Almost immediately after it announced it was working on a new mirrorless camera system, Nikon launched a D-SLR that’s clearly designed to keep its reflex business ticking over nicely for the time being. The new D850 essentially replaces the hugely popular D810 and will – like the EOS 5D Mark IV for Canon – represent the bulk of Nikon’s D-SLR sales to professionals and enthusiast-level users for the next year or so.
Built around a new weather-sealed magnesium alloy bodyshell which no longer has a built-in flash, the D850 employs a Nikon-design, full-35mm back-side illuminated (BSI) CMOS sensor with a total pixel count of 46.89 million. Nikon is emphasising its involvement in the design of the sensor – its first BSI-type device – but fabrication is likely to be by Sony (which holds the patents to the BSI architecture). The BSI design frees up space on the sensor’s surface for bigger photodiodes which becomes more important when the effective pixel count is 45.7 million. 
Consequently, the D850’s sensor still maintains a base sensitivity range equivalent to ISO 64 to 25,600. Expansion is available down to ISO 32 and up to ISO 102,400. There’s no optical low-pass filter (OPLF) in order to optimise resolution, and the maximum image size is 8256x5504 pixels, but the D850 offers a selection of capture formats including 1:2, 5:4, 1:1 and ‘APS-C’ (a.k.a. ‘DX’ in the Nikon lexicon). RAW files can be captured at one of three sizes (with either 12-bit or 14-bit colour), and batch processing for conversion to JPEGs is available in-camera.
Nikon’s current-generation ‘Expeed 5’ processor delivers up to 7.0 fps continuous shoot at full resolution, and up to 9.0 fps when the optional MB-D18 battery grip is attached with an EN-EL18 battery pack. Importantly, the faster processor also allows 4K video recording – in the Ultra HD resolution – at either 24 fps or 25 fps (PAL standard) plus time-lapse sequences at 8K. Nikon has significantly increased the D850’s appeal to video-makers so, in addition to full-width 4K recording at 16:9, the D-SLR has a focus peaking display, zebra patterns, 4K/2K HDMI output (8-bit 4:2:2 colour, and with simultaneous internal recording), both an audio input and output, electronic image stabilisation, and a range of slow-motion speeds for Full HD recording.
The D850 inherits the same 153-point AF system used in both the D5 and D500, which provides 99 cross-type sensors with 15 still operating at maximum apertures as slow as f8.0. Area modes are available using nine, 25, 72 or 153 points plus ‘Group Area AF’, ‘3D Tracking’ and ‘Face Priority’. Low light sensitivity extends down to EV -4.0 (at ISO 100), and a focus stacking mode records up to 300 frames, adjusting focus over user-set steps. The D850 also inherits the 180,000 pixel RGB metering system from the D5 and D500, and its focal plane shutter is rated to 200,000 cycles. A sensor-based shutter is provided for totally silent shooting in live view and at up to 6.0 fps.
Dual memory card slots are provided for the XQD and SD formats, which is perhaps the one questionable aspect of the D850’s design, given the desirability of having two slots of the same format. The SD slot supports UHS-II speed SDHC and SDXC cards. Tilt adjustment is available for the 8.1 cm LCD monitor screen which has a resolution of 2.36 megadots, brightness adjustment and touch controls (again more extensively implemented). In addition to the audio connections mentioned earlier, the D850 has USB 3.0 (Micro-B), mini HDMI (Type C) and a ten-pin remote control terminal. It retains a PC flash socket and is compatible with Nikon’s radio-controlled ‘Advanced Wireless Lighting’ flash units.
Both WiFi NFC and Bluetooth Low Energy (BLE) connectivity are built-in (the latter supporting Nikon’s SnapBridge always-on arrangement and remote camera control), and the D850 is compatible with the optional WT-7A wireless transmitter for IPTC transfer.
An interesting new accessory is the ES-2 Film Digitising Adapter which – in concert with a compatible Micro-Nikkor macro lens – allows for high-resolution film scanning of 35mm negatives or transparencies with in-camera inversion and colour correction.
Locally, the D850 body is priced at $4599, but discounting has already started and it’s being advertising by some retailers closer to $4000. Availability is the more pressing issue, as early shipments have already sold out and back orders are starting to stretch out towards deliveries nearer the end of the year. 
For more information about the Nikon D850 visit