Tesoo 4.5 mm lens not only extends the focal length of a camera, but also amplify its angle of field. The sensor size of 4.5mm lens is 1/2.7'' and 1/3''. TTL: 8.47mm. EFL: 4.60mm. F.NO: 2.6. MBFL: 1.48mm. Get 4.5 mm lens price from Tesoo, the leading cctv lens manufacturer now!