Whether you can film police at work is something that has been hotly debated. People have been arrested for filming the police, but others have been able to film police procedures with no trouble. Often, other factors come into play, such as whether you are obstructing officers in their performance of their duties, or whether you are failing to obey orders that they give to you in a particular situation.
Filming police who are out working in the public is generally more acceptable than filming police when they are working in private. Of course, each state has laws about this issue and some of those laws vary quite a bit. Be sure that you check your local laws before you assume that you can or cannot film the police, either on public or private property. It is much better to be informed than to be arrested for something you thought was acceptable.
Video and audio are not the same. Recording audio without the consent of all parties is something that you should avoid. That can violate eavesdropping laws, and can be a felony. Spending years in prison because you recorded your interaction with a police officer isn’t worth it, so many sure you know what the laws are where you live – as well as federal law – before you make any recording decisions.
Overall, your rights are important and you should know those rights. Keep in mind that disagreeing with what is your right and what is not does not give you an excuse to overlook legalities. Because of that, you must follow the laws on recording or filming police procedures, whether you like those laws or not, in order to avoid arrest and possible prosecution.
Contract phones often have better quality cameras than prepaid ones. As many cell phone company provide damage insurance.