A couple of weeks ago we walked across the Golden Gate Bridge. We were fortunate to have a clear day without the typical fog that covers the bridge. As we were about a third of the way across I noticed this structure across the bridge highway and stopped to make a long exposure. I setup my camera and tripod on the walkway and backed up to a support post to avoid the pedestrians walking by. I made a three minute exposure using a -10 stop neutral density filter. During the exposure hundreds of cars crossed in front of me on the roadway going in both directions. There was a steady stream a people walking in front of my camera during the exposure that never interfered with the image. One thing nice about long exposure photography is that you can make moving objects disappear in the scene. The other concern I had to deal with was the bridge vibration from all of the traffic crossing the bridge. I knew if the camera and tripod moved up and down with the bridge motion, that the image would be sharp regardless of the long three minute exposure time. This is what I love about photography, the challenge of making new and interesting photos in difficult situations.