One of my workshop attendees, Shakeel Tufail from Washington D.C. shared his zoom exposure technique with the class. Normally, we use this technique on existing light/night photos but it seems to have a nice effect shooting these trees. I used a Canon 24-105 zoom and only zoomed during the 1/15 sec exposure from 24 to 35mm thus giving some sharper trees for reference. Everybody learns something in a workshop. Thanks Shakeel.