a href="http://www.securitycamerasandmore.com">Security cameras are the most common method of surveillance. Originally, they were analog video, but digital security cameras have become more commonplace.

Digital security cameras do not rely on videotape recorders and subsequently do not have to have the tapes constantly replaced. However, the digital file can fill up hard drive space. Higher quality security camera images, comparable with DVD quality, only make the files larger. Fortunately, several techniques exist to solve the problem. One of the most common solutions is the use of motion detectors. These signal security cameras when to begin recording, and when to save power by intermittently filming.

People have repeatedly challenged the widespread use of security cameras, claiming that their use results in loss of privacy and loss of civil liberties. This is particularly true in London, where critics have argued that security cameras exist more for controlling the general populace than for crime prevention. Similar arguments have cropped up in Chicago and New York, where security cameras have become more prevalent.

Personal security cameras have also become more popular. These can be plugged into a computer's USB port, and monitor cubicles or single rooms. As many of these security cameras have a resolution of 4 million pixels, quality is not a problem.