Megapixels are easy to sell. Eight sounds better than four, and four sounds better than two.
But resolution is only one part of image quality, and in real security footage it is often not the part that determines whether you can actually identify what happened.
A sharp daytime image on a product demonstration tells you very little about how useful that camera will be at eleven o’clock at night when somebody is moving through a poorly lit driveway.
What megapixels actually tell you
Megapixels describe how many pixels make up the image.
More pixels can capture more detail. That matters when you need to zoom into a face, clothing, a vehicle or another identifying feature after an event.
So resolution is not meaningless. All else being equal, a higher-resolution camera can produce a more detailed image.
The problem is that all else is rarely equal.
Night is where cameras separate
Most modern security cameras look reasonably good in daylight. There is plenty of light available, so even fairly ordinary equipment can produce a clean image.
At night, the differences become obvious.
A camera has much less light to work with. The sensor, lens, exposure settings, infrared performance and available lighting suddenly matter just as much as the number of pixels.
A high-resolution camera with poor low-light performance can produce a detailed image of noise and motion blur. A lower-resolution camera with a better sensor and better lighting can produce footage that is far more useful.
This is why a properly specified CCTV system installation needs to consider the actual lighting and viewing conditions at each camera position, not simply the resolution printed on the box.
Motion blur ruins more footage than low resolution
A person standing still under good lighting is easy for almost any modern camera.
A person walking quickly through a dark side passage is different.
In low light, cameras often use a slower shutter speed to gather more light. The image looks brighter, but anything moving through it can blur.
That is how you end up with footage that looks perfectly acceptable when nothing is happening and becomes useless at exactly the moment you need it.
The solution can be better camera hardware, better configuration, additional lighting, or a combination of all three. Simply replacing a four-megapixel camera with an eight-megapixel one does not automatically solve it.
Camera position still matters
Resolution cannot recover detail the camera never captured properly in the first place.
If a camera is mounted too high, a higher-resolution image may simply give you a clearer view of the top of someone’s head.
If a person’s face occupies a tiny part of a very wide scene, there is only so much useful identifying detail available even from a high-resolution image.
If the camera is pointing toward a bright light source, additional pixels will not fix the exposure problem.
For residential properties, home security camera installation should therefore start with the areas that need to be identified and the conditions in those areas, then select cameras and positions to suit.
Infrared has limitations too
Infrared lets cameras see in darkness, but it is not magic.
Its useful range is limited, reflective surfaces can cause problems, and objects close to the camera can become extremely bright while the area behind them remains dark.
Spider webs are another surprisingly common problem. They sit close to the infrared LEDs, reflect strongly at night and can dominate the image.
Sometimes a small amount of ordinary lighting produces a better security image than relying entirely on infrared.
More resolution means more storage
Higher-resolution footage produces larger files.
That means an eight-megapixel camera generally uses more recorder storage than a lower-resolution camera running comparable settings.
If you upgrade the cameras without increasing the recorder capacity, the system may keep fewer days of footage than it did before.
That trade-off matters because there is little value in having extremely detailed footage if it has already been overwritten by the time you realise you need it.
We cover that relationship in more detail in our guide to how long CCTV footage is stored.
Do not judge an existing system from one daytime image
If you already have cameras and are considering an upgrade, check what they actually do at night before assuming resolution is the problem.
Look at footage when somebody is moving, not just a still frame. Check faces at the distances that matter. Look for glare, blur, infrared reflection and areas that disappear into darkness.
An existing system may need different settings, better lighting, repositioning or maintenance rather than an entirely new set of higher-resolution cameras.
A CCTV maintenance and repair check can identify whether the limitation is the camera itself, its configuration, lighting, positioning or the recorder.
What to compare instead of the number on the box
When comparing cameras, megapixels should be one item on the list rather than the whole decision.
Look at:
- Low-light and night performance
- Sensor and lens quality
- How moving subjects look at night
- Infrared performance at the distance you actually need
- The camera’s field of view and intended position
- How much storage the chosen resolution will require
The best camera is the one that produces useful footage in the conditions where you actually need it, not necessarily the one with the biggest resolution number.
Security installation is licensed work in New South Wales. AVsion holds Security Master Licence 000103421 and Security Operator Licence 000233371. All installation work carries a 12 month labour warranty.
Written by Yariv, Owner and Lead Installer at AVsion. 14 years installing AV, WiFi and security systems across Sydney’s eastern suburbs.
Frequently asked questions
Do more megapixels mean better security camera footage?
Not necessarily. More megapixels give the camera more resolution and potentially more detail, but useful footage also depends on the sensor, lens, lighting, camera position, exposure and how well the camera handles movement. A high-resolution camera with poor low-light performance can produce worse identifying footage at night than a lower-resolution camera with a better sensor and better lighting.
Why does my security camera look good during the day but bad at night?
Daylight gives the camera plenty of light to work with. At night the sensor has much less available light, so exposure, infrared performance, sensor quality and nearby lighting become much more important. Cameras may also use slower shutter speeds in darkness, which brightens the image but can cause moving people to blur.
Why are faces blurry on my CCTV footage at night?
Motion blur is a common cause. In low light, a camera may use a slower shutter speed to gather enough light, and a person moving through the scene becomes blurred even though stationary objects look sharp. Better lighting, different camera settings, improved positioning or equipment with stronger low-light performance may solve the problem.
Is 4K CCTV always better than 1080p?
No. 4K provides more resolution, which can be useful when you need additional detail, but resolution alone does not determine image quality. A well-positioned lower-resolution camera with good low-light performance can provide more useful footage than a poorly positioned 4K camera. Higher resolution also requires more storage.
Does higher CCTV resolution use more storage?
Yes. Higher-resolution video produces larger files, so increasing camera resolution without increasing recorder capacity can reduce how many days of footage are retained. Resolution and storage should therefore be specified together rather than treating them as separate decisions.
Can an old CCTV system be improved without replacing every camera?
Sometimes. Poor footage can be caused by incorrect settings, bad positioning, dirty lenses, infrared reflection, inadequate lighting or recorder configuration rather than the camera resolution itself. Checking the system in the actual conditions where it performs poorly, particularly at night and with moving subjects, helps identify what genuinely needs upgrading.
