DSLR Lens for close up videography?

I just bought a Nikon d5200 and it is my first DSLR camera. I bought it primarily for video and have the 18-55mm and 55-300mm. I'm really interested in artisitc videography so I need a lense that is capable of autofocusing to a moving subject at close range, any suggestions? I was looking at the 35mm for shots that aren't tracking a subject, but would it work well for what I'm describing? When I shoot video on auto with my 18-55mm and it is within the 8 feet range it is all junk, I kind of want something to pick up from there. Any suggestions or other ideas?

The biggest problem with any auto focus in video, this is my experience, is that it tends to jump around with any tiny movement in the frame. My suggestion would be to learn to use your lenses properly and quickly to master auto focus during video.

I also have a couple of other things I do for video that may help you. One is to use the widest lens you have… Mine happens to be an 18mm with IS. Wide means it helps to hide hand movement for the hand held stuff I always do. The IS goes a long way to hide hand movement as well so my video comes out without shake - a very irritating thing to your viewers.

Another thought is a screen view finder like this.
http://www.amazon.com/...004HD3G6Q/

Having done a career in broadcast television video shooting for news and sports I can tell you it's critical to show you viewers a steady shot… You don't need a tripod if you can hold a camera steady.
With dslr cameras they are so light and small shake is difficult to avoid without doing proper technique and equipment to avoid it.

I find that adding the above view finder along with the other things I do, the view finder gives me another point of contact - three, both hands at the finder, that my video works pretty well when it comes to being steady.

For stills the 18-55mm lens zoomed to 55mm should be able to get very close. Only a macro lens (which the 35mm is not) can get closer. Maybe the Micro Nikkor 40mm AF-S would work for you.
If it is a matter of choosing the right settings for auto focusing in video, that I don't know.