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  Home >> User Guide >> CCTV Buyers Guide

Buying a CCTV system is by no means an easy task, the vast array of products available nowadays could confuse anyone so we have tried our best to put together a guide to help you make an informed decision about what system should fulfil your requirements.

Before we go through how to choose a complete CCTV System, some people may only want to connect a camera to a TV/Monitor to view and record via a video recorder.

This is simple to do, when you have selected the camera you want pick the option with the correct length 'Plug & Play' cable. Make a note of the 'connector' type, this is usually BNC, then check your TV connections. They will probably be phono or scart. Then you will need to buy a BNC to Phono connector, and if necessary a scart connection. And your done, you simply plug these connections into the end of your cable, and into your TV. Place the camera where you want and record images on to your video recorder, keeping in mind that it can only record for as long as there is space on the video tape.

CCTV Buyers Guide

We start by splitting this guide into the four sections below, if you can learn to understand these separate sections then you will have a good idea of what products will be suitable for your situation. Please bare in mind this guide is focused around products that we offer, for example there are multiplexers, switchers and VCR's - however we don't supply these products as a Digital Video Recorder replaces each one, so they do not feature in this guide.

There is a large selection of Digital Video Recorders on our website alone, we understand trying to buy the right one is not simple, and differs for each situation. So we have put together some information about the features available so that you can try to make a more educated decision. Simply look through the features listed above, and try to see what is important for you, keeping in mind the purpose of your CCTV system. Once you have decided what features are important to you why not see what Digital Video Recorders fit your requirements with our Digital Video Recorder product finder.

Digital Video Recorder Basics...

Some common features are covered below, this section is for those with no knowledge about a CCTV set up. The Digital Video Recorder is the "brain" of a CCTV system, it takes the images from the cameras and stores them on to a hard disk drive. You can then look at the images recorded on the hard drive, and review what the cameras have been viewing by connecting a monitor (or other form of display unit) to the DVR. You can forward & rewind through the images in much the same way you may have done so with a typical Video recorder. On many you can search for specific dates & times to quickly find the footage you want to view.

Once you have your images recorded on the hard drive, from time to time there may be an incident which you will be required to give to the police as evidence, you will then need to back up the data they require from the hard drive on to another storage device.

Digital Video Recorders are available as Standalone units or PC based units. Choosing which one is for you is a personal preference, but I'll take this opportunity to point out a couple of things.  Although many PC based digital video recorders offer lots of added features & familiar use, standalone digital video recorders are purpose built for the job and are considered more reliable and therefore less likely to fail. With PC based units we would strongly recommend the pc is used as a security device only and not used as a standard pc with surveillance, this should reduce the risk of failures.

Also if you are "PC savvy" and decide to buy a Digital video recorder PC Card and install it into your PC yourself, please check that you will not void your PC warranty before you do.

Last but not least, and this goes for all Digital Video Recorders, where possible try to use a purpose built hard drive. By this we mean that some people, to save costs, use a normal PC hard drive in a digital video recorder. Unfortunately this usually ends up with the hard drive failing simply because a pc hard drive is not designed to be constantly "working" twenty four hours a day - seven days a week. At JMC we only offer digital video recorders from manufacturers who use purpose built hard drives, but as not all of our digital video recorders are offered with a hard drive pre-installed for you please bare this in mind. Also please check the compatibility of the hard drive with your digital video recorder, as some may require IDE drives, others SATA, some may work better with Seagate, others Maxtor. Where available we have stated this information in the product information.

Ok, now hopefully you have a better idea about what a digital video recorder is, and its purpose, now I would advise you refer to the features listed below to learn more about what a digital video recorder is capable of and then use the digital video recorder product finder or browse through our site to find one that fits your situation.

Number of Channels:

Have a good look around your premises and decide how many cameras you are going to need, you should take your time with this and make sure you have all the angles covered. Failure to do so will leave 'blind spots'. And if people can see your cameras, it stands to reason, they can see your blind spots.

"To limit expenses you can consider planting dummy cameras in areas you think are less sensitive"

Digital Video Recorders come in several sizes, most commonly :

  • 4 Channels
  • 8 Channels
  • 16 Channels

But once you have decided how many cameras you need, you can then start looking at appropriate Digital Video Recorders. For example if you only need to use 2 cameras, there are not many 2 channel Digital Video Recorders on the market, so you will probably need to buy a 4 channel Digital Video Recorder. But buying more channels than you actually require, isnt a bad thing, as many people find they want to add cameras in the future that they didnt initially think about.

Frame Rate:

The recording frame rate is measured in frames per second (fps) (sometimes referred to as Images per second (ips)). 25 frames per second per channel is considered 'real-time', this means a 4 channel system would need to record at 100fps to record real-time on all 4 channels.

"The thing to keep in mind here is the fact the more images being recorded per second, means the hard drive within the Digital Video Recorder is having to store more information every second. So it will reach capacity quicker and start to rewrite itself"

You will see that many 'budget' Digital Video Recorders do not offer real-time and the Digital Video Recorders that do often allow the frame rate to be manually adjusted to your choice. Just because a Digital Video Recorder is capable of real-time recording does not make it compulsory. There is, in most cases, no law requiring a certain frame rate for images to be used as evidence. As it is the quality of each image that is important. So you need to use the frame rate depending on what you need to see being recorded.

For example, if you were using your CCTV system in a shop and a camera was trying to record the faces of people as they entered your shop. These people might only be in view of that particular camera for a single second, so it would be wise to make sure you got several images in that second, so you had a good chance of a recognisable image. 6-12 fps would be suitable.

Then, in the same shop you may have a camera in a corner looking down at an overall picture of the entrance and shopping area, this camera might only require a few images per second, as this would be enough for you to see what these people did while in your shop. As they are not going to enter your shop, walk around, and leave all within the space of 1 second. 3 fps would be suitable.

Motion Detection:

Almost every Digital Video Recorder on the market comes with motion detection built in nowadays, this can be a very important feature that can considerably extend the recording capacity of your Digital Video Recorder.

It works on a fairly simple principle, the cameras that are connected to the digital video recorder are constantly sending images to the dvr. The dvr reads these images as thousands of pixels, and it simply waits for the sequence of pixels to be different from the previous image. Once it notices a change in pixels, it begins to record.

Some DVRs have different levels of motion "sensitivity" levels, this simply works by changing the number of pixels that need to be different from the previous image. For example, a digital video recorder on motion sensitivity level 1 may require 100 pixels to be different, but on level 5 it may require 1000 pixels to change.

The higher end Digital Video Recorders also allow 'Masking' which is a handy feature within motion detection, basically it allows you to mask certain areas of the screen where you do not want motion to be detected. Useful to mask objects like trees that may move in the wind and cause a Digital Video Recorder to start recording for no reason.

On some Digital Video Recorders you can also set the 'sensitivity' level of the motion detection, this again helps you reduce the amount of motion that is detectable, but in this case it does it on motion speed. slow moving objects will not be detected.

Recording Times:

There are many variables that will adjust the recording times of any Digital Video Recorder, this is why any 'recording time tables' on this website, or anywhere else for that matter, are only an approximate guide.

Some of these variables are listed here:

  • Hard Drive Size
  • Frame rate
  • Compression format
  • Motion detection settings
  • Actual scene (image recorded)
Data Backup:
Common forms of back-up include

Back Up Type

Description

Connecting to Video recorder This is mainly only for 'budget' Digital Video Recorders and involves connecting the Digital Video Recorder to a video recorder and recording the information on to tape.
USB to PC link Quite common, and simple to do, simply connect the Digital Video Recorder to a PC via cable and copy information to PC Hard drive, from there you can write on to disk, pen stick etc.
USB Pen Stick Quite common, and simple to do, amount of storage depends on USB pen stick used.
CD Rewriter (built in or external) Simple to do, some Digital Video Recorders would also require you to load software on to any device that you wanted to then watch the CD on. You should keep this in mind if giving CDs to police as with this software they would not be able to view the CD. Also bare in mind CDs are limited to 750 Megabytes.
DVD Rewriter (built in or external) simple to do, some Digital Video Recorders would also require you to load software on to any device that you wanted to then watch the DVD on. You should keep this in mind if giving DVDs to police as with this software they would not be able to view the DVD. 4.7Gigabyte of space available.
Networked You can copy data from your Digital Video Recorder on to any PC while viewing it over the internet

Common forms of back-up include

Back Up Type

Description


Please check individual Digital Video Recorders to see what forms of backing up they offer.

Remote Viewing

Last but by no means least, when choosing your Digital Video Recorder, bare in mind if you want the option of viewing it over the internet from another location. If you do make sure you choose a Digital Video Recorder with Networking (often referred to as remote viewing).

"Most Digital Video Recorders that offer networking come with software that needs to be installed on the PC that you wish to view your Digital Video Recorder over. If you are on holiday and want to check from a public PC installing software may be impossible, so if you think this is the case try finding a Digital Video Recorder with a built in web server so you can view it directly from any browser"

DVR Compression

There are several different types of compression formats, and its not easy for anyone, including installers, to decide which one is more suitable for there requirements. So for now we will try to educate you on what compression actually is, and then let you know a little about the different types of compressions used by the manufacturers of the Digital Video Recorders we offer.

So what is compression?

If you consider a digital camera with a Gigabyte of storage capacity can only hold a few hundred images (photos), CCTV systems may need to store up to 25 images every second for every camera. Unless we decrease the size of these image files the amount of storage capacity required for CCTV systems would be huge, and unpractical.

Compression is basically the process of reducing the file size of images to reduce storage space required





A guide to CCTV Cameras

There is a large selection of CCTV Cameras on our website, it can be very confusing trying to figure out what cctv cameras will be most suitable. So we have put together some information about the features available, so that you can try to make a more educated decision. Simply look through the features listed below, and try to see what is important for you, keeping in mind the purpose of your CCTV system. Once you have decided what features are important to you why not see what cctv cameras fit your requirements with our cctv camera product finder.

CCTV Camera Basics...

For those who know little or nothing about what a cctv camera is, or what it does.

Cctv Cameras are the "eyes" of a cctv system, you place them inside and outside buildings to enable you to see and also record (via a digital video recorder) what the camera is looking at.

Unfortunately that's where it stops being easy, we cant emphasise enough how you need to educate yourself as much as possible about what cctv cameras are capable of and then look seriously as to what you want to use a camera for and what you need that camera to do. By this we mean there are literally thousands of cameras available nowadays, but this is because there are so many different situations where a camera is required that there isn't just one camera for all jobs. So please do take time to learn as much as you can from the features at the top of this page before you make a purchase.

So how do you go about choosing a camera, well you have to start with basics....

First where is the camera going? indoors or outdoors? If outdoors use the weatherproof guide to choose what kind of an IP rating your camera requires.

Once you know this, go to the area where you want to install the camera and look at what you want the camera to see. how far is the scene you want to capture from the camera? how big is it? think about this and use our lens calculator to make sure you know what lens size you need to be able to see the scene you want at the distance it is away.

Consider, will you need to be able to see in dark conditions? or only during the day time? If its needs to see in low light conditions, how dark does it get? is there a street lamp near by? or is there a security light on the premises? go back at night time and see how dark it actually is, then use the Lux guide to see what kind of "minimum illumination" your camera requires. Keep in mind during the winter it gets dark very early, no  good having a camera that's only useful during the summer.

Is the camera going to be installed in such a place it may be subject to vandalism? if so make sure you use a vandal resistant camera.

Ok, now hopefully you have a better idea about what a cctv camera is and what kind best suits your situation, now I would advise you refer to the features listed below to learn more about what a cctv camera is capable of and then use the cctv camera product finder or browse through our site to find one that fits your situation.

Image Sensor

Most CCTV cameras are now almost exclusively ‘CCD’ sensor type. CCD stands for Charge-Coupled Devices.

These are light-sensitive chips, the sensitive area being split into a large number of individual pixels. An image from a scene is focused through a lens onto the chip surface and charge is built up in each pixel proportional to the intensity of the light falling on it. Hence an electrical representation of the optical image is formed.

These image sensors come in several sizes, but for CCTV the main ones are:

  • 1/2"
  • 1/3"
  • 1/4"

The most common of the above is the 1/3" CCD, which is suitable for over 90% of CCTV applications. The main point to bare in mind if buying a lens separately from the camera, is to make sure the CCD and lens are compatible.

"To keep things simple, stick to the same size. if 1/3" CCD, then choose a lens with 1/3" image format. Never Use a smaller CCD than the Lens Image format!"

The other image sensor type is "Cmos", this is rarely used in good quality CCTV cameras, however some IP cameras still use it. Also bare in mind it is widely accepted that SONY produce the best quality CCD image sensors, so we recommend you choose a camera with a SONY chip.

TV Resolution:

The resolution of a camera is measured in 'TVL'.

The term TVL or “TV lines” has been around since the invention of analogue television. Its purpose was to provide a measure with which the usable resolution performance of a TV system could be assessed. TVL is in general terms a horizontal measurement of how fine a detail from a scene can be resolved on a display. This number relates the resolvable fine detail to an equivalent number of equally spaced black and white vertical lines across the width of the viewing screen.

"The higher the TVL the better quality picture the camera will produce"

 "Lux" Level:

Infrared LEDs, aka IRs, are what give a camera the ability to see in low light situations. This ability is measured as the "Lux" Level, below are some approximate lux levels to help give you an idea of how good a cameras night vision is.

Lux Guide:

  • 0.00005 lux = Starlight
  • 0.0001 lux = Moonless overcast night sky
  • 0.001 lux = Moonless clear night sky
  • 0.01 lux = Quarter Moon
  • 0.25 lux = Full Moon on a clear night
  • 1 lux = Moonlight at high altitude at tropical latitudes
  • 3 lux = Dark limit of civil twilight under a clear sky
  • 32000 lux = Sunlight on an average day (min.)
  • 100000 lux = Sunlight on an average day (max.)
IP Rate:

Weather proof is measured using an IP Rating, if a camera doesn't state an IP rating you can consider it is for internal use only.

IP Ratings Guide

The IP classification system designates the degree of protection provided by an enclosure against solid objects or water ingress.

There are always two digits in an IP rating, the first digit refers to the protection against solid objects (dust) and the second digit refers to the protection against water.

Dust Protection (first digit):

  1. Non-protected
  2. Protected against a solid object greater than 50mm, such as a hand.
  3. Protected against a solid object greater than 12.5mm, such as a finger.
  4. Protected against a solid object greater than 2.5mm, such as wire or a tool.
  5. Protected against a solid object greater than 1.0mm, such as wire or thin strips.
  6. Dust-protected. Prevents ingress of dust sufficient to cause harm.
  7. Dust tight. No ingress of dust.

Water Protection (second digit):

  1. Non-protected
  2. Protected against dripping water.
  3. Protected against dripping water when tilted up to 15º.
  4. Protected against spraying water at an angle of up to 60º.
  5. Protected against splashing water from any direction.
  6. Protected against jets of water from any direction.
  7. Protected against heavy seas or powerful jets of water. Prevents ingress sufficient to cause harm.
  8. Protected against the effects of temporary immersion in water.
  9. Protected against the effects of continuous immersion in water.

So for using CCTV cameras outdoors, I would recommend a very minimum IP rating of 55, but preferably 65 and above.




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