The advantage to CCTV-C/CS Mount camera is that lens can be changed. If you need to see further than 35 or 40 ft the you can see camera with a special lens. Lenses of this cameras are available from 4mm to 50mrn. A 4mm lens provide facial detail and 70 degree angle if view focused upto about 35ft. An example of where you might use a fixed 4mm lens is in a small office to focus your driveway. A higher millimeter lens will provide further distance but narrows field of view. So, a 16mm lens would provide about a 15 to 20 degree angle of view at a focus distance of about 35 ft. So, the best option is to use vertical lens.