I bought this hoping for 1050mm on the D500. There are already 200-500 and others. Too new to have any 500pf ratings with TC 1.4 III. Consider it first. Works poorly with TC as well as 200-500. The sharpness is good to very good without TC, but with significantly less sharpness. Maybe 600pf will be enough when it comes out? My credentials; Over 130 images published in the last 4 years, 7 landscape books published, many awards and museum exhibitions. Regarded as one of the best landscape and nature photographers on the east coast.