Jeff I use a Nikon D850 and a Sigma 150/600 C lens. I generally shoot BIF at around 1/1600. I prefer to get a little wing blur to show motion. Thanks for looking at my photos Larry James
We use the same camera. My 150/600 is the G lens by Tamron. Do you use a floating ISO setting? I try to keep the aperture between f/8 and f/11 unless I want a pure bokeh background, in which case I'll opt for f/2-2.8.