Thanks for your reply. Your information is what I was looking for. I got the lens for an attractive price, so have some room to pay for repair if needed. It is intended as a gift, so it needs to function properly, hence the questions

This is an interesting discussion. Just a couple of comments..

Lens correction should be done early. It must be done before stitching a panorama. Many cameras will do lens corrections for branded lenses at the time of shooting. This is convenient and saves time later. If you do in-camera correction, do not follow up with a second correction during processing. And it's pretty easy to verify whether your camera applies the correction to raw files...just take two exposures ( one with correction, one without) using an extreme wide angle lens. See if the corner vignetting has been corrected.

Also...I would never crop an unprocessed image anywhere early in the process, before adjustments are made. There is no way to know for sure how peripheral components might look with adjustments, or how they might impact the finished image if left in place. (Never might be a little too strong a word, but you know what I mean. )

Thanks, but that isn't the question. I'm trying to determine whether mine is functioning as intended or whether it needs repair beyond what I've been able to do.

Yes...there was a well-publicized launch of an important rocket on the night of the full moon. I received several invitations from NASA to attend. There is nothing preventing this from being an actual exposure other than an unhealthy dose of uninformed skepticism. Of course, there is nothing preventing it from being a well-executed composite, either.

Rockets follow very well-defined paths at launch...at least on those occasions when everything goes as intended.

Thanks for the hint. I actually exercised the Manual/Auto switch on the lens a number of times. That seems to have made a big improvement...the lens now at least tries to focus every time instead of just sitting silently.

Still looking into the compressed focus throw situation at the short focal length end. I figured it would be easier to get a understandable answer from a user than from Customer Support.

It's the aperture changing as light levels change. If you have an "E" lens, mount it and see what happens. E lenses use a stepper motor instead of the mechanical linkage to set the aperture. It's almost silent.

The mighty Googler told me that the first position activates VR only during exposure. The second also activates it in the viewfinder. It wasn't clear if this means full-time or just duting half-press of the shutter release button. With that in mind, try it out and see what happens.

In the past, I have been pretty vocally critical of this lens. My statements were based on an honest trial and appraisal when I considered buying one a few years ago. Recently, however, I became the owner of one of these as part of the purchase of a package of several items. I have found the behavior of my lens to be different in several ways from the one that I previously tried out. My belief now is that it is a decent lens...better than my initial assessment, but still short of being a really nice lens, despite the Gold Ring designation awarded by Nikon.

Anyway...I have a question for owners and users of this lens. My copy occasionally fails to try to focus at shorter focal lengths. It's not that it can't see to achieve focus...it's that the process doesn't start at all...as if the lens is set to Manual Focus (but it's not...and neither is the camera). Sometimes continuing to try will eventually make it start, sometimes zooming to a longer focal length will do so. This behavior usually occurs at focal lengths of 28mm or less, but has occurred at focal lengths up to 50mm. It has also been observed on three different D500s, including one that is just back from Nikon with a Major Overhaul. The other symptom us that at 16mm, proper focus is achieved at an indicated distance of Infinity or greater (which is something I was accustomed to seeing on my Nikkor 18-200mm DX zoom.

My next step is, of course, to contact NikonUSA and possibly send the lens for repair, if such support is still available. My last checkpoint before doing this, though, is to ask here whether others have noticed similar bad behavior.

Sales and trades between friends can be great, or they can be really complicated.

The first and most important thing to establish is whether the friend is more important or the lens is more important. Hopefully, this will mesh with your friend's assessment of whether the money is more important or you are more important. Once that is acknowledged, then it would seem that open and honest discussion based on all of the parameters that have been suggested here should yield agreement on a price that makes everyone happy and preserves the friendship.

When I bought my D850 in 2018, I bought Sony XQD cards and a Sony XQD/SD card reader. Model number is MRW-E90. Both the cards and the reader are still going strong. There were some claims that Sony cards would not read in a non-Sony reader. I cannot speak to that, and I haven't heard it mentioned recently.

After Nikon updated the firmware to enable the D500 and D850 to utilize CFExpress Type B cards, I bought a Delkin reader and gradually bought some Delkin cards. Mine is a Delkin DDREADER-54. These cards and readers also have been serving without incident for several years.

Each of these readers also has a slot for SD cards. I do not know if they are still current models.

As noted in this discussion, a few folks seem to have found combination XQD/CFE-B readers that they say work for them. I have never had sufficient faith to use a device from a manufacturer or seller whose name I don't recognize as part of a critical link in a data management chain. Your risk tolerance may be higher than mine.

Good luck as you search.

Cameras are very complex systems. Design and manufacture of complex systems involves carefully balancing a whole host of trade-offs. That's why it is always interesting (and sometimes a little bit fun) to watch how "single issue foamers" sometimes get so knotted up in one line of a camera (or some other device's) specification sheet. Technological progress will usually eventually ease the problem, as advances help everything on both sides of the tradeoff, but that can take a while. And sometimes, the tradeoffs are associated with affordability, not capability.

In the early years of this century, we had at work an Olympus digital high speed video camera system that we used to analyze operating problems in our factory machinery. It could capture several thousand frames per second with a reasonably achievable level of lighting. It did not exhibit rolling shuuter or any other distracting artifacts. It did cost about $50,000.

Fifty years ago, when pocket scientific calculators were new, there was a big thing over precision of results. HP calculators worked with and displayed 10 digits. Texas Instruments scientific calculators also displayed 10 digits, but worked internally with 12 or 13 digits. The extra laces were called "guard digits," but were easily accessible by simply subtracting the visible ones. TI claimed that their calculators were "more accurate," despite the fact that both of them provided results with between 4 and 8 more digits of precision than were generally appropriate for engineering calculation that would be done on a hand-held calculator.

By the way...a foamer is an over-enthusiastic railfan. Comes from the situation where poirly treated or over-agitated water would "foam up" in the boiler of a steam locomotive, reducing its efficiency.

I think one reason the description tends to be called AI Photography is that painters and others in the art world have already said pretty clearly and vigorously that they will have nothing to do with AI. So the dust from that explosion has settled mostly over the photography world.

Thanks for the reminder. I try to keep my cameras current and the clocks correct. Whether there is an intent to assert copyright protection or not, there is a long list of reasons why it is a good idea to mark any work created with the creator's name and the date of origin. This was first impressed on me during the first week at my first job (with a large research and manufacturing company) 50 years ago. The validity of doing it has never changed, except perhaps to become even more important.

Yes. Occasional disappointment goes along with having freedom of choice.