Panasonic is trying to promote its brand new Lumix GH3 as "the first DSLM". That's "digital single lens mirrorless" for the uninitiated, thought it sounds - obviously and intentionally, no doubt - a lot like "DSLR" to us. Hardly a surprise then that it looks, feels and functions a lot like one too. Pocket-lint had the chance to get our hands on a near-complete, pre-production model to have a play with. Here's what we made of this Micro Four Thirds big gun.

Even if we're not sold on the acronym - let's just stick with compact system camera or CSC for now, until it takes hold - we have to say that the GH3 has a lot of promise.

The moment we arrived at London Zoo to pop some long lenses on the front of the camera and snap some animals, the heavens opened and it poured down. Good job this is the first dust and weather-sealed G-series model then, eh? We couldn't even make it up. Using it outside in the rain we were reassured that it wasn't going to get drowned to death - although, at present, there's only one weather-sealed Lumix lens (the 12-35mm) and another one (the 35-100mm) that's just around the corner on the release schedule lineup.

Sun or rain, we were determined to get snapping and see what the camera was all about. All previous G-series models have impressed us with the autofocus speed and ability, and the GH3 is no slouch either. It's said to be slightly faster than its predecessors with the 12-35mm lens and although our brains couldn't time the difference between the two, needless to say it's quick. Real quick.

Autofocus is split into a whole bunch of modes - from face detection, to tracking, auto area, single area, and pinpoint - that make acquiring focus easy whatever the scene. It's pinpoint that really steals the show though, as its crosshair area zooms in to 100 per cent to acquire and confirm - for want of a better word - pinpoint focus. Shooting zoo animals through netting and bars is the perfect set up to test it as the black-against-white contrast of netting is a prime target for a camera to clock on to. With pinpoint at our fingertips though - and literally, as the GH3 has a touch-sensitive OLED screen - we were able to slip past those barriers (not literally, of course) and grab some great shots.

Controls come aplenty, including both an AF-S/C/MF switch around the AF/AE lock on the rear of the camera and a continuous shooting mode dial to the top left to accompany the more common mode dial. Add five function (Fn) buttons and there's no doubt that customisation will be a big draw with this camera - right down to the drag-and-drop quick menu that can be adjusted using the touchscreen to select which options will appear. It's this level of control that makes this mirrorless look and feel a lot more like a DSLR - but that's exactly the market in which place this advanced model is looking to place itself.

The GH3 we used wasn't complete, so image quality isn't yet final, and therefore Panasonic asked us to sign on the dotted line not to show them at full scale. We do have a selection of shrunken-down shots though that go some way to portray what the latest 16-megapixel Live MOS sensor is capable of. It's impressive stuff from what we've seen and really shows off what this sensor size can do, right into the higher ISO settings. We're not just saying that either, take a gander at the detail in this bird, which was shot at ISO 2500. Crisp, isn't it?

As well as stills, movie recording is a major part of what the GH3 is about. Arguably that'll be one of its key sells. We were able to shoot and view some super-smooth 1080p25 footage output as MOV files using ALL-I compression at an incredible 72Mbps. That's beyond broadcast quality. 50Mbps is also offered at faster frame rates or 720p, dipping to 28Mbps if using the AVCHD option. Frame rates include 24, 25, 50 or 60fps options - the latter two differ depending on region, i.e. 50p is PAL, 60p is NTSC.

Needless to say, we're impressed with what the movie mode can do on paper, and have no doubt that semi-pro and pro outfits will be able to use this camera in conjunction with various accessories and rigs for exceptional results. There's a 3.5mm mic in (XLR is only possible via an adapter), another 3.5mm headphone monitor out, timecode option, plus a clean HDMI out should you want to use an additional recording device (though the time is still limited to 29mins 59secs - the same as if recording to an on-board SD card). Talk about rolling out the big guns.

However, saying that, the model that we had showed some issues when in continuous autofocus mode. Using Face Detection autofocus, too, the camera was quick to identify faces within a scene but was too slow to follow them and maintain focus. Strange, because another member of our group had no such issues - so, for the time being, we're putting this down to the early firmware. Worth bringing up though, as we're unconvinced by any mirrorless camera's ability to focus continuously during movie mode - something we had hoped that the GH3 would crack. Maybe the final version will finally hit the nail on the head.

The electronic viewfinder also adds lots of good points to the mix: the four-colour OLED panel has a great 1.744k-dot resolution and motion is lovely and smooth. However glasses users may find that it throws a bit of a spanner in the works by "blurring" bright points towards the finder's edges. An oddity that we've rarely seen before; not that it affects the final image in any way. 

On paper and in use, aside from a few issues as outlined, this premium mirrorless camera has a lot of good going for it. It might not have the external "sassiness" of the Olympus OM-D in our view, but this is like the techie's version with bags more features on offer. The £1,000 body-only asking price is right up there though, but with those movie features - continuous autofocus ignored - there's really nothing else on the stills market that can compete.