Any Video Security System starts with CCTV security cameras. The images you see and record can only be as good as the images produced by your CCTV security cameras. Good security cameras produce good images and vice versa. There are several critical specification factors which affect the performance of your security cameras and consequently, the quality of your camera images. These factors also affect the price of security cameras. We offer a selection of CCTV security cameras to meet almost any situational need and budget. All our security cameras provide excellent specification factors, overall quality and excellent video images, coupled with very competitive prices.
Black and White (B/W) CCTV security cameras were the most widely used just a few years ago because of price and better light sensitivity. Today, color CCTV security cameras have narrowed the price gap and some of our color CCTV security cameras are as light sensitive as B/W security cameras. Because color video is more lifelike than B/W and provides much more positive identification, most CCTV security cameras purchased today are color units.
The main performance factors are:
The Type and Quality of the Imaging Chip in the camera
CCTV security cameras produce images using CMOS or CCD (Charge Couple Device) chips. Tiny and/or very low price CCTV cameras usually use CMOS technology, produce poor quality video and have very poor light sensitivity. Decent quality and better 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 older 1/3" or 1/2" chips.
The Make of the CCD chip in the camera
Not all CCD chips are equal, even with the same specifications. Quality varies by manufacturer. Sony and Sharp are generally recognized as producers of the best CCD chips. Most CCTV security cameras supplied by Automated Surveillance use CCD chips from these two manufacturers.
The Type of DSP (Digital Signal Processing) Chip in the camera
Digital CCTV security cameras use a DSP chip to digitize the analog video stream produced by the CCD chip, in order to improve certain picture quality elements and to add additional functionality. The DSP chip in the camera can have a very large effect on the quality of the video images produced by the camera.
Number of TV Lines
The number of TV lines in the video produced by the security camera is a measure of picture resolution (sharpness). The larger the number of TV lines, the better the resolution and hence, overall picture quality. Over 370 TV Lines is generally considered good resolution while over 450 TV lines is considered high resolution.
Light Sensitivity
Sensitivity ratings are generally given as the minimum "Lux" levels at which the camera will produce a useable image (1 Lux equals 1/10 Foot Candle). The lower the Lux number, the lower the light levels at which the CCTV camera will produce an acceptable image. In other words, the lower the Lux level rating, the more light sensitive the camera.
Lux level ratings (and the amount of light entering the camera) are inversely proportional to the aperture of the camera iris and so are stated at a specific “F Stop” (Focal Length divided by Aperture). A camera with a Lux rating of 1.0 at F1.4 will only have a Lux rating of 2.0 at F2.0.
B/W security cameras generally have lower Lux level ratings than color cameras (i.e. B/W cameras will produce acceptable images in lower light conditions than color cameras). With the adoption of enhanced light sensitivity ExView CCD chips from Sony we can now offer exceptionally light sensitive color cameras. Our Day/Night cameras change from color to B/W when Lux levels drop below about 1.0 and produce useable B/W images down to a Lux level of about 0.03 Lux.
Signal to Noise (S/N) Ratio
The higher the Signal to Noise ratio, the clearer the video image produced by the camera. Good CCTV cameras will have a S/N ratio of at least 48dB.
Fixed (non moveable) CCTV security cameras come in two main styles
The first style has a camera body, to which lenses of different focal lengths and/or fixed or variable irises may be attached. Features such as BLC (Back Light Compensation), Auto Iris Drive and AES (Auto Electronic Shutter) on/off are provided, as is availability in several power inputs (e.g. 12V DC or 24V AC). New technology cameras now provide an "On Screen Display" (OSD) for choosing and setting functions. Because of their flexibility of configuration, body or box cameras are widely used in most commercial video surveillance systems.
The second style is basically a fixed lens mounted on a camera circuit board (board camera). These cameras may be packaged in a small case (Mini Cameras) or dome (Mini Dome) or tube (Bullet, Lipstick or Tube) 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. 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 or retail environment.
Pan, Tilt, Zoom (PTZ) Security Cameras
PTZ security cameras are able to rotate horizontally through 3600, vertically through 900 and have electrically powered zoom lenses capable of giving better than fifteen times optical zoom. Movement can be very fast and is controlled through a connected controller and/or through an appropriate DVR. In addition, PTZ cameras can be set to auto-scan or to move through a pre-defined range of pre-set positions and amounts of zoom.
New advances in technology now provide digital zoom in addition to optical zoom; day/night light sensitivity; intelligent movement that prevents too much incremental movement at bigger zoom factors and user definable movement “patterns” rather than guard tours consisting of numbers of presets.
PTZ security cameras are normally mounted in domes and when used outside, the domes are weatherproof and thermostatically cooled and heated. Vandal resistant domes are also available.
Glossary of Terms & Technical Specifications
Choosing A Digital Video Recorder
Frames per second Demonstration
Live Remote View Demonstration
Choosing A Surveillance Camera
Laws Regarding Video Monitoring
Installation Checklist
