What exactly is Photojournalism?
While doing your research for your wedding photography you probably came across this term. By definition, a photojournalist captures the moment as it's happening without interfering or influencing. However, just having a photographer present is enough to influence the scene because some people have a difficult time acting natural in front of a camera. They'll ham it up, shy away, or "cheese" for the camera.
Another way to think of photojournalism is capturing the truth. There are no contrived or posed images, only true emotions and true moments. These moments are usually very fleeting and it takes a skilled photographer to capture them.
In addition to being at the right place at the right time, a photographer will use a powerful zoom lens. That way the person being photographed won't even know their photo is being taken because the photographer is on the other side of the room!