My feeling and noticing it in this TAMMY 24-70 is I am seeing better results with it off at the higher shutter speeds and with it on better at low but not great at higher shutter speeds. I remember my Canon system when on tripods the IS on was really bad and off much better results. I equate that same results to high shutter speeds where the need is questionable since its trying to counteract movement. Well there is no movement at fast shutter speeds. Now gyros are used to counteract vibrations of aircraft. You as a shooter are more the cushion of vibrations. It's interesting how they work but I feel they are not the same as these VR setups.