D850, VR systems and long exposure

Hi all.

I notice a section in the D850 manual (p.285 of the EU version) which mentions that some lenses "are not recommended for long exposures or photographs taken at high ISO sensitivities, as due to the design of the ... (VR) control system the resulting photos may be marred by fog." This appears to be even if VR is off, since the manual suggests turning VR off on "other lenses".

Worryingly (since I've used it at night before) the original 200mm f/2G is on the list, as are the same superteles of its generation (which may be a factor in my 400mm f/2.8 choice in the distant future) and the 24-120mm VR (both versions - the f/4 version of which I contemplated using at night because it fits my 77mm LPR filter). I don't believe there's anything similar in the D810 manual.

Does anyone know anything about this? It seems unlikely to be specific to the D850, but I can't rule it out (in case it wiggles the VR system in some way).

This is also in the D5 manual. Something must have been lost in translation since the instructions are not at all clear. I read that old VR lenses use a faint LED for positioning which then causes a faint fogging at ultra high ISOs and long exposures. I guess the other possibility is some electronic interference.

I have read some discussions also where people have been trying to make this effect appear, without being able to. I think setting the maximum ISO and going in a completely dark room, and making exposurea of several seconds might possibly do it. I don’t think this is something to be concerned about in normal photography. For long exposures, one should turn VR off anyway.

You can find the same note at page 326 of the D500 user manual and as I was told this has to do with the lens VR not with the cameras.

You can find an explanation if you follow the link bellow and go down to the part titled as "VR Image Flare":

All About Nikon VR | DSLRBodies | Thom Hogan

Thanks, both - I read some of Thom's article but clearly bailed early. I don't think I've seen this from my 200 f/2 at night, but maybe I'm misattributing any effect to atmospheric fogging. The manual suggests the effect applies even with VR off, which is why it worried me.

Fortunately when I eventually get the chance to be under a dark sky I'm planning to put my old 300 f/4 on a tracking mount anyway, which avoids the problem I'd have had trying to use my 200 f/2 at high ISO - but it's a bit disappointing about the 24-120 f/4, which I'd hoped to use for wider tracking shots. (Although I'm a bit worried I can't find my LPR filter at the moment - it was quite expensive...)