On Wed, November 18, 2009 07:45, ADavidhazy wrote: > Very good discussion around this topic in my opinion! > > The 1.25 might indicate that the background was not totally black and > during the exposure of the > moving image it added a bit of density to the negative or exposure to the > area that was uncovered by > the moving subject. At the time the shutter opened the image was in one > place but its trailing edge > moved almost immediately away from its position so it will be very > underexposed and dark. Then it > rises to maximum possible level once it gets to where the leading edge was > at that same (initial) > time. In addition the shutter is not 100% efficient so it adds yet another > layer of complexity to > the situation. The opposite happens on the other side. The leading edge is > at the farthest point for > a VERY short time and thus way underexposed as well. I thought about shutter efficiency, and decided to ignore it. I find when taking real tests for a real course, that I can often figure out some of what is wanted in the answer based on what was taught in the course :-). Working on the question with no information whatsoever about the course, I find my mind wandering into wider and weirder spaces pretty much without limit, and sometimes do things to limit that. I also considered vertical and horizontal focal-plane shutters briefly, and ruled them out based on the evenness and pattern of gradation. -- David Dyer-Bennet, dd-b@xxxxxxxx; http://dd-b.net/ Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/ Photos: http://dd-b.net/photography/gallery/ Dragaera: http://dragaera.info
