TVL stands for Television lines. In general the more TVL you have the clearer the images.

420 TVL gives perfect viewing on monitors up to 17”, If using 19” monitors you will still get an excellent picture, but for sharper images over a distance, a 520 to 700 tvl camera will produce a more defined image.

If you purchase a colour infra red camera it will be provide colour pictures until dusk when it automatically changes to a black and white picture which gives better clarity for night time vision. LEDs sited within the camera provide infra red invisible light sensoring. At dawn the picture will revert to colour.

Put simply CMOS uses a cheaper technology where CCTV is concerned and gives a good image on small monitors but not very good on larger (14” and above) monitors or in low light conditions. CCD uses a “chip “ to convert images and is faster and crisper producing a clearer picture with very good low light images.  We do not stock CMOS as all our cameras are of a professional standard.

Depending on your range and width of viewing area you wish to cover this will determine your lens.  3.6mm to 4mm should cover most applications for domestic and light commercial uses.  3.6mm for example will give a wider view and will cover more square area.  6mm will give a narrower view but will bring the subject closer, but please if not sure call our Technical Support Line for any guidance you may require.

Bayonet Neill Concelman. BNC is an industry standard for connector for various uses, but is widely used in CCTV terminations. Think of it as a sophisticated coaxial plug like on your television only the BNC is a more robust means of joining a cable to apparatus TV, DVR etc.

Not really. Some bullet cameras, vandal proof dome cameras and most infrared cameras are designed for outside use with the waterproof cases they are enclosed in. Mini-dome CCTV security cameras, and some hidden cameras are for inside use only, and should not be used outside. Currently ALL the cameras on our site are IP rated and suitable for outside use.

Outdoor cameras or cameras indoors facing a window will have varying light conditions. CCTV display and recording systems are set to a certain level of image brightness and contrast. When light levels change, the displayed and recorded images will either be too bright and washed out or too dark and non-resolvable. The only way to solve this is to use an auto-iris lens. These lenses have an electric motor-driven iris which is opened or closed according to signals fed to it from the camera. Once set, a camera equipped with auto-iris drive will attempt to produce a video signal of constant brightness by opening or closing the auto-iris of the lens, as light levels change. Most of our cameras are auto-iris.

Yes you can, provided they are returned in the original packaging and are in "as new" condition.

Using RG59 Coaxial Cable, each CCTV security camera can be placed up to 200 metres from the DVR. Even longer distances can be achieved using Baluns and CAT5 cable. Please ask our Technical Experts at Security Cameras Online.

Yes, providing certain conditions are met. Some older cameras and some newer cameras mixed together can cause problems because of very different image synchronizing systems. In this event, you can get interference between one camera image and another. Colour cameras are more prone to this type of problem.

This depends on the hard drive size, how many cameras you are using and under what conditions are you recording (on motion, on alarm, continuously, etc.) and what type of compression you are using. Assuming that you are recording only when motion is present (the most common recording method today) that you have 4 CCTV security cameras and that there is movement in the surveyed area for 16 hours a day, 5 days a week, and you are recording at industry standard compression, a 500GB drive would hold about 4 months of recordings under those conditions. Of course, different recording parameters use more disk space. Because of the way that video is compressed, there is not a definite mathematical formula that can be applied to say exactly how much hard drive space is used, but since hard drives are now relatively inexpensive, it pays to use as big a capacity drive as possible if storage is a concern, before overwriting.

Normally the system will begin to overwrite the recorded image files, oldest first.

Because most of our customers are professional distributors, they have their own adapters. But we appreciate that a lot of our customers are also DIY and to that end we include a free Power adaptor with every camera. If you any need further adaptors, please refer to Security Cameras Online Technical Support.