Further Documentation - showmewebcam/showmewebcam GitHub Wiki

Good documentation on the inner workings of the hardware:

• Raspberry Pi Foundation Camera hardware page: Detailed specs of the cameras, general information.
• Picamera's Readthedocs: A bunch of interesting information, including the field of view explanation, mmal, etc.

Lens:

• Autofocus on the 16mm lens
• Commonlands' lenses review: Disclaimer: The author also sells lenses.

Code:

• Buildroot all-in-one manual
• Linux v4l2 docs
• UVC-Gadget docs
• UVC-Gadget code

Linux Composite-gadget:

• OpenWRT
• HackPi
• usbarmory

Some other interesting resources:

• Jeff Geerling's code/video
• Hackaday's post on Raspberry Pi webcam
• David Hunt's guide