CCTV-FAQ

BNC Connector

This type of connector is used with CCTV cameras and takes care of the transport of the video signal. The connector has a lock, to prevent it from unintentional disconnecting.

Video signal is called "Composite Video" This is the same kind of signal as used with regular AV inputs as found on TV's. TV inputs are often is RCA/tulp, but we have connectors to change from BNC to RCA.

Cable used with these BNC connectors is always RG59 coax.

CCTV Camera

Generic name for a surveillance camera. CCTV stands for "Closed Circuit Television".

CCTV cameras use these connections:

12V supply voltage

Composite videosignal

RS485 control signal, only for (PTZ) steerable camera's

Digital Recorder

All your CCTV cameras can be connected to a digital recorder. These have 4, 8 or 16 inputs for simultaneous recording. Recordings are stored on a hard disk. A storage capacity of 160GB satifies most applications, allowing recording for several days.

Connections on the back are all in BNC female. The monitor output provides a composite video signal, suitable for composite monitors (or TV) only. Some models also provide a VGA output, suitable for a standard VGA computer monitor.

Most digital recorders also have a network connection. This enables you to view live images on your PC, including easy playback of recordings. This can also be done over the internet, at any place in the world.

Click here to see our offers on digital recorders.

Image Sensor

Every camera uses an image sensor. There are several sizes used:

1/4 inch (very common)

1/3 inch (very common)

1/2 inch (very rare)

Through the years these sensors have become smaller and smaller. The biggest advantage was the reduction in lens dimensions, which also made cameras cheaper to manufacture. Practically this means that today we only see 1/4 inch en 1/3 inch sensors used.

Using the same lens, a 1/3 inch sensor compared to a 1/4 sensor gives a wider image, with a greater angle of view. Of course this also works the other way round. If you want the maximum of effective zoom you better use a camera with a 1/4 inch sensor. On the other hand, a 1/3 sensor has the advantage that there is more light sensitive material, which is why 1/3 tend to give a slightly better image quality in particular under low light conditions.

Instructie Filmpjes

Hier vindt u enkele instructievideo's...

Montage van BNC connectoren

Camera op TV aansluiten

Digitale videorecorder aansluiten

Digitale videorecorder via Internet gebruiken

Lux and Sensitivity

Camera sensitivity is expressed in lux. It's the minimum amount of light needed for acceptable results.

This table gives an indication of the amount of light:

A sunny day: 100.000 - 130.000 lux

Daylight, indirect sunlight: 10.000 - 20.000 lux

Cloudy day: 1000 lux

Office: 400 lux

Very dark day: 100 lux

Dusk: 10 lux

Dark dusk: 1 lux

Full moon: 0,1 lux

Quarter moon: 0,01 lux

New moon, no clouds: 0,001 lux

Cloudy night, no moon: 0,0001 lux

A regular CCD camera has a sensitivity of 1 lux. That gives you even in a dusk setting usable images, with all the aspect of such a setting. Infrared cameras are often rated as 0 lux. This is correct, since the camera needs no other light apart from the infrared light it produces itself. However, the image sensor inside is still 1 lux.

Note that there are large differences in lux when you compare day (100.000 lux) and night (0.1 lux). This can be explained because we apply a logarithmic scale. The difference between 1 lux and 0,1 lux suggest a factor of 10x, but for us humans it is only a factor of 2. Do not focus too much on lux value alone. A camera of 1 lux or 0.8 lux makes no difference at all in practice. However, a factor 10, or 100, or 1000, yes that can make a difference indeed.

Monitor

A CCTV sysem is not complete without a monitor. The composite video signal from a scamera or digital recorder can only be displayed on a compatible monitor.

Good to know that:

A regular TV (tube or LCD/TFT) is always suitable

A computer Monitor is VGA, NOT composite video!

Some digital recorders have a VGA ouput as well. Please read the product descriptions carefuly.

A VGA monitor can be used for displaying composite video, when used with a video/VGA converter

Use a monitor or TV in 3:4 (normal) instead of 16:9 (widescreen) format

Click here to see our collection of monitors.

Pan Tilt Zoom PTZ

Sommige camera's zijn op afstand bestuurbaar. Dit noemt men afgekort PTZ. Pan betekent heen en weer, Tilt betekent op en neer, en Zoom betekent dat u het beeld groter en kleiner kunt maken. Soms is er alleen Pan en Tilt mogelijk, en ontbreekt de zoom functie.

Het signaal waarmee PTZ camera's bediend worden noemen we RS485/PelcoD. Er zijn meer varianten, maar dit is de meest gebruikte. Het RS485 signaal gebruikt twee signaal aders, A (PLUS) en B (MIN). Zijn er meerdere PTZ camera's, dan is er nog steeds maar 1 RS485 kabel, die langs elke camera loopt, van camera naar camera. Doordat elke camera zijn eigen unieke nummer heeft (1-128) kan elke camera afzonderlijk via deze kabel worden aangestuurd.

Het RS485 stuursignaal kan op verschillende manieren worden aangeleverd. Dit kan afkomstig zijn van een digitale bewakingsrecorder waarmee u de camera's dan ook kunt bedienen. Of het komt van een losstaande PTZ controller, waarmee u de bediening doet. Het kan ook van een PC afkomen, voorzien van opnamehardware en waarop u camerabewakingssoftware draait.

Power Supply For Cameras

Each camera needs power. The most common voltages used are:

12V DC for CCD and infrared cameras

6-9V DC for cheap CMOS cameras

24V AC for motorized pan/tilt cameras

The majority of cameras work with a 12V DC power supply. There are 3 ways of achieving this:

Each camera uses a dedicated 12V power adapter

A central power supply for all cameras

A combination of both

If you decide to use a central power supply, you can use cables that also deliver the power to the camera. These so called siamese cables transport both video and power.

Click here to see our offers on power supplies.

Recording with PC

CCTV cameras have composite video output. This can't be recorded with just a regular PC. To do so, you need to install a PCI recording card, or use a USB video grabber. Please take a look in product folder 1, sub folder S3.

PC recording of multiple cameras: Use a PCI recording card

PC recording of 1 camera: Use a PCI recording card or USB video grabber

Note: Recording with a USB video grabber is only suitable for relative short recording times of 2-3 hours at max. This is because of the large files becoming difficult to handle.

Securitynews

"Beveiligingsnieuws" is an interesting dutch website that brings daily news about all aspects of security.

See everything

Customer often ask for a camera with a wide angle lens. After all, they want to see as much as possible. That is a wish we can understand!

But..... did you know that...

The more your camera sees, the smaller the objects become?

The smaller the objects are, the less detail you get?

The less detail you have, the more difficult it is to reckognize something?

What do you see in the image above?

Most cameras with their standard lens have a normal viewing angle. That is the most sensible choice for most situations. A wide angle lens or narrow angle lens are only needed in specific situations.

If you only want an overview as large as possible, without caring much about detail, a wide angle is what you need. If you only want to view a door opening from a greater distance, then a small angel lens (tele lens) is a good choice.

The bottomline... in most situations a standard camera/lens combination gives you the most satisfying results. If you want to see more, use more cameras to cover the area.

Siamese Cable

There are two ways of connecting your CCTV cameras:

Siamese cable RG59 + 12V

Ordinairy RG59 coax cable and 12V power adapter nearby

Siamese cable consists of a RG59 coax cable and 12V power cable. The power supply is done at the meeting point of all cables.

We also have finished siamese cables, simply plug and play. Available in lengths of 5, 10, 15 and 20 meters. You can extend these cables using a cheap BNC female-female adapter.

Click here for our offers on siamese cable.