Ooh, hehe, just ask since got posted the related picture.

As I read before, it's not accurate and it needs to be tuned every once in a while.

I bought the digital hygrometer, I tried measure the humidify level inside the camera bag in the cupboard before, the humidity level is below 45. The digital hygrometer will also record max humidity level and min humidity level so you can check what's the highest humidity level and what's the lowest humidity level. So far, seems it's below 45.

He's using the Nikon1. It comes with Hybrid AF.
Anyway, mirrorless is known to have smooth, fast, and accurate AF especially for videos. Even Sony's SLT have super fast and smooth autofocus for videos.

For Nikon1, you can watch some YouTube demo and comparison. They tested and compared it's autofocus mode (tracking) for moving subject against the Panasonic G series, it's very fast and accurate.

Not really sure about the sound, but if not wrong, they have a special lens for movie which supposed to be silent and have smooth focusing.

As for manual focus, I'm not sure how Nikon1's lens. I think it's not easy to use manual focus with the lens. Even for DSLR, it's not easy to do it and manual focusing can introduce "shake"; When I took video previously with DSLR, I try to minimize touching the camera, so I fix the focus instead.