Detaining Witnesses and Seizing cameras/phones

I saw a thread about this on another site. Lots of back and forth but I didn’t feel satisfied that either side was correct. Please note that I’m talking about the US here.

If I am a witness to a crime and I happen to record that crime with a camera what rules must the police follow in detaining me and seizing my camera/media into evidence?

If I come upon a crime scene after the fact and I start filming/taking pictures do the police have a right to tell me to stop and/or seize my camera and/or instruct me to delete the video/pics?

I will give the typical lawyer response: It depends. These are pretty good articles addressing the issue.

http://www.associatedcontent.com/article/66181/freedom_of_information_vs_police_can.html?cat=62

http://www.infowars.com/do-police-have-the-right-to-confiscate-your-camera/

http://www.indybay.org/newsitems/2009/01/22/18565104.php

I read through Carlos’ site. There was an extensive thread on this subject. It came down to 1 side saying that police do not have the authority to detain a witness and seize thier property without a court order vs some cops saying they could invoke exigent circustances to detain a witness and seize their property without a court order.

The thing that bothered me about the whole thing was the cops basically said that they would order you to stay and turn over your camera and if you did not, then they would arrest you for failure to obey a police officer and then they could seize your camera incident to the arrest. And now you get arrested, booked, charged and spend a little time in jail and spend thousands of dollars in legal fees fighting your case.

So, who is right?