Cameras are objects that raise suspicion if you're doing any criminal acts, such as mining(?), digging, destroying, fighting and searching another inmate's desk. They can detect if you have any contraband items on you.
You can use Duct Tape, Shaving Cream, and Toothpaste to cover it temporarily.
Mobile and console versions do not allow you to use toothpaste to cover it, and Mobile and Console do not have shaving cream as an item.
When a camera detects something suspicious, it will flash red and call the nearest Guard to check it.