Arguably the most significant upgrades that Panasonic has made concern the GH2's sensor and processor, particularly as many of the company's claims for the new model concern these.
The 18.3MP Live MOS multi-aspect chip has more than 4 million more pixels than the GH1's sensor, which results in an effective resolution of 16.05MP over the same 17.3mm x 13mm area. As with the GH1, the 'multi-aspect' moniker refers to the camera maintaining the same angle of view with any chosen focal length, as different aspect ratios are selected.
Given the increase in pixel count, the expansion of the camera's sensitivity range – now from ISO 160 to 12,800 – may concern some, although Panasonic claims that revisions to both the sensor and processing technology mean that the camera can nevertheless turn out images with less noise than the GH1.
Specifically, changes to the architecture of the sensor are said to improve signal to noise ratio, while separate applications of noise reduction to chrominance and luminance noise allow for more effective noise reduction for different areas. Also, with three CPU's handling processing, Panasonic claims that its Venus Engine FHD boosts speed and performance in general.
In good light the LCD screen displays its feed with clarity and plenty of detail, and maintains good stability even when longer focal lengths are used. The same is also true of the upgraded live-view finder, now a little wider and at 1.533million dots, which does an excellent job of displaying detail right up to the corners and edges, and with no unsightly artefacts common to many other electronic viewfinders.
Understandably, as lighting conditions drop so does the performance of the two, but it's impressive how quickly the feed stabilises itself as the camera moves around a scene. Not only that, but even in darker shooting conditions the amount of noise visible on either device is surprisingly minimal.
Next to the same images presented on a calibrated monitor, however, the LCD can be a little cold in its reproduction of colour; quite how significant this is is debatable, although it's perhaps worth remembering when selecting white balance options in camera.
Panasonic has also made some noise about the GH2's focusing capabilities, and put to the test it's hard not to be impressed. With the Lumix G Vario 14-140mm f/4.0-5.8 optic fitted, the camera is able to swing from one end of its focusing scale to the other in a similar time to that of a comparable DSLR and optic.
AF tracking is also available in conjunction with continuous focusing, and as on previous Lumix models it does an excellent job, staying with the target as it travels around until it moves towards the peripheries of the frame.
During the test the only time the system was thrown off course was when shooting a white duck in a pond, as it became confused by the similar intensity and movement of surrounding reflections, but even here the system did brilliantly to keep track on most occasions.
Thanks to its far-reaching AF-assist light, the system continues to shine in poor lighting conditions, although it's here where it shows its shortcomings too. If the focusing point has been selected the camera generally can get it right, and get it right fairly quickly too, although when left to its auto setting it either struggles to work out where it should focus, or alternatively, claims to be in focus when it clearly isn't.
Whether it outclasses the performance of a DSLR in this area - as Panasonic claims - is debatable, but it can certainly hold its own in good light, and it does pretty well the rest of the time. Just that it can manage to compete with its DSLR peers is praiseworthy in itself, when you consider the physical disadvantage of its contrast-detect AF system.
Movie recording is arguably what the GH2 is all about, and the system makes a positive impression. The GH2 records full HD footage at 1920x1080 at 60i/50i for NTSC and PAL systems respectively, while 720p footage is recorded and output at 60p/50p.
For cinematic results straight out of the camera, a new Cinema Mode captures at 24fps, while stereo sound is recorded the camera's internal microphone as standard. A port for attaching external microphones is included, as is a HDMI output for transferring images and videos out of the camera.
Viewing video footage on the camera's LCD screen - both while recording and in playback - is a pleasure, thanks in part to the clarity and contrast of the screen itself, but also to the smoothness of the video. Moving subjects, or the camera moving in relation to some subjects, does introduce a touch of smearing, but otherwise subjects are captured well and with plenty of detail.
Just how smoothly the camera captures video is only apparent when the footage is viewed on a larger display, where the quality of sound recording can likewise be appreciated. With the 14-140mm optic there's with no distracting whirring from the lens's focusing motor, although certain situations do benefit from changes to the sensitivity of the camera's microphone and the wind cut filter, to cut down on ambient noise.
How the camera brings subjects into focus is likely to be a contentious issue. The priority is placed on speed rather than a gradual fluidity between focus on different areas, in contrast to Sony's SLT system, for example, whose cameras attempt to bring subjects into focus with a little more discretion.
Of course, this is only really relevant when the camera is left to its own devices, and it's less of a problem if the subjects all fall within a certain range of distances. Videographers using the camera in any professional capacity are also more likely to give greater consideration to the right lens choice for their requirements, manual focusing and so on, which again makes this less of a concern.
The relatively small sensor and comparatively poor availability of wide-aperture lenses does make it harder to isolate subjects in the way a full-frame camera can manage, although with a plethora of adapters now available for mounting many older objectives, this latter point too is surmountable.
Finally, although three guide line options are selectable from the menu system, the omission of an electronic levelling function is a disappointment, particularly as the articulated LCD means that the camera is likely to be held in unorthodox positions. This is fast becoming a standard feature on DSLRs and high-end compacts, so hopefully it'll make an appearance on future Micro Four Thirds models too.