With so many choices of surveillance cameras in the market, it is easy for a consumer to get overwhelmed in choosing the best security camera for their system needs.
No matter what type of surveillance application you are installing, there are some basic things that all consumers should consider in order to make a good choice.
This will be the first of a series of articles to help guide a non-technical person that is researching the purchase of a surveillance system. The main topic for this first article of the series is security camera resolution.
It is important to know what resolution means when shopping for a surveillance camera. CCTV cameras have a resolution range 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. What does this mean?
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 record equal to or greater resolution than TV.
Obviously the higher the resolution of the camera 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 surveillance cameras, the only choice is IP based megapixel cameras, which connect over an IP network instead of a closed circuit. Generally, 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 are unrealistic (because of their lack of experience) about what a surveillance camera can capture (especially CCTV cameras). I will go into more detail about lens types and sizes in the next article in this series.
I must touch on it briefly now as it is so closely related to resolution. 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 not true. While the 3.6mm lens will easily pick up the object in detail at 20 feet away, it cannot pick it up at 80 feet away also with the same 3.6mm lens. In order to pick up the object at the further distance, you have to either use a larger lens that would make the image appear more close up or use a high end megapixel camera that would allow the operator to zoom in digitally without distorting the picture.
Digital zoom is possible with high end megapixel cameras, but not with normal resolution CCTV cameras. Because of the huge price difference between CCTV and IP mega-pixel cameras, a lot of times it makes sense to add additional CCTV cameras instead of upgrading to megapixel cameras. This will lead us into the next article which will be about understanding and choosing the right camera lens.
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