These kits attach to the end of your camcorder and allow you to get a film-like shallow depth of field by using 35mm lenses. You can use Nikon still photography lenses off eBay or buy ultra nice actual Panavision film camera lenses. All kinds of adapters exist from a $10,000 professional one to cheap low-grade $200 models. The drawback usually to the less expensive ones is you have to flip the image in post (not that big of a deal, just use an external upsidedown LCD monitor during shooting), and you may get some grain in your image if you don't have a good adapter. The Redrock Micro35 kit is an excellent way to go (no, I don't get paid to endorse them unfortunately) if you can afford its price range since it's reliable and won't produce grain even in HD. You can learn more about it here.
