PTZ Controls: Focus Near/Far? What does that do?

[YrbkMgr]

I feel this is a stupid question, but I've spent a few hours trying to find out what "Focus Near/Far" does in the PTZ controls of the BI Console.

focus near or far.JPG (14.94 KiB) Viewed 2081 times

Is that function driven by the camera's capability (to zoom, e.g.)? Another way to ask I guess is... what does that do and what are the requirements for it to do it?

My Amcrest IP3M-943B camera specs say:

focus near or far-camera lens specs.JPG (27.46 KiB) Viewed 2081 times

I don't know what Focus Control = Manual means and the documentation from the camera's user manual doesn't address it.

Is Focus Near/Far in BI even relevant to that camera? Any help in understanding this is appreciated.

[TimG]

As I understand it, it is only for optical zoom, and only for manually focusing a camera that won't do it itself. My Dahua varifocal and the Dahua ptz's focus automatically after changing the zoom level - you can then see the focus changing in/out perfect.

[YrbkMgr]

thanks. that leads me to think that it's driven by the camera features, and mine don't have it. I can put that to bed now.