I Want to Buy SLR Camera For Video Recording Purpose To Make Some Short Movies?

I'm Doing VFX Visual Effects Proffessional Course So i wanted to Buy A High resolution Camera For High defination (Full HD) Recording, it should consist & Focus the features only On Video Recording like optical zoom, Megapixel, HD 1080p Resolution, Clarity of video Should be Superb ///
So, which one is better Amoung this Brands?
SONY, CANON, NIKON?
Suggest me the Brand & Model.

First of all, don't buy an SLR. An SLR camera only uses film, it does not take video.suggest you look at dSLR cameras instead.
audio on all dSLR cameras suck, if that is important then look at alternatives.
you didn't say what you intend to record, the recording time on all dSLR cameras is very short, typically in the range of only 8 to 12 minutes. If you need to capture longer events, then you need to get a camcorder.
virtually every camera/camcorder made is HD, that is not a quality specification.
as to lenses, you can use the same identical lenses that a dSLR uses on a camcorder instead by using a Letus adapter.
Sony and Canon make both good cameras and camcorders. Nikon does not make any camcorders.