The GH3 is a well-built camera that's very nice to handle. Build quality has largely been improved here and there's a new all-weather finish. As a result, the GH3 is pretty chunky, looking more like a mini-SLR than an interchangeable lens compact. The rubbery finish feels comfortable to handle, and the new control layout is pretty intuitive. In fact, the row of three buttons just next to the shutter-release (ISO, white balance, exposure correction) is reminiscent of certain Canon SLRs. We even sometimes mistakenly found ourselves looking for a second LCD info screen on the camera's shoulder—there's no sign of that in the GH3, though!
The updated interface has two settings thumb-wheels, a notched settings wheel around the four-way arrows, a couple of settings dials (exposure modes, drive mode, etc.) and a whole load of customisable controls. There are no less than five physical Fn buttons, plus two virtual Fn controls on the screen. Unfortunately, the functions you can assign to the various Fn keys vary from button to button. For example, Wi-Fi is automatically attributed to Fn1 but can't be set to Fn5. Such limitations are quite incomprehensible, but a simple firmware update could no doubt put them right.
The electronic viewfinder has been updated here too, ditching the sequential LCoS display and its inevitable rainbow effects for a nicely defined (1,744,000 dots) OLED screen that's really quite effective. In good light, the image is smooth, precise and nice to view. In low light, you do start to get some glitches. We weren't able to measure colour fidelity in the EVF during our test. Some users will love the fact that so much information can be overlaid onto the EVF (histogram, electronic level, live white balance and exposure views, etc.) and the fact that you'll still be able to see what's going on in darker conditions. Others, however, clearly won't appreciate having this electronic screen between their eye and the scene being photographed. It's ultimately a matter of taste.
On the back of the GH3, you'll find a full swivel screen that flips out from the side of the camera. It has 614,000 dots (OLED) and is gives good performances, with high contrast levels and relatively accurate colours, even if they are a little on the cold side.
One of the things micro four-thirds cameras have long been criticised for has finally been resolved in the GH3—the noisy shutter release. Lumix G-series cameras were always a bit on the loud side until Panasonic decided to integrate an optional electronic shutter, making them a heck of a lot more discreet. In fact, when used in this mode, the GH3 is pretty much silent—nice work Panasonic! Note, however, that in this mode ISO sensitivity is limited to 1600 ISO and the flash can't be used at all. Then again, if you're looking to shoot with discretion you probably won't need it.
Finally, the GH3 comes with loads of handy connections, including a microphone entry, a headphones out, an HDMI out (uncompressed, for video), a flash sync port and a USB 2 connection (there's still no sign of USB 3 in the world of micro four-thirds cameras). The GH3 has also been brought bang up to date with built-in Wi-Fi (see inset). The only thing we really think is missing is a second memory card slot, which could be handy for separating photos from video, for example.
The Lumix GH3 doesn't disappoint in this field, with a contrast-detection autofocus that's still very good and a start-up time of not much more than a second. We've got no complaints there. The autofocus works perfectly in video mode too, proving perfectly smooth and fluid. A 6 fps burst mode is on hand for continuous shooting. Better still—in electronic shutter mode, the burst can be upped to 20 fps (JPeg shots, 4 Megapixels, no autofocus tracking).
The GH3 has a new MOS sensor that can shoot images of up to 4608 x 3456 pixels (16 Megapixels) in a 4:3 aspect ratio. This unfortunately isn't a multi-aspect ratio sensor, so the different image formats (16:9, 3:2) are resized from the 16-Megapixel, 4:3 sensor. Definition therefore changes with each image format, as does the angle of view.
The new sensor is particularly effective at handling digital noise, shooting very good-quality images up to 3200 ISO. Quality soon drops in Jpeg shots taken at any higher ISO settings. In fact, Panasonic has taken its own precautions by limiting the ISO Auto setting to 3200 ISO. When shooting in RAW mode and using decent RAW processing software, shots taken at 6400 ISO will be usable.
The 14-140 mm standard kit lens is a more than decent piece of kit, giving good levels of sharpness with very quiet motorisation. Plus, Panasonic has become something of a master when it comes to correcting optical defaults on the fly with its internal software. Here, vignetting, chromatic aberration and distortion are all practically invisible.
Video is a flagship feature of Panasonic's GH series and, true to form, the latest model is packed with plenty of attractive options. The Lumix GH3 can record AVCHD video at 50, 25 or 24p and up to 28 Mbps (note that in some regions you get NTSC at 60 or 30p instead). In .Mov mode, the GH3 flexes its muscles with All-I encoding (frames are compressed independently to facilitate post-editing) at 50, 25 or 24p and up to 72 Mbps, a bitrate not yet seen in an SLR! Plus, the HDMI output is uncompressed. You can therefore record 4:2:0 8-bit video onto an external recording device to optimise quality or to broadcast directly. With a video mode like this, the GH3 moves way ahead of most of its competitors to become a real star product. Note that slow-motion and high-speed modes are available and that you can take a still photo while filming video.
While the autofocus works like a dream with the 14-140 mm lens, we do think it's a shame that Panasonic's engineers didn't think to include a peaking function to highlight sharp parts of the image when focusing with manual lenses. A zebra function could also have been handy to make sure subjects are properly exposed. Finally, a picture profile like Technicolor CineStyle could have made a nice addition to help optimise the dynamic range.