When using below 0.332 fps values, the camera automatically restarts after some seconds. No video is saved to the card. From 0.332 fps and over, everything is good.
When recording at sub 1fps every roughly second frame gets totally overexposed.
The camera is very less responsive for something like the first 40 frames after record is pressed. I believe this is a limitation from the canon fw, but it is annoying to not being able to start or stop the record for e.g. 1 min when using 0.50 fps.