http://www.aclu.org/free-speech/know-your-rights-photographers

Taking photographs of things that are plainly visible from public spaces 

is a constitutional right ? and that includes federal buildings, 

transportation facilities, and police and other government officials 

carrying out their duties. Unfortunately, there is a widespread, 

continuing pattern of law enforcement officers ordering people to stop 

taking photographs from public places, and harassing, detaining and 

arresting those who fail to comply.

When in public spaces where you are lawfully present you have the right 

to photograph anything that is in plain view. That includes pictures of 

federal buildings, transportation facilities, and police. Such 

photography is a form of public oversight over the government and is 

important in a free society.

When you are on private property, the property owner may set rules about 

the taking of photographs. If you disobey the property owner's rules, 

they can order you off their property (and have you arrested for 

trespassing if you do not comply).

Police officers may not generally confiscate or demand to view your 

photographs or video without a warrant. If you are arrested, the 

contents of your phone may be scrutinized by the police, although their 

constitutional power to do so remains unsettled. In addition, it is 

possible that courts may approve the seizure of a camera in some 

circumstances if police have a reasonable, good-faith belief that it 

contains evidence of a crime by someone other than the police themselves 

(it is unsettled whether they still need a warrant to view them).

Police may not delete your photographs or video under any circumstances.

Police officers may legitimately order citizens to cease activities that 

are truly interfering with legitimate law enforcement operations. 

Professional officers, however, realize that such operations are subject 

to public scrutiny, including by citizens photographing them.

Note that the right to photograph does not give you a right to break any 

other laws. For example, if you are trespassing to take photographs, you 

may still be charged with trespass.

If you are stopped or detained for taking photographs:

Always remain polite and never physically resist a police officer.

If stopped for photography, the right question to ask is, "am I free to 

go?" If the officer says no, then you are being detained, something that 

under the law an officer cannot do without reasonable suspicion that you 

have or are about to commit a crime or are in the process of doing so. 

Until you ask to leave, your being stopped is considered voluntary under 

the law and is legal.

If you are detained, politely ask what crime you are suspected of 

committing, and remind the officer that taking photographs is your right 

under the First Amendment and does not constitute reasonable suspicion 

of criminal activity.

Special considerations when videotaping:

With regards to videotaping, there is an important legal distinction 

between a visual photographic record (fully protected) and the audio 

portion of a videotape, which some states have tried to regulate under 

state wiretapping laws.

Such laws are generally intended to accomplish the important 

privacy-protecting goal of prohibiting audio "bugging" of private 

conversations. However, in nearly all cases audio recording the police 

is legal.

In states that allow recording with the consent of just one party to the 

conversation, you can tape your own interactions with officers without 

violating wiretap statutes (since you are one of the parties).

In situations where you are an observer but not a part of the 

conversation, or in states where all parties to a conversation must 

consent to taping, the legality of taping will depend on whether the 

state's prohibition on taping applies only when there is a reasonable 

expectation of privacy. But that is the case in nearly all states, and 

no state court has held that police officers performing their job in 

public have a reasonable expectation. The state of Illinois makes the 

recording illegal regardless of whether there is an expectation of 

privacy, but the ACLU of Illinois is challenging that statute in court 

as a violation of the First Amendment.

The ACLU believes that laws that ban the taping of public officials' 

public statements without their consent violate the First Amendment. A 

summary of state wiretapping laws can be found here.

Photography at the airport

Photography has also served as an important check on government power in 

the airline security context.

The Transportation Security Agency (TSA) acknowledges that photography 

is permitted in and around airline security checkpoints as long as 

you're not interfering with the screening process. The agency does ask 

that its security monitors not be photographed, though it is not clear 

whether they have any legal basis for such a restriction when the 

monitors are plainly viewable by the traveling public.

The TSA also warns that local or airport regulations may impose 

restrictions that the TSA does not. It is difficult to determine if any 

localities or airport authorities actually have such rules. If you are 

told you cannot take photographs in an airport you should ask what the 

legal authority for that rule is.

The ACLU does not believe that restrictions on photography in the public 

areas of publicly operated airports are constitutional.