The new 4K-shooting Panasonic GH4, which should arrive sometime next month, has gotten quite a bit of attention, not just because of its specs, but also because of its price. Unfortunately, there have been some confusing details about what the camera is actually capable of doing without the expensive add-on grip, the YAGH Interface Unit, which adds XLRs, 3G-SDIs, and a full HDMI port. Thanks to Zacuto, we've now got some better details from Panasonic about what the camera can really do.
Here is Panasonic's Matt Frazer talking with Steve Weiss and Jens Bogehegn from Zacuto about the new GH4:
Something that has been a little confusing at the outset was whether the camera was capable of outputting 4K from the HDMI, or whether you needed the interface unit. That is cleared up nicely in the video, and it is confirmed that while the GH4 will only give you 8-bit 4:2:0 in 4K and 1080p to the SD cards, it will give 10-bit 4:2:2 4K and 10-bit 4:2:2 1080p from the HDMI port on the camera. There aren't any 4K HDMI external recorders just yet, but something like the Convergent Design Odyssey 7Q could theoretically get a firmware update to support it. The HDMI is completely selectable to whatever frame rate you need it to be, whether that's 24, 25, or 30fps.
If you want to use the YAGH interface unit (which will need some sort of external power) to get the 4K from the 3G-SDI outputs, the Odyssey 7Q and AJA Ki Pro Quad may also support it at some point as they both have 4 SDI inputs and are already capable of 4K with other cameras (that's if they can't take the signal natively right away, which is possible).
Rolling shutter will also be improved over the GH3, and dynamic range should be better. Matt mentions that it should be safely 11 stops of dynamic range (possibly as much as 12), but it's unclear whether this is in a standard color profile, or in some sort of log/CineGamma mode. The last thing that really needs to be clarified is how this camera will output flatter profiles to preserve more dynamic range. Since you have the ability to get 10-bit 4:2:2, recording in log makes sense on this camera, as you have more room to push and pull the image in post. We know that the camera will have some sort of additional color profiles, but we don't yet know how flat they will be.
In terms of native ISO, Matt says that ISO 800 is equivalent to 0 dB in the camera, so that could be where the Panasonic engineers see the most dynamic range with the least amount of noise, or it may be where they think video shooters will be happiest with the image in terms of balancing noise, dynamic range, and sensitivity.
Lastly, Steve mentioned that Zacuto is trying to come up with some sort of rig that will give you servo zoom from a handle with still lenses, so we'll have to wait and see at NAB to learn more about that. For those running one-man-band operations, that could be an interesting and incredibly useful piece of kit.