The limitations of the internal memory, that's what the video clips are written to.
You're card may hold 256 MB, but it's not fast enough to write directly to so it writes to the buffer first, then to the CF.
Sony's Digicams can record for as long as the Memory stick can hold, but that's a totally different type of memory technology, which some may argue is superior.
I may be completely talking about of my ass, but I think I read this somewhere and it seems logically correct
