I bought a Phantom 4. I flew the drone a couple of times and then I started to record videos. The videos recorded with the Phantom 4, if compared with those recorded with my Phantom 3, have a very poor quality, thery are blurry and with many other defects and imperfections; this is anacceptable because the Phantom 4 is a new product and should be better and improved then the old one. The video settings of the P3 and P4 are the same, the 3d noise reduction in the P4 has been disabled. The P4 lens has been checked and cleaned as well as the UV filter lens. I use Sandisk Ultra, that are high quality micro sd cards, and I tried many of them. I strongly hope that this problems affect my Phantom4 only and I ask at dji to replace my Phantom4 with a new one, promptly tested before shipping because of urgent work reasons. Setting: 4k 3840x2160 ntsc 29.97 or pal 25 - white balance auto or sunny, mov or mp4, default for other settings.
I attach a video that compares P3 and P4 with same settings:
I looked closely at your footage, and the first thing I noticed is that all the Phantom 4 material was very much under-exposed. Shooting into the sun at the end of the day is difficult to control and you will find it hard to expose it properly.
Other than that, I could not see any problems, and where the arrows indicated I could not see anything. The camera on the P4 is exactly the same as the P3, just with a better lens, but there also seems to be some changes to the MPEG encoding that can introduce macro-blocking on fine detail, however I did not see any evidence of that in your clip.
Picture quality is subjective, so no two people will agree on it, but describing it in your title as 'poor, out of focus and unstable' does not make sense. Poor? Maybe, that is an opinion. Out of focus? Nope, could not see any out of focus sections. Unstable? Unstable how?
If you don't see the video in high quality and without 4K monitor, you can't see the areas out of focus. I'm using the p3 from one year and in all light conditions and doesn't have any of these problems.