If you're lucky enough to catch Bob Dylan in concert, you'd better be ready to take a mental snapshot, because Dylan has long had a no-photos policy that he takes VERY seriously.

So seriously, in fact, that he stopped a concert in Vienna just to chastise the audience for snapping photos.

In an Instagram video (that Bob Dylan surely wouldn't approve of), Dylan can be seen muttering something about "pictures" into the microphone before stepping backwards and tripping over an amp.

He then returns to the mic to stop the show and tell the audience:

"Take pictures or don't take pictures. We can either play or we can pose, OK?"

Dylan then reportedly left the stage and left the band alone to play and instrumental version "Just Like Tom Thumb's Blues", which has been his finale throughout the tour.

According to The Rolling Stone, Dylan has had a no-photos policy in place during his concerts for years.

Before every concert, audiences are informed of the rules, and anyone who tries to take a photo during the show is approached by security guards.

Of course, this won't stop everybody, resulting in the on-stage drama from the Vienna concert. Dylan's short admonishment also happened to be the first time he's spoken directly to the crowd in roughly two years.

Though he used to introduce the band, he's recently taken to appearing on stage only to the sing his songs before leaving.

Photographer Jerry Schatzberg, who's worked closely with Dylan during several important moments in the singer's life, notes that the iconic folk singer is notoriously private, and "what Dylan wants, Dylan gets."

"I fell in love with his music, as everybody else did. And it just evolved. And we got along personally… He's not very open and cordial to the press."

"He doesn't like being asked questions and they're always asking the same ones. It's just not him. But he knew he had to put up with it for a while. I'm sure he still does."

Though demands may seem strange, Schatzberg insists they all come from a real, human place:

"In my way of thinking, and maybe I met too many people in my life, I don't find him so inaccessible. He wasn't inaccessible to me. Sure, I was intimidated at first… But he's just a real person with an extraordinary talent."

Reactions to Dylan's outburst were mixed, with some people online standing up for the 77-year-old icon, and others lambasting his grumpy attitude:

Whether or not you like the policy, if you're at Bob Dylan's concert, you'd better do what Bob Dylan asks or before you know it the concert will come to an abrupt end. Remember that!