The Panasonic S1R has a serious bug with XQD cards which results in loss of images. The camera warns of a write error then cannot be used any more until power cycling the camera or pulling/reinserting the card. At this point, I do not know if the same bug occurs with SDXC cards (much slower so I prefer not to use SD).
Although my rigorous verification of the Sony 256GB XQD Card as reliable was compelling evidence the S1R was at fault, I wanted to give the Panasonic S1R a chance to prove itself with a different card. Accordingly, I started using a Lexar 128GB XQD card., formatting it in camera first of course (as I’ve done repeatedly with the Sony XQD card).
The very first day shooting with the Lexar XQD card, the S1R reported write errors numerous times over 3 hours, destroying the exposure every time. Typically, truncated RW2 raw files remain on the card, e.g., 4MB or 17MB or whatever (random file size, aborted recording). These files are of course useless.
A side effect when a write error is reported by the S1R is the need to power cycle the camera or pull and reinsert the card. Either resets the lens focus—disruptive and time-wasting when shooting a series or in HighRes mode. As if loss of camera operation were not disruptive enough. Still, that the S1R warns when the problem occurs is a good thing, even though it is inconvenient—better than silent errors.
Reader Benoit D writes:
Yes, the S1R is prone to card writing errors with my 3 QXD cards (different brands and capacity). Sequences are exacerbating the issue. No issues so far with SD cards.
DIGLLOYD: a bug that Panasonic needs to fix ASAP. The times I have seen the issue is when shooting several frames in succession, which is what Benoit is saying too.