This in general is a comparatively difficult decision. Many aspects of the installation must be taken into consideration in order to obtain the correct performance that meets your requirements. A high resolution camera should be considered where greater detail of scene is required. E.g. Colour 460 TVL, Monochrome 570 TVL. Choosing a more sensitive camera will improve reproduction in poorly lit areas. The sensitivity of a camera is indicated by the minimum amount of light in order for the camera to produce a usable picture. e.g. Colour 1.0 Lux at F1.2. A conventional camera produces a pale backdrop when an object is shot against a bright background. BLC (Back Light Compensation) will counter strong light sources retaining picture quality. Concentrated light sources directed towards the camera (e.g. car head lamps) can be inverted by an optional peak white inverter or an eclipser function. This has the effect of bringing detail to areas and making an object clear, that would otherwise be shadowed.

The addition of the following: When setting the back focus of a Colour camera for low light conditions you should place an ND1 (Neutral Density) filter in front of the lens. When setting the back focus of a Mono camera for low light conditions you should place an ND3 (Neutral Density) filter in front of the lens. When setting the back focus of a Mono camera fitted with I/R lighting for low light conditions you should place an IRP (Infra- Red Pass) filter in front of the lens. Should you not have any of the above filters you may have to attend site during the hours of darkness.

The most common resolve to this is to ensure that both camera and lens are the same mount i.e. 'CS' mount lens on a 'CS' mount camera and a 'C' mount lens on a 'C' camera.

OSD (On Screen Display) cameras have a menu system within the camera assembly that can be accessed in order to set functions such as Iris levels, AGC on/off and most features of standard and advanced cameras.

This is due to the depth of field changing as the light conditions change and can be easily overcome by following set procedures.

A general rule of thumb is only to use a MI lens in an internal application. This is because you are reliant on the electronic circuitry of the camera compensating for light changes in the scene and this is not able to compensate to the same degree as that of an Auto Iris lens.

This is achieved by following five simple steps. 1.Set the physical focus of the lens to infinity (clockwise from the front). 2.Aim the camera at the subject to be viewed. 3.Release the camera back focus mechanism. 4.Adjust the back focus to obtain the best possible picture. 5.Secure the cameras back focus mechanism.

The simple answer is NO

This is usually performed by a simple plug-in connection to the rear or side of the camera. However you should always refer to the relevant camera handbook.

An Auto Iris lens is one that automatically adjusts its iris for changes in the scene lighting levels. The motor that opens and closes the iris is driven by an Amplifier that processes a small electronic signal changing with the light level. A Direct Drive 'DD' lens does not have this Amplifier and can only operate with a camera fitted with one. A camera specification will indicate the available output options.

Yes, lenses are usually specified as having a minimum and maximum 'f' stop rating; the 'f' stop is a measure of how efficiently the lens allows light from the scene, to pass through the lens and onto the camera CCD sensor. The maximum aperture (when the lens is fully open), is the minimum 'f' stop number and the minimum aperture, (just before the lens completely closes) is the maximum 'f' stop number. A low minimum 'f' stop number means that the lens can pass more light through during dark conditions, which will produce better pictures at night. A high maximum 'f' stop number may be necessary where there is a high level of light or reflection. This will prevent the camera 'whiting out'

This can be achieved by following these steps. • 1. Set the lens to full wide angle view. • 2. Set the physical focus of the lens to infinity (clockwise viewed from the front). • 3. Aim the camera at an object at least 30 Metres away. • 4. Release the camera back focus mechanism. • 5. Adjust the back focus to obtain optimum clarity. • 6. Zoom the lens in to full telephoto and focus on a nearby object. • 7. Keep this object in view as you slowly zoom out and if all is set correctly it should remain in focus (track). • 8. Secure the back focus mechanism.

An Auto Iris lens has two 'pots' on the side commonly marked ALC (Automatic level control) and LEVEL. The ALC control has settings of PEAK and AVERAGE (P+A). The LEVEL control has HIGH and LOW settings 'H+L'. ALC The adjustment allows control over any bright areas in the scene e.g. sun reflection through windows, street lighting etc. There are two settings PEAK and AVERAGE. If set to PEAK, bright areas in the scene are taken into account more, reducing the contrast in the surrounding area. This allows more detail to be seen in the bright areas. If set to AVERAGE the lens takes the bright areas less into account which usually causes over brightness or flare in these areas, but raising the contrast of the surrounding area. LEVEL The only correct way to set the VIDEO LEVEL is by the use of an oscilloscope, for most Engineers this is not an option. A more practical method is to use a service test monitor and a camera that you know has been set up correctly to 1 volt peak to peak. Put the video output from this tested camera into the test monitor and adjust the contrast and brightness until you are satisfied with the picture. Mark the contrast and brightness controls so that you can set them to this position again. Set up each camera adjusting the ALC (as above) then adjusting the LEVEL to obtain a picture similar to that achieved with the test camera. (Making sure that your test monitor is set to your marked positions) NB: On most zoom lenses the ALC adjustment is a speed control for the Iris motor and is best left in the mid position. The Amplifiers on Auto Iris lenses are sensitive; so adjust the LEVEL and ALC with a proper trimming tool instead of an ordinary screwdriver, which can induce small voltages.

The correct size monitor is dependent on its use e.g. the number of images to be displayed at any given time, the viewing distance and the available space.

This is the end of line resistance of any CCTV system and this should be set to 75 ohm. Should you encounter any double image or ghosting this is more often than not caused by two pieces of equipment in series both having the 75-ohm switch set on. Only the last piece of equipment should be set at 75-ohm.

Camera housings come in various shapes and sizes. With regard to the correct IP rating protection, this will range from dust and water ingress. This system is governed by a number of European and British standards. IP55 • Protected against dust - limited ingress. • Protection against low pressure jets of water from all directions – limited ingress permitted. IP65 • Protection against dust - no ingress. • Protection against low pressure jets of water from all directions – limited ingress permitted • Protection against high pressure water from all directions - limited ingress permitted.

Video multiplexers are designed to allow recording of several cameras onto one recorder. Simplex A simplex machine is best suited to applications where recording only is the priority. Simplex machines cannot display multi screen images (i.e. quad, 9 way and 16 way split) while in the record mode. Duplex If an operator is monitoring the system (i.e. security guard) then a duplex machine is more suitable. A duplex machine can provide screen splits and user selectable images without affecting what is recorded onto the recorder. Should you use two recorders, it becomes possible to record and playback simultaneously.

In general the main difference apart from cost is the increase in overall resolution. A standard VHS machine may achieve in the region of 300 TVL (mono) whereas S-VHS machines may achieve in the region of 400 TVL. However this being achieved will depend on the correct ancillary equipment being used.

The choice is wide and varied dependent on the system requirements. You may require Top mount, Side mount, 230V AC or 24V DC to name just a few. TOP MOUNT • Pro: Can fit two IR lamps on the side of the Pan/Tilt. These act as a counter balance enabling you to use a lighter duty Pan/Tilt head. • Pro: Compact size. • Con: Restricted tilt often -45 to 0 dependent on the housing fitted. • Con: Cannot be inverted. SIDE MOUNT • Pro: Can be inverted. • Pro: Often cheaper. • Pro: Large tilt often +or- 180 • Con: Difficult to mount IR lamps. • Con: Generally large size.

Only lighting within the visible wavelength should be used with colour cameras. Tungsten Halogen is often the recommended source of lighting.

The answer to this is a definitive NO. Colour cameras are typically fitted with an IR cut filter and will not allow IR light in excess of 700Nm to pass resulting in the camera performing poorly in these circumstances.

An ISDN (Integrated Services Digital Network) Line is a digital system allowing a camera to be updated at a rate of 15 frames a second.

A PSTN (Public Switched Telephone Network) Line is an analogue network allowing a camera image to be updated every few seconds and is therefore slower than that of an ISDN network.

Also known as Broadband, an ADSL (Asymmetric Digital Subscriber Loop) line is a form of Digital Subscriber Line in which the bandwidth available for downstream connection is significantly larger than for upstream. Although designed to minimise the effect of crosstalk between the upstream and downstream channels this setup is well suited for web browsing and client-server applications as well as for some emerging applications such as video on demand.

Leased Line, sometimes known as Kilostream, Megastream or Private wire. This is NOT a dial up line but is connected 24hrs a day and is usually subject to an installation charge and a quarterly bill.

Full picture update is a technology that enables a transmission system to update a high quality full picture refresh at very fast speeds.

In general the answer is yes. Most manufacturers will recommend the use of such power supplies as standard with their equipment. You should always consult the manufacturers specifications prior to the connection of any power supply.

This is a commonly asked question and there is no simple answer. Some manufacturers may recommend that their cameras can be run over (X) distance with (Y) cable. This however should still be considered as a general guide. Cable conductor size and installation route must also be taken into consideration. If you are unsure, we would recommend that you contact Technical Support for guidance.

In general there is little difference. However RG59 is a hard drawn conductor and is best suited to fixed camera installations. URM70 has a multi stranded centre conductor and is more suited to installations such as PTZ cameras.

An AC current that can be produced in a cable. This is usually caused by parts of the system being fed from different electrical sources resulting in different earth potentials at each end. The result is interference on the signal, usually in the form of dark bands across the monitor and on occasion tearing in the top third of the image.

This can be achieved in a number of ways, the easiest of which is the installation of a Ground Loop Isolation Transformer. This is best installed at the monitor or recording end of the system.

The correct level is 1 volt peak to peak. This can only be accurately set either with an oscilloscope or with a video level meter.

In general it is recommended that all video tapes should be replaced after a period, no greater than 20 passes of each tape. That being 10 record and 10 play back. This will also be dependent on the quality of tape being used and that the recording equipment is in good operational condition.

The iris is the part of the lens that determines how much light falls upon the camera CCD sensor. The Manual Iris 'MI' lens has this fixed at the time of installation. As the light levels change in the scene, the lens can do nothing to prevent either too little or too much light entering the camera. Virtually all cameras employ an Automatic Electronic Shutter 'AES' to compensate for these variations when fitted with an MI lens. However they are only able to cope with a relatively small change in light levels. An MI lens should never be used in an external situation, as the camera will be unable to cope with large changes in light levels. Use an Auto Iris 'AI' lens in this case, or indeed anywhere where large scene illumination changes take place. The advent of new sensor technology such as PIXIM may result in a change to this situation in the future.

Installers and end users are often disappointed by the life they get from Halogen bulbs. Manufactures quote life expectancy figures as 'Mean Time'. They are not a guarantee of the bulb life. This simply means that on average after a number of hours quoted by the manufacturer HALF OF THE BULBS WILL HAVE FAILED. If the 'Mean Time' of 4,000 hours is quoted, half the bulbs will fail within that 4,000 hour period (5.5months). Matters appear worse during the period of October to March, obviously because of the longer hours of darkness. During this period, lamps may be on as much as 16 hours each day. A simple calculation may be used in order to provide adequate maintenance on these systems. If you have 5 external cameras each with 2 lamps that gives us a total daily lamp usage of: 10x16hr = 160 hours per day. If the lamp has a mean life expectancy of 4,000 hours, this means that you can expect a bulb to fail every: 4,000/160 = 25 days. You should make sufficient provision for this within a maintenance contract.

A network camera, also known as an IP camera or an internet camera is NOT a webcam. It is a new generation of digital surveillance camera, capable of passing its images over a computer network such as the internet or a company ethernet. These cameras do not need to be attached to a PC in order to operate – they are small computers in themselves, and just plug into the network or a phone line via a box called a router. Network cameras are gradually replacing traditional analogue CCTV cameras, because of the additional features that they offer, such as automatic recording and sending of images if motion is detected, and the ability to see live images at any time on any PC anywhere, just using a standard browser like Microsoft Internet Explorer. You can also log in to see live images on most modern mobile phones.

Yes. The first of these cameras appeared in 1996, and since then the leading players have continually improved their products to the point some years ago that they became a workable option for surveillance. Now, these cameras are often as not the equipment of choice for new security camera installations. The leading manufacturer, whose products we use, has 300,000 units installed.

Common sense and numerous surveys say yes – if you were a burglar, would you choose a property where your every move would be recorded in full colour? This is why we provide you with signs for the outside of your property, so that potential burglars will have the opportunity to think again before acting.

We realise that even if you tell your visitors the camera has been deactivated, it may give little comfort if the lens is still pointing at them. That's why we supply a lens cap or camera cover with all cameras, that you, your staff or your visitors can physically put in place for the duration of the rental period, for complete reassurance. Some guests will actually prefer to have the protection of the camera, as long as they are reassured that nobody can see the images except authorised personnel – i.e. you.

All of the main phone companies offer various call-barring options that can be switched on and off with a simple phone call. You can choose to bar international calls, or even all outgoing calls. This would still enable you to market your rental property as having an ADSL internet connection – very valuable for business people. This is because the router has extra sockets that a tenant (or you!) could use to connect a PC or laptop to the internet – this adds nothing to your phone bill and still works with call barring in place.

Yes, of course, it is your broadband line. However, your PC may take bandwidth away from the camera, so may reduce the camera's frames per second if it is transmitting a live picture at the same time. We should also add the proviso that if, following your own use of the broadband line, your camera system is found to be not working, we will need to make a chargeable visit if we cannot sort the problem out remotely.

Motion detection is designed to ensure that the "act" is caught on film and transmitted in near real time for safe storage away from the premises.

If the power is accidentally switched off, or there is a power cut, or a phone line fault, the equipment is designed to reset and operate correctly when power returns or the fault is corrected, and will do so the vast majority of the time. We only use commercial-grade Axis cameras, used in shops, schools and airports, where reliability is paramount. Having said that, we cannot guarantee absolutely that your equipment will always reset following a fault on the phone line or a power cut. Switching off and on usually resets the system, but in the unlikely event that we need to carry out a site visit to reset equipment following such a service failure for whatever reason, this will be chargeable at our normal rates.

Once you have paid our initial invoice, you own outright all of the equipment that we supply. We retain ownership of your web page, as it forms part of our customer website.

any passwords and usernames, but you may give the password to chosen people as you see fit, for example so that friends can take a look at the weather outside your villa, or your new swimming pool. Your agreement gives our staff the right to access your camera remotely and view images for specific support and maintenance purposes only, and we do not record images from it.