Some cameras like the Phantom allow you to set how the record trigger operates. Most of the guys that I know that used to shoot some really HS stuff had it set so that they hit the trigger AFTER the event happened(so they would get something like the 5-10 seconds before they hit record. I don't remember how big the buffer was exactly). I don't know if the F5/55 will operate like that(I don't think, but I won't bet anything valuable either), but my P2 Vari doesn't. It's only 60 frames, but I could have saved a LOT of time and wasted data space over the years if it operated with a buffer for slo-mo instead of just punching and waiting for it to happen.
Actually it might I have been known to set the pre record on my 400 up to max just so that I can hit the button after an event. The problem again lies with the buffer size available, actually for that matter I think all high frame rate recording past a certain point may be pre recording, as you are recording the info faster than the hard drives can write it.
I did a job last year where I got to sit around and talk shop with a dedicated Slo Mo guy for about 8 hrs while we waited for some engineers to figure out that the device we were supposed to record would not go off with the equipment on site. The long and short of it is that there are three factors to keep in mind.
1) each bump in speed will cut your available buffer time by half so the farther you go the more finite your window becomes. The more triggering can become an issue.
2) One way around this may be to cut your frame size and push the image back a resolution step, you all know the implied issue there. On The FS-700 if you kick the seed up you need to go to 250fps before you need to go down to 720p. I am not sure if the F-55 will do 4k slow mo but my gut wants to say you need to be in 1080 or lower as well.
3) The issue of light the faster you go the more you will need. Think of it as setting a DSLR exposure to 1000 or higher while maintaining a Low ISO say in the 200 or 400 range. Sure you could try to introduce some gain but it will only do so much.
