"Posted situation above: If you're shooting a band on an interior stage, the "stage" will be sharp, but the band will be out of focus because THEY are moving - get it?" Surely, that is due to bad photography skills? Personally, I would be focusing on the band! >Shooting say.. an stationary animal with a long lens and low shutter speeds then it's an asset Again, do not agree!!! Mode ii IS is used for panning!!! Not sure what camera your shooting with but I use a 1D Mk ii and the 5D coupled with EF 500mm...very very capable at capturing all types!!!