Does anyone know how to achieve interval or stop motion recording on the XL1

As far as I know...you can't. You would have to record the full time length...then "edit" it.

It's an HDV thing, not just an H1 thing. 'Post' is the only way

Yup...forgot to add....LONG GOP !

I always here rumors of being able to do this with the firestore's don't know if it's actually possible though. The other option may be with the new aja box and stop motion recording tethered to a laptop. But again, not 100% sure. Should work though.

Thank you everyone for your replies.
My question was related to my earlier experience with a Sony PD170 which allowed for interval recording. I learned that video could never capture just a single frame. With regular 30min intervals it captured 12 frames. In post it was a simple matter of saving 1 frame and deleting 11 frames. The end result was a smooth rushing cloud sequence like film stop motion.
It was the regularity (interval recording) that made the post job easier.
With XLH1 I guess I'll shoot bursts in 30 min intervals with the remote. Each time identifying each break with a card or clapper.

You can do interval recording with the FS-C recorder, but in DV mode only, not HDV mode.

From page 59 of the FS-C User Guide:

Time lapse provides the ability to record a single frame at specific time intervals, for example one frame per minute, 00:01:00:00. Time lapse applications can include capturing the traffic on city streets, the growth of a plant from seed to maturity, and construction projects.
Features of the Time Lapse function include:

• All the captured frames are recorded in a single clip.
• The time between recording periods can be set in frames, seconds, minutes, and hours.
• The maximum time between recorded frames is 24 hours.

HTH