Closed circuit TV cameras, or CCTV have been around for years but they are now smarter, smaller and higher resolution, meaning the images they can produce, particularly at night are very high quality. If you want to secure your home or business premises from burglars and vandals they are definitely the best way to go. You will have the highest level of deterrent possible when you have security cameras installed around the outside of your buildings, any potential burglar will see them and pass your premises by and look for somewhere easier to rob instead.
The choices available to you are vast and it pretty much depends what the situation is, whether you want the cameras to be installed outside or inside your premises and if you want them to operate during the day or night. Then you need to think about the field of view you want the cameras to have, whether you want them to be fixed in one place or have the option of pan,tilt and zoom so that they can move around and zoom in on one particular place at any given time. You can have the option of having manual control of these cameras which is bound to be of great use in a large car park but something of an overkill when it's just to monitor your back yard!
If you want your cameras to operate well in low light conditions then you can get cameras that are dedicated to giving the clearest night images imaginable- they really do produce amazingly clear images these days and then you will ideally have these cameras sending their video feeds to either a digital recording unit or better still to a location on the internet where it is stored for reviewing later if needed. You can even have the feeds from your cameras sent to your smart phone, if you have indoor cameras you can also see what's going on in your house in real time or view recorded footage after the event if you have had a break in.
Another choice is if you want the cameras to be wired or wireless. Wireless cameras have the advantage of being small, inexpensive and can be mounted almost anywhere quickly and easily, they are not as reliable or weather resistant as the more heavy duty wired versions and the picture quality is usually not as good but improvements are being made to the quality of the image sensors on wireless cameras all the time so this may not be such a problem nowadays. Plus as they have no visible wires they can't be deactivated by cutting the cables.
One criticism of wireless cameras was that it is possible for the images they are sending to the receiver to be intercepted and viewed by unauthorised people (namely burglars) who have managed to pick up the signal. The solution to this problem, which is obviously very serious as there would be the potential for the burglars to actually be watching what the camera is seeing so they can time their burglary perfectly, is to ensure that your system only broadcasts on an encrypted channel. This is becoming standard with new wireless security camera systems. It is worth having a chat with either a security firm or CCTV installation specialists to ensure that their wireless cameras broadcast on encrypted channels.