To add to the confusion about DOF, if one assumes the vision standard of 20/20 vision, even the manufacturer standard for CofC leads to overly generous DOF zone sizes, and a person with 20/20 vision would really NOT consider all of the out-of-focus zone to be 'acceptably sharp'. That is why many of us long ago had adopted the practice of looking at the DOF scale corresponding to an aperture value which was ONE LARGER than what was selected on the lens, for the DOF scale references....i.e. use f/5.6 marks on DOF scale when the lens aperture was f/8