Don’t Let Misleading Numbers Fool You
If you’ve been researching security cameras for a while, you have probably noticed that some cameras measure resolution using TVL (600TVL, 700TVL, 1000TVL) rather than 720p, 1080p, or Megapixels. This can be confusing and even misleading, which can make it very frustrating to figure out what you need for your home or business. In this article we’re going to break down what all of those numbers actually mean so that you can make an informed decision.
The 1000TVL Gimmick
1000TVL cameras are the best (or worst) example of this. At a glance, you might think that 1000TVL resolution is comparable to 1080p resolution, but there is a huge difference between the two.
Measurements in TVL refer to the horizontal pixels of the image, while HD resolutions measure the vertical pixels on the image. This means that 720p, which is 720 pixels tall by 1280 pixels wide, is actually a better image than 1000TVL.
This is a scheme with the goal of getting you to spend top dollar on subpar equipment. Even with “1000TVL cameras,” you can hardly recognize a face or read a license plate from more than 10 feet away, and what good is video footage if you can’t tell what you’re looking at?
There is no “1000TVL DVR”
Analog DVRs usually record in 480TVL (D1), 600TVL, 650TVL, or 700TVL (960h), and the absolute highest resolution that an old Analog DVR can view is 720TVL. If you are hoping to hook up a 1000TVL camera and get better resolution on your existing analog DVR, you will be disappointed when you only get 720TVL. It doesn’t matter how good the image sensor is in the camera, because as far as Resolution goes, your system is only as strong as your weakest link.
TVL has Always Been Deceiving
TVL as a measurement standard has always been mostly made up since the beginning. When TVL was the normal way to measure camera resolution, manufacturers made up their own formula to make their cameras sound a little bit more appealing. For instance, if you were to truly test a 700TVL camera using a resolution chart, you would find that it can actually only decipher 525 TV Lines. Here’s how the manufacturers turned 525 into 700 magically:
525 (actual readable TVL) ÷ 3 x 4 = 700TVL
Using this “creative math,” that 1000TVL camera would really be a 750TVL camera. But since Analog DVRs max out at 720TVL anyhow, nothing beyond that matters.
Make Sure It’s HD
The best way to ensure that you’re getting a High Definition camera is to avoid any camera that uses “TVL” as a way of measuring resolution. The true HD resolutions are 720p, 1080p, 4 Megapixel, and 4K (8 Megapixel).
Security camera systems that use Cat5 or Cat6 ethernet cable are always going to have the best resolution. If you are setting up a new system, you should be looking at IP cameras that use Cat5 cable and Power Over Ethernet. This is another way to be sure that your cameras will record in HD.
This doesn’t make cameras that run over Siamese Coax cable and BNC connectors completely obsolete. There are certain technologies that can record decent High Definition using those old “analog cables.”
If you are looking to upgrade an old Analog CCTV System to HD and use the same cables, you should look at a true HD over Coax technology like HD-TVI. Keep in mind that an HD-TVI camera will only get you HD resolution if you have an HD-TVI DVR as well, meaning that you cannot connect an HD-TVI camera to an Analog DVR.