I'm shooting a music video in which I want to use a subtle slo-mo effect. The artists will be miming to a sped-up version of the song @ around 0.8 time stretch. We'll be shooting under lights in a studio.

I've done some experiments using variable frame rate (32 fps) at 1080/25p on my AF101, but had problems with light flicker and/or motion blur. In a 50Hz country only 25 or 50 fps seem to work without any light flicker, and obviously neither is of any use.

So instead of using VFR, I've tried shooting in 1080/50p using a relatively high shutter speed (around 250th) and slowing it down down in post, using Optical Flow in FCPX, which looks OK, but there's still some jerkiness in the faster movements. I just can't seem to find the right balance between blur, jitter or light flicker - any suggestions?

Reading around I've seen conflicting info - some say always stick to the 180d rule, others say shoot with as high a shutter speed as possible if you're going to slow down in post (i.e. not shooting with VFR). I'm shooting the day after tomorrow, so any help much appreciated!