Can a Canon lens say 50mm fit to a Nikon D7100?

Can a Canon lens say 50mm fit to a Nikon D7100?

In practical terms, no. A brand spanking new Nikon 50mm f/1.8d lens is only $105 (grey market) which will work with your D7100.

No. Adaptations of different mounts often have issues. This one is too much trouble for anyone to even try, because the Canon EOS mount is wider than the Nikon F mount.

No, you need a lens specifically with a Nikon mount.

With an adapter, yes.
http://www.amazon.com/...zon.com/s/

No.

Different camera brand, different mount.

No. Canon lenses can't be adapted to fit onto Nikon bodies due to the distance required between the rear element of the lens and the sensor. However, since Nikon lenses need a larger distance and the Canon bodies are thinner than Nikon, you can therefore adapt Nikon lenses to fit onto Canon bodies.