If you want to adjust and monitor the camera view manually then you can use a manual zoom lens. Most of the PTZ’s have this option. If that is an expensive option then you can go with a normal zoomable lens. For example, a normal 2.8 ~ 12mm zoom abled varifocal lens can secure a wide angle of 2.8mm and 12mm narrow. So, it depends on the versatility and requirements of surveillance.