lowfat
The devil is in the detail..
As soon as you secure it to the machine or hard wire it you need a STC.
What is the interpretation of "secure" or "attach ? (You can get around the hard wire by simply using a battery or a cigarette lighter socket).
"Cap1369 camera mounts guide", appears to be just a guide and does not apply to EASA aircraft anyway.
Where is the legislation (Law) that states temporarily (without modifications to the aircraft) carrying a camera mount requires a STC?