At what point do crime scene photographers enter the scene of the crime and
why?

­In detective movies or TV shows like "CSI," photogr­aphers swarm in and take countless pictures of a crime scene. They twist and turn their cameras haphazardly as agents discuss leads over the background hum of the photographs' flash explosions. But how does crime scene photography really go down? Since its purpose is to record evidence that will be admissible in court, it's hardly a haphazard operation. Crime scene photography, also called forensic photography, has been around almost as long as the camera itself. Criminologists quickly realized that such technology could freeze time -- creating a supposedly incontestable record of a crime scene, a piece of evidence or even a body. The 19th century French photographer Alphonse Bertillon was the first to approach a crime scene with the systematic methods of an investigator. He'd capture images at various distances and take both ground level and overhead shots.

So how do crime scene photographers go about their business?

­Crime scene photographers must be methodical in their work.­ They can't afford to leave out an important piece of evidence or produce photographs that could be considered misleading in court. But they also have the press­ure of the entire operation behind them. Before other CSIs can touch or move any of the evidence and even before the medical examiner can remove the body, the forensic photographer must document the scene.

There are three classifications of forensic photos -- overviews, mid-range and close-ups.