The GH4 is a great little camera that has held up reasonably well, with one repair for the rear thumb dial after 2 years of daily use. I'm not a low-light shooter in most cases so the noisy performance at ISO 1600 and above wasn't a problem for me. The only other issue that bugged me was that it always seemed that the audio was out of sync by about 2 frames. Maybe that was just my copy or perhaps it was a setting that I never figured out. Not a huge issue since I generally used a slate or clap to manually sync sound to the video.
But aside from those two main factors, I really, really love the GH4. It helped me produce a lot of content that my clients appreciated.
I like its color science straight out of the camera and almost never find myself doing secondary color corrections to pull the look back into reality. I generally find myself shooting with the Neutral profile with the contrast, sharpness, and saturation reduced a couple of notches. I turn off all of the other little gizmo features like the i.Resolution and i.Dynamic. Those just made the footage look unnaturally crunchy and over-sharpened and flattened them without a much benefit, even with post color correction and grading.
The battery life is quite good, and I find that I can get through an entire production day with 2 or 3 batteries. The 4:2:2 10 bit color which I record as ProRes using an Atomos Shogun makes my post workflow much smoother, especially with 4K footage.
So I was excited when we finally heard the GH5 announcement. For me the big news was the ability to record 4:2:2 10 bit internally, in-body image stabilization, and a full-size HDMI port. There are lots of other little additions as well including waveforms and dual SD card slots. This makes the GH series even more helpful to me at a practical level. Now I don't need that massive Shogun and a huge Anton Bauer battery attached to my rig when I need to fly the camera on a gimbal or travel light.
So last night, I brought home a new Panasonic GH5. I used it in my most recent episode to shoot some of the insert shots and b-roll. I'm obviously not ready to do a full review or even a give my high level impressions aside from saying that it seems really promising. Everything feels right and the footage it produces is every bit as good as I would expect. The in-body image stabilization looks good with a very short informal test.
The GH5 looks like it will be a good, solid B camera for me, and an A camera when I need to keep things light, like when flying the camera on a gimbal or going to a job where we won't have the luxury of lots of set-up or strike time before and after the shoot.
I have the Panasonic XLR audio interface on order with B&H and will be testing that when it ships in a few weeks.