How many megapixels (or “MP”) your camera has can greatly affect the quality of your CCTV footage. This number can be a great starting point for comparing cameras, and it’s often the first thing we look at. While it’s generally a good indicator of how a CCTV camera will look, there’s more to the story.
What are Megapixels (MP)?
We use megapixels as a way to describe the quality of a camera because it’s a simple number to understand. The more megapixels it has, the better the camera should look. Instead of saying a surveillance camera has a total 2,073,600 pixels, we make things easier for ourselves by just saying it has around about 2MP.
The ‘Mega’ in ‘megapixels’ is a prefix that equates to a factor of one million (1,000,000). If an image contains a total of 1,000,000 pixels, we could also say that it has just 1MP.
We can find out the total number of pixels a camera has from its resolution. A CCTV camera with a resolution of 1080 pixels by 1920 pixels has a total of 2,073,600 pixels, or roughly 2MP. We get this by multiplying the pixel dimensions of the screen together (i.e. 1080 * 1920).
Advantages of Having More Megapixels
The most obvious advantage of having more megapixels is the increased clarity of CCTV footage. Something like an 8MP CCTV camera will tend to produce a considerably cleaner & better looking image than a camera with 2MP or less. The benefits of this does vary between different use-cases and personal preferences.
In addition to looking like a higher-quality image overall, cameras will be capable of capturing more fine details. This can be an important advantage in many circumstances as low-quality footage can easily obscure critical details. Such details might include the faces of any persons of interest, identifying features like tattoos, vehicle number plates, and so on.
We’ve all seen CCTV footage of criminal activities where any important details are too blurry to be useful and faces are completely unidentifiable. Such footage is almost always produced CCTV systems equipped with low-MP cameras and/or analogue cameras.
Higher resolution cameras also offer more flexibility when it comes to positioning and installation. The CCTV camera can be placed further away from an area of interest without sacrificing clarity or details. This gives it a superior field of view over equivalent lower-MP CCTV cameras, allowing it to capture more of the scene than normally possible.
Disadvantages of Having More Megapixels
There are a few notable drawbacks of higher resolution cameras which can vary depending on how the CCTV camera is being used. The first of which is the storage requirements that come with a high-resolution camera.
Upping the megapixels of a surveillance camera produces significantly more video data that all needs to be stored somewhere. While compression algorithms (which you can read more about here) have come a long way, they aren’t magic. If high resolution cameras are a must, data storage capacity will need to be increased to accommodate them. The cost of this can fall outside of some budgets. The alternative to purchasing more storage space would be to keep CCTV footage for less time before being overwritten.
With that, another major disadvantage of higher-resolution cameras are the price tags. As the MP of a camera increases, the retail price of that camera tends to go up. This means some of these cameras will be out of the price range for home installations, some small businesses, etc. Fortunately, this isn’t always such an issue depending on how the CCTV camera is being used
Although this isn’t necessarily a disadvantage, having more megapixels isn’t the only factor that affects footage quality. Details like the quality & size of the camera’s sensor also have a large hand in determining how visually accurate the image is. Flashy features like ‘Backlight compensation’ or ‘3D Dynamic range’ have a similar contributions.
In short, while MP count is a strong starting point, having more doesn’t always mean you’ll get better footage on the other end.
Limitations of High-Res CCTV Cameras
While ‘the more the better’ is generally true and the way to go for many different types of installations, there are a handful of limitations that apply. Some of these might mean a high-MP camera could become redundant in certain situations or be a less cost-effective solution.
Aside from the actual specs of a CCTV camera, the transmission medium has the largest influence over footage quality. Both wired and wireless mediums can negatively impact transmissions for different reasons, and are often responsible for unexpected drops in quality. For example, a 5MP digital CCTV camera will tend to produce more consistent & higher-quality footage than an equivalent 5MP analogue CCTV camera.
Analogue camera cables tend to be more susceptible to interference and drops in quality over long distances than ethernet cables. Similarly, wireless surveillance cameras can experience considerable drops in quality depending on signal strength and network speed. It’s important to consider these medium limitations when deciding on a camera, as they often determine how footage looks on the other side.
Another limitation of high-res cameras is the lack of benefits they offer in certain applications. While having more MP will produce a more detailed image, this isn’t always necessary. A CCTV camera installed to monitor a single static point like a cash register or door typically won’t benefit from having an obscenely high resolution. In such applications, using a larger lens size can have the same result as installing a higher resolution camera.
So What’s the Verdict?
To summarise things into one sentence – Bigger is better if you can afford it, but it’s not the only thing you should be looking at. Having a CCTV camera with more megapixels will produce a more detailed and better looking image overall. This comes at the cost of storage space and bigger price tags, which can put high-res cameras out of reach for lower-budget systems.
Despite the advantages, it’s simply not necessary for certain applications (depending on requirements) - but can prove to be a valuable asset in most surveillance systems.