Before you read this review, please know that I am very pleased with my D850. I am happy to have it, and I am using it more and more, especially in extreme lighting situations. I sincerely believe, however, that it is important that reviews be objective, and that they consider shortcomings in design or execution, even if those shortcomings are only perceived and related to the way that I work to do photography. Almost every review of this camera that I have read over the past year has failed to point out what I feel are some obvious design misses that make a real difference (at least to me) in its use. With all that in mind, here goes:
The D850 is a really nice camera. It has good balance and feel...my right thumb fits the back of this body better than any other that I have owned. It seems to be a little bit thinner front-to-back than my D810, but to me, the D810 still has an overall nicer feel, some of which I attribute to its all metal body and overall dimensions. Any weight reduction resulting from the switch to the hybrid body is negligible. Still to be seen is how the new design holds up under use and over time.
I appreciate the addition of lighted buttons on the rear of the body, but to me, this is a job that was only half done. Unfortunately, the really important controls on the right side of the body, some of which have been significantly relocated, are still dark. And these are the controls that are actually likely to be accessed while shooting. I do night sky and other extremely low light shooting, and since critical controls have been moved from their location on the D810, the D850 will not become my primary body for these situations for some time to come.
Swapping the Mode and ISO buttons was, from my perspective, a really bad idea. I am perhaps different from many other photographers in that I do not change ISO ´´on the fly.´´ Choice of ISO to me is a fundamental decision which affects the character of resulting photographs...it is not simply an exposure decision. (I never, ever use Auto ISO.) I do, however, change metering modes in the midst of shooting. This is a change that could have been made with the introduction of a completely new model line, not a new body that I expect to use alongside my D810.
The new joystick puzzles me. This is perhaps because I do not use the D850 to capture video. The only use I have found for it is to use the pushbutton to activate the viewfinder artificial horizon. Similarly, the new F2 button is nice to have. Unfortunately the range of choices to assign a function to this button is too limited. I´m using it to directly access ´´My Menu,´´ but there are a number of functions which would be more useful if available (see the next comment).
I am very disappointed in the elimination of the AE Lock button from its historical spot near the viewfinder. No one else may use this button, but I use it all the time, and its removal is another prime reason that the D810 will continue for now to be my primary body. In fact, it seems to me that with the extremely large number of available autofocus points, the AE Lock button is perhaps more useful than the AF lock button when recomposing images. According to the manual, the old AE Lock function can be programmed elsewhere, but all those other buttons are less accessible, and I have not found the functionality to be actually the same when I do assign it.
Finally, even though I am very careful with my photographic equipment (my D200 purchased in 2006 still looks and works almost like new), I miss the ability to install a polycarbonate protector over the rear monitor. I do not currently use the touch screen functionality, nor do I tilt the screen, and would much prefer the ability to install a non-contact cover over the screen. I do have a direct-contact glass protector installed, but it is not going to be as effective in protecting against an accidental impact in the dark. The design of the top hinges and the groove along the bottom would appear to support the addition of such a protector, but that may not be true, and in any case, none seem to be available.
In general, it appears to me that the designers have tried to squeeze too much into a limited space. Addition of enhanced video capability and features seem to have come at some expense to established still photography layout and functionality.
So in summary, I am happy to have the D850 as a second body. I will recommend it to others, while pointing out what I believe are shortcomings. It will not replace my D810 as my primary camera, at least for now. And it is not for sale...I will keep it. I do wish that I had been able to read a more objective review, especially since it was not available for hands-on inspection before purchase, even currently. But be aware that some of the advances have come at fairly significant cost and consider carefully before you decide.
