Although the application of CCTV security have not changed very much over the past years, the tools and equipment have significantly. Cameras became smaller, cheaper and better, but the major breakthrough happened in recording equipment.
Therefore many customers shopping for complete CCTV monitoring and recording systems are confused by such a verity of available products. Goal of this article is to guide buyers toward best possible and most economical type of CCTV equipment, based on intended implementation and requirements.
Selecting the right cameras.
It is virtually impossible to describe all types of available security cameras in this short article. We will focus our attention on most popular and widely used camera types instead.
CCTV security cameras produce images using CMOS or CCD (Charge Couple Device) chips. Tiny, very low price CCTV cameras usually use CMOS technology, produce poor quality images and have very poor light sensitivity. Decent quality CCTV cameras use CCD technology. The size of the CCD chip is normally 1/4", 1/3" or 1/2". As a rule of thumb, the larger the size, the higher the quality of the image produced and the higher the price. However, higher density 1/4" and 1/3" CCD chips can now produce as good an image as many 1/3" or 1/2" chips.
The number of TV lines in the security camera image is a measure of picture resolution (sharpness). The larger the number of TV lines, the better the resolution and hence, overall picture quality. Standard resolution camera may have 350-380 lines, over 400 TV Lines is generally considered good resolution while over 500 TV lines is considered high resolution. B/W chip cameras produce greater resolution and better light sensitivity, therefore suitable for use in dark areas where light conditions are poor most of the time.
On the other hand color cameras offer more realistic and natural picture. CCTV cameras are usually divided into different types based on the body of the camera used.
Professional grade cameras.
Have box type body with the ability to use different types and size of lenses. Exchangeable lenses enable this camera, to monitor objects from virtually any distance.
Although for indoor use, they can be used for outdoor when combined with weatherproof housing. They are considered to be the most flexible and widely used by professionals for commercial installations.
Bullet cameras.
Bullet cameras are, as the name suggest contained inside bullet shaped housing.
Most bullet cameras are weatherproof and sealed without the ability to use different lenses. Great advantage of bullet camera is the small size and integrated design, some bullet cameras will even have infrared LED future built-in. Infrared technology is simply LED light in infrared spectrum (not visible to human eye). This light will illuminate viewing area, making possible monitoring in complete darkness. This is great future, but it only works up to certain distance (usually between 10 and 50 ft. depending on model) Vary simple to install and estheticly designed, bullet cameras are great choice for residential and do-it-yourself installations where monitoring objects are within about 25ft from the camera location (with standard 3.6mm lens).
Board Cameras.
Board Cameras are basically fixed lens mounted on a circuit board. These cameras may be packaged in a small case (Mini Cameras) or dome (Mini Dome) or simply sold unpackaged, for mounting by the purchaser. Lenses in these cameras are either of a normal industry aperture or a "pinhole" lens of very small aperture. Pinhole lens cameras are often called "spy" cameras and may be mounted in a concealed way for covert surveillance purposes. The most popular examples of covert board cameras are smoke detector and motion detector cameras.
Since the lenses in board cameras are pre-mounted, have a fixed iris and are usually of a short focal length (i.e. wide angle), their flexibility of usefulness is limited. However, this type of camera can provide a low cost solution in the right situation, particularly in a home environment.
We have shortly described most popular types of cameras, lets now discus, how and where they mite be used.
Professional type cameras with C/CS mount lens attachment generally offer best performance and many important futures, like lens control output, Back Light Compensation and many more