Bingo. That did it, thanks Godfrey, it makes sense to me now. So the aperture matters, but the focusing distance shouldn't.
Thanks! j On Wed, 9 Mar 2005 14:33:00 -0800, Godfrey DiGiorgi <[EMAIL PROTECTED]> wrote: > >> Obviously a small (higher) f stop shows up fine detail that might get > >> blurred > >> with a shallower depth of field. > > > > This is precisely what is not obvious to me. If the dust is on the > > front element of the lens yes, it will be more visible at smaller > > apertures. But we are talking about sensor dust, which is right on the > > sensor, without a lens to "focus" it. > > The visibility of dust has *nothing* to do with Depth of Field or any > of that malarkey. > > "Dust on the sensor" is analogous to a little ball held half an inch > from the wall. If you light the ball with a broad light source (large > lens opening), its shadow on the wall is very soft and difficult to > see. If you light the ball with a point light source (small lens > opening), the shadow is very well defined. > > Why? Just imagine ray tracing light from a point source compared to a > broad source. It should be obvious to you. > > Godfrey > > -- Juan Buhler http://www.jbuhler.com blog at http://www.jbuhler.com/blog
