember that the dof has to be devided by the 'crop factor' since the circles of confusion are 1.33x larger relative to full frame. Thus the dof marks on the lens barrel are wrong. It seems some people like to argue about this, saying the dof of a 50mm lens for example is absolute, but the dof determination is based on a ratio of the circles of confusion relative to the whole area, which was assumed to be a full frame of 35mm film.