randave2001 wrote:
This pool had a natural rotation to it. was able to capture this image by timing the rotation of debris and setting exposure time to approximate rotation time. Too quick and you won't get the circling effect and too slow it will tend to blur out. The flow here was pretty quick so an exposure of approx. 10 sec was enough. Interesting to note that I went back to this area this morning and the debris was not rotating. Don't know why.