This is the Nikon USA version; the other version for $100 is the imported/grey market version. The Difference of USA and Grey (import) at B&H is a matter of warranty. The product is identical in all respects and both are made in the same factory. A USA warranted item may be repaired in any manufacturer's authorized service facility worldwide if the item required in-warranty service. The direct import item would have to be returned to B&H Photo-Video Corp. in New York City if it required in-warranty attention. Nikon USA lenses come with a 5 year warranty, the first year being valid world-wide, the remainder 4years valid in the USA only. Please note: Nikon USA will NOT service any product they identify to be imported/grey market.

Since the D7000 is a DX body you should use the 10.5mm fisheye lens instead.

The lens will fit but will not autofocus. The Nikon D5100 to autofocus needs a lens that has a built in focus motor. Nikon brand lenses marked AF-S not AF have a focus motor built in.There a couple of lenses that will work fine on the D5100.This one works on the D5100, http://bhpho.to/1g9t1iV

This AF Fisheye-NIKKOR 16mm f/2.8D Lens also works with the Nikon D800.

I'm sorry, no, the hood is not removable.

No. An adapter would be needed. Please review the following item Nikon FTZ II Mount Adapter BH #NIFTZ2 • MFR #4264 https://bhpho.to/3Lir89q

Yes, this lens is fully compatible with D700 camera without any cropping. It is an FX format lens and covers the entire frame of the camera.

For the Nikon 16mm f/2.8 lens, I would suggest the Op/Tech Hood Hat Mini: http://bhpho.to/SoZjAWFor the Nikkor 24-120mm, the Small Op/Tech Hood Hat will be fine: http://bhpho.to/1vNV2GoFor the Nikkor 80-400mm lens, the Medium will suffice: http://bhpho.to/1aD863l