2K Security Cameras are not 2x1080P - Misleading Marketing Claims
0.89% more is not "double the resolution"
Recently we came across this absolutely terrible, mathematically-impossible, marketing claim.
What is 2K?
2K is half as wide as 4K - which is the new standard for Ultra High Definition TVs, and, like 4K, it can refer to a few different resolution combinations that have a common theme.
Both 2K and 4K are using the Roman numeral K as shorthand for 1000, which then means that 2K refers to any number of resolutions that are approximately 2000 pixels wide and 4K refers to a bunch of resolutions that are approximately 4000 pixels wide.
1080P TV is 1920 by 1080 pixels. So, a 2K TV could be 2000 x 1080--only 80 pixels in length more than a 1080P TV.
2K is certainly not double the size of 1080P! 1080P (1920 by 1080P) is even considered 2K by some people as it is approximately 2000 pixels wide.
Using its most strict definition of 2000 pixels exactly, 2K is only 0.89% wider than 1080p.
2K vs 4K vs 1080P - a Visual Representation
Here's a visual from CNET showing the area difference between a 1080P, 2K, and 4K screen:
It is absolutely obvious from this image that 2K is NOT twice the resolution of 1080P.
What is 4K?
4K is twice as wide as 1080P and twice as tall. This means that the area is four times as large. In other words, if all the pixels were exactly the same size, you can fit four 1080P TV's in the space of a single 4K TV, as shown in this image.
Resolution vs Pixels
Most people refer to 4K TVs having four times the resolution of a 1080P, but a more technically correct way of phrasing this would be that 4K has four times the number of pixels as 1080P. Our language hasn't caught up with technology and this is a colloquial way that we talk about a television's resolution.
The problem is the word "resolution" can mean "density of pixels in an area" or total pixels.
Consider the way that we talk about printers, for example. DPI (Dots per inch) is a measurement of pixel density, not the total number of pixels, and is the normal way of talking about printer quality. We often say that a 300 DPI printer is "twice" as good as a 600 DPI printer, but a 600 DPI printer has four times the pixels of a 300 DPI printer because DPI measures both the horizontal and vertical density.
Our language with TVs doesn't typically use DPI and instead people usually talk about total pixels. Talking about resolution this way is normal for televisions and cameras, but can be very confusing for people who are more used to printers. Therefore, it is a better practice to include the total pixels or total image quality when talking about, for instance, dome camera quality. This is why we always display the total number of pixels and image dimensions on all our cameras models.
4K is 3840 x 2160 pixels or 8,294,400 total pixels.
An 8MP camera records in 4K because "MP" stands for "mega" pixels. Mega is Latin for "million." So, an 8MP camera is recording 8 million pixels, just like 4K.
How many megapixels is 1080P?
1080P is 1920 x 1080 or 2,073,600 total pixels.
If 8MP is 4x 1080P, what's double the resolution of 1080P?
4MP is 2560 x 1440 or 3,686,400 total pixels, which is close to 2x the size of 1080P*.
*editors note: despite having a 4 million pixel sensor, 4MP cameras record approximately 3.7 million pixels in order to fit correctly on a monitor. This is a strange quirk of how images are displayed on screens, but it is industry standard.
Back to the original claim
What could this company do to make this "double the resolution" claim true?
If they were selling 4MP cameras as double the number of pixels as 1080P, they would be much closer to correct and within industry standards for communication. There's no way that a 3MP camera with 3 million pixels is two times the resolution of a 1080P camera with 2 million pixels. That's nonsensical.
Here are some 4MP cameras that are true twice the resolution of 1080P
Looking for a complete 4MP system? In the menu at the top of this website, there's a link that says "systems" delineating them by the number of cameras. In each of those pages, there are two different 4MP systems. If you need a 4MP four-camera system, look for the "systems" link at the top of the page, click on "4 Camera Systems" and then scroll down. Two of the three systems on that page will be in 4MP resolution.