For a good introduction to lenses and lens geometry, see the Lensespage on the ArduCAM website. For details of all ArduCAM lenses, along with sample images and sample videos, see the ArduCAM downloads/Lenses archives.
ArduCAM has developed a new collection of high quality M12 Mount lenses. These lenses have an approximate angular field of view ranging from 10° to 200°. An excellent catalog describing each of these lenses can be downloaded here. These lenses sell individually, and collectively as a lens kit with a variety of mounting hardware. High quality, low distortion lensesare also available, with an approximate angular field of view ranging from 60° to 110°. Another excellent catalog describing each of these low distortion lenses can be downloaded here.