With detachable lenses, focus is a mechanical adjustment, so there is a scale where you can set a focus distance which will be accurate. On film sets you see focus checked with tape measures! On permanent lenses focus is usual powered with a servo, and there is no direct mechanical link so the ring is just a rotary knob. Turn it one way, it focuses out and the other focuses back, but you need to do it visually. Sony introduced the XDCAM format quite a while ago, originally recording to special disks. The broadcasters lived it. The other format is newer and has some spec differences that's all.
