(Pocket-lint) - The camera rumour mill turns again ahead of Photokina 2012, and this time it's all about the rumoured Panasonic Lumix GH3.

It's not far off the two-year mark since the GH2 was announced, and in the wake of the Olympus OM-D E-M5 it's no surprise that Panasonic is re-focusing on its top-tier compact system camera.

The leaked specs, as revealed on 43rumors.com, report that the GH3 will come with a "wide dynamic range" 16-megapixel CMOS sensor. Whether this will be the multi-aspect ratio of its predecessor is unclear, but it will undoubtedly be the latest Micro Four Thirds sensor.

The site goes on to speculate that the Lumix GH3 will be designed to take on the likes of the Nikon D7000 and Canon EOS 7D DSLR cameras. It sure sounds like it's aiming high, so this new sensor is really going to have to amp things up to next level image quality.

But it's the movie capture specifications that caught our eyes the most. The GH2 was among the best stills cameras for movie capture upon its release, but the GH3 looks to wipe the floor with the majority of other kit that's out there.

Not only is it said to capture AVCHD, MOV and MP4 file options at up to 50Mbps (or 72Mbps using the ALL-I intraframe compression method) - that's acceptable professional broadcast quality - but there's also timecode, a 3.5mm microphone input, headphones monitor and an optional XLR input accessory too. Looks like Panasonic just opened up a whole new can of worms for serious video enthusiasts. We're just glad that the miniature 2.5mm jack of the GH2 is said to have been axed.

Other claims include that the GH3 will have the "fastest AF of any interchangeable system camera". Last time Panasonic released such a statement it was bang on the money, though competitors soon followed suit. Whether this will be achieved in the GH3 via a faster sensor refresh rate coupled with an enhanced contrast-detection algorithm, or a hybrid autofocus sensor (or even a combination of both) is yet to be seen.

Up to six frames per second (6fps) burst mode is said to depend on an electronic shutter, but it's unclear whether this means the GH3 will ditch any mechanical shutter, in the same way Nikon's J1 and J2 - see our exclusive Nikon J2 full review here - models have.

As per its predecessor there's a built in electronic viewfinder, though this one is a 1,740k-dot OLED version, paired with a 610k-dot OLED touchscreen on the rear. The former isn't quite as high resolution as the Sony NEX-7, but if the GH3 has a better control of contrast then it may make it the better viewfinder. Here's hoping.

Other high spec features are said to include a PC output for studio flash control, plus the usual built in flash and hotshot fitting for adding extras.

A tough magnesium alloy body ties up the GH3 package with a bow. Sounds good to us but - and there's always a but, isn't there? - there aren't any leaked pictures as yet and the alleged 1700 Euro price tag (no UK price yet, but it'll probably be £1700 with the 14-140mm lens) is far from cheap.

We'll be scouring the web to see if anything turns up in advance of Photokina 2012...

Writing by Mike Lowe.