Good Advice on Choosing the Right Surveillance Camera - Resolution

Published: 29th December 2008
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With so many different models of CCTV cameras available in the market today, it is understandable for a consumer to get overwhelmed in choosing the most appropriate camera for their system needs. It does not matter if you are purchasing a camera for a home or business system, there are some basic things that all consumers should be aware of in order to make a good decision. This will be the first of a series of articles to help guide a non-technical person that is shopping for a security camera. The main topic for this article is security camera resolution.



It is very important to understand what resolution means when shopping for a surveillance camera. CCTV cameras range in resolution from 330 TVL (television lines) to 600 TVL. For color resolution, CCTV cameras max out at 560 lines, however you can get black and white CCTV surveillance cameras in 600 TVL. IP security cameras are now available in much higher resolution (up to 5 megapixels in resolution). What does this mean when planning a system?



In the United States, regular TV transmission (not high definition) displays 480 lines of resolution. So it is possible to purchase CCTV cameras that can capture equal to or greater resolution than TV. The higher the resolution that you choose, the more detail you will see in your surveillance video. High definition television (HDTV) displays either 1080 or 720 lines of resolution depending on the channel and the type of HDTV that you have. In order to get higher resolution from security cameras, the only choice is IP based megapixel cameras, which connect over an IP network instead of a closed circuit. IP mega-pixel cameras are much more expensive than CCTV cameras. For high end applications that demand ultra-high resolution, megapixel cameras can capture surveillance video at more than twice the resolution of high definition television.



Some people that are shopping for a security camera have an unrealistic expectation about what a surveillance camera can capture (especially CCTV cameras). I will go into more detail about lens size and types in the next article in this series. I must touch on it briefly now as it is so closely related to resolution when planning your system. For this example, we will use a 3.6mm lens which gives you about a 90 degree field of view outward from the lens. Some people think that if you take a 480 lines of resolution camera with a 3.6mm lens that you will be able to get a clear picture both of an object that is 20 feet away and an object that is 80 feet away. This is very far from the truth. While the 3.6mm lens will easily pick up the object in detail at 20 feet away, it cannot pick up the same object at 80 feet away also with the same 3.6mm lens. In order to pick up the object at the further distance, you must either use a larger lens that would make the image more zoomed in or use the more expensive megapixel camera that would allow the operator to zoom in digitally. Digital zoom is possible with high end megapixel cameras, but not with normal resolution CCTV cameras. Because of the large difference in price between CCTV and IP mega-pixel cameras, most of the time it makes sense to add additional CCTV cameras instead of upgrading to an IP based megapixel system. This leads us into the next article in the series which will be about understanding and choosing the right camera lens.



This article was written by Mike Haldas. CCTV Camera Pros specializes in government, business and home surveillance systems. Please visit www.cctvcamerapros.com to read the rest of this article series and to find additional resources on video surveillance systems.



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