Here is an example of what I just tried to explain. This is a crop from a picture in my gallery (Night Crabbin'). It was taken the same evening as the above picture on this thread. It obviously is an open exposure by the movement of the two sets of people walking in the water, looking for crabs with a flashlight. But note the reflection on the water from the group on the left. It has reflection breaks in the water (from the wind blowing), as if it was shot at 1/60th or maybe even 1/30th of a second. But I know for a fact that this one was at least :20 seconds, maybe more, so the reflection in the water should be smooth, shouldn't it? But it's not.