Should I Use a 2.8mm or 4.0mm Lens? | XLR Security
LTS Platinum, Comparison Video - 2.8mm v 4mm v 6mm Lens Comparison Video w/ LTS IP Cameras - YouTube
ELP 8Mpixels USB Camera Sony IMX179 Sensor HD PC Webcam With UVC Fixed Focal Length Manual Focus Webcam For Windows, Linux,Android (4mm/6mm/8mm optional) [ELP-USB8MP02G-MF40] - $70.40 : ELP USB Webcam