S-mount (CCTV lens)

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An S-mount lens is a small lens used on CCTV cameras and webcams. It uses a male M12 thread with 0.5 mm pitch, and the mount has the matching female thread. Because they’re often attached directly to the sensor’s PCB, they’re usually called board lenses. They support sensor sizes from under 1/6 inch up to 1 inch (about a 16 mm diagonal). These lenses generally don’t have iris control. There is no fixed lens-to-sensor distance (no flange), so you must adjust focus manually. The small barrel size limits performance, and most S-mount lenses are relatively slow, around f/1.6 or slower. High-end CCTV cameras use C- or CS-mount lenses, which can have faster apertures like f/1.0.