Thu 03-Jan-13 07:35 AM | edited Thu 03-Jan-13 07:36 AM by icslowmo
An easy test you could perform, not too scientific though, would be to get a ball of sorts that has writing or patterns on it and have some one roll it, as close to the same speeds as passable, across the floor/ground. Now you stand 15-20 ft away and try to track and lock focus and see what shutter speeds/iso is needed to "freeze" the balls rotation. You should try this in a controlled area with lower light. Should give you an idea how motion is related to shutter speed/aperture/iso.
Like others have said, VR has to do with camera shake not subject motion and the newer VRIII is rated to be one stop better then the VRII. How effective it is for each person will differ depending on each persons ability to hand hold their camera/lens combo. You maybe able to get 3 stops slower shutter speeds for a static subject from the VRII lens and 4 stops from the VRIII version. Someone else that is generally more unstable may only get 2 stops with the VRII and 3 with the VRIII.
One scenario where the new VRIII maybe better for some is in lower light and they need at least f/4 or smaller for DOF reasons and are hand holding the camera at 200mm. Lets say you could "freeze" any movement and meter for a posed portrait shot at say 1/60th @ f/4 @ iso 800. Now with the VRIII, having newer technology, you would have a higher chance of getting a sharp picture due to the VR's ability to reduce vibrations from hand holding the camera at slower shutter speeds compared to the VRII, where with the VRII, you may need to shoot iso 1600 @ 1/125th to feel better about getting a sharp picture.