Nikon has many excellent lens for this kind of subject, the 85, 105, 135 and
180mm focal lengths all are superb but the 105mm f/2.5 has the best size,
wheight and performance relationship followed by the 85mm f/2, or the
135mm f/3.5 in my opinion. I love, also, the old 85mm f/1.8, the 135mm f/2.8 and
the 180mm f/2.5 but they are bulkier and not so "portable" like the first ones.