Channel Vision offers 3 types of 960H cameras, the 6404 which is a mini pinhole camera but that has a fixed lens so it could not be the camera you are looking at. The other two are the 6333-O 960H Bullet Camera and the 6822-W Eyeball Dome Camera. I am not sure where you saw the 4-9mm lens description however both of these cameras show a 2.8-12mm varifocal lens. This means you can manually adjust the zoom and focus between those ranges. By using a “Field of View Calculator” which you can find online and plugging in the numbers you provided the size in mm to capture that field of view would fall around 6mm. At 6mm the image captured is 45’ deep, 35’ wide, and 26’ high. You can zoom the camera in from the 2.8mm to 5/6mm to cover your desired field of view with either of the cameras mentioned above.