There's an amazing amount of detail in the bird flock. The bright sunny day set the exposure at 1/2000th of a second. I watched the flock circle over the field then arc over in my direction. When the first redwings flew into the frame, I pushed the switch and the lens focused on the movement. Click click click in fastest succession i shot the chaos of a flock of blackbirds. I will have to take this shot until I get it right.