What is a reporter's legal interview activity? Is it legal for a reporter to put a camera in his bag to take candid photos?

Strictly speaking, this kind of behavior is indeed illegal. If you have a clear conscience and find that you have been photographed, you can take decisive legal measures to safeguard your rights and interests. But if everything you are photographed is shameful, then you have to eat the turtle yourself. Even if the other party breaks the law, no one will speak for you. So the most important thing is to make sure that you are clean first.