Yes, more details please, dherring. What example do you have in mind?
If your question concerns whether Photosynth can reconstruct both an environment as well as a solid object that moves through the scene, then no, it can't. Either focus on the object, moving the camera enough that it doesn't spend its time tracking the environment, or vice versa.
Today's Photosynth only understands stationary scenes. Any part of the scene that changes (people walking through a town square while you're synthing the square) won't be part of the reconstruction. If there are people sitting on a bench in the scene, though, they stand a good chance of making it into the point cloud as long as they don't shift in their seat or whip their head around too much.
Again, an example of what you were wondering about would be easier to answer.