when converting to widescreen, I've been told that you should right click on clips and check off "Reduce interlace flicker" Do I have to do this on still images that will contain motion, or is this only for video?
Using that switch will mean a slight loss of vertical resolution. I wouldn't apply it unless needed. If you start to see nasty jaggies down sloping edges then that'll fix it. When I say nasty jaggies they're what looks like interlace artifacts but they are bigger than one line.
Bob.