When Nikon released the D610 , it was a minor update to the D600 , and created mainly in response to a technical problem, with many customers reporting dirt on the sensor that was creating spots on their images. Our natural response to the announcement of the Nikon D810, then, was understandably to ask if this was a similar release - a minor tweak to the exceptional Nikon D800 .

Unfortunately, the answer to that question is a little more involved than a binary yes or no. You can't expect a step change over the Nikon D800, as its revolutionary sensor simply can't be improved significantly year-after-year. And you also shouldn’t expect a dramatic in design or software, especially in a semi-pro camera such as this. Nikon die-hards would be up in arms if the company changed too much.

Within those boundaries, however, Nikon has made the biggest changes it can, refining the control layout and installing a brand-new sensor and processing engine. It’s much more of an update than the D610 was.

New sensor and performance

For the D810 Nikon has created a brand-new 36.3 megapixel sensor. Resolution-wise, it's no big change from the D800, which had a 36.2 megapixel sensor. That's fair enough as resolution was never one of the D800's problems. What Nikon has done this time around is refine and improve the performance of its sensor. Combined with the new Expeed 4 image processing engine, the D810 is designed to be quicker, producing cleaner, sharper images. For this model Nikon has removed the optical low pass filter (OLPF), so the D810 effectively replaces both the D800, which had an OLPF, and the D800E, which didn't.

For starters, the new sensor and processing engine mean that the camera is faster, managing 5fps at full-resolution and up to 7fps when set to DX crop mode. The D800 could only manage 5fps in DX crop mode (15.3 megapixels), so this is a big improvement, particularly if you're shooting fast action and want to snap of a burst of shots to capture the perfect moment. Even better, switching to JPEG mode, the camera can rattle off an unlimited amount of shots, as long as the memory card isn't full This works for any shutter speed of less than 4s.

Post production and image capture have also been given a boost thanks to the RAW Size S format. This creates 12-bit uncompressed Nikon NEF RAW files, which are much smaller in size.

One of the disadvantages of having such a large sensor is that less light falls per pixel than on cameras with lower resolutions. This can lead to noiser images. With the D810 Nikon has looked to address that, promising cleaner photos. ISO range has been expanded, too, with the camera able to use ISO 32-51200 in an extended mode (regular mode is ISO 64-12800).

Nikon has also added an electronic front-curtain shutter, which you can use when the mirror is up in live-view mode. This is designed to minimise internal vibrations caused by the mechanical shutter, eliminating micro-blur. It could prove very useful when using telephoto lenses, such as for wildlife photography.

Auto-focus has been improved, too. The D810 now has the D4S' Multi-CAM 3500FX 51-point AF system, which can be configured in 9-point, 21-point and 51-point coverage settings. The AF points are clustered towards the centre of the frame, though; switching to DX crop mode gives you almost 100 per cent coverage. The D810 also gains the D4S' Group Area AF mode. This is designed to make focussing in challenging lighting conditions easier and more reliable.

We'll need to wait until we get a review sample in before we can fully test all of these claims, but the sample shots we've seen certainly look impressive.

Video mode

Video is one of big growth areas for cameras, so it's no surprise to see that Nikon has boosted the performance of the D810. It has added 50/60p shooting, and has made full ISO control available from 64-to-Hi2. As well as recording in-body, the feed can be sent to external device, or even broadcast live.

It's great to see Nikon boosting the video capabilities of its DSLR, but the one crucial thing that's missing is the ability to record 4K video. Currently only the Panasonic Lumix GH4 has that mode.

Build quality

As you'd expect from Nikon's high-end DSLR, the build-quality is second-to-none. It has a magnesium alloy body, with weather and dust sealing as standard. You'll need to make sure that you buy weather-sealed lenses for the best experience, though.

Nikon has also redesigned the shutter, with a new kevlar/carbon fibre-composite unit. As well as reducing shutter lag, the new unit is designed to be quieter, while still guaranteeing a minimum of 200,000 releases.

Controls

Nikon's cameras are well-known for their ergonomic and cleverly-thought-out controls. The Nikon D800 had it about right, so there's no major revolution with the D810, rather an evolution and refinement of what's on offer. Most of the design changes have come about because of feedback from photographers.

Now the metering mode button has moved to the main control dial, making it easier to reach and change when shooting. Making way for it is the Bracket (BKT) button, which moves to the front of the camera.

Nikon has modified an upgraded the grip, too, making it more comfortable to hold. In our short time with the camera, it certainly felt comfortable and easy to hold. Otherwise, it's business as normal for the buttons and dials, letting anyone familiar with Nikon cameras pick up the D810 and start using it immediately.

Screen

Nikon has used the same size screen, as on the D800, but the 3.2in model has been upgraded to a 1,299K-dot resolution, up from 921K-dots. It's a fairly chunky improvement that should make reviewing shots and composing in live view that bit easier. In addition, Nikon has added a new split-screen mode, which lets you pick two points on a straight line to make sure that you've got the shot level and that everything's in focus. It's particularly useful, we're told, for architectural photography.

Memory card slots

As with the D800, the D810 retains two memory card slots. There's one SDXC slot and one CF slot, which will appeal to the professional photographers. The slots can be used together, with one set as primary and one as an overflow for when the first card fills up. You can also choose to shoot RAW on the primary slot and JPEG on the secondary. In all cases, dual slots give you flexibility and control over how you shoot, so it's good to see this feature retained.

Conclusion and availability

From what we've seen of the D810, Nikon seems to have addressed many of the little niggles that we had with the D800, boosting performance, image quality and video recording. It's also tweaked and refined the controls, making it even easier to shoot with. First impressions, then, are very positive, but we'll have to wait until we get a final model in for review to give it a proper test.

Nikon will make the D810 available from 26th July, with the body-only model due to cost £2,700. We don't have a price for a kit yet, but expect to see a variety of deals available.