Sigma 85mm F1.4 EX DG HSM Lens (77mm filter thread) for Nikon lens mount (Electronics)
Sigma for Nikon in new Loock and quality, on the D 800 and D at the 700 and the D 3X. When D 800 when the AF should work, you need such lenses. (Even with the Nikon D 600 + D 3X) I have (or still) so the 85mm 1.4 Nikon and Sigma, I believe a lab test