What are M12 (S-Mount) lenses?

M12 or micro-video imaging lenses are typically board lenses that are small and feature an S-Mount type camera or lens mount. The S-Mount is a standard lens mount used in machine vision and M12 refers to the metric thread type with a nominal diameter of 12mm, a pitch of 0.5mm (M12 x 0.5), and without a standardized flange distance (see The Anatomy of a Lens) as many other mount type have including the C-Mount and TFL-Mount for example. These lenses are often ideal for space- and weight-constrained applications including OEM implementation, CCTV, and other board-level cameras. Additionally, M12 lenses are low cost alternatives to standard-sized fixed focal length lenses. For more information on imaging lenses and their differences, read Types of Machine Vision Lenses.