The GH3 is arguably the most capable video camera we've seen as dpreview, so we asked EOSHD's Andrew Reid to assess its capabilities, its quality and the experience of shooting with the GH3 from a videographer's perspective.
Codec and recording modes
The recording codec is one of the most important features for videographers and filmmakers - along with the ability to have full manual control in video mode.
One of the GH3's main rivals for stills, the Olympus OM-D E-M5 is an example of a poorly implemented video mode - it lacks the traditional film frame rate of 24p, uses an NTSC video standard in PAL countries and has very heavy compression, resulting in an image which falls apart on a regular basis - especially with fast action, handheld footage and when colour is adjusted in post. Panasonic has excelled in understanding the needs of video users and is a model for other manufacturers to follow. The GH3 has the most extensive range of recording options and frame rates available on any consumer camera and extensive manual control in video mode.
The ALL-I option of the codec mimics the one found on the 5D Mark III and as with that camera I find a negligible difference between ALL-I and the standard long-GOP recording mode (IPB) in terms of image quality. In some cases the 50Mbit bitrate of the GH3's IPB mode is actually spread less thinly than the 72Mbit higher bitrate in ALL-I mode resulting in very subtly better image quality at 50Mbit.
The use of Quicktime H.264 MOV as a high quality file format is a new feature on the GH3 and something I use all the time. AVCHD is still an option but Quicktime MOV makes for a more sensible folder and file structure on the card and easier editing with a wider range of video editing software.
The maximum frame rate has doubled over the GH2. 1080/60p is useful for slow-motion as footage at 60fps can be conformed to the cinema standard 24p in post (50p and 25p in PAL countries) for smooth flowing slow-mo (there's even an option in the camera to do just this), though it would have been nice to see the addition of 120p in 720p mode like on the Panasonic FZ200 bridge camera.
Focus and exposure
There's no built in ND filter or focus peaking on the GH3, despite it being so hospitable to video shooters. These seem to be features reserved for higher-end, dedicated models like the Panasonic AF100 and Canon EOS C300 but I consider them two of the fundamental basics for shooting video. The mass-market Sony NEX models have focus peaking so it's harder to justify its exclusion from the Panasonic.
Both can be added to the GH3 but not without compromising ergonomics. A variable ND filter can be used to allow the relatively long shutter speeds that video demands (1/48th or 1/50th sec for 24fps shooting) and focus peaking can be added on a monitor or EVF connected to the camera via HDMI. A vari-ND filter has the drawback of changing the look of reflective surfaces, so if you're shooting something like a car commercial you have to use standard NDs.
Manual focus aids
Filmmakers prefer manual focus for more control and more predictable results, since auto-focus has a tendency to unexpectedly wonder off during a shot when a subject moves. AF is great for stills but cannot yet reliably track motion, and unintended focus shifts look amateurish. Oddly all the manual focus aids on the GH3 are optimised for shooting stills and none of them can be used at the same time as recording video, making manual focus pulls more difficult and less precise without an external HDMI monitor.
New to the GH3 is timecode. It embeds metadata in the clip, a precise run-time counter, so that on a multi-camera shoot you know what the chronological order of a scene should be in your edit and can coordinate action to the split second. The time code can be displayed on the LCD in video mode and can run when you hit the record button or continuously in 'free run' mode whilst the camera is switched on. It works well but the video record button on the GH3 appears to be less responsive than it ideally should be. There's a lag of 1 second from when record button is pressed and recording begins. More annoyingly there's a 1.5-2 second curtailment at the end of the clip so if you stop recording a stopwatch on 10 seconds, the end of the clip will show the watch on 8.5 seconds meaning you're likely to miss some action accidentally. Hopefully this can be solved in a firmware update.
The more standard 3.5mm mic jack is an improvement over the GH2 which used a very unusual 2.5mm mini-jack. There's also now the edition of a headphone socket like that found on the Canon 5D Mark III, (though not on the $2000 Canon 6D!). Audio monitoring via headphones can be performed by the camera in real-time or as it is recorded to the video clip. In 'real-time' mode, camera settings such as mic gain are not processed. In 'record sound' mode the audio is processed but there is a short lag between reality and what you hear down the headphones. Audio mic levels are displayed and adjustable on the rear screen, giving access to a wider-than-average 19 levels of sensitivity.
HDMI on the GH3 is full screen, full HD 1080p. This is an advantage over the 5D Mark III which has an HDMI output of 720p and a year-long wait for a firmware update that addresses the shortcoming. The HDMI output on the GH3 can be made 'clean' - the display button toggles an output with no overlays so it is suitable for recording on an external device. Unfortunately there's no real image quality advantage to be had from recording this way. The HDMI recording is slightly softer than internal recording and colour remains sampled at 4-2-0 with an 8bit colour-space.
For monitoring the HDMI output remains on during recording to the SD card so full marks there. In common with all video capable DSLRs the mini-HDMI socket is more designed for cabling up a TV than for use 'in the field' whilst shooting - it doesn't feel robust for connecting external monitors and EVFs. Given that the lack of focus peaking necessitates the use of an external monitor in many cases - I feel a more robust video output port would be an advantage.
Unlike most Canon and Nikon DSLR lenses, the Micro Four Thirds system includes some enthusiast-grade lenses with stabilisation suitable for video. The optical image stabilisation mechanism of most Lumix lenses is not picked up by camera mounted microphones. Sadly, the GH3 doesn't offer anything to match the Olympus OM-D's in-body stabilisation that is effective with a vast range of lenses. However when it comes to most video shoots the most aesthetically pleasing stabiliser is still a tripod or a shoulder mounted rig with handlebar.
The GH3 is a significant step up from the previous GH-series cameras in respect to the body. For video users it is good to see the SD card slot remain on the side of the camera rather than go in the battery compartment like on many other mirrorless models, so you don't have to dismantle a large motion picture rig upon changing media. Also helpful is the fact that the tripod socket is aligned with the centre of the lens mount but there's still no camcorder style hole in the base for an alignment notch, meaning the camera is liable to rotate on a quick release plate if a lot of rotational pressure is put on the camera body.
In terms of finish and materials the GH3 still does not feel as professional as a 7D and I think the overall build can be improved further. The gap in build quality to the 5D Mark III is forgivable as there's a price difference of nearly $2000, however the gap to the 7D and D7100 is something which should be addressed. It is also fair to say the camera has a few handling quirks. Whilst handling overall benefits from a larger body than the usual Micro Four Thirds offering, the edge of the rear grip gets in the way of operating the rear dial plus the HDMI and headphone outputs get in the way of the screen when it is articulated outwards and rotated upwards. The camera lacks the tactile raised rubber buttons of the Olympus OM-D or the cold alloy feel to the touch of that camera. So though a good step forward I feel there's still a lot which can be improved.
You can read more about Andrew Reid's findings over at EOSHD.com