I was shooting to memory card with a Canon MVX25i, which is the PAL version of the Optura 40. I had a "low battery" warning but I kept going in the hope of completing a shot. The battery died on me. I assumed that the camera would do a graceful shutdown in that event but I discovered that is not the case!
I now had 34 minutes of event filming as a file of length "0". The file recovery was long and difficult. I have written it up as an article in the hope that if this happens to anyone else the information may be useful. I regard myself as an I.T. expert but this would have to be one of the most difficult problem-solving challenges I have faced in a long time. Moral of the story, if you see that battery warning then STOP. It is also a good idea when using Memory Card to stop and restart often so you do not build up a large at-risk file.
The rescued movie: