I have read articles that suggest that when we default to use the focus-on button to focus rather than the shutter release button, the VR function on the lens is disabled until the shutter release is pressed. A pro that I know says this is not the case - that on the D800 VR is active with either focusing method. Can anyone please confirm this? Thank you. John
On earlier cameras VR did not activate until the shutter release was pressed down halfway. On the D800 and later cameras, VR activates with the AF-On button, and stays active for a few seconds. If the shutter is not fired, the activation stops after a few seconds.
If the shutter is pressed - or pressed halfway, VR is activated just as in the past.
VR stays active as long as the button that activated it is pressed - and then for a second or less afterwards - but Eric is correct that only on cameras from the D800 and D4 onwards does the AF-ON button activate VR - on the D700, it does not.
This is information I had not known and it explains a few things to me. I use the AF button but I will use it and then recompose the shot. Sometimes taking many seconds after setting focus to do so. I have always wondered why some shots will be soft while others are sharp and the fact that VR may have stopped working while recomposing the shot could very well explain it.
So, as I ruminate over a move from my faithful D700 to a D800 (or even to the Df (for the weight and sensor improvement over the D700) but if and only if manual focusing is improved over my D700 and there's no reason to think that it would be, especially with eyeglasses, if the Df viewfinder technology is not significantly different from, or superior to, that of the Ds 700 and 800), I'm wondering if the AF-on process for the D800 is any significant improvement over the D700's with the apparent need for two VR actuations with the D800 (we don't know about the Df's attributes here yet).
I do use AF-on back-button focusing as the default on my D700 (perhaps it's comfortable for me based on my Nikon F SLR focus first, shoot later film background) and that has also worked extremely well for me with my travel camera the M43 Panasonic GX1 and the time gap between focus and shutter press has always been more than acceptable, even with the Panny 14-45 zoom lens using the len's built-in image stabilization which seems analogous to Nikon' VR. (I've been perhaps fantasising that the Df could be a compromise size/weight FF camera with, say, the fairly recent 24-85 VR or my old 28-105 ADF).
All of the recent cameras with a back button AF option activate VR with both AF activation and a half press of the shutter. Either button works.
The D800, D4, DF and others have a dedicated AF-On button that can be used for Focus. On the D600, D610, D7000, D7100, etc, you assign the AF/AL Lock button instead as there is no AF-On button. The difference is a relatively easy adjustment.
The VR activation of the newer cameras is a big improvement. And while it takes a fraction of a second for VR to settle, it is near instantaneous.
Terrific information I did have before. Nikon's 300mm f2.8 has rather noisy VR, making it easy to confirm the gist of this discussion. Our four Nikon bodies are all set up to focus with the AF-ON button, not shutter release. The D700 and the D7000 AF-ON button does not turn on VR; the D800 and the D7100 both have VR turned on with that button.
Now the question.........I've never noticed this feature(?) before, shooting primarily wildlife with long lenses that have VR. Does it make any practical difference in the end product, the images? I doubt it.
The practical side is it depends on your shutter speed - and luck.
Under 1/500 sec, use VR if it is available. For slow shutter speeds used to create blurs - under 1/100 sec with a longer lens - you might have some situations where Active is better than Normal.
From 1/500 sec to 1/1000 sec, you are in the range where luck matters. VR compares images of two cycles and the cycles are 1/1000, so you might end up with two cycles to compare in a 1/800 image - or you might not. I've seen some hits and misses at 1/750 sec.
Over 1/1000 sec, VR cannot cycle fully and is unlikely to help. The slight vibration of the VR on extreme magnification may actually hurt. And it is possible that VR looking to add stability incorrectly interprets the scene and is timed wrong. So over 1/1000 sec I would avoid VR. This can apply at 1/500 to 1/1000, so you may get some missed VR as well as the cycle mentioned above.
For birds in flight, you are shooting above 1/1000 second most of the time so VR should be avoided unless you are looking for longer exposure blurs.
For conditions around dusk when you struggle for shutter speed, use VR. In bright light, don't use VR since you probably have enough shutter speed.
A 2-3 image burst can be useful in borderline situations. AF and VR tend to do better on the second or third frame.
Thank you, Eric! This discussion, in a nut shell, is why I find Nikonians so valuable. In essence, it doesn't make a difference for me shooting wildlife. When I cannot up the shutter speed in low light, I'll likely use auto-iso to maintain a reasonable shutter speed. Better to get a noisy image than none at all. Typically, that will be a shutter speed of >1/1000sec.