I'm really impressed with my Nikon D810. Unlike most "new" cameras that are pretty much the same as last year's models, my D810 is significantly better than my old D800e. It's also about an ounce (30g) lighter. I'm impressed because it's sharper, and mostly because it's much smoother, faster and quieter than my old D7000.
The D810 astounds me with how well it can handle multiple assignments, from ultra-high resolution gallery and fine art production, botanical field work and scientific record-keeping, military reconnaissance and industrial espionage to family, portraits and fast action — and it works astounding well down into the dark with autofocus that's fast and sure in dimmer light than I can see. Of course it's super-clean at insanely high ISOs.
It's a real multi-mode camera, easily handling everything from fine art to industrial use to portraits to sports. It has so many pixels that we can use any of its crop modes and still have more than enough pixels left for anything.
Its easy HDR mode is ideal for landscapes and real estate listings. Just turn it on, and now everything from bright daylight to dark indoor shadows look as detailed as they do to our eyes, instead of washing out to blank white and pitch black.
The Nikon D810 is the world's highest technical image quality DSLR. The only way to get higher technical quality is to pay as much as a new Mercedes for a clumsy medium-format camera, and even then it's not clear that it would be any better — and the D810 is far smaller, lighter, faster and quieter. You can shoot anything, anywhere on the D810, while if I gave you a $50,000 medium format system for free you still wouldn't want to lug it around or deal with its slow speeds and balky prima-donna handling.
The D810's autofocus is superb - far better than anything competitive from Canon, because the D810 not only focuses fast and sure in nearly total darkness, it automatically recognizes faces and focuses properly on the nearest eye. While I'm always having to fiddle with the AF Sensor selector on my Canon 5D Mark III, my D810 always selects the correct sensor automatically for my sports and people pictures. Unless your subjects are posing, the superior AF system of my D810 lets me capture action and life better than ever.
The old D800 and D800e had more resolution than any other full-frame DSLR by a large margin, but were too slow for just about anything, Now the D810 is much faster and quieter with the same resolution and more sharpness, and may also be used for sports, whoo hoo! In fact, why bother with the D4s when you can get the D4s' AF performance with far higher resolution for half the price in the D810? Exactly!
No matter how you slice it, if gallery exhibition is your end product, no DSLR can make better images today than the Nikon D810 — and it now runs fast enough for action, too!
Sharp
The D810 is the world's highest technical performance DSLR ever for outdoor, nature, reconnaissance, landscape, espionage, intelligence gathering, fine art and many other kinds of precision high-resolution photography.
In fact, there may be talks of restricting its sale, or at least limiting its performance, as it now allows any unauthorized person to gather huge amounts of sensitive data in any light in both public and private places without being obvious. The D810 is an artist's and forward observer's dream, with 36 actionable megapixels at every near-silent shutter click from a normal-looking camera about which no one asks any questions.
On the other hand, the D810 gathers so much information due to its ultra-high resolution that it could be considered negligent to use anything else for medical and dental record keeping. There is so much information in D810 images that one can go back years later and see things that might not have been obvious at the time. Likewise, the D810 is great for aerial photography and documentation of large crowds and public spaces. You can go back later and see more detail if you need to than from any other camera.
The D810 has no anti-alias filter, allowing it to replace the old D800 and the D800e.
But wait: the D800e had no anti-aliasing filter, but still had an optical low-pass filter (OLPF) over its sensor. The D810 has no anti-alias and no OLPF either, for sharper images than either old camera.
Fast
Faster internal processors allow the D810 to process enough data fast enough to shoot at 5 FPS over the slow 4 FPS of the old D800 and D800e. The D810 is now as fast or faster than the original $5,000 high-speed professional DSLRs, the D1 and D1H, that brought professional news, action and sports photography into the digital age.
But wait — the D810 runs at 7 FPS in DX mode with the right grip and batteries, which is much faster than the D1 and D1H, which were only DX anyway! This makes the D810 perfect for sports as well.
The D810 not only runs at a full 5 to 7 FPS much more quietly than any Nikon professional D1, D2, D3 or D4 series camera, the D810's autofocus is also uncannily fast, intelligent and accurate.
The D810 has the autofocus performance of the D4s. It's fast and accurate in any light. It's much better than the D600 and D610, whose AF systems tend to go blind in the dark.
The D810 has a clairvoyant Auto AF-Area Select mode (hold AF button under lens turn front command dial Auto) that instantly selects the correct AF areas, almost always finding the faces and focussing on the subject's closest eye, all instantly.
Better, in the Auto AF-Area Select mode, not only does it find the correct AF point immediately, this selected point tracks that eye or subject all over the frame as it moves around. It's like a very fast pit bull, finding it's target and not letting go as it moves around the frame until you have your shot.
The D810 has more than enough computer power to breeze through all these calculations far faster than other cameras. Other cameras take a moment to identify the correct AF area, or may not actually use facial recognition to find the correct eye, or may not be able to track it all around as the target moves in three dimensions — but the D810 can and does.
Quiet
The D810 is very smooth and quiet. It is one of the few Nikons other than the amateur D3300 that is quiet enough to be used indoors during meetings. The D810 is quiet enough so that I can photograph my family continuously and they don't tell me to knock it off, as I do when shooting the other large DSLRs.
The D810 is much quieter than the clattery old D800 and D800e from 2012 that it replaces. In fact, the D810 is much quieter than the noisy D4S, and quieter than the D600. The D810 in its regular mode is quieter than the old D800 in its Quiet mode, and the D810 gets even quieter in its own Quiet modes.
Unlike all other Nikon DSLRs, the D810 is the only Nikon DSLR that runs quickly in its Quiet Continuous (QC) mode, about 3 continuous FPS. I always shoot in QC mode for everything other than sports; the QC mode is fast enough for almost anything and I prefer not to be noticed as I shoot.
Multi-mode
When the extreme resolution of the D810 isn't needed for day-to-day photography, just set the resolution down to 20 MP or 9 MP. Personally, I always shoot in the 9 MP mode, which is more than enough resolution for anything except for forensics or gallery work.
The D810 also lets us crop the sensor with a few clicks. I set my Fn button to let me shoot in 4:5 crop mode, which gives a squarer image than the usual 3:2 shape. The D810 has so much resolution that even when cropped there is always more than enough resolution for anything.
With the D810, we have ultra-high resolution when it's needed, as well as a fast, quiet camera for sports and portraiture..
With the D810, we have it all in one camera unlike anything ever from anyone.