What follows is not a review, per se. It's just some knee-jerk impressions of the highly-anticipated Lumix GH4 camera from Panasonic, from the perspective of a curmudgeonly still photographer and videographer.
I've rented the camera, along with a Panasonic 7-14mm f/4 zoom, for the week to use on a video shoot. I specifically wanted to use the GH4 because I needed to be able to shoot 4K video for the project I'm working on, and I needed to be able to mount a lens with a really wide angle of view. As far as this goes, the combination provided exactly what I wanted for the shoot, and so far, the video footage looks brilliant.
When I opened the box from the rental house, my first thought was that the body was quite large and heavy, especially considering that it's a Micro Four Thirds, mirrorless camera. In fact, the body is almost exactly the same size and weight as a Canon EOS Rebel T5i! However, the 7-14mm f/4 lens is much smaller and lighter than the Sigma 10-20mm f/3.5-4.5 I have for my Sony camera.
For most operations, the camera shares the paradigm of most modern DSLRs with video capability -- common photographic controls (shutter speed, aperture, ISO and exposure compensation) are hidden behind command dials and function buttons. The GH4 does add a fairly intuitive and accurate touch screen, but there's still no marked shutter speed dial or aperture ring. In other words, the very control layout I moved away from by switching to Fujifilm! So, from a still-camera-perspective, I don't really care much for the camera. From the perspective of video, the operation is as good as any DSLR. I've said before that I don't really care for using still cameras for video, though I can't argue with the quality of the video the camera records. Again, I chose this specific rig because it is the only camera/lens combination available that allowed me to shoot the video that I need for the project at hand. In other words, it's not just the right tool for the job, it's the only tool for this job.
The image above is a frame from the video I shot today, and clicking the image will let the pixel-peepers among you take a look at the image in all its glory. Grabbing a frame of 4K video from the GH4 gets you a 3840x2160 pixel image (about 8.3 megapixels), big enough to make a pretty decent print (about 7.2 x 12.8 inches at 300dpi, or 12x21 inches at 180dpi).
One annoying aspect of the camera is that I am not able to find manual exposure control for video recording. The camera did, however, appear to lock the exposure once recording was started. Using the touch screen, I was able to select an area for my exposure and lock it in.
An area where Panasonic has really got it right is in their WiFi implementation. It's very easy to create an ad-hoc connection to the camera from an iPhone 5 or iPad, and have full control of the camera, including a high-quality, real-time live-view. For video use this is really handy, as it provides an easy way to provide a "producer monitor" without having to dangle a cable off the camera. If a powered zoom lens is mounted, then focal length can be controlled from the remote device as well, making operation by a camera operator and assistant easy to set up.
That's about it for now. I've got the camera for another week, and I'll shoot some with it over this weekend -- both stills and video -- and post some results.