I just started going some videos, with the finished clips posted on Youtube for a business I am involved with. It has been fun, I have to admit, even though I don't care about watching videos or watching films much(gave my last TV away 15 years ago). I have been shooting two camera takes and find the 24-70 very good for my purpose. Manual focus it best if any perspective changes are needed. DSLR's can be excellent for technical specs but are clumsy for hand held shooting. They are much better for formal scripted clips than as a hand held gonzo street shooting or reportage. A camcorder is better suited to that. For effective use of a DSLR, a fluid video tripod is a must. Manual focus is needed if the scene will involve a change in focal plane. AF works fine if you AF before recording and not change it during the take. An external mic close to the source is necessary for any serious dialog or ambient sounds, if field sound is going to be used in the clip. I use a wireless mic pack on the talent and receiver attached to the tripod with a 3.5mm plug and cable going to the mic in jack. Se the internal sound gain to low and not automatic. Automatic will cause pumping were the ambient noise level will increase when the total sound level of the ambient + dialog drops, between sections of dialog for example. The results can be excellent. Fed with a good clean signal, the audio recording is quite good on the d7000 and D800, the two I use.
For lenses, smooth old wide angle zooms or primes with aperture rings are the best for this. The older lenses or new ones that are carry overs from the golden age of lens construction are a pleasure to focus and are very smooth. Optically, they are not as good as newer designs with the coatings available now so expect a bit more flare and CA wide open. I have tried my new(yes, they still make these) 50 1.2MF what is even smoother and possibly better built than Zeiss lenses and offers razor thin DOF if that is the look you want for a dream scene or obliterating the background if you have no clean set to use. The most useful of the zooms will be the 14-24 and for general work, the 24-70. Much longer and you need a very heavy duty tripod. Good luck and have fun Stan St Petersburg Russia