As long as the objects can be seen by the camera, there is no maximum/minimum distance at which the camera can detect the objects and make the associated features be part of the map. However, the farther the objects are, the less accurate is the triangulation (because the pixels move less from one frame to the other). We would safely say, for objects farther than 30 meters, that the mapping could be an issue, but it is pretty rare that in indoor use-cases there is no other single object (and thus features) visible at less than 30 meters.