This was captured with the Rodenstock 70mm/5.6 HR Digaron-W lens. A large image circle allows room for considerable movements, used here to swing to selectively focus on the WTC tower. A polarizer darkened the clear sky a bit, as well as taming some of the highlights reflected off the glass wall of the tower.
The shape of the new One WTC makes the light catch it differently throughout the day and in different weather. I made several exposures at different times before settling on this one.