So, is the issue when your strobe light flashes you only see the light flash in a horizontal chunk of the frame? or you are using a constant light source and you see thick horizontal lines scrolling across your screen?
The latter issue is caused by the way your cmos chip captures an image. It is the same reason CMOS chips succumb to rolling shutter jello-vision effects. It is unavoidable while recording video around flashes. You can “fix it it post” if you like by adding the effect to the rest of your footage over that frame.
Otherwise use a camera with CCD chips.
The later issue is caused by certain light sources (most commonly fluorescent tubes). If your shutter is not set to a multiple of the power frequency of the light source (60 in NTSC countries, 50 in PAL areas) you will see these lines. Good old fashion tungsten light sources do not cause this issue.
Colin McQuillan
Vancouver, B.C.
“Live, love, laugh and be happy.”