Video Surveillance System Buying Guide
Security cameras have been around for a long time, but recent developments in technology have made the cameras less expensive, smaller and loaded with more features. Many of us have seen the older videos from security cameras and found that they were blurred and fussy and only in black and white. Today’s cameras are clear, sharp and offer color.
When choosing between wired or wireless systems, the wired system offers better video quality, less interference, lower cost and longer distance from the camera to the security DVR. Today wired cameras use a “Siamese cable” that provides video and power in the same cable. Wireless systems are more expensive and usually depend on Line of Sight for transmission between the camera and security DVR. Also the camera sends its video signal wirelessly, but still must have power available to the camera. When there is a definite need for a wireless camera, you can mix wired and wireless cameras in the same system.
The CMOS or CCD chips used inside the camera to produce the picture are much smaller and less expensive while producing a higher quality image. The dome camera blends well with the surroundings and works well with drop-down ceilings. High Speed dome cameras have the ability to adjust to changes in light, object distances and have 360 degree continuous monitoring. Infrared cameras use infrared (IR) illuminators to see in total darkness, but the IR illuminators are visible to the naked eye. The bullet camera is smaller and less visible when in place. The PTZ camera has the ability to pan, tilt and zoom in on an image. The choices for type of lens and ability to see in day or night are available on almost all styles of cameras today. Finally we have the IP Camera that has its own IP address. This means the camera can go directly to a computer or modem and the image viewed on a monitor, laptop or smart phone from anywhere in the world. This camera setup does not have a recording function.
Megapixel cameras offer wider coverage than an analog camera, but are more expensive. These are great for larger areas such as a parking lot. The larger the number of megapixels the wider the area the camera can cover, with the standard being 2 megapixels. An analog camera is measured in TVL or TV lines of resolution. The higher the number of TVL lines the better the quality of the image. Standard TVL is 380 to 420 TVL, with high quality being 480 TVL and very high quality being 540 to 700 TVL.
Color cameras give a better image for identification in normal light while the black and white camera sees better in low light conditions. Some cameras are designed for outdoor use and if you decide to use an indoor camera outdoors, you must put it inside of a weatherproof enclosure.
Light sensitivity is measured in LUX, the lower the LUX rating the better the camera sees in reduced lighting. A camera with a LUX rating of 0.1 would be perfect for use at night with a full moon. The main Lux ratings are:
· Direct sunlight 100,000 – 130,000 Lux
· Indoor office 200 – 400 Lux
· Full Moon 0.1 Lux
· Moonless Clear night sky 0.001 Lux
The cameras field of view (FOV) is the height and width of the picture size. With the fixed focal lens, the FOV is fixed and can’t be changed. The varifocal lens can be adjusted for FOV and this is usually done manually at the camera when installed. The Zoom lens can be manually adjusted or remotely controlled. An auto iris lens works well where the light varies and the camera will automatically adjust for the changing light. It the light is constant the manual iris camera is less expensive and can be set manually when installed.
You can buy a PC-based DVR which is simply a card you put into your computer to capture the video and send it to your monitor, router or the internet via your modem. While this sounds simple and inexpensive we have found that your personal computer is prone to lock-ups, crashes, virus and hacking. In addition video takes quite a bit of hard drive space usually requiring an additional hard drive. The stand alone or security DVR has its own hard drive and internal operating system that is not susceptible to virus or hacking. These security DVRS come in 2, 4, 8, 16 and 32 camera models for the average user. This DVR provides instant replay, live view, camera control and motion sensing for your cameras. The motion sensing can save recording space and is a function of the DVR not the camera. A good 4 to 8 camera DVR should have a 500 gigabyte drive. Most security DVRs allow viewing on a TV or computer monitor and include a quad splitter to allow four cameras to be viewed on one screen at the same time.
Popular cables are an RG59 or RG6 cable. The most popular is the Siamese RG-59 which is a RG59 cable and two 22 gauge wires for power all in one jacket. This is good for up to 750 feet and is more economical than RG6. It your cable run is more than 750 feet, it is recommended that you use a Siamese RG6 cable. Precut Siamese cable will usually come in lengths of 25 to 150 feet, while longer cables can be special ordered or made in the field.
Each camera will come with a 12V or 24V power supply which is a good choice for 1 to 3 cameras. The power supply can be connected at the DVR end of the Siamese cable for wired cameras or at the camera for wireless cameras. If using more cameras in a wired system, it is recommended to use a multi-port power supply.
For the average user that wants a Do-it-Yourself project to save money, I recommend buying a complete system that will come with the cameras, wire, security DVR, power supplies and all attachments required. The components will be matched for optimum performance and cameras can usually be interchanged at the time of purchase to meet your specific needs.
Video Surveillance System | Security DVR | Security System Cameras | Dome Camera | Bullet Camera
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ABOUT THE AUTHOR
Doug Harper is a former Marine, Drug and Transport Officer and Airline Pilot. Doug retired from the airlines in 2011 and opened Sharper Safety to sell video surveillance equipment and accessories. http://www.sharpersafety.com