Sigma 15mm vs Nikon 16mm

I'm in the market for a fisheye for my d700. At this point I'm leaning toward the sigma because the focus distance on the Nikon isn't as attractive. Does anyone have any input on these two lens and or which is better. I've never owned a non-nikon lens and I'm concerned about the sharpness and overall quality with sigma.

Any thoughts will be appreciated.

Adam

http://www.blueoceandream.com

There are already threads relating to this point. Search for Alex Mustard's commentary on these 2 lenses. I read it but do not recall the title. He discusses the close focus point you raise and more.

The Sigma 15mm is the sharpest lens I own, wouldn't hesitate to recommend it.