Back then, I wrote a column on photographer's rights, in which I explained where you were allowed to shoot pictures and what you were allowed to do with them. I was glad to see people were reading and spreading it.

Since then, I've seen an incredible amount of misinformation bandied about, and I've had a lot of questions posted on my blog that tell me people aren't getting the message. Worse, I've read accounts of photographers being harassed for perfectly legal behavior by people whose ignorance of the law ought to get them in trouble.

The most notable was the story of Neftaly Cruz, a senior at Penn State who on July 19 was not only harassed but taken into custody by Philadelphia police for obstructing an investigation. How did he do this? By taking pictures of the cops while standing on a public street.

Cruz's actions were absolutely and undoubtedly legal, and not surprisingly he was released without being charged with anything.

It's not just cops who need reeducation classes. Last week I received a note from a reader:

"Today I was stopped by a security guard with the North County Transit District in Solana Beach, California, and prevented from taking photos of a great new train station they have," he wrote. "The guard said they don't allow it since 9/11."

Note to security guard: Just because you or your boss "don't allow" something doesn't mean it's not legal. I can post a sign on my lawn, "Hopping on one foot in front of this house is prohibited," but I'll have a tough time enforcing it.

Stories like these all have something in common. Invariably, it seems, the guards or cops either invoke non-existent laws (e.g., "It's illegal to shoot any building on 3rd Street"), or they use the all-encompassing "security."

Well guess what: Neither "security" nor "9/11" are magic words that will cause everyone to follow your every unjustifiable instruction. Say either as often or as loud as you want. It doesn't let you take away someone's rights.

Keeping it simple

The law in the United States of America is pretty simple. You are allowed to photograph anything with the following exceptions:

• Certain military installations or operations.

• People who have a reasonable expectation of privacy. That is, people who are some place that's not easily visible to the general public, e.g., if you shoot through someone's window with a telephoto lens.

That's it.

You can shoot pictures of children; your rights don't change because of their age or where they are, as long as they're visible from a place that's open to the public. (So no sneaking into schools or climbing fences.)

Video taping has some more gray areas because of copyright issues, but in general the same rules apply. If anyone can see it, you can shoot it.

And yes, you can shoot on private property if it's open to the public. That includes malls, retails stores, Starbucks, banks, and office-building lobbies. If you're asked to stop and refuse, you run the risk of being charged with trespassing, but your pictures are yours. No one can legally take your camera or your memory card without a court order.

You can also shoot in subways and at airports. Check your local laws about the subway, but in New York, Washington, and San Francisco it's perfectly legal. Airport security is regulated by the Transportation Security Administration, and it's quite clear: Photography is A-OK at any commercial airport in the U.S. as long as you're in an area open to the public.

Don't let anyone tell you otherwise.

Restrictions

There are a few more restrictions on publishing photos or video, though, as mentioned back in December.

You can't show private facts — things a reasonable person wouldn't want made public — unless those facts were revealed publicly. So no long-lens shots of your neighbors' odd habits.

You also can't show someone in a negative false light by, for example, using Photoshop tricks or a nasty, untrue caption.

And you can't put someone else's likeness to commercial use without their permission. This is usually mentioned in terms of celebrities, but it applies to making money from anyone's likeness.

For example, if you shoot individual kids playing in a school football game, you can't try to sell those shots to the parents; the kids have a right to the use of their likeness. You can sell photos of the game in general, though, and any shots where what's happening ("A player celebrates a goal") is more important than who's doing it ("Star running back John Doe takes a momentary rest").

Sound like a gray area? It is if you're planning to sell the pictures, but not if you're simply displaying them. And if you're using them for news purposes, all bets are off — you can pretty much publish whatever you want if it happens in public view.

The other gray area is copyrighted material. Even if it's in public, you can't sell pictures of copyrighted work — a piece of art, for example. But if the art is part of a scene you can probably get away with it.

All this in mind, it's almost always a good idea to get permission where you can and to be polite and friendly with anyone you deal with. Like good urban legends, people are absolutely sure they know the law about photography, and they're absolutely wrong.

If you want to know more, I've got a PDF on my site with all this spelled out, and you shouldn't miss Bert Krages's "The Photographer's Right." Print 'em and carry 'em.

Andrew Kantor is a technology writer, pundit, and know-it-all who covers technology for the Roanoke Times. He's also a former editor for PC Magazine and Internet World. Read more of his work at kantor.com. His column appears Fridays on USATODAY.com.