Is Sigma 12-24mm for Nikon D7000 good for portrait?

Is Sigma 12-24mm for Nikon D7000 good for portrait?

Added (1). and does it have vignetting on DX body?

This shot was taken with a Canon A590 IS. It should have about the same angular field as a 24mm lens on a Nikon D7000.

On your D7000 a 50mm lens is an excellent choice for portraits.

A focal length of between 85mm to 105mm has long been considerd an ideal focal length for portraits when using a 35mm film camera or full-frame DSLR. On your D7000 with its 1.5x crop factor a 50mm lens will have the equivalent angle of view of a 75mm lens on a 35mm film camera or full-frame DSLR thus making it acceptable as a portrait lens.

The 12-24mm lens is great for landscapes or shooting building interiors but not so much for portraits.

It's too wide to be a decent portrait lens unless you like to make humorous portraits. Portrait lenses for DX bodies are generally in the 50 to 100mm focal length range.

It will have less vignetting on a DX body than a FX body. Go do a search on Flickr for this lens and you'll see how this lens performs.