How's the Nikon D5100 with filming?

Need a new recording camera

If you want to shoot video, get a dedicated video camera, not a stills camera that can shoot video

You'll find some info on You Tube (even some material captured on one) to help you make your mind up.

Camcorders are the sensible route, better features and specs.

It's not as good as Canon, which is not as good as Panasonic or Sony.
Get a real camcorder and avoid the problems that come with using a tool specifically designed for still photography as video device. The only reason one should buy a DSLR for video is because it allows them to achieve a look that can't be done with a traditional camcorder. Otherwise the recording limitations, horrible audio, lack of basic functions and features all make using DSLRs for video a less than ideal option.

Go on youtube and do a search for D5100 video test. I mean, you can the word of a stranger on some forum, or you can look at actual footage. Then do another search for DSLR or Camcorder. Be sure you know what you're giving up when using a DSLR for video.

Agree with the others who say the video is best captured with a device designed to captures video - not a device designed to capture still images that happens to have a convenience feature for video.

If warnings from at least 4 people have not deterred you, download and read through the manual for the D5100. Here is a link to the manual, available for free download from Nikon:
http://cdn-10.nikon-cdn.com/pdf/manuals/dslr/D5100RM_EN.pdf
All the major/reputable manufacturers have links to their product manuals for relatively current products.

Start on page 107 for recording movies.

Page 108 which warns you of file segmentation and video file duration limitations (assuming the dSLR has not already shut down from overheating). You will find similar warnings in pretty much any dSLR in the less-than-$1,000 (body only) range.

This does not mean low-end dSLRs can't capture good video, they can - but you are wanting to use a device for a capability that is not its primary design. Sort of like wanting to use a rock to hit a nail instead of a hammer. It will work, but not the best selection you *could* make to get the job done.

That there are a total of 3 pages in a 230+ page manual for video capture should tell you something… The rest of the pages are about using the device for still images.

And just a clarification: "Filming" means using a *film* camera. Neither dSLRs nor camcorders use film, so there's no unexposed film to worry about, no sending out exposed film for chemical processing and no need to convert from film to a digital format (scan each frame one-by-one) for computer-based editing…

If you are convinced that a dSLR is what you must have, then you need to increase your budget and owe it to yourself to investigate devices with dSLR features (APS-C or larger imaging chip, interchangeable lens system, a few other items), designed for video capture… Like a Sony NEX-EA50M, Black Magic Design Cinema Cam or Canon EOS C100/C300/C500 series - a few others…

As good as you can be.