I think the digital aspect of this discussion is seriously misplaced. The easiest way to gain DOF is to use a longer focal length lens although this introduces a size of eqipment problem. At 1:1 a 420 mm lens at f32 gives a DOF of about an inch (COC .1 mm). In the next couple of weeks, I will do some tests at higher magnifications and smaller aperatures and post them in this thread.