Ahead of the curve - that’s the phrase that first sprang to mind when we saw an early version of the Panasonic Lumix GH4. This consumer compact system camera is the first to deliver 4K video, the Ultra HD format that’s going to be the next big thing.

And we don’t mean a half-baked 4K at unusable resolutions - the GH4 can shoot 4K at 30/25/24fps at 100Mbps using ALL-Intra compression. At 1080p that rises way beyond broadcast standard to 200Mbps. Impressive.

It does this thanks to its brand new 16.05MP Live MOS sensor and latest Venus Engine IX which is much more powerful than before. It’s this one feature that really sets the GH4 apart from the earlier GH3. To look at from the front it’s nigh on impossible to tell the two apart - there’s the same weather-sealed magnesium body and layout, only there’s a lock on the main mode dial and flipping the body around also reveals a new larger eyecup around the viewfinder.

It’s here that things step up a level too, as the electronic finder on board is now a 2,360k-dot OLED panel - far more resolute than its predecessor. Although, in this instance, we saw the model so far ahead of the as yet unknown release date that the viewfinder wasn’t functional. We can only hope it’s as good as that in the Fujifilm X-T1, although with the Lumix’s 0.67x magnification we already know it won’t be quite as large.

READ: Hands-on: Fujifilm X-T1 review 

The rear LCD screen, however, was fully functional. All 1,040k-dots of the 3-inch OLED panel glowed brightly and the vari-angle bracket mount meant it was possible to position the screen in any direction. That’s another pro point for both stills and video capture.

The new sensor also brings new capabilities including a brand new autofocus system, known as DFD - depth from defocus - for optimum performance with Micro Four Thirds lenses. Each lens’s minimum and maximum defocus points are known, and such data can be extracted via the electronic coupling between lens and body to deliver a defined range to minimise unnecessary focus hunting.

How much faster is it? It’s hard to tell by eye; the human brain probably can’t realistically tell. But when something is near instant as this focus system is, it can only be called a success. The earlier 23-point system has also been upped to a 49-point array for more pinpoint accuracy, while sensitivity to -4EV means shooting in moonlight is plausible. That’s a claimed greater low-light responsiveness than any other system camera we could name.

Short of darkness or a full moon, we had to settle for the inside of Panasonic HQ which even during a presentation on a 103-inch screen wasn’t, not unsurprisingly, quite so dark. But a good testing ground nonetheless, and even in such dim conditions everything worked super quick. Being the unfinished sample that it was, this pre-production GH4 did deliver some visual on-screen quirks when focusing, but these will be gone come release time. The speed, though, is clear to see.

Fast focus should also be echoed in fast performance, as the GH4 is said to support 12fps burst shooting, sustaining 7.5fps while in continuous autofocus - if you have a super-fast UHS-II SD card. This is still in the works, so we couldn’t fully test at this moment in time.

If manual focus is more your thing then the GH4 adds in both focus peaking and zebra pattern, available for use in both stills and video capture. We know this will please a lot of users who wondered why it had been absent from the GH3 - particularly when newer models such as the lower-spec GX7 had focus peaking from launch.

READ: Panasonic Lumix GX7 review

The new sensor has also been designed to deliver Panasonic’s best signal yet, for better noise reduction, sharper resolution, smoother gradation and a wider dynamic range. All sounds positive, but we still can’t shake the feeling that this is a camera where video that stands out the most. That’s what we think will resonate the most with high-end users, although it does work in a two-tier system.

When writing to SD card the camera captures 4K video with 8-bit colour and the data rate is limited to 100Mbps. Use an optional accessory camera - the Panasonic DMW-YAGH, which is about as big as the GH4 body - and its four SDI ports that can be used in tandem to extract uncompressed 4K at 10-bit colour. Power input, independent volume adjustment and twin XLR sockets ensure everything a broadcast pro is here - but only via the DMW-YAGH which is far from a consumer product. But the very fact a consumer camera can develop into such a pro tool shows Panasonic’s understanding of what the GH-series represents.

READ: Panasonic DMW-YAGH transforms GH4 into uncompressed 4K broadcast tool

There are two 4K formats available too: the standard 3840 x 2160 resolution at 30/25/24p, or the cinema widescreen 4096 x 2160 resolution available at 24p only. Variable frame rates are also available for video capture at up to 96fps, which is four times the rate of 24p.

As a far more significant portion of the camera’s sensor is used to capture 4K than it is for 1080p Panasonic has also opted for a straight "pixel for pixel" capture system - the top and bottom sections of the sensor aren’t needed for capture and so are binned. That means a true representation, no pixel mapping, binning or zooming required to obtain the final output. The crop adds a 17 per cent addition to equivalent focal length, so if you’re using a 50mm Micro Four Thirds lens (100mm equivalent) you’ll achieve a 117mm equivalent for 4K capture. Something to keep in mind, but a benefit as the central portion of a lens’ imaging circle tends to be sharper than the outermost edges, and as only the central portion will be used this will be a benefit. We were shown a 4K sample video on a 20-inch 4K tablet and it did look crystal clear.

READ: Panasonic Toughpad 4K UT-MB5 tablet hands-on: 20-inch pro-spec slate shows off 4K potential

At this moment in time there’s no word on final price or release date, but with the GH4 eyeing up the likes of the Canon EOS 70D and outdoing any other sub-£10k interchangeable lens camera with its 4K video capture we don’t anticipate it to be an impulse buy.

Our only real criticism - other than why no dual SD slot? - is the lingering question: does its 4K prowess provide too much too early and, therefore, will consumers be on board at this stage?

The Panasonic Lumix DMC-GH4 will be available from 5 May body only for £1300, with a 14-140mm lens for £1750, or with body only and an Interface unity for £2500. For those pre-ordering a free battery grip and battery is on offer from 10 March until 2 June.