Even with an indicator rod, some loaders seem to be much more touchy to keep level than others. I have had ones that work great, and others that when you think you are level you are either digging a hole or not picking up anything. I am not totally sure why. It may be the shape of the bucket (I am thinking maybe the longer the bucket bottom the better), or if it is how the indicator is mounted, or if it is the geometry of the loader linkage. Maybe it is just the tractors I have used, but the older the tractor, the better the FEL seems to work at staying dead level.
Recently I was fine leveling of ground for a new yard, and even with my indicator the only way I could make a straight cut was to have my wife watch the leading edge and tell me to tilt the bucket up or down. I once had an old Ferguson TO30 with an FEL that was easy as pie to make a straight cut. Then my '80's Yanmar was a bit worse, but better than my new tractor.
A camera would be nice, but I have no doubt I would destroy it in a hurry.