In averagely-lit conditions, raw images display no visible noise up until around ISO 800 where slight coloured patches begins to develop in shadow areas. Noise levels continue to rise steadily until ISO 6400 where dense chrominance noise begins to obscure details, and this becomes particularly heavy at the maximum sensitivity of 12,800.
Despite this cast, images details are still visible, just obstructed rather than destructed. For such a densely populated sensor, it's remarkable that images are able to maintain such quality at these settings, although, predictably, any attempts at processing away this noise require that some detail be taken with it.
In-camera JPEG processing does an excellent job of removing virtually all chroma noise from high-sensitivity images, though images lose a little of their bite because of this. Even so, the overall standard of JPEGs is above average, with fine details compromised to a lesser degree than perhaps expected.
We found JPEGs also show pleasing and accurate colour, with the Standard Film mode providing a welcome boost in contrast over Raw files. The choice of black and white modes is also sure to please monochrome enthusiasts, particularly the Dynamic Black and White option which produces high-contrast, atmospheric images straight out of the camera.
Exposures are balanced and consistent in a range of situations, and even when challenged with tricky scenarios the metering system can only be persuaded to slightly underexpose. The camera's auto white balance system can also be relied upon to provide consistent results in natural lighting, although some may find the more faithful results lacking a little of the punch of other cameras, where images are optimised a little to be more pleasing to the eye.
Under tungsten lighting the camera does impressively well and records the scene as it appears, and even under a mixture of different sources the camera makes good judgements as to an agreeable balance. Only certain fluorescent sources seem to lead the camera's auto white balance astray, although in this respect the GH2 is hardly alone.
The camera is available with the Lumix G Vario 14-140mm f/4.0-5.8 lens as part of a kit option, and not only does it offer a capable focal range but it proves its worth as an all-purpose lens. Its detail resolution is excellent, particularly at the centre of the frame, and sharpness is maintained at slower shutter speeds thanks to the lens-based MEGA OIS image stabilisation system.
At its telephoto extreme, the system produces sharp images at up to 1/25sec with ease, and even manages a few reasonably sharp results at 1/13sec. When the focal length conversion of the Micro Four Thirds system is taken into account, the represents an advantage of between three to four stops of usable shutter speed past the usual limits, which is on a par with comparable systems.
Panasonic GH2 ISO performance - Raw files
Panasonic GH2 ISO performance - JPEGs