Hi Choen,
From the CF adapter data sheet. (Its in the instructions too)...
3. Use of Converters and Extension Tubes: Converters
and extension tubes are attached and removed in the
conventional manner. They should be attached to the
adapter first. When detaching, however, remove the
lens first and then the converter/extension tube. If
you remove the lens and converter/extension tube
together as a unit and then separate them, there is a
possibility that the shutter in the lens will be tripped.
Note: Only converters and extension tubes from the
V-system can be used.
David