Gearing up for 4K
All the video functions of the GH4 are welcome, of course, but the standout feature of the camera is its 4K capability.
As we are based in the PAL world, most of our tests – and all our paid for work – with the GH4 has been in UHD mode, as this allows 25 fps rather than 24fps recording.
Such is the quality of Panasonic’s 4K that we’ve felt little need to record in HD; Panasonic’s UHD recording mode is not especially storage hungry and records without any problems to a good-quality 95mbps SD card (Panasonic recommends higher-speed, U-3 cards for a 4K, but in practice a U-1 card seems fast enough for UHD).
In fact, we’ve found – and other reviewers seem to agree – that the sweet spot for the GH4 is to record in UHD 4K and down-res to HD in post. Again, the camera produces files that are not too demanding on most editing applications, given their resolution. The bitrate for both 4K and UHD is 100Mbps, IPB mode.
There is also the option of cropping in on the 4K recording to re-frame in post. This is a highly useful feature, and whilst it comes at the expense of some sharpness and detail, the loss is more than acceptable in most cases – and it makes the GH4 far more versatile than APS-C or full-frame DSLRs.
By cropping in on a 4K frame in post, the GH4 can cover more camera angles, or work with a smaller selection of lenses, which is great for travelling. Our IBC footage was filmed with just two lenses, the 35-100 f2.8 and the Panasonic 20mm prime.
Higher bitrates – up to 200mbps, all Intra, – are available for potential HD broadcast use, as is AVCHD for more economical recording. EU buyers of the GH4 should note, though, that the camera is limited to a 29 minute 59 second recording time, internally (this does not apply to external recorders or a feed out from the YAGH).
One reason the 4K recording mode has proved popular with film makers is it provides a full-sensor read out (a 1:1 crop) without pixel binning or scaling, maximising the potential of the sensor. Potentially this gives the GH4’s 4K mode a better image quality than either its 1080p modes or than was possible on the GH3. Practical experience using the GH4 bears this out. It does, though, result in a 2.3x lens crop factor.
Next: Image quality and samples