For video, it is important to use constant aperture zooms if you want to actually zoom within a shot. But the aren't many constant AI manual zooms from Nikkor. The more common ones are the 35-70 f2.8 AF (focusing ring too loose in manual mode)and the manual focus 35-70f3.5. (haven't tried) I recommend the Canon FD 35-105 f3.5 instead. (It even has macro!) Back focus is perfect and tack sharp.My only complaint is the barrel rotates when focusing, so can't use a matte box. If you are using NEX or M4/3 body, you can pair it with a speedbooster (metabones) or lens turbo mitakon to get a one stop boost and (almost)eliminate the crop factor. If you want something much faster, wait for the next Sigma constant f1.8. I don't think their current f1.8 wide zoom is very useful.