Hi sthedlu
From what you have detailed by best guess would be a sticky shutter (technical term ;-)) especially as the subsequent shots seem to be ok.
One thing I would ask is what happens if, after it starts shooting ok, you turn it off and back on again, is the first frame in this instance also dark?
It might work itself out. If not its, something my colleagues at Sony Central Service will be able to fix.
Regards
Lee
