Hands-on review
With a Panasonic G-system camera with a 4K designation tucked safely away behind glass at the CES expo in January, the launch of the Lumix DMC-GH4 perhaps comes as no surprise. Of course, the ability to shoot 4K video footage is the camera’s key feature, which is impressive given its size. However, this doesn’t mean that the small micro four thirds CSC is only for videographers, and Panasonic was keen to tell us more about the GH4’s still imaging capabilities.
Key features
Although the GH4 has the same 16.05-million-pixel resolution as its predecessor, the Lumix DMX-GH3, it does in fact house a brand-new sensor. According to Panasonic technical representatives, new semi-conductor production technology introduced since the GH3’s launch has helped to improve imaging sensors, resulting in less image noise and a wider dynamic range. With many APS-C sensors now offering resolutions in excess of 20 million pixels, the resolution of the GH4 seems to be a little low; however, in practice, the improvements made to the sensor to increase dynamic range and reduce noise should help to compensate for the slightly lower resolution. It is also worth remembering that 16.05 million pixels is still more than enough resolution to produce a good A3-sized print.
Also helping to improve image quality, and required to handle the processing of 4K video footage, is a new quad-core processor that forms part of the Venus engine image-processing system. This new system enables a 1EV increase in sensitivity from ISO 12,800 in the GH3 to ISO 25,600 in the GH4.
The faster processing engine also helps to improve the speed of the camera, enabling it to capture bursts at 12fps, or 7.5fps with continuous focusing. Speaking of AF, the GH4 has a new system, named DFD (Depth from Defocus). The GH4 firmware contains a built-in database of all existing Panasonic lenses, and the camera will be able to estimate how out of focus the lens is and thus focus it accordingly. Contrast detection then fine-tunes the precise focus. All of this happens at a maximum speed of just 0.07secs – at least, that is what Panasonic is hoping when the GH4 receives its final firmware.
The autofocus has also received an upgrade in the number of focus areas, with the GH4 now having a 49-area system compared to 23 areas on the GH3. Again, this should enable more precise focusing across the frame, benefitting those shooting both photos and video.
Build and handling
The magnesium-alloy body of the GH4 is almost identical to that of the GH3. It feels very comfortable to hold; in fact, I’d go so far as to say that, for my hands at least, the grip is as close to perfect as it could possibly be.
For more demanding users, the body of the GH4 is weather and dust-resistant, and the shutter life has now been tested to 200,000 actuations, which is about the same as you would expect from a professional DSLR. Battery life is now rated at 500 shots.
Video
The Panasonic GH series has proved extremely popular for both amateur and professional videographers, and with the GH4’s ability to shoot 4K video footage, this popularity looks set to continue. High-definition 4K video is captured at a resolution of 4096×2160 pixels.
The video capabilities are too much to go into fully in this overview, but the key points are all to do with the quality of the footage that can be captured. Not only is it of a 4k resolution, but video can have a bit-rate of either 100Mbps or 200Mbps, which is far in excess of the 73Mbps maximum bit rate of the GH3. This level of quality is actually in excess of what most television companies are setting as the standard for 4K video capture, so we could see footage from the GH4 used by broadcasters.
For professional users, there is also an optional Interface Unit for the GH4. Think of it as being like a giant grip that attaches to the bottom of the camera. Attaching this unit provides the GH4 with 2x XLR microphone sockets, as well as providing phantom power for microphones, microphone level control and sound level monitors. It also adds four SDI terminals, Micro HDMI output, a colour bar signal and an audio reference signal, as well as external time control so that a number of cameras can be linked together and their time codes synchronised.
It really is an extremely comprehensive video-recording camera kit, and I can see many photojournalists opting to use the camera to combine both still images and video capture in a single, small, lightweight camera. This is, of course, made possible by the four thirds sensor used in the GH4, which allows both the camera and, importantly, the lenses to be smaller and thus more travel-friendly.
New SD cards
Naturally, the quality of the 4K footage requires extremely fast recording to ensure that dropped frames don’t become an issue. As such, the GH4 is to be the first camera that will uses the new UHS I class III SD card format. These SD cards are capable of saving data at a rate of 30MB/s, which is around 240Mbps, and therefore so capable of capturing footage produced by the GH4
Mr Uematsu of Panasonic with the new Lumix GH4
Initial thoughts
At first glance, there doesn’t appear to be too much that is new in the Panasonic Lumix DMC-GH4 for the enthusiast photographer. However, the camera has seen a number of refinements over its predecessor, notably the faster shooting rates and improved AF. Quite whether these changes alone will be enough to warrant an upgrade for those who currently use the GH3 for photography, will depend on what the image quality is like on the final version of the camera.
We will have to wait until we test a full-production model of the camera to see exactly how much the new semi-conductor production has improved the image sensor, and the images that it produces, although the sample images we were shown did look impressive. Panasonic is still currently working on the final firmware, which will be loaded onto the camera for its launch.
