Closed-circuit television (CCTV) is the cornerstone of security when it comes to your home or place of business. We will discuss how CCTV cameras work and explain their function and the benefits of security around these products in further detail.

CCTV or Closed-circuit television is a video surveillance system that works by recording or displaying footage from one or more cameras and transmitting the footage to one or more monitors. The owner can view the video in real-time or as it’s being recorded to a DVR/NVR or directly to the cloud.

To understand this answer in a bit more detail, I have written this article to explain further how these systems work.

In earlier years when CRT monitors were around, CCTVs were being used for security to keep an eye on employers, people who aren’t authorized to be on private property, or keep public areas safer.

Although there are a wide variety of CCTV cameras, I have put together some information to cover as many different types as possible to paint the most complete picture I can.

What is a CCTV camera?

A CCTV camera is a camera specifically designed for surveillance that is capable of recording video (and sometimes audio) with enough lens angle to maintain enough visual clarity while maintaining a wide enough view within today’s current limitations of technology.

These kinds of cameras are usually built to be vandal proof although certain types of CCTV cameras are vulnerable to physical damage.

These are usually the cheaper variety or ones used more for home use. They are often a camera concealed inside an acrylic dome.

The camera’s audiovisuals get transmitted by the means of a network connection to a central location where the information is stored or viewed.

A CCTV camera is commonly equipped with IR lighting, so the camera has plenty of light to record at night while isn’t visible to the naked eye.

How a CCTV camera works

An image/imaging sensor from inside a camera.

A CCTV camera works like most cameras in that it takes reflected light from objects and focuses it through a lens which focuses the light onto an internal image sensor.

There are a few different types of image sensors. But for CCTV cameras, CCD and CMOS image sensors are most commonly used.

The image sensor data is processed further with some internal electronics within the camera and sent out as wireless or network data. This is where CCT cameras start to work a little differently.

Most CCTV cameras work off motion. This saves storage space for recorded footage as the camera will only start recording once any kind of movement is detected.

This sometimes has an unfortunate disadvantage when a camera is installed and directed toward a tree on a windy day to mention one example.

How CCTV cameras connect up to a surveillance system

An install technician is connecting up CCTV cameras.

We will cover the two main types of connectivity, namely wired and wireless, a little further along in this article.

For now, let us focus on how these cameras integrate into surveillance systems. In most cases, cameras are connected directly to a centralized DVR or NVR.

These units are usually located inside some sort of control room that has increased security in order to gain access inside it.

The recording devices either store the camera footage in a local storage unit which can be accessed remotely, for both the stored footage and the real-time feed.

Cloud storage is another way that these systems can store recordings and offer some additional benefits like securing the recordings straight after the cameras have begun recording to data centers or servers with plenty enough redundant backups to ensure your information never gets lost.

Different styles and features of various CCTV cameras

There are many differences between the makes and models of CCTV cameras. Here are some features that are offered by various cameras.


Some models of camera offer recording directly to an onboard SD card. This takes away the need of connecting the camera to anything and allows it to function as an independent unit.

For most of these kinds of CCTV cameras, they offer one or more connectivity options in addition to being able to store the recorded footage directly on an SD card.


Here is a comparison of the two connectivity options when it comes to CCTV cameras.

Wired connectivity

A CCTV install technician crimping the end plug on CAT cacble.

Some CCTV cameras offer a wired-only connection to the DVR or NVR. This is usually done using CAT cable used in networking.

Of course, CCTV cameras come in both wired and wireless, but let’s look at wired connections first.

CAT cable is an excellent way to transfer data over a wired connection as this is what it was designed for.

The shielding and solid core cable strands allow for excellent bandwidth and interference reduction.

Most security camera installers will have rolls of ethernet or CAT cable on hand and crimp on the connectors at both ends after the cable has been correctly installed.

The wired connection is the most reliable and able to maintain good connectivity over longer distances.

Wired cameras will be able to deliver a more consistent and quality image compared with wireless cameras.

Wireless connectivity

A wireless or WiFi CCTV camera.

One obvious beneficial feature of wireless CCTV cameras is the ease of installation. You don’t need to run any cables over a long distance to get them working.

However, you will need to perform a signal quality test before considering installing a wireless-style camera.

It may be easiest to purchase one to test first. If it doesn’t work out, you could keep it for the closest camera to the control room if at all possible if returning it isn’t an option.

Another way to test the signal is to set up a wireless router in the control room and take a laptop to the location where you need your camera.

Check the signal quality to establish a baseline as to whether a wireless camera would work.

Seeing as there are many factors to diminished signal quality and strength, a practical test is always a sensible choice.

It only takes a wall with metal inside between the central location and your camera to ruin the signal making it a no go.

So, there are no guarantees that things will work reliably with a wireless connection, so it’s always a gamble in this situation.

Mounting style

There are a few different mounting choices for CCTV cameras when it comes to brackets and camera design.

There are mounting variants for each of the following, but here are some examples:

  • Wall mount. (I shape, L shape).
  • Ceiling mount. (I shape, U shape).
  • Pole mount. (All various proprietary designs).
  • Universal brackets. (Swivel, three-dimensional adjustable joint).
  • Box or junction mounting. (Round, square).

In addition to this, CCTV cameras come in body mount options for various applications like the police to name one example.

Built-in lighting

A close up of a CCTV camera with infrared LEDs.

More often than not, CCTV cameras have an array of Infrared LEDs built around or somewhere on the camera to shine IR light in the direction of where the camera is recording from.

This is excellent for poorly lit areas at night where you don’t have an outside floodlight or lights turned on inside a building.

As we can’t see this type of light with our eyes, it allows clear vision filming in the darkest conditions where people aren’t able to see given the poor lighting conditions.

Casing style

There are various different styles of cameras depending on their function. Here are some examples:

  • Bullet-style cameras.
  • C-mount cameras.
  • Dome-style cameras.


Like with any camera, you get various image resolutions which are usually reflected in the price tag. HD cameras range anywhere from 720p to 1080p or better.

Some older non-HD cameras wouldn’t be desirable as you would see much when the time comes to review footage for any given needed situation.

So it goes without saying that anyone would want the best resolution possible when choosing a camera. The best resolution suited for the budget that is.


Not all CCTV cameras are able to deliver audio with the feed. Some older models don’t have this feature and it’s important to check to see if the one you are looking to buy has sound capabilities if it’s something you need.

I would recommend getting CCTV cameras with audio. It’s better to have it and not need it, but have it when you do need it. You simply never know.

Power sources

Some CCTV cameras are powered with the CAT or ethernet cable. This makes the wired option more attractive as you only have to be concerned with one cable.

Wireless cameras can have a power adapter or power brick that is required to be plugged into an outlet to function.

While other wireless cameras can operate off batteries. It goes without saying that this option does have a major drawback and you had best set up a schedule for replacing batteries to keep it going.

Another type would be solar power in conjunction with a rechargeable internal battery. It charges the battery throughout the day and relies solely on the battery at night.

Solar-powered cameras for wireless connectivity is the preferred choice as you won’t need to replace the battery as often. You will only need to replace the battery after it has gone through its expected lifespan of cycles of draining and charging.


Some CCTV cameras have motorized motion capabilities that allow cameras to be rotated to specific areas of choice by either automatic control or manual control which also can be done remotely.

This allows cameras to pan left and right, as well as up and down. It opens up the surveillance area for cameras a great deal.

Quite often this feature is present on cameras with zoom capabilities to make observations in specific places of better quality.

These kinds of cameras are commonly referred to as PTZ (Pan Tilt and Zoom).


There are two main types of zoom technologies used in this feature.

  1. Optical zoom. This relies on the manipulation of the lenses themselves.
  2. Digital zoom. This is simply a software-based solution that zooms into the image itself.

There is no question that optical zoom is superior. Having the lenses so the work of bringing something closer into view will deliver higher quality and less pixelated image.

You can think about digital zoom as viewing an image on a computer or phone and zooming into it. As you zoom further into the image, you will notice how the quality quickly drops leaving you with a grainy and sometimes unviewable image.

When lenses are used to zoom, the light is concentrated further into a specific area by using the lens to make a form of magnification.

Seeing as you are doing this before the image gets processed by the image sensor, you get a better quality result.

How the outdoor elements affect CCTV cameras

Two main types of cameras are found on the market today in terms of the chosen construction and materials. Ones made for indoors and others that are made for outdoor use.

Obviously, it will be a bad idea to use an indoor camera outside. It will rust and corrode in no time, leaving you with something that probably needs to be thrown away.

Outdoor cameras are designed to withstand the various elements that the outdoors subject upon them.

Sunlight over time and water are the two major concerns. The sun causes plastics to go brittle and water can cause metal corrosion or rust.

So, outdoor cameras are designed with special seals to stop water from entering anywhere internally inside the camera.

Quite often installers must be careful when installing cameras outside. Directions must be followed as per the manufacturer to ensure that the product remains waterproof after cables are installed and the camera is finally mounted.

How CCTV cameras are usually set up

A wireless CCTV camera baing fastened to a wall.

The camera is more desirably mounted on a wall or ceiling high enough that potential vandals have a difficult time gaining physical access to them or noticing them.

Cameras are usually placed in multiple locations to provide some overlap of all the possible areas that need to be monitored.

The importance of using multiple CCTV cameras

It is seldom the case that one CCTV camera is enough. In most situations, a network of carefully placed CCTV cameras ensures that there is less chance of dead zones.

This means that if someone knows the camera viewing locations, they can conduct whatever bad business they wish where cameras are unable to view them.

This can be detrimental to the entire surveillance efforts and can render an entire CCTV system useless as a result.

So it’s vital that careful planning and testing are carried out to make sure every angle is covered by the camera system.

When do you need a CCTV camera?

Whenever you feel that monitoring a specific location with video or audio surveillance could solve a problem for you, this is the time to consider a CCTV camera.

The possible list of needs is so extensive that I wouldn’t even try to list most of them.

But just be aware that there is a camera at a convenient price point for most situations. You won’t always need an expensive camera for certain needs.

Uses can be anything from trying to provide a little home security to making sure a large business property remains carefully surveilled to persecute unwanted wrongdoers.

Smart CCTV camera and surveillance systems

Smart CCTV cameras and surveillance systems are evolving to become equipped with what most people refer to as smart technology.

They now are able to detect in more detail, identify behaviors, and employ facial recognition, as well as smartphone interaction.

While some feel that this is becoming a problem and is gradually taking away our privacy rights, others feel that these features help provide an extra layer of security.

Another advantage, recording directly to the cloud, is a great way to avoid potential perpetrators from grabbing your storage unit to get rid of the evidence.

All the recorded videos or images are stored on cloud storage to make the retention of data safer and more robust.


CCTV Cameras are sophisticated devices that are becoming more and more affordable as time goes on.

Gone are the days when surveillance technologies were only available to people with deep pockets. More features are available with even the cheaper cameras making them a potential solution for a lot more usage cases.

Smart doorbells are an example of a scaled-down version of these cameras and offer excellent security features for your front door area.

So now that you know a little more about how they work, you can make better decisions when purchasing or considering CCTV cameras.