Added to my review of the Sigma 135mm f/1.8 DG HSM Art in Advanced DSLR:
Sigma 135mm f/1.8 DG HSM Art Aperture Series: Trees on Barren North Rocky Face0)
Includes images up to full resolution from f/1.8 through f/5.6.
The about $1399 Sigma 135/1.8 DG HSM Art is an outrageously good bargain and an outstanding match for the new Nikon D850.
View over Lower Conness Creek Drainage to Saddlebag Lake
f5.6 @ 1/60 sec, ISO 31; 2017-10-26 15:23:22[low-res image for bot]
NIKON D850 + Sigma 135mm f/1.8 DG HSM Art