The majority of Panasonic's G-series has focused on the more entry-level product: the GF3 and GF5, for example, epitomised point-and-shoot style compact system cameras. But if the announcement of the Lumix GH3 - unveiled at this year's Photokina 2012 trade show in Cologne, Germany - is anything to go by, the Micro Four Thirds series' top-spec product is gunning for the higher spec user.

Pocket-lint got a hands-on session with a pre-production Panasonic Lumix GH3 in advance of its grand unveiling at the show, where we got a chance to test its wide array of features.

The first thing that's striking about the GH3 is its size. Initially we handled the product with its brand new battery grip, which sure bulks up this beast. But we reckon that's a good thing: the camera uses a new, more powerful battery; and with a second one loaded into the optional grip it's said to last for up to 1000 shots - far beyond what any other compact system camera will offer. Note that Panasonic is keen to push this as a "DSLM" camera, rather than the compact system camera or "CSC" title that's often chucked around. That may make for yet more confusion as manufacturers battle it out to offer up a sensible category name, but the similar-to-DSLR namesake might hit home with those looking for a modern-day DSLR equivalent.

Everything's a little larger than the GH2's controls were: the main mode dial and the rear thumbwheel feel up-sized and are therefore easy to get a good handle on. The camera's not short of function buttons either: there are five scattered around the body itself (four if discounting the LCD/EVF button), which increases to six if the touchscreen-based "virtual button" is included. Direct buttons for ISO, white balance and exposure compensation; a dial for burst shooting selection; and a switch to flick between AF focus types ensure there's little to nothing that's not a click or press away.

The GH3 has an essence of Olympus OM-D, albeit with more of a "techie" angle. Think movie mode with all the possible bells and whistles and near-endless function buttons and it may not look as retro-cool as Olympus' offering, but it does tick a lot of boxes that serious snappers will want. That includes weather-sealing, a first for a Panasonic G-series compact system camera.

At its core there's a brand new 16-megapixel Micro Four Thirds sensor. It's not the same as that in the GH2 or the G5 - this one doesn't appear to be a true multi-aspect-ratio sensor as per the previous GH-series cameras - as Panasonic claims the GH3's is considerably better than its predecessor. In a dim-lit room it wasn't possible for us to check this in detail, but there's certainly no going backwards from camp Panasonic.

But that same dimly lit room did give us a great chance to play with the updated autofocus system. The GH3, paired with the 12-35mm lens, can deliver focus in an apparent 0.07 seconds. Now that's as fast as it currently gets. It might not have been at that speed in low light, but the camera had no issues finding the edge of a poster on the wall at top speed.

There's no hybrid sensor wizardry at play here: Panasonic has stuck to its guns and enhanced the contrast-detection autofocus method which, to our minds, is the better option. It just feels genuinely quicker than its competitors, though we haven't (yet) had the chance to try it with a longer lens.

Image previews are catered for by a 3-inch, bracket-mounted 614k-dot OLED panel and a new 1,744k-dot OLED electronic viewfinder that uses RGBB (yep, a second blue) for better colour reproduction. We weren't able to shoot outside, so it's hard to tell the difference as yet - something we'll certainly test more thoroughly at a future date when we have the final production product in for testing and review.

The movie modes are likely to be the most interesting of the bunch though. Back when the GH2 was launched (at the last Photokina two years ago) it really pushed forward moving-image capture from a stills camera. In the last two years there have been big advances from the likes of Canon, Nikon and Sony that may have chipped away at Panasonic's hold, but here's where the GH3 looks to take back in abundance.

1080p capture is available in 50, 30, 25 and 24p in AVCHD, MOV and MP4 formats. That's all well and good, but it's the top-end nitrate that will impress. Use the AVCHD capture and the camera can sustain 50Mbps, or up to 72Mbps using the ALL-I compression. That first figure is the threshold for professional broadcast quality, so that'll certainly get some ears pricked up.

But there's more: the 3.5mm input and output jacks cater for live monitoring via headphones (whether in real time or record time with a slight delay) and external microphone recording. There's a clean HDMI output for visual monitoring too.

During capture, although it's not yet possible on this test model, it will be possible to adjust the focus point via the touchscreen, while live manual control is also available. The inclusion of microphone levels and a timecode - both of which can be turned on or off in the menu settings - will be welcome from demanding video editors. They're useful to have, but we'd like a larger, more analogue-type audio level display as the current one looks a bit small and sits on a horizontal line. The ability to move it around the screen would be cool, but that's not currently possible.

There's also a Wi-Fi mode that allows for remote control use, though the lack of a good connection in the Koelnmesse here in Germany, coupled with early firmware, meant that this wasn't possible to test. The Wi-Fi option sits on the Fn1 function button so is a mere press away whichever shooting mode you happen to be in, and can also be used to share and backup images.

Then there's the price. With the 12-35mm lens the package will be around £2,000; with the 14-140mm that drops to £1,700; or body only the GH3 is anticipated to cost around £1,000, possibly a quid under that mark. It's not cheap, but there's a lot on offer and it's likely to be those video modes that make for the real sell. We look forward to testing a finished version in full to see just what this li'l beast can do.