1- The two big camera brands used to be Nikon and Canon. Now it is Canon and Sony;
How do you make that out? Sony is at 23% Nikon 21%, if I recall last year's data correctly (hmm. Sony's could be by value, the other in volume, not sure). That doesn't allow one to be characterized as big and the other not. By contrast, Canon's ILC market share is a little under 50% and they are aiming to reach that next year. Clearly, there are either three big camera ILC manufacturers, or only one big one.
2- The AF-S 500mm f/5.6 PF was released a long time ago. I tried it at Photokina last year, but It is not available at B&H, Adorama, eBay or Amazon. Is it selling so well or what?
From what I was told by the local NPS representative, it's difficult to make the PF element and a lot of the elements that have been manufactured have to be discarded. Nikon probably didn't anticipate it to be as popular as it is.
3- As I said in another post, the new Noct was supposed to be released in spring. Did not happen;
Well, Nikon sometimes take a long time to refine the optics of their favorite projects. The price is likely to be very high and sales very small in number, so it's not like many people are depending on this lens for their livelihoods.
4- The flagship model used to be updated each 2 years. The D5 is 3.5 years old (which for me is good because I don't receive that subliminary message that my excellent camera is outdated).
The D5 appears to have sold relatively poorly, so it didn't get a mid-term minor update, instead, they released a series of significant improvements in firmware (and more is coming). Personally I think the D5 is really excellent for some things but has a few minor issues; first, it is quite loud and I often have to use Qc and even then people pay attention to the sound. Not so much with the D810, for example. I think Nikon should refine the sound in the D6. Second, the ISO 100 results from the D5 are not what one has come to expect from a modern Nikon full-frame camera; the images do not have the kind of leeway for adjustments in the shadows that e.g. D850 images (and D750, and D810, and ...) have at ISO 100. I noticed this recently at a wedding where I used both cameras that the difference is quite striking. However, at high ISO the reverse is true, or the D5 files contain more clean information in the shadows at low ISO that can be used for adjustments. I think there are users who would prefer there to be less compromise at base ISO, even if it doesn't matter to the majority of users of this camera. I would use it more if these issues were addressed. Even though the D850 files are large and that is a bit of an annoyance to me, as it increases editing time of large projects, the extra dynamic range is truly valuable when one has to shoot in sunny conditions or with spotty lighting where the brightness varies from subject to subject within the same scene and this cannot be controlled in the fast pace of an event. I know people use fill flash, and sometimes this is the solution, but I intensely dislike the effect of direct flash fill (it removes the natural tonal gradation of shadow areas and increases the visibility of skin imperfections in those aras), and a larger setup is more time- and labour consuming to contstruct and move about. The D850 base ISO is quite wonderful in this respect.
Obviously, when sales are low, there are ramifications to the development and release of new products. However, I would expect to see the D6 announced quite soon, possibly this year or early next year.
