Panasonic Lumix GH2 review
Panasonic Lumix GH2 review - Performance
In use the GH2 has its high points and low points: The most prominent and positive feature has to be the sheer speed at which the contrast-detection autofocus system can operate. It's near instant, doesn't over- or under-focus to a great degree and is generally very reliable indeed. It's so much faster than before that it's impossible to overlook just how much better this system is. Saying that, the standard 23-area array for focusing is still very centrally-arranged over the sensor, which vastly limits the focus sensitivity towards the frame's edges. Bringing up the focus areas immediately shows the out-of-bounds border box to the outer edge of the LCD screen, which doesn't option as much versatility as, say, the Nikon D7000's 39-point AF system has available at (crucially) a very similar price point. In single focus the Lumix GH2's green focus box is very prominent to represent where focus has been attained, while in continuous focus this presence can be far more intermittent. Furthermore continuous focus can ‘flutter' at rapid speed in and out of absolute focus, particularly when shooting at more telephoto focal lengths and even when subjects are relatively stationary.
However the way that the GH2's focus point can be selected using the touchscreen is fantastic. A simple light press of the finger and you'll see the focus areas move accordingly - it's even possible to quickly resize the focus area for more accuracy without any need to digging through menus. This comes into an even fuller effect in movie mode, where pressing the focus point on a subject and then to the background performs seamlessly smooth focus transitions.
As previously mentioned, the GH2's sensor has double the refresh rate of that in the GH1 (it now runs at 120 refreshes per second rather than 60), and this doesn't only benefit the autofocus system, but also the fluidity of the electronic viewfinder and LCD screens too. Fluidity is certainly an improvement, but there's still no getting away from lag and a ghosting-type lag that's prominent when panning in lower light. It's one of the relatively unavoidable downsides of an electronic viewfinder system, something that a DSLR's optical system does not suffer from. And yet the GH2's electronic viewfinder is actually very successful in what it does. The 100% field of view is great to have and the physical size of the viewfinder itself is generally very impressive, plus the 1.53m-dot resolution (852x600px) is certainly as high as they currently come. In good light it's a pleasure to use, but it's in dim conditions or when panning that it can become a downside. However, test it out in your local camera shop to decide whether or not it's for you or not: it's tricky to convey just how different the systems are or, indeed, how much better the EVF systems have become over the last few years.
The GH2's LCD is a similar story to the viewfinder in terms of lag and, while the increased colour gamut is a step in the right direction, there are still some subtle issues in what the LCD's exposure and colour balance shows compared to the final image on a computer screen. Unlike many fixed screens on competitor cameras, the GH2 has a vari-angle screen which brings a variety of benefits: it's possible to stow the screen face-down against the camera for protection, while the variety of angles means shooting is possible from innumerable points of view for self portraiture, overhead, waist level and similar shots.
The GH2's 5fps burst mode successfully captured a consecutive seven Raw + JPEG frames before a brief pause and capture of the eighth. Pop the camera into ‘SH' burst and it can capture 40 frames in under a second at a lower 4MP resolution that's then presented as a stacked slideshow in the playback menu (individual images can also be extracted).