[biz-engineer]

When I'm using the K1 in video mode, it sometimes goes through a mirror-down shutter-closed mirror-up shutter open cycle. This surprised me, both during video recording and also while not recording. It happened a few times, but I haven't been able to reproduce it. Any idea what the problem could be?

[kypfer]

I vaguely remember similar symptoms being caused by dirty lens/body contacts, though probably not in video … I don't do much video
Initially I'd try cleaning both sets of contacts and/or try a different lens.

[ProfessorBuzz]

Also try running off external power or battery grip - things might be getting toasty warm inside.

[biz-engineer]

I've looked into the manual. It say the video recording can't exceed 4GB or 25 minutes. But I've seen the reset happen both during recording and without recording. Then I used the timer of my phone to check if the reset cycle happened at fixed time intervals, but the reset didn't occur again. During the recording I've lost an entire record, so maybe it was a problem triggered by the SD card writing process. Maybe the card writing failed when the battery temperature increased (next to SD card slots) during video recording and the camera firmware didn't know how to handle it?

---------- Post added 15-11-21 at 19:22 ----------

I vaguely remember similar symptoms being caused by dirty lens/body contacts

I've thought about that, I've checked the lens contacts, no issue there, everything is clean, nothing weird happens outside of the video recording mode.

---------- Post added 15-11-21 at 19:24 ----------

Also try running off external power or battery grip - things might be getting toasty warm inside.

Yes. I used the K1 in video mode the whole day, and it did get warm, lost 15 minutes of recording, although I didn't see the reset cycle occur later in the day when the camera was warm.