50i is actually 50 interlaced fields per second, which translates to 25 frames per second (the PAL standard). There are 2 fields for each frame of video, unlike progressive video which records complete frames (and therefore has no interlacing).
The Canon XL2 records in 50i (interlaced) and 25p (progressive) - that's for the PAL version of the camcorder. When importing clips, iMovie '11 should give you a frame rate option of PAL 25 fps (as well as 24 fps and NTSC 30 fps). To the best of my knowledge, using the PAL setting in iMovie will allow you to import either 50i clips or 25p clips.
My Sony camcorder (HDR-SR7E) records at 1440 x 1080 interlaced in PAL format (this translates to the widescreen 16:9 aspect ratio of 1920 x 1080 - something to do with square versus rectangular pixels). So my clips are actually 50i which gets imported as 25 frames per second. At least that's my understanding!
In stating that "50 fps will give you slow-motion", I believe Klaus is referring to 50p (progressive) footage) - not 50i (interlaced). I don't have personal experience with 50p, but again, that's my understanding.
So, if you are recording at 50i, that will be fine with iMovie. Just use the PAL 25 fps import setting, as I do for my 50i clips. It might also be worth trying the 25p setting in the Canon XL2, as iMovie apparently works best with progressive video (as does Final Cut Pro X).
Message was edited by: John Cogdell
No worries Klaus! A lot of questions here refer to using 50p with iMovie (but not much on 50i). I nearly made that assumption too (50p) when I first read the OP's post, but then noticed the little i after 50. It can get confusing at times!
On that note, I think I'll have another cuppa (tea that is - too much coffee already today!).