Many portrait photographers prefer the 100mm and 105mm focal length over the 85mm length. Nikon released an interesting and expensive 105mm F1.4 lens that has received a lot of praise. However, 100mm at F2 still produces a very desirable level of depth of field. This lens has far less elements than Nikon’s, but that sometimes produces a character that some photographers find more pleasing for portraiture than the look provided by modern lenses.
At an expected price of $170, this might turn out to be the best budget portrait lens of 2017.
At $1200 this lens need to impress, which remains to be seen. We’ll let you know how it does. Sigma primes are sharp but sharpness is overrated.