I use a .43X screw on converter with the 14-140 which seems to be the best Lumix lens for video. I shoot medical & dental office interiors so wide angle is a must. In order to avoid vignetting I have to back off the widest angle on the 14-140 just a bit. I also have a 7-14 which is smaller and lighter and instinctively should be better when considering quality of glass, weight etc – however the fellow that renders my videos tells me the 14-140 with the converter does a better job at capturing the basic video (AVCHD) – which I am assuming is due to the video oriented continuous focusing.
I would be interested to know if anyone else has tried the 14-140 with a converter versus the 7-14. Also at such wide angles (6mm – 7mm) how important is auto focusing?