profpb Loc: Venice, Florida

One aspect of VR that confuses people is activation. Nikon's manuals don't make this very clear, but it really is quite simple: only the shutter release activates the VR system. A partial press of the shutter release engages it and allows it to begin a sequence of corrections. A quick full press of the shutter release engages it but it really doesn't get much in the way of samples to rely upon and make predictions from (on the pro bodies we're talking 1/33 of a second or so between the press and the shot being taken). Basically, if you engage VR prior to the shot, you tend to get slightly better and more consistent results. That doesn't mean you should always wait for VR to engage before fully pressing the shutter release. If it's time to take the picture, take the picture! VR will give it its best shot at fixing your motion when you just punch the shutter release. But there are two factors that tend to make early VR engagement a better choice if you can do it: first, the VR system gets a stream of data it can predict from; and second, it's difficult to move the camera as much by jabbing the release if you've already partially pressed the release!

The usual issue that comes up with the preceding is the line in Nikon's manual about "VR doesn't function when the AF-ON button is pressed." This is one of those places where the translation in Nikon's manuals is out and out misleading. If the line had read "VR doesn't engage when the AF-ON button is pressed" it would be more correct. VR is not "turned off" by using the AF-ON button, it simply isn't engaged by that button press. Only the shutter release button engages VR. Thus, if you use AF-ON to focus instead of a partial shutter release, VR is not engaged during the pre-shot focusing. But it is during the shot.

More about VR: http://www.bythom.com/nikon-vr.htm