Photographers covering musician Jay-Z's recent appearance at the Wireless Festival in London were apparently asked to sign away their copyright to the multi-millionaire rap artist.
Press Gazette has been given a "photographer's release and grant of rights form" which a photographer, who asked not to be named, was handed at the recent festival.
In the form photographers are asked to sign away their copyright in exchange for having the right to photograph the rapper, whose real name is Shawn Carter.
The form states: "You agree that any and all photographs and images captured or obtained on any media, known or future, are not for commercial sale, or distribution in any form, except for use in the below mentioned publication.
"You further agree that this permission is for a one-time use only, unless agreed in writing and attached to this document.
"All copyrights and other intellectual property rights shall be entirely Artist's property; free of any claims whatsoever by you or any person, firm or corporation."
According to well-placed sources in the music press, such forms are now commonplace at concerts. One journalist told Press Gazette that they believe the forms are legally unenforceable.
National Union of Journalists freelance officer John Toner, who represents photographers for the union, advises members never to sign such forms.
He said: "Our advice would be that it's not worth anyone's time to work on the basis of this contract. We have devised our own contract which photographers are starting to use with some success.
"Management are ripping off photographers and trying to get them to agree to terms that they would never expect for their own artists.
"If a photographer is confronted by one of these contracts we would urge them to contact their publisher as a first port of call, because they don't want photographers signing these contracts either."