How do CCTV cameras work & can Cheap CCTV cameras be worth it?
Why buy a CCTV setup for your property?
If you watch any crime show, real or fiction, you’ll notice that one of the first things the inspectors look for is – you’ve guessed it, witnesses!
Of course, producing an e-fit from your cat’s recollection isn’t possible, so the next best thing is snapping the perpetrator in the act. And we’re not just talking so that you can get the thief behind bars; if you have a snap of a thief in the process, you straight away know: What they look like, What they were wearing, if it’s someone that is already known to you, or the police, what car they towed your boat away with, the list goes on!
So it’s no surprised that residential CCTV installations are rising daily. But with certain companies charging an arm and a leg for ‘consultation’, it can be a very costly process. Some information that just might help you wade through the waters is below that we hope helps whether you decide to DIY install a camera kit or hire professional assistance.
There are several elements that we recommend you consider in your purchase.
1) What is the purpose of your system?
Seems simple, doesn’t it? But think about this. A camera is both surveillance AND a deterrent. We often see clients purchasing dummy cameras for a standalone deterrent, but we also believe that high visibility cameras means that the crooks know where to hide from, or to go equipped. Whilst you need signage to notify that the recording is in place, it’s often an idea to mix more visible cameras, with slightly more covertly placed ones!
2) What do you want to watch?
This affects your choice of camera entirely. Camera viewing angles can vary greatly, and whereas a narrow field camera with a viewing angle of 30 degrees might be perfect for a hallway, it’s going to miss a lot of information if you place it on a driveway or overlooking a courtyard!
3) What are the lighting and environmental conditions?
The positioning and setting of your setup will directly impact the cost. If you’re in a well lit environment, that you perhaps only want to watch by day because you’re home at night, or perhaps it’s constantly lit, then you can get away with a much more basic camera. If it is completely dry, then you may not need to worry about waterproofing (however with many cameras in our range coming equipped to this spec as standard, it may just be an added bonus!)
4) How much coverage do you need?
You need to assess how many cameras you need to cove your area, with the simplest way being to find out what sort of viewing angle you have on your camera of choice, draw a plan of your house and plot the cameras on this plan. Make a plan of what you want to watch and it will make it much simpler to assess how many cameras you require.
5) How do you want to connect and record your footage?
Whilst traditionally, you would record via wired cameras and a DVR. However technology widely available today means that there are the options of local DVRs with Wireless cameras which has the advantage of ease of installation with no chasing of camera cables. Some cameras even come battery powered for this purpose but that does induce a lot of maintenance for obvious reasons.
Cloud recording is become increasingly popular – this has not only the advantage of not having a hard drive that could become corrupted, or vandalised by an intruder, but also allowing you to remotely view your cameras from wherever you might be in the world! The below shows a typical example of how a DVR based kit addresses this, connecting each camera to your DVR as per normal,, in turn to your own router to allow you to stream your footage! Some DVRS allow you to record on the hard drive as well as streaming which gives you double the backup!
There are of course variations to this, with some kits removing the DVR altogether. This is usually achieved by LAN based cameras which are wired to a network switch and then directly to your router, like our 16 camera kit. This removes the need for of high cost, high-capacity hard drives.
How a CCTV Camera Works
CCTV, or closed-circuit TeleVision cameras are cameras connected to a centralised recorder as opposed to being broadcast. The cameras themselves at the basic level consist of a lens, a sensor, a digital signal processor all encased within the body. Added to that you require a means to record or view your footage. There are also variations on this as below with some cameras having integral LED or Light Emitting Diodes around the lens to bathe a scene in infra-red light to enable night recording and more kits today are coming equipped with wireless transmittal.
The Right Lens
The lens is effectively the first component in your CCTV setup. Everything that you see comes through the lens. The lens is what gathers the light for the sensor. Everything the viewer sees, or that gets recorded on the DVR comes through the lens. It determines the distance at which a car’s number plate can be read, and a face can be recognized because the lens controls focus just like your handheld camera. The lens therefore controls the viewing angle and depth of vision.
The Right Sensor
Most CCTV camera sensors are either CMOS or CCD. CMOS being less expensive and less power consuming, but it is also less sensitive and can produce a noisier image, which of course is what you don’t want if trying to identify the man who is stomping on your petunias! This in turn means that CMOS sensors require better processors to produce a usable image.
The Sensor Size is also an important factor. Just like your DSLR or even your point and snap camera, the larger the sensor, the more light it can absorb and the higher quality picture it can produce. Most commonly, CCTV cameras will have 1/4 inch or 1/3 inch which has over twice the surface area. A large sensor means more light. More light means more detail. More detail means more information for the DSP to process which helps for the less premium DSP’s that might not be as capable as some others.
The right Resolution
One common specification traditionally for CCTV cameras is the number of horizontal lines of TV resolution it outputs; it’s TVL. This can range up to 700TVL. Many cameras range from 380 to 540, but many experts attest to 420TVL being a good workable resolution. That said, it depends on your deployment, some areas simply won’t need high resolution if the light is good and the target nice and close. It’s also worth nothing that the output is governed by the input which falls on to the DSP. So if the DSP simply can’t process the high resolution sensor’s information it is effectively wasted. The correct resolution is the resolution that can handle the camera’s output, anything more and you risk overspending for little benefit.
CCTV Camera Types
Like people, cameras come in an assortment of shapes and sizes!
Bullet Cameras
Small, tubular cameras, often used discretely. Perfect for around the home or in shops .
Dome Cameras
You will have seen dome cameras in high population areas. This is because the protective dome around the camera not only protects it from malicious attacks, but it also obscures where the camera itself is pointing due to the tinted casing.
Day/Night Camera
The typical box shaped InfraRed cameras have the advantage of round the clock coverage indoors or outdoors, producing a colour image at day and black and white at night. Noticable but extremely versatile and often rated for waterproofing.