Rapids at Great Falls National Park, Slow Shutter, Great Falls National Park, Potomac River, Virginia; Canon EOS-1D Mark II, 100-400 f/4.5-5.6 L IS USM zoom lens, perture priority and Evaluative Metering; ISO 50, f/32 and 0.4 sec; File ID: Y2F2145, full image 3504 x 2336.