Take advantage of some of that great old vintage glass! D-mount lenses were commonly used on 8mm film cameras – which means they are pretty much a perfect match for the sensor size of the GoPro! They’re also very commonly found online for reasonable prices. Most D-Mounts work best on CS-Mount and will not require the use of the 5mm C-Mount spacer that comes with your Back-Bone camera.
1 x D-Mount to CS/C adapter