The megapixel value is simply a shorthand means of expressing the camera's image resolution in a single figure.
Multiply the horizontal resolution by the vertical resolution to arrive at a value which expresses the total number of pixels that the image device can deliver.
Because this multiplication, typically of thousands times thousands, results in such a large value we use the term mega (indicating 10 to the power of six, which is 1,000,000) to express the result.

CIF, QCIF, 2CIF, 4CIF. Sounds like a bad nursery rhyme, right? If your eyes glaze over when you hear terms like these you are not alone.

The table below lists some of the more commonly used resolution terms in CCTV applications. Any resolution over 1 million pixels is considered 'megapixel'. In the case of megapixel cameras, the labels are approximate. For example, a 2 megapixel camera actually captures 1,920,000 pixels per frame. A 3 megapixel camera captures 3,145,728 pixels per frame.

 

Term Pixels (W x H)

720p - HD1280 x 720  "1Megapixel""

960P - 1280 x 960  Sony specific HD standard  "1.3 Megapixel 1280 x 1024" 

1080p - HD  1920 x 1080      "2.0 Megapixel"

3 MP - 2048 x 1536 Megapixel

4MP 2688*1520  "4.0 Megapixel"

5 MP - 2592 x 1944 Megapixel "5.0 Megapixel"

 

Those of you familiar with CCTV know that the resolution of an analog camera is typically listed as "TV lines". These "lines" refer to the horizontal resolution of the image; therefore a 700 line camera has better resolution than a 420 line camera. Digital video recorders, however, list their resolution according to the terms in the chart above. DVRs that are 'Full D1' can record all the detail captured by the highest resolution analog cameras.

One of the most common questions we get is "What resolution camera should I buy?" Of course, it depends. Each camera in your application may require a different resolution. It comes down to how much detail you want, what platform (if any) you already have in place, and how much is your budget. Examples of applications where you can easily justify spending more for higher resolution are recording monetary transactions, desiring facial recognition, or reading license plates.