I finally have enough images on my Z7, after getting out for a long shoot (the third with the Z7) yesterday, to have formed some real opinions based on about 500 shots.
My background is that I've been shooting landscape for over 15 years, using digital cameras ranging from the first Canon EOS-D30 to the brand-new Z7 plus some medium format film. I'm most familiar with Fuji and Nikon, but I taught photography at the university level for years, and have dealt with most cameras (and their files) at some point.
First, the positives...
There's something special about the files at low ISO. While I have largely used Fuji APS-C in recent years, I am quite familiar with the A7r (original) and the D800e, although not with the successors of either. Compared to any other camera I have used, there is a "presence" to Z7 files at or near ISO 64 that I have not seen in other digital files - yes, they have enormous resolution and dynamic range, but there is something even more than that. Looking at a file of this quality is like seeing a large format transparency for the first time (I'd place the overall quality quite securely above any medium-format transparency I've seen, scanned on any scanner I've had access to - I have never used an Imacon or a drum scanner). I suspect that the "presence" is created by a combination of three factors - the resolution, the dynamic range, and the fact that low-ISO files are utterly noiseless. Medium-format digital shooters talk about something similar - I've only handled medium-format digital in shows or stores). I'm quite sure D850 files with a good lens would be similar (it's a very similar sensor), and I strongly suspect the A7r mk III might have it too.
It's a very nice camera to handle. It really does feel like a Nikon DSLR, and Nikon DSLRs handle very well in general (my personal bias about camera handling is that Nikons and Fujis handle very differently from each other, but both very well - then Olympus, then Canon and Panasonic, with Sonys close to the bottom of the pile - they always feel a bit off to me) . It's small and light (lighter than any midline APS-C DSLR, let alone a D850) and hikes well. Roger Cicala's teardown is extremely reassuring about the ruggedness and sealing - if you can take a camera other than a waterproof compact somewhere, you can take a Z7. I've been caught in one surprise downpour so far with no ill effects. The only thing that's a bit disconcerting at first (and you soon get used to it) is that, because of the size, you kind of expect it to handle like a consumer Nikon DSLR (D3xxx or D5xxx), while the majority of the controls are set up like a pro Nikon DSLR (D850).
The 24-70mm f4 is a great lens for the size and price. The center and even edge sharpness is as good as any zoom I've seen anywhere. The extreme corners are weaker, but weaker in this context is "pretty good for a zoom, and better than any full-frame zoom this small has any right to be this far into the corner", while the strong center is "wow, it's at least as good as things like the best 24-70 f2.8 zooms and the Fujinon 16-55 f2.8". Overall, it would be a very good lens even if it were heavy and expensive - it's neither one... I can't wait for the 14-30 to arrive on the market, and I encourage Nikon to consider a 70-200 or 70-300 other than the f2.8 - if they can make compact zooms like this, I want a full line of them...
Despite all the complaints about the AF, it's extremely consistent in my use. I've had it in Precision AF - with a camera this sharp, you want to point the AF at exactly what you want. I'm using it as a (backcountry) landscape camera, not a sports camera - I don't especially need speed or tracking. It focuses where it says it's going to, and it gets it right. Is it fast? A few years ago, it would have been notably fast. Even in Precision AF, it's much faster than an X-Pro 1, an original A7r, or other slow-focusing cameras. It's not as fast as an X-H1 or even an X-T2... It's a lot faster than manually focusing a 4x5" view camera
Using it for what it shines at, it's more than fast enough (and much faster than any of its medium-format competitors).
The IBIS is excellent - I get most shots sharp down to 1/25 of a second or so (on a camera with this much resolution, that's quite a bit), and I've landed sharp shots at 1/8. I haven't dared shoot it slower than 1/8... Slower than 1/8? On a camera with resolution like this? Try handholding a Hasselblad 501C with Tech Pan in it at 1/4 second... There is some shutter shock, completely controlled by the optional electronic first-curtain shutter, so turn it on and leave it on...
The EVF is the best viewfinder I have used, optical or electronic. EVFs have reached the point where good ones are competitive with really good prisms (and much better than the mirror prisms on lower-end DSLRs). The advantage of a great EVF is that you can choose what information is displayed, and how it is displayed.
Now, the actual downsides (things where the camera could have been designed better).
The battery life is better than CIPA says, and significantly better than any "small-battery" mirrorless camera (any Fuji, any Sony prior to the a9 and the a7III generation, many others that use the little rectangular batteries rated around 1000 mAh), but it isn't anywhere near the "charge it on Monday and use it all week" life of many DSLRs that use the ~2000 mAh battery. I haven't run a battery down all the way yet, because I've been using it on one-day shoots so far. After ~200 shots and a pretty good day on the trail, it's down two bars out of five. Assuming the battery meter isn't too badly off (and recent ones tend not to be), I suspect it of getting 400-500 images per battery in my usage. It'll get more in event photography or the like, where you shoot a ton quickly. I'll carry 3-4 batteries on an extended hike (I need to come into town once a week to resupply, anyway, and I'll charge up when I do). Much better than 7 Fuji batteries (the worst offenders I know of on battery life are the X-H1 and full-frame Sonys prior to the battery upgrade), but I'd only carry two for a D850.
The latch on the memory card door can come open as you're getting the camera out of a tight bag - it is designed to open by pulling it towards the back of the camera. There's nothing you'd do while photographing that does that accidentally, and the door on the D850 works exactly the same way... The problem is that scraping it against the edge of a bag can pop it open. It takes a little extra care in a small vertical holster bag in the rain (where popping the door would be a bad idea). I'll probably tape mine in that exact situation. Not a problem in any bag where the camera is horizontal, nor in any bag where there is space on the grip side. There should be a secondary lock on the card door, though - the only flaw in an otherwise excellent sealing job.
High ISO image quality is disappointing compared to one particular competitor - the Z7 itself at low ISO! At ISO 1600, it's not especially noisy, but you can see the noise when you look at an image at 1:1 on screen. Pixel-peeping noise at 1:1 at ISO 1600 on an image approaching 50 MP is not a disappointment by any rational standard, but it is when the last image you looked at is ISO 64. It doesn't have that large-format look at 1600 that it does at low ISOs (of course, who ever shot large format at ISO 1600)? It's as good as any camera I know of at ISO 1600, and better than most, and I'd happily print it at 20x30, but the disappointment is that I know what it's capable of at low ISO. DPReview's image quality test shows this well, and, for those who know either the D850 or the A7rIII, the DPReview test shows that they both do the same thing. Don't get me wrong - it's still very, very good - but it's capable of more...
Here are some things to think about - not actual advantages or disadvantages, and not Nikon's doing, but inherent to this class of camera.
You don't have the depth of field you think you have, if you are coming from a camera with a smaller sensor or less resolution. This is true of any high-resolution FF camera, and I suspect it's even more true of MF digital. The sensor size is one factor, but the high resolution is another - it's so sharp that you notice very quickly as that sharpness fades.
It eats memory cards for lunch, and computers for dinner. It's fully capable of writing nearly 130 megabytes to the card in one image (14-bit NEF plus large/fine JPEG). Nikon claims a 14-bit, uncompressed NEF alone is 85.1 MB - capacity on the card suggests that either this is a little smaller than reality, or the JPEGs are really big (I don't have my laptop hooked up to my RAID right now, so I can't check which file is big). Anyway, with all the quality options turned on (and why turn them off on a camera this capable), you only get around 500 files on a 64 GB card. Of course, any film camera capable of this kind of quality got one shot on each side of the film holder
The move to XQD probably made sense, due to the speed and reliability of the cards, but, unless you have a D5 or a D850, you don't have any, and they're expensive. A firmware update will bring CFExpress compatibility, and those are supposed to be cheaper (the disadvantage is that we'll probably see low-quality ones pretty quickly - Sony keeping a tight rein on XQD means they're expensive, but there are no counterfeits).
A 2017 15" MacBook Pro handles most edits smoothly in real time, but building Smart Previews for a card full of those huge files takes a long time. I haven't tried really time-consuming things like pano stitching, but I suspect that will make anything except a Cray feel slow.
Do you want/need one:
If you never print - no. The files overwhelm any digital display device on the market right now. A really good monitor will show off some of the other special qualities (the noiselessness and DR), but only a substantial print will show the full capabilities of the sensor.
If you like to shoot sports and action most of the time - no. I don't do that often, and haven't tried it yet with the Z7, but people who have don't like the AF all that well, and you'll want higher shutter speeds that will push it out of the low ISO range where the image quality is at its most special.
If you don't care about the size and weight - not yet. A D850 will give you essentially the same sensor in a package with better AF speed, broader lens compatibility and longer battery life. The Z-mount is an important technical advantage for the Z7, but the line of Z-mount lenses so far is limited. The one exception might be if your other camera
is a D850, and you are deciding between a second body and something different.
If you are looking for the absolute finest image quality you can get in a very portable package - emphatically YES! It's a 4x5" you can carry for 20 miles with a backpack full of food, water and tent and shoot handheld at 1/20 of a second, getting a few hundred images on a card. If this is what you want, there is nothing on the market that comes close right now. The D850 is twice the weight with a zoom as sharp, the A7r mkIII is heavier with any comparable lens (the 24-70 "Zeiss" doesn't hold a candle to the 24-70 Nikkor, leaving the Sony shooter with the superb, but heavy G-Master or perhaps the 24-105), has severe sealing flaws, and handles much less well (if you have an A7r II or III and are happy with it, there's absolutely no reason to switch). The other competitors are the X1D and the GFX 50 R, both of which lose on lens weight and lack any sort of stabilization with most lenses. The GFX is a surprising amount larger in person - I had expected it to be about the size of a Z7 or other substantial mirrorless camera, although differently shaped. It's really about the size of a
D850 (or a 5D mk IV if you prefer). It is the size of a Mamiya 6, or one of the Fuji 645 rangefinders, the "Texas Leicas" of film days, and the lenses are larger.
If you're looking for higher image quality coming from any mirrorless system
other than Sony full frame - yes, if you understand its limitations. It doesn't have Fuji's superb lens lineup, although Nikon is committed to getting lenses out there, and it's not going to focus like an E-M1 mk II. It does offer files on another level, even from Fuji's excellent 24 MP images. I'm keeping my substantial Fuji system, at least until there are native (non-adapted) Nikkors that do what all my Fujinons do.
If you're coming from Sony full frame - no, unless you're unhappy with something specific that the Nikon does better. If you have a 24 MP Sony body and any investment in lenses and want a sensor like this, why not an A7r mk III? If you already have an A7r mk II or III, the image quality difference will be minor, and you'll actually lose battery life if you have a mk III. The three situations where I might give it any consideration coming from Sony full-frame are: if you aren't happy with the 24-70 "Zeiss" and don't want the weight of the G-Master (if the 24-70 is a bread and butter lens for you), OR if the Sony's weather sealing is keeping you from photographing when you want to, OR if you dislike the ergonomics of the Sony strongly.
If you're coming from a DSLR system you like: If it's Nikon, a Z7 would be a great addition - start with a body, an FTZ adapter and a 24-70. If it's Canon, I'd wait to see what's next in EOS-R bodies. No, the first body isn't even close to a Z7, but they didn't build those lenses for that body... If it's Pentax or something else odd, the Z7 is worth a very close look - it's a great choice if it matches your shooting style.
