I remixed my own thing for two reasons:
Therefor I now designed a camera mount which consists of 4 parts: the camera mount, a separate 'pole', a camera enclosure front and back.
The camera mount snaps onto the bed Y-carriage of the MK3 - it has a slot that fits perfectly around the carriage. You only need one zip-tie to avoid the piece sliding off the Y-carriage and in order to fix it even more tight. Another slot is provided for the ribbon cable of the camera. If you want you can use some extra zip-ties to guide the ribbon cable a bit towards the printer. To mount the 'pole', just use a square M3 nut and a M3 bolt/screw to install the 'pole' onto the bed mount. The camera enclosure has 3mm holes in the lips to fix it to the 'pole' with an M3 screw/nut. You can use the spare M3 bolts/screws and nuts as provided with your printer.
I have made 45 degree angled versions and a straight versions as well as left and right versions. The angled versions make sure the camera mount is parallel to the bed.If you use the intake duct as described above, you will need the 'long' versions - if not, you can use the shorter versions.
The Pi camera I use is a wide angle (fish eye) version.