What you need to know about Cameras
Any Video Surveillance System starts with CCTV cameras. The images you see and record can only be as good as the images produced by your CCTV cameras. Good cameras produce good images and vice versa. There are several critical specification factors which affect the performance of your cameras and consequently, the quality of your camera images. These factors also affect the price of cameras. We offer a selection of CCTV cameras to meet almost any situational need and budget. All our cameras provide excellent specification factors, overall quality and excellent images, coupled with very competitive prices.
Black and White ( B/W) CCTV cameras were the most widely used just a few years ago because of price and better light sensitivity. Today, color CCTV cameras have narrowed the price gap and some of our color CCTV cameras are almost as light sensitive as B/W cameras. Because color video is much more lifelike than B/W and provides much more positive identification, most CCTV cameras purchased today are color units.
The main performance factors are:
The Type and Quality of the Imaging Chip in the camera.
CCTV 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" CCD chips can now produce as good an image as many 1/3" 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. Panasonic and Sony are generally recognized as producers of the best CCD chips. All CCTV cameras supplied by Pro CCTV use CCD chips from these two manufacturers.
The Type of DSP (Digital Signal Processing) Chip in the camera.
Digital CCTV cameras use a DSP chip to digitize the video stream from the CCD chip, in order to improve certain picture quality elements and to add additional functionality.
Number of TV Lines
The number of TV lines in the 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. Over 400 TV Lines is generally considered good resolution while over 500 TV lines is considered high resolution. All our CCTV cameras have a resolution of well over 400 TV Lines.
Sensitivity ratings are generally given in "lux" (a light level measurement). 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. B/W cameras have lower lux level ratings than color cameras ( i.e. B/W cameras will produce acceptable images in lower light conditions than color cameras). A lux rating of 1.0 or less is considered good for color cameras, while 0.1 lux or less is considered good for a B/W camera.
CCTV Cameras come in two main types.
The first type has a camera body, to which lenses of different focal lengths and/or fixed or variable irises, may be attached. The factors involved in choosing a suitable lens are given on the CCTV Camera Lenses page. Features such as BLC ( Back Light Compensation), Auto Iris Drive and AES 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" for choosing and setting functions. Because of it's flexibility of configuration, this type of camera is normally used in most commercial video surveillance systems.
The second type is basically a fixed lens mounted on a circuit board (board cameras). 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. 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.