The HC3 can do that, not the HC1.
It's 120frames-per-second for a max. of 3 seconds (NTSC version).
Only downside really is dramatically reduced resolution, but it's still a pretty clever feature.

So, again the low light question:
i have 2x500W halogen lamp for wedding evening.
This is just enough for XM2/GL2 to produce video with following settings:
shutter 1/50
F 1.6
Gain: 0db
So, the picture is very sharp and absolutly free of noise.

I'm afraid.
What can do in this situation the HC1? Gain up to 9db? And the picture will be noise? :(

Max. aperture on HC1 isn´t much worse at f1.8.

Doubt HC1 will give 9dB gain in a situ where XM2/GL2 will give 0dB.
Can\'t see any reason, optical or electronic for such a big gain differential.

Maybe 0.5stop = 3dB.