I somehow managed (GAS) to acquire an early (1926-28) Box Tengor camera in great condition. But in trying to understand it I find that it is significantly more primitive than later versions, ie, that it has no focus adjustment. The later cameras have three focus settings but this one has none. So I guess that means that every thing from a certain distance from the camera is more or less in focus. Any idea what that distance might be? The camera does have three F-stops, F11, 16 and 22, so I guess that the smaller stops would give sharper focus. Any other advice for using this camera would be much appreciated.