On my Fedora 28 set up afer Fedora is updated it reinstalls the mount sharing for my Canon DSLR and I have to do the FAQ DSLR tricks again plus even after unmounting the camera (its Gnome) the permissions for the USB device are wrong and the CONNECT fails.
So I created a new rule to change the permissions to 0666 which seems to work even if I unplug and reinsert the USB camera cable.
However I notice that there are rules (very long) that Gphoto2 provide which just looks,amongs other things, for a PTP device but this seems not to be working on Fedora 28. I have read somewhere that if the rule is too long( 1ms ?) Udev will drop the rule - is this true or is it per line in a rules file !