|  | Buyers Guide |  | BUYERS GUIDE TO CCTV SECURITY CAMERA SYSTEMS
There are a vast range of products and prices to choose from in the CCTV security camera marketplace but little information to help discriminate between them.
We hope this buyers guide will help you learn more about selecting a CCTV security camera system. If you have any queries please call us on 0870 744 2298 for independent expert advice.
Wireless CCTV
Increasingly popular is wireless transmission. Government regulations now allow licence-exempt systems that can transmit signals up to 100 metres in line of sight. This reduces to approximately 30 metres when used indoors. Simple wireless cameras will only work on one frequency so you cannot use 2 such products within 100 metres of each other. Cameras and receivers are available with 4 selectable channels making multi-camera systems feasible.
Even the small covert type of camera can be supplied with its own built-in transmitter. Go Wireless Spy Cameras to see our full range of covert wireless cameras.
Remember that CCTV cameras require power to operate. The voltage is usually in the range 9-12V DC and this is typically derived from a small power supply plugged into the mains supply. So \"wireless\" does not mean totally \"wire-free\". Battery operation will be measured in hours, so is not suitable for permanent installations. However, it is often easy to pick up the power for the camera in some areas such as the loft of the house. Wireless systems are great where it would be difficult to run the video cable back to VCR or monitor.
Wireless transmission is also useful for temporary monitoring of an office or reception area. The miniature wireless cameras with battery power can be fitted to model aircraft or model trains. The receiver can be connected to a domestic camcorder to recorder the \"ride-on\" experience.
Wireless connectivity is nevertheless very useful for some applications. Go to Wireless CCTV Cameras to see our full range.
Wired CCTV
Wired cameras guarantee zero interference and can be positioned hundreds of metres away from the monitoring/recording equipment. Often with wired cameras you do not have to power the camera locally. Instead one cable will take both power and video signal back to the recording device. With some of our DIY kits the camera can even be powered by the base unit, eradicating the need to plug the camera in to a mains power outlet. Go to Wired CCTV Cameras to see our full range.
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. If you do need a site survey please call 020 87660150 we have a nationwide network of installers who will be able to visit you at your convenience.
Cameras
The traditional CCTV camera has a very industrial style look and feel and, therefore, many people would not find this suitable for fitting to their homes or shops. 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.
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 based cameras are generally cheaper but do not produce as clear or sharp images as CCD cameras. 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 cameras provide pin-point clarity and should be specified wherever possible.
Integrated cameras and lenses 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. Integrated 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.
Many of our integrated cameras are fitted with a 3.6mm lens which gives a 72deg angle of view which is suitable for most domestic and small commercial properties. We also have cameras with a narrower angle of view allowing the cameras to ‘see’ further the angle of view for all of our cameras is stated within the bullet point copy.
Colour or monochrome?
The human eye remembers and recalls things better if they appear in colour - it\'s easier to track down a brown-haired person wearing a red sweater and blue jeans than a dark, grey-clad figure that would be produced in monochrome.
Colour cameras carry an additional premium in price compared with monochrome cameras. But they are also less sensitive making night usage an impractical option unless good lighting is available.
Monochrome cameras can offer Infra Red (IR) sensitivity allowing their use with covert IR illumination possible. This can be particularly useful where planning permission makes extra lighting impractical or the security requirement is such that intruders should not be alerted to the existence of CCTV surveillance.
Indoor/outdoor cameras
If a camera is to be sited outside and is not going to be mounted in an enclosure it must be classed as weather resistant. All of our outdoor cameras are fully weatherproof. The cable entry points are sealed and most cameras come with trailing leads that allows the connections to be made inside the building.
Day/night cameras
Very popular in domestic and small commercial CCTV applications, day night cameras allow great quality, colour recording during daylight hours. When light levels drop below a certain level the camera’s infra red LED’s allow the camera to continue recording good quality footage even in complete darkness. The distance the cameras will see at night is dependent on the strength of the LED’s. See our Day/Night CCTV Cameras section for the range of Day/Night cameras we do.
Light levels
Choosing the correct camera to operate in the ambient light conditions is possibly the most important although most tricky specification to understand.
Light levels are usually measured in Lux. This is a measure of the light energy arriving on an area 1m2 of surface per second.
Typical light levels are:
Full Summer Sunlight: 50,000 Lux
Dull Daylight: 10,000 Lux
Shop/Office environment: 500 Lux
Dawn/Dusk: 1 - 10 Lux
Main Street Lighting: 30 Lux
Side Street Lighting: 0.5 - 3 Lux
The golden rule when deciding which camera to use for a given lighting condition is not to choose one that will only just give a picture. Try to give the camera approximately 10 times its quoted minimum scene illumination. Most cameras will be able to cope with excess light. The major problem is when they do not have enough light to produce a picture.
A monochrome camera rated at 0.05 Lux will produce reasonable results. Colour needs a little more. However, colour cameras achieve good night-time vision by switching to a monochrome mode. You will never get good night-time colour pictures without huge amounts of additional lighting. So think carefully about the added cost of colour over monochrome cameras. As most people are used to colour television it sets a standard so it is very common to still select a colour camera knowing it will switch to monochrome mode at night.
Monochrome cameras respond well to additional IR (infra red) lighting. With this in mind true night-vision cameras include a ring of IR LEDs. Colour cameras also offer IR illumination but as stated previously will switch to monochrome at night even with the IR LEDs turned on. These are true night-vision cameras and are rate at 0 Lux.
Resolution
The value referred to here is the horizontal resolution in TV lines, that is the number of black to white transitions that can be resolved across the image. This is a function of the number of pixels that make up the CCD imaging area and the bandwidth of the camera circuitry. Typical entry level camera resolution is 330 TV lines, with high resolution cameras producing better than 400 lines. Note that resolution costs money!
How to display the picture from more than one camera
Most CCTV systems deploy several cameras so a method is required to view and record the images. There are various ways this can be achieved; use a video switcher, a quad processor or a multiplexer. Here are the simple benefits of each system.
Switchers:
A CCTV switcher is a unit that changes between camera pictures one at a time, the output being viewed on a monitor or passed to the recording device. As switchers can use any VCR to record in true real-time, the pictures which are captured can be of a very high quality. The fact that they provide true real-time recording unlike a snapshot from a multiplexer means they provide a superior picture quality. This can sometimes outweigh the disadvantages that switchers can only record one picture at a time.
Advantages - Simple, low cost, good quality real-time pictures.
Disadvantage - Can only record one camera at a time.
Quad Processors:
Quad units enable 4 camera pictures to be displayed on a screen simultaneously.
They are useful where it is necessary to monitor several areas at the same time. As with a switcher, what is seen on the monitor is the picture that is recorded on the VCR.
Advantages - Simple to use - shows multiple displays which can be recorded.
Disadvantage - Records only 1 camera at a time real time or 4 at a quarter of the resolution.
Multiplexers:
A multiplexer allows simultaneous recording of multiple full-sized camera pictures on to one VCR tape providing more comprehensive recorded surveillance than with a switcher or a quad processor. Most have variable display options such as quad and picture in a picture allowing flexible surveillance of more than one camera at once.
When to use a multiplexer
Generally use when a high degree of surveillance is required and it is necessary to record full resolution pictures from a number of cameras at the same time.
Advantages - Records all camera pictures full size on one tape - gives better monitoring of areas simultaneously - enables large areas to be monitored without losing surveillance due to camera switching time.
Disadvantages - Does not record in real time - Raises the overall cost of the system.
More on Multiplexers
Video multiplexers overcome the problems of both switchers and screen splitters. The pictures from the cameras arrive at the multiplexer unsynchronised. i.e. they all start and end their picture at different times.
These signals cannot be recorded directly because a VCR needs to be synchronised to the incoming video signal. If the incoming video signal is constantly changing then the VCR would be permanently re-synchronising to the new video signal. This can take up to 1 second to achieve.
Multiplexers digitally grab pictures from each camera in turn and feed them out to a video recorder at exactly the correct rate for them to be recorded reliably. Hence, up to 50 different pictures can be recorded every second and from any of the cameras connected to the multiplexer.
Triplex - capable of performing all three functions at the same time (simultaneous recording and playback of cameras and a multi-screen display with both live and playback images). This allows the operator to keep monitoring the site whilst reviewing previously recorded tapes.
Recording CCTV Images
Domestic VCR
The simplest low-cost solution is to use a domestic VCR. These will typically give 8 hours recording time and can be used in conjunction with a Video Activator to provide event-only recording. We sell wired and wireless kits consisting of cameras with built-in motion detectors plus VCR activators. Recording will automatically be triggered on motion detection.
Disadvantages - most domestic recorders have a slow \"take-up\" time. (the time taken to start recording)
- cannot use the VCR to record TV channel whilst camera input is selected.
Advantages - very low cost. Worth considering purchase of a dedicated VCR for camera recording. The dedicated VCR can be hidden in the attic or a cupboard making it less likely to stolen by an intruder. Go to Video Activation to see our full range.
Time-lapse VCR:
Similar to a domestic VCR but with a slower-moving tape that records the camera pictures as snapshots at split second intervals. The time-lapse can be set to give 24, 240 or 960 hours of recording on standard VCR tapes.
Advantages - very long recording time, cost-effective. Added features like alarms, auto tape-rewind.
Disadvantages will need a quad processor or multiplexer when recording multiple cameras which adds to the cost of the system.
- the longer the recording time the longer the period of time between the snapshots.
- tapes do wear out through over use.
Go to Time Lapse VCR’s to see our full range.
DVR:
Digital Video Recorder as its name suggests can record images onto a built-in hard drive from one or more cameras. All of our DVRs now come combined with multiplexer functions and are generally considered the future of CCTV recording.
DVRs can generally be split into two groups - standalone black box and PC-based solutions. PC-based solutions are discussed in their own section.
Advantages - all-in-one box for recording, multiplexing, alarms and motion detect.
- higher resolution than S-VHS VCR is possible
- near instant access to recording from known time and date
- no loss of quality when copies taken
- can record events in real-time before an alarm actually occurs with \"Pre-event trigger\"
- enhanced playback function, forward and reverse frame by frame playback
- easily connect to networks/internet for remote viewing and playback.
Go to our Digital Video Recorders guide.
Go to Digital Video Recorders to see our full range.
PC-based Systems
If you already have a PC then with the addition of a video-capture card and surveillance software you have a powerful digital system. The purchase of a video capture card and software is a very cost effective method of providing a high specification system.
Advantages
- remote viewing
- software allows many configurations for monitoring e.g. quad display
- records in real time, simultaneously from all cameras
- time and date stamping with motion detect
- alert wizard, send email with photo or video clip,
- SMS alert
- audio alert
- motion detection recording featuring different sensitivity settings and ‘masking’ feature. Only movement in the masked rectangle will trigger the output. By resizing and repositioning the rectangles it is possible to allow for pet activity within the observation area.
- low-cost all-in-one solution does away with the need for separate motion detect, splitters, quads or multiplexers.
It is easy to see the benefits of the PC-based system providing you satisfy the following criteria:
Competent in installing additional hardware and software programmes
Have good housekeeping to ensure adequate free disk space
Do not intend to use the PC for any other video capture or editing
Do not wish to mix colour and monochrome cameras.
Go to CCTV Computer Software to our full range.
Other Digital CCTV Systems
Other digital products on the market allow remote viewing and recording via internet connection or telephone network. Advances in compression technology allow excellent quality recording and remote viewing putting the old style ‘web casting’ methods firmly in the past.
See our Remote View Guide
See our full range of easy to install Remote View Systems
Motion Detectors
Even with the long-recording facilities of DVRs and digital systems it is sometimes not desirable to continuously record. The most common method is to fit a PIR (Passive Infra Red) detector in the area to be monitored. Most people will be familiar with this concept as applied to security lighting.
The output of the PIR can be fed to a Video Remote Control module, hence the video recorder will only turn on when motion is detected. As a basic system it works well and wireless models are available that remove the need for additional cabling. As they are low-voltage devices battery life can be up to three years.
A VMD (video motion detector) is the modern alternative to the PIR. It works by analysing the video signal from the camera. When it detects changes in the signal it recognises this as movement within the camera\'s picture the output being used to switch on the recording device. The sensitivity can be adjusted which will overcome the problem of bright lights being turned on causing the VMD to activate.
The more sophisticated units feature an on-screen marker or rectangle. Only movement in the rectangle will trigger the output. By resizing and repositioning the rectangles it is possible to allow for pet activity within the observation area. In the example the blue car turning into the drive will activate the recorder but the grey car passing on the road will not. It is difficult to achieve this degree of accuracy with PIRs.
Most digital and PC-based systems have VMD built in to them. This can make multi-camera digital systems very cost effective as it alleviates the need to buy motion detectors for each camera or observation area
Getting the picture signal from the camera to the monitor, recorder or TV.
The most common method used on professional installations is RG59 Coaxial cable. The centre core is the signal conductor while the outer shield protects the signal from electro-magnetic interference. It is a low-loss cable which will allow cable runs of up to 250 metres.
Professional DVR’s. switchers, multiplexers, monitors etc. will all use BNC connectors. If you are connecting to a domestic TV or VCR you will need to convert to phono or SCART connectors. Simple adapters are supplied with all of our kits. BNC to scart leads are available also.
Many DIY CCTV products do not use coax cable and BNC connectors. The cable is more expensive and the connectors are difficult to fit. With our wired cameras we supply 10–20m of composite cable. We also sell extension leads from 15m to 36m. It is advisable to keep cable runs as short as possible. Before ordering a camera kit measure the required cable run and then add extension leads as required
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