Panasonic’s flagship GH series of Micro Four-Thirds ILCs has developed a strong reputation as cinematography cameras, starting with the GH2, which had its firmware hacked to enable much higher bit rates than the stock model. The GH3, introduced last year, took many of the capabilities added by third parties and built them into the base camera. Last month, at the Consumer Electronics Show, Panasonic showed a prototype of a new GH that looked almost identical to the GH3 but supported 4K video. As of this weekend, we’ve learned the specifications for the new camera, called GH4, but not the price or release date.
The GH4 16.05 megapixel CMOS imager doesn’t break any records for still imaging, but it does support 4K video at both standard resolutions: Ultra HD (3840x2160 @ 30p,) the broadcast/video 4K standard and the resolution of consumer Ultra HD displays, and Cinema 4K (4096x2160 @ 24p,) the baseline standard for theatrical production, post-production and exhibition. In 4K mode, it uses IBP compression with I and B frames at 100mbps, while in 2K mode, it supports All-I compression at 200mbps.
The GH4 has an interesting (and confusing) approach to how it handles storage of 4K video: When using an SD card, video is stored in 8-bit 4:2:0, and is output to the HDMI terminal as 8-bit 4:2:2. If you remove the SD card and use an external recorder, the HDMI output is 10-bit 4:2:2. You can also opt for a dock (Panasonic refers to it as an “interface unit”) that provides two XLR audio inputs with LED meters, four SDI outputs (two of which are 3G) and a 12VDC power socket. The SDI outputs can presumably drive an external recorder and monitor simultaneously at 10-bit 4:2:2. The dock won’t win any design awards—it just about doubles the size of the GH4—but it does add the interfaces that professional users need (or are forced to add with third-party hardware.)
Panasonic’s approach to storing 4K video means that an external recorder will be a necessity. In this regard, Blackmagic Design’s Production Camera 4K (the camera most likely to be compared to the GH4) has an advantage, because users can insert a SSD directly into the Blackmagic camera, eliminating the need for an external recorder.
I have to admit that I’m disappointed with how Panasonic chose to implement storage on the GH4. It would have been nice to be able to use the camera in a handheld mode without a lot of additional hardware, but in 4K mode, the SD card is only good for proxy recording in 4K mode. (To be clear, you can store 4K video on the SD card, but if you're serious enough about 4K to put up with all the other issues you'll need to deal with in post-production--massive storage, faster PCs, bigger monitors, etc.--8-bit 4:2:0 won't cut it.)
Update (March 10, 2014): Panasonic has revealed prices and availability dates for the GH4. The GH4 body's suggested retail price is $1,699.99 (U.S.). The dock (officially called the DMW-YAGH XLR/SDI Interface Unit) is priced at $1,999.99. If you buy both the GH4 and dock as a bundle, it's priced at $3,299.99. I’d love to see a third party develop a more elegant (and cheaper) dock, but there may not be a big enough market for it to make financial sense.
The GH4 is one of the least expensive ways of getting into 4K, if not the least expensive way. However, as we’ve learned from Blackmagic’s cameras, inexpensive means compromises, and the GH4 is no exception. It remains to be seen if the GH4’s compromises are ones that you can live with.