Video surveillance cameras are classified according to the technology that is used in their design. CCTV [closed circuit TV] cameras are those that have a completely closed circuit and all the components are connected together. On the other hand, advanced digital cameras are those that connected by a circuit but can be located at any site around the world. Digital video recorders [DVRs] do not need VCR's and other recording equipment in order to capture or record on-site activities. The software is designed to automatically record unusual activity even in odd hours of the day. 

You can find video surveillance cameras used in many different places. They are used in school buses and schools to monitor activities of students. You will also find them being used in retail establishments, public gathering places, traffic reporting, and many more places. Small hidden cameras know as nanny cams have been used successfully by parents concerned about their children's care from sitters and caretakers. Hidden cameras are also available for sale in "brick and mortar "stores and on the Internet. You find these cameras hidden in clocks, smoke detectors, and soft toys such as a teddy bear, just to name a few. 

This style of camera is differentiated according to its effectiveness. A 360-degree revolving dome camera can capture images anywhere on the site. Infrared surveillance type cameras are found used by government and law enforcement agencies such as the SWAT for tailing suspects at night. They too are found mounted in police helicopters to aid them in searching suspects hidden in brush by either day or night. 

Detective agencies and security agencies use these cameras to monitor people at their client's request. It is currently lawful in most areas to install a camera in a common public area and record public activities; however, there is a lot of debate over this subject. Even government agencies such as the Federal Bureau of Investigation [FBI] need a warrant in order to carry out video surveillance in private places or homes. Small hand held cameras, also available in the marketplace, help monitor the elderly and in nurseries and preschools where children are kept under watch. 

Video surveillance cameras are available in the price range of $100 to $800 for the most part. However, it depends on the complexity of the technology used in them. Well-made fake cameras are also available for as less as $3, which act as deterrents for robbers and thieves but are not recommended in some applications.