With close-up adapters such as the corrected Raynoxi and uncorrected cheap +diopter screw-ins, the close-up adapter lens diopter selects the working distance, while the focal length of the host lens determines magnification. Here is a table of diopters and working distances:
+1 >> 20-38" (500-950mm)
+2 >> 13-20" (330-500mm)
+3 >> 10-13" (250-330mm)
+4 >> 8--10" (205-250mm)
+5 >> 6.5-8" (165-205mm)
+6 >> 6-6.5" (153-165mm)
+8 >> 5" ---- (127mm)
+10 > 4" ---- (102mm)
So the DCR-150 (+4.8 dpt) has a working distance around 6.5-8.2" and the DCR-250 (+8 dpt) has a working disance around 5". Cheap screw-in adapters of different diopters have their own working distances, but are not corrected for optical aberrations. They can be fun to play with though!
Last edited by RioRico; 05-30-2011 at 08:26 AM.