It may sound odd ... but my recent acquisition of a D6 and the 600 f/4 E was a back to my roots move. I started my photo journey August 2011 with a Canon Rebel and a fuji finepix XP10 pocket camera borrowed from my wife for a trip to Alaska. I progressed to a D300s and a D4s and an assortment of lenses over the years. I have images on the wall take with everything from a P900 Bridge Camera to a Large Format 4x5 film camera and ironically quite a few with the aforementioned 28-300. But as I went through old files and thought of what I like to photograph while spending time with wild critters in cool places. I pondered that I like to shoot in low light, I like to photograph birds sitting and flying for ID and beauty and the occasional mammal and reptile that comes along. I have won many contests, my work is in our State Capitol and I sold enough while venturing into retails sales that it got me back to spread, sheets, inventory, marketing and sales "work" so I retired again

But I decided to focus on what brings me joy and what I hoped would make others happy and help me share God's creation and encourage conservation and help others learn about birds etc. along the way. I had been chasing tech and mega pixels D850 wide angle landscape lenses, ND filters etc. portrait and still life lighting gear etc. that sat in the cabinet or closet after a acquiring them to branch out into "trendy" and marketable photography. I began regretting selling the gear that simply accomplished my favorite photographic goals ... a D4s and big heavy Sigma 150-600 sport (almost always at 600mm). I also liked the simplicity of my 2 camera 2 lens set up in Africa. D4s and D500 and 28-300 and 200-500. The 150-600 Sigma sport arrived just before I left for Africa but left it home because of weight ... regretted that should have found a way. Long story short I decided to not chase the mirrorless trend and go back to my roots with the type of gear I could use for what I wanted and that the learning curve would not be steep with. The D6 replaces my old D4s and the 600 f/4 E the 150-600 sigma sport and my D500 with a Tamron 18-400 on it gets used more than my D850. My last planned lens purchase will be a replacement for the long sold 28-300 .... probably a Tamron 100-400 or a Nikon 80-400.
Hi Ken, Enjoyed the read, lovely, I like to go for a walk through the Bush and take a long lens 150-500 200-500 getting artistic compression shots of nature, I miss that.
I must admit one of my favorite cameras of all time was the D4s its was just sharp fast accurate bullet proof, and my D3x ( I bought for $5k AUD when they were $11K AUD) that combination worked as I was missing in the D3X FPS speed and focus attacking speed, I still have a 150-500 Sigma my first long lens, I loved the compression I got on the long lens and don't laugh that lens today still takes nice sharp image, and on the D3X was just stunning LOL.
I mean you cant get more than $300 for the Sigma Lens and the VR is Broken but I never need that anyway, and $1200 for the D3X that's just ridiculous for so much camera, plus The D3X I still love and will keep, its my old friend that took me places and did things that people wouldn't dream of doing things with or going places. It defied all the reviewers in every way, I did sports action, studio, wild life, landscapes, I loved the 5:4 mode, street photography, it just did everything well and perfectly usable to 6400 iso which the Goroos said Oh its a studio camera you cant use it beyond 400 iso, please click like me if you found this review helpful, what a lot of BS, sorry.
It was for me 25mp when everything was 12 mp.
I would love to have the D6 and 600f4 E but I really didn't use the D4s D5 600 f4 combination that much, maybe 10% 15% of the time, for me I found with such little compromise the D850 basically did 85 to 90% of what I wanted to do so it was a lot of capital sitting there, yes I would have it tomorrow if I like you shoot often a lot of low light work.
28-300 gee not many people admit they use it or have one LOL good to hear, its been good to us, I love mine simply for its versatility, its got nice colour, its adequately sharp enough, ok it gets a little red hot on the D4s D5 LOL but gee it delivered LOL. The 100-400 sounds great with the magnification ratio would seem far more attractive than 10.4 times of the 28-300 but gee I would miss the 35mm 50mm 70mm range.
The D500 on the 28-300 would be using the center of the lens also being its sharpest area, I find while the D500 is a brilliant camera if I put the D850 into crop mode I pretty well have a D500 in the D850, I do get 9fps however there is the extra weight. So yes it makes sense I think the D500 and 28-300 is an awesome match.
As mentioned once before, I sometimes like to take my light weight (rifle but) mono pod a 50mm 1.4 manual Zeiss lens place it on the Df (D4 Sensor), set the Df up to manual only and in mono and RAW and then walk the city and foreshores,
It slows me down, it takes me back in time, it gets me away from the eye tracking animal tracking yady yada..........and slowly I start to see things I didn't see before rather than just document in full auto.
Any way I am cruising with a little time out to refresh, see where things go, I use the 14-24, the trio, 200 500, 28-300, 16mm fish eye, now rent the big stuff only when needed.
Should I jump in and have the demand then yes buying can make sense. Rentals are becoming more popular and more competitive.
The mirrorless future, I will wait for mirrorless to mature fully and till at least its in the 3rd 4th generation. One question is am i willing to reinvest in a system again, the I feel at the moment 100 mp MF and a backup D850 with the trio lenses is a good system and rent everything else as needed.
You see while my surfing still shots are greatly enjoyed, the community mostly by a massive amount prefers to now watch short surfing video clips from Drones and video cameras but Drones are preferred 100 to 1 to land based video.
So much so I didn't even bother going to take photos of the events, Its the way of the world, I mean I was sitting in a café with my head phones on watching live on my smart phone the World surfing league competition here at Narrabeen Sydney, the worlds best riders are visiting (Brazilians Americans) etc etc all came here and are touring Australia, we basically don't have Covid, and are now traveling, flying freely domestically and with New Zealand with no restrictions basically life is normal.
My friend emailed me killer still shots from the surfing event followed by some video clips taken by drones, like the masses I didn't even look at the stills I went straight to the video clips, Why, this is what's killing a lot of the camera industry and forcing them to go hybrid and mirrorless. If you look at Jared Polan and Northrups their reviews have shifted greatly to evaluating new video features of the Hybrid mirrorless cameras then they go to stills.
I think for wild life photography stills has a future for a little while. Although someone recently used a drone to go out get really close and cover a Polar bear catching a seal, a lion catching a Zebra. A drone at 10 meters traveling along with Dolphins surfing, Birds high up in a nest, Puffins feeding chicks on a cliff face mountain ledge inaccessible by foot. Is this fair on the creatures not really, but that doesn't stop people doing this just to be popular on U Tube or Face book, so many people they have no regard for animals as they don't even have regard's for plants like paper daisy's I mentioned in my previous post.
We are in a time of great change it seems.
Only and opinion as always