Guide to CCTV - Introduction
There are a vast range of CCTV products and prices to choose from in the marketplace but little information to help discriminate between them. Here are some examples.
A camera described as good in low-level light will often not produce images at night unless there is additional lighting. There may be no explanation or qualification of the term low-level light.
Wireless cameras can be fitted in minutes as there are no cables to run back to your TV or monitor. However, the cameras still require a power source and while battery power is convenient the consumption is great giving a working time of less than 24 hours (as low as 2 on some products tested).
Wireless connectivity is nevertheless very useful for some applications as described later.
There are plenty of professional CCTV installers who will give you a site survey and recommend appropriate products but, of course, you pay for this service. Modern technology has now made CCTV products much more affordable and they can be very easy to fit for the average DIY person. This guide will help you choose the correct products and show some simple methods of fitting complete systems to domestic and commercial properties. DIY CCTV Systems can easily be fitted by people with moderate DIY skills.
The traditional CCTV camera has a very industrial style and, therefore, many people would not find this suitable for fitting to their homes or shops.
This traditional style is actually a housing that is designed to keep the camera dry and within the recommended operating temperature. Thermostatic heating elements within the casing also reduce condensation and misting.
These types of top-end cameras are usually specified without a lens, this being chosen to give the required focal length and field of view. Motorised pan and zoom lenses allow an observer to follow or move in closer to the person or object in view.
We can supply these types of cameras to those of you who do not find the price prohibitive. Please contact 2SEETV with your requirements.
Fortunately, for those of us with more down-to-earth budgets modern technologies now allow the production of cameras with excellent performance. There are two common types of CCTV cameras, CMOS and CCD (see glossary of terms). CMOS sensors were used for the lower quality cameras. However, with the introduction of High Definition CMOS sensors from Sony this is no longer the case.
There is little point installing a CCTV camera if it is incapable of allowing you to easily identify who or what is being captured and recorded. CCD and HD CMOS cameras provide pin-point clarity and should be specified wherever possible.
The KT&C, and Concept camera range, in general use the Sony chipsest. Beware of competing products that do not state whose chipset is used.
At the lower resolution the Sharp sensor is now extremely good and is ideal for vehicle cameras.
Integrated cameras and lenses often referred to as "bullet cameras" are sealed to prevent ingress of moisture. The sealing is so good that they can be permanently immersed to some considerable depth in water if required.
Bullet cameras do not need a heater and their small size makes them highly suitable for fitting to domestic and commercial properties. It is not possible to make adjustment to these cameras because they are permanently sealed. Most of the bullet cameras in the 2seetv store are fitted with a 3.6mm lens which gives a 72 deg angle of view which is suitable for most domestic and small commercial properties. Please contact us if you require alternatives.
Another type of enclosure is the Anti-Vandal dome. Again the cameras are sealed and often specified with IR LEDs for nightvision. These type of cameas are now the most popular for domestic and commercial installations.
Choosing a Camera Specification
The main criteria of a camera's performance are its sensitivity and resolution. Secondary considerations are colour or monochrome and indoor or outdoor suitability.
Sensitivity is the camera's ability to respond to light levels. Resolution defines the amount of picture detail in the image produced by the camera.
This is expressed as the number of television lines that the camera is capable of producing. For example a basic bullet camera may have a resolution of 420TVL.
Cameras with much higher resolution have become more affordable in recent times, with small dome cameras now offering 1000TVL resolution.
IP Cameras (Internet Protocol) offer resolutions of 720p(1280 x 720) and 1080p (1920 x 1080). They are connected to recorder by CAT5 network cables.
The latest format is HD-Turbo or HD-TVI. These cameras offer 1080p resolution but the images can be sent over standard coaxial cable.
Whichever type and resolution of camera chosen it must be matched to suitable recorder.
Indoor and Outdoor Cameras
Dome and Bullet style cameras for outdoor use must be water resistant. The specification is classed as a number from the Ingress Protection scale. Typicaly cameras to be mounted on a building need to berated at IP66 or higher. Vehicle cameras need a much higher rating to withstand the force of water at speed.
A common idea to reduce installtion costs is to place a camera inside on a window sill looking out over a garden or drivewat. At night the IR nightvision beam will be reflected back from the window glass so you will see nothing outside. The camera must be mounted on the exterioe of the building.
Displaying more than one camera image
This was traditional achieved using a Switcher, a Quad or a Multiplexer. Modern digital recorders now incorporate a multiplexer that will allow you to display one or many camera images on screen at the same time. They also offer the functionality of being able to continue recording images while playing back stored images.
Recording CCTV Images
A digital video recorder will take analogue images from a cctv camera, digitise them and store them electronically. The most common media for storage is a hard disk drive as used in most personal computers.
Most DVRs now come combined with multiplexer and motion detect functions and are generally considered the future of cctv recording.
If using 1000TVL resolution cameras you will need a DVR with a resolution of 960H to achieve the best results.
HD-Turbo cameras need an HD Turbo recorder to achieve the 1080P resolution. HD Turbo DVRs are backwards compatible with standard cameras. Hence you could mix lower resolution cameras and HD Cameras.
A Network Video Recorder (NVR) is used for IP Camera systems. Functionality is very similar to that of a DVR but greater storage capacity is required. The higher resolutions means more pixels so more data to store.
It may be desirable to record only when motion is detected rather than continuously record a non-changing scene.
All our DVRs offer a Motion Detection recording mode. Sophisticated functions allows wind blown trees to be masked out and small animals to be ignored.
However, it should be realised that this function is really changed detection. Car headlights shone into the field of view will trigger the recorder even although the car does not enter the area of view. Some DVRs have alrm inputs which can be coupled to PIRs or door contacts. Triggering of these alrms gives more accurate movement detection but does involve much more cabling. The DVR's built in Motion Detection function is invaribaly used due to its simplicity of use despite not giving 100% accuracy.
CCTV Systems need to connected to a good quality monitor. If using an HD system with 1080P you will need a monitor capable of displaying HD 1080P resolution. Connection must be through a good quality HDMI cable.