Normal mode
This mode on VR lenses reduces camera shake. The lens will automatically detect if you pan the camera horizontally and only vibration in the vertical axis is reduced.
Active mode
This mode should be used when taking images from a moving vehicle or vessel. The frequency of camera shake experienced during handheld shooting is different from that encountered when trying to shoot from a moving vehicle or vessel. The VR active function is designed to be able to compensate for severe vibrations encountered when you're in a car, boat, on a train or airplane, and even aboard a helicopter. The active mode does not automatically distinguish panning from camera shake unlike normal mode. If you wish to pan it is recommended you use normal mode.
Thankyou.I think it's to do with prioritising vertical over horizontal stabilisation. So if, say, you were photographing race cars and panning horizontally it doesn't try to stabilise as, well, it just won't be able to, so it just does it vertically (mostly). I may be wrong but that's what I gather.
Thankyou. Great table in the source as well. Think I've got it now. Wondering if I can blame my soft photos on the setting being selected to active all the while