How to Not Get Robbed and Ripped Off When Hiring a CCTV Company or Buying a CCTV System
Part 2
· Camera Resolutions. Analog and digital camera resolutions are rated for consumers in TV Lines (TVL) and mega pixels (MP). Below is a list of CCTV resolutions and the corresponding camera formats. There are 2 things to remember when choosing cameras:
(a) the quality of the image you get depends on the quality of “the glass” (lens) and the CCD image sensor on the camera. Do you really think you’re gonna get jaw-dropping images from that $50 blow-out camera?
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(b) the proper camera resolution and type must be matched with the proper recording format. Also, “too much” or “too little” resolution or the wrong format are both really a waste of time and money or simply won’t work.
analog
1. CIF cameras will be between 420-480 TVL. Known as “standard res.”
2. D1 cameras should be 600 TVL (although 500+ TVL cameras exist for D1). Known as “hi-res.”
3. 960H cameras should be at 700 TVL and used with a 960H DVR. Known as “super hi-res.”
digital
4. IP cameras vary from 1MP to 5MP. IP cameras can only be used with IP systems and NVRs
5. HD-SDI cameras should be at 2.1-2.2MP and will only be used with HD-SDI DVRs.
6. HD-CVI will use 1.3MP (720p) and 2MP (1080p) HD-CVI cameras and can only be used with HD-CVI DVRs (well, you can use HD-CVI cameras with analog DVRs, but they won’t be hi-def, so what’s the point).
Just because a camera boasts “700 TV Lines” or 8MP does not mean you’ll get superior video resolution. Mentioned above, many things come into play: quality lenses, image processors, outright lying, etc. One way to test this is with an ISO line chart and software to analyze the results and some CCTV companies will take this upon themselves to do this. Oh yes: larger MP cameras means smaller pixels. More is not always better. So, anything less than these camera specs for each format is really a waste of time because you’re not getting the full resolution out of each format. Also keep in mind, for example, that if an installer tries to sell you a 700 TVL camera with a D1 system (600 TVL max) you will see no added resolution and a 420 TVL camera will not provide the full resolution, either (“too much” and “too little”).
· Frame Rate. How many frames per second (fps) the DVR can record per channel (camera). 30fps per channel is the maximum and will use the most hard drive space. 15 fps is more than adequate. In a lot of cases I have used 7fps on a client’s system with excellent results. If a DVR isn’t capable of recording at least 7fps on ALL channels, do not buy. The option of at least 15fps on ALL channels is preferable. You can always reduce or raise this later. Oh yeah, I almost forgot. Some manufactures will use “ips” in their marketing material. IPS is “images per second” (not frames per second). So, for example, you may see a 16 channel DVR that lists “30ips on all channels.” Looks good, right? WRONG! It is nothing but one big lie. 2ips=1fps. In other words, you would need 60ips to equal 30fps. So, if you did see the above DVR listed as “30ips on all channels” you would only be getting a max of 15fps on all channels. All this is, is an attempt to scam the consumer by using “impressive” numbers so you’ll buy their product.
Important Points
· Beware of “techno babble.” Usually, but 閉路電視 not always, this is used to scam you by keeping you in the dark and uneducated. It sounds impressive when you hear it, but if you are not educated, you won’t know what you’re getting. Ask the salesperson or installer to clarify before you make the deal. This is a good test to see if they actually know what they are talking about. Of course, now that you have this report, you may be able to school them. Either way, I think it’s just poor manners to talk over someone’s head to begin with. Explain what you are saying.
· You need to know and ask the company all of the above tech specs before you hire. Actually, they should be more than happy to explain everything to you before you ask (see 3 lines above).
· Get all of the specs in writing or get some type of tech spec sheet. You want to be sure you are getting the exact system installed as promised and that you’re paying for.
· You need to know about the hard drive(s) in the DVR. Specifically:
(a) how many days of recording do you need/want?
(b) how big are hard drives in the DVR and how many days recording will you get?
