Most all sporting goods stores cell cameras that have a built in motion detector and only take a picture when something sets them off. They are digital so they don't use film. The pics can then be viewed in the camera or up-loaded to a computer. Most all use a flash, but that could be turned off or covered so as not to give away it's location, as the flash is very fast. Once it re-sets the person wouldn't know where the flash came from. If they move again it will take another picture after it resets. 😎