Fixed Camera Focal Length
What is the minimum and maximum focal distance of the camera?
How close can you get to a object before it is no longer in sharp focus?
We set the cameras to be in focus at a distance of about 4-6 inches which puts them in focus from there on out to infinity. The focus is however adjustable (by turning the lens) and you can focus in on closer objects, down to about an inch or two away.
As far as the maximum viewable distance is concerned, that's not really a focus issue. The camera is in focus from about 6 inches out to infinity. So an object at 100 feet is in focus. Whether you can discern any details at that distance is another issue. The naked eye could not recognize facial features at 100 feet. The camera basically sees what you see. How legible the image is also depends on the resolution of the TV you're viewing it on. As you can see, this isn't really a black-and-white subject (forgive the pun). It is very subjective.