The Meizu M5s rear camera features a phase-detection AF support which helps improve the autofocus responsiveness and accuracy when shooting moving subjects. Great to see this high speed PDAF sensor feature in an low-priced mobile phone, which in China costs just 799 Chinese Yuan, which is approximately $116 as of the time of writing.
This feature is available due to the sensor technology of the Meizu M5s rear camera. I personally can't imagine shooting without it. The contrast-detection AF technology is really slow compared to PDAF, especially when shooting in dim light.
I've read that the rear camera uses a Sony 13-megapixel sensor. It might be the Sony IMX215 Exmor RS sensor that comes in tons of devices already, but I am not sure.
I overall think it's great to see that a cheap phone comes with a camera that is capable of supporting high speed AF performance. I think that in 2017 most of the mobile phones that we get to see will come with sensors that have this feature.
PDAF doesn't use the scanning process that moves the lens until it sees a sharp image like it works in contrast-detection AF system. This is why contrast-detection AF us jittering and slower, due to the number of number of times needed to shift the focus aback and forth until the subjects appears in focus. Phase-detection uses phase-detection AF points on the sensor. This like having two images split in to two, and once they are perfectly aligned, this tells the camera that the subject is in focus. It can also quickly adust the focus because it knows the phase difference between the two images. This is why phase-detect AF seems to focus almost instantaneously and can track moving subject really fast.
Here is a very short video that I've found on Sony's YouTube channel that demonstrate how fast phase detection auto focus is.
So when you buy the Meizu M5s, you can rest assured that the rear camera can focus really fast on moving subjects, no matter if they are close or far from the camera.