Sat Dec 25 11:26:39 CST 2010 Doug Franklin wrote: > I should note that a similar effect can be expected when the tire > > makes > > not about 1/15th of a turn, but also 2/15th, 3/15th, etc. (N/15), > > but the contrast will be lower, and it probably wouldn't work beyond > > N=3 (or maybe even 2, depending on the light conditions). > > Yeah, that's part of the moire effect. Many integral > multiples/fractions will give related effects.
I don't think that it is exactly the moire effect, as there are no true interference, and there are no different-angle grids. Or, I should say, - this (as well as what Doug originally showed) would be the most trivial version of it: overlap of several circular (covering a solid arc) objects (the area covered by each spoke within the shutter-open time) with the same offset from each other. It is trivial in the fact that you are not gaining any new periodicity of the pattern, as what usually is significant in moire. Igor -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
