Wirelessly posted (BlackBerry9000/4.6.0.167 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/102 UP.Link/6.3.0.0.0)

Just throwing it out there. Have you done any preliminary testing aiming the lens at a bright light source (ie. The sun) in a darkroom against the wall? You could determine focal lengths that way to get close and you should also be able to determine DOF with closer subjects in the same manner. Just a thought.