I just got of the phone with one of our customers that had some strange issues with his camera. The camera would not power on correctly and POST. The cam did not spin around or display address bawd rate and protocol on boot up. We could get video but could not move PTZ or gain control of it. His power was just under 150 FT AC as this is a 24VAC cam. He was using cat5 for power and video with baluns. I had the customer check power at cam and he got 24vac. Looked good to me. Power camera up again and now power reads 14vac.... Cat 5 cable was creating a voltage drop by 10 volts. After testing with 18 gauge wire he had no problems. The Cat5 just could not carry the voltage required.
So the moral of the story is any camera will act very strange when it does not have enough power. That is why in trouble shooting it is best to connect camera directly to DVR and power supply.