amfoto1 Loc: San Jose, Calif. USA

On the one hand you wrote, "I'm getting tired of lugging my D 850 kit and want to lighten the load." But then you wrote, "Weight of the two new systems is a non-issue."

Isn't weight your primary motivation for this switch from DSLR to mirrorless? It sure sounds like it... until it doesn't. If so, the Canon R6 and RF 24-105L lens weigh about 3 lb., which is about 1/2 lb. savings compared to D850 with a 24-120mm Nikkor. The Nikon Z6II and it's Nikkor 24-120mm weigh about 2.5 lb, for a savings of about 1 lb. compared to your D850 and F-mount 24-120mm.

Will you miss the 45MP resolution of the D850? Only you can say. You mention landscape photography, for which some people prefer a high resolution camera to allow for large prints. There are "work-arounds" when you have a lower resolution camera, such as doing a multi-shot panorama. Allowing for some overlap, three vertical shots with either the R6 or the Z6II would be pretty equal to a single horizontally oriented shot from the D850. You also mention some wildlife photography and there are times when higher resolution can be helpful with that, too, by allowing more latitude for cropping. This is particularly true shooting wildlife with a full frame camera.

In terms of resolution the Nikon Z7II or Canon R5, both with around 45MP, would be more of a direct replacement for your D850. Of course, these are considerably more expensive.

Z6II with 24-120mm lens.... $2700
Z7II with 24-120mm lens.... $3700
R6 with 24-105mm lens...... $3600
R5 with 24-105mm lens...... $5000

I like that Nikon includes an F to Z-mount adapter with those cameras. Canon doesn't do that. There are several EF to RF adapters available that range from $50 to $400 (the latter have drop in filters that increase the cost). You wouldn't need these, unless you purchase some Canon EF/EF-S lenses too.

Another consideration... you mention sharing a Nikkor 80-400mm lens with your wife. That lens can be adapted for use on the Nikon mirrorless cameras without any limitations. You'll have both autofocus and aperture control.

While it's possible to adapt that lens for use on the Canon cameras, too, you'll lose autofocus and will need an adapter that has a manual aperture control ring.

I'm afraid that with the Canon cameras you would be better served either purchasing an EF 100-400mm L IS USM "II" and an EF to RF adapter to allow it's use on those cameras, or going straight to purchasing an RF 100-500mm L IS USM lens. Both these lenses are superb. The EF 100-400mm II weighs about the same as the Nikkor 80-400mm. The newer RF 100-500mm actually weighs about a half lb. less than either of those lenses, even though it gains an additional 100mm "reach". Of course, these Canon lenses ain't free. You'd be looking at considerable additional cost. The EF 100-400mm II sells for $2400 and the RF 100-500mm costs $2700.

I do think the Canon R6 and R5 have the best AF system... better than both the Nikon mirrorless, better than the older Canon R, and even better than your D850's. However for landscape and travel photography, you wouldn't see much difference. Most likely it would be with active wildlife where the latest-and-greatest AF system the R6 and R5 share would be a big advantage. But is this worth the additional cost involved? Only you can say.

Hope this helps with your decision.

tcthome Loc: NJ

I agree with Gene on the Sony or Canon just because you shoot wildlife. I shoot a Nikon D810 & if I was going all in for mirrorless with some wildlife in mind, I would do just that. If your not worried about money, the R5 would be it for frames per second or the new Sony A7R4A if you can live with 10fps & have a computer to handle the large 61 mp files. Good luck with what ever you enjoy & happy shooting.

edit. You will most likely like Canon's menu's better coming from Nikon.

Architect1776 Loc: In my mind

Canon R6 out performs the Z6II. Has a better selection of lenses and the IBIS gives up to 8 stops vs Z6II is about 5.
No comparison.
Do not go with the R unless you really do not want IBIS.

Larryshuman

I got a Z6 from NPS and I sent it back a week early. MY old D600 gives better results the the Z6 did.

SuperflyTNT Loc: Manassas VA

Actually Canon and Nikon mirrorless both have the same number of native mount full frame lenses.

DaveyDitzer Loc: Western PA

CO: just a nit with the comparison. I had a 24-70 lens and one that zoomed to 120. I sold the 24-70 because the range from 70 to 120 is significant to me. The 70 felt like I could use my nifty fifty and move my feet just a little.... or even crop. I have both a 16-80 DX and a FF 24-120 These stay in my bag. I even bought an old 28-105 for times when I want to save a little weight.

Doc Mck Loc: Terrell,Texas

The R6 has the same sensor as the 1DX MK III. The lower megapixel count allows for much faster process times if you are shooting action. Talented photographers have been producing amazing work wit 5-10 megapixel cameras for a long time. I just bought a perfect used R6 for less than $2000. It was advertized on this website.

mundy-F2 Loc: Chicago suburban area

I have the same concerns after my heart surgery last year. As a result of this problem, I decided to use either my 35mm or 85mm prime for travel and street pictures. I love my 17-35mm zoom, but I do get tired after a full day of pictures. I will probably start using a monopod with my wide angle, unless I know I will be taking a landscape shot, then I will use my tripod.
Mundy

Architect1776 Loc: In my mind

All EF lenses can count as native as they work 100% and better on the RF cameras.
So you have the entire EF (EFs) range of lenses as well that Nikon does NOT have even close.
Also Canon has "Native" RF lenses from RF 14-35 to 400mm, 600mm, 800mm, 100-500mm and the so called trinity.
And many other very useful lenses including a 100mm f2.8 macro that goes to 1.4 X that no one has including Nikon is lacking.

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

Why switch? As you said, you are primarily a landscape shooter, for that you don't need eye focus do you, and you don't need fancy focusing menu's do you? As far as traveling goes, I sometimes only take my D850 with the 24-120 and for wildlife I take the Nikon 500 5.6.
And as for "some wildlife", I use the d850 with GROUP AUTO FOCUS, as long as the subject is in one of the four dots the subjects eyes, as well as the body, will be in focus.
The image below was with the D850 when we were recently in Iceland, I used the Nikon 24-120 and the Nikon 500 5.6 lenses.
IMHO, you have the best camera for what you do now, why switch? Plus, you have more megs to work with. What could be better?
And, I believe memory cards may be more expensive? Not sure about this one, I could be very wrong.
First image with the 24-120, second of the Puffins is with the 500.
Good luck and keep on shooting until the end.

Jimmy T Loc: Virginia

IMHO you have previously received a LOT of great advice from previous posters.
The only thing that I might add, as a Canon guy, is to KEEP the Nikon D850 if financially reasonable for you to do.
I wish that I had one because on paper, reviews, and from the comments here on UHH the Nikon D850 is one terrific unit.
Saving ~1lb is not very significant, especially when toted with a quality cross-shoulder carry strap. I'm way past senior citizen status. (there are lots of UHH Posts on this subject - https://www.uglyhedgehog.com/search-topic-list?q=carry+straps&sectnum=0&username=)
Trade-ins net you so little, and private sales are a PITA. But then I'm not known for my patience, sigh.
Best wishes on your journey. . and. . .
Smile,
JimmyT Sends

mundy-F2 Loc: Chicago suburban area

Very nice pictures!
Mundy

DaveyDitzer Loc: Western PA

I have a recently purchased D850, and have a Df and a D5300 and a pocket Nikon. I've found that I can match the size and weight to my "mission" for the day. I plan to use the D850 more like a larger format camera, i.e., tripod and more sturdy set up. Hand holding all day is more than my damaged shoulders can manage now.

BobHartung Loc: Bettendorf, IA

First I use a Z7 (version 1) + FTZ + 24-120 all the time. It is a great combination and as you are already familiar with the Nikon menu system you will find minimal trouble changing. Don't let the "Nikon Naysayers" twist your arm, Nikon makes quality gear and you will retain the image quality to which you have become accustomed.

joecichjr Loc: Chicago S. Suburbs, Illinois, USA

Eye-catchingly beautiful duo ✳️🏆🏆✳️