Photography is remarkable in its ability to freeze a moment of time. But when the exposure gets really long, like in this image of a San Francisco Bay ferry passing in front of a working barge near Port Oakland, time is no longer frozen. Instead, the moment of time kind of slips by, with the time slice of the ferry beginning its transit in front of the barge and the time slice of the ferry ending its transit both in the image. At the same time, the fully solid ferry as we know it isn’t really in the photo at all. A temporal shift has occurred.