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Optical Range


The most important thing to get right is the lens on your CCTV cameras

Far too many people fit wide angle CCTV cameras and then wonder why they can't identify people. In most cases the worst thing you could do is use fixed lens wide angle cameras because as you move away from them detail capture deminishes rapidly. Forget what the advertising info says wide angle cameras only have a very short effective range.

Zoom or varifocal CCTV camera lens

We always recommend using cameras with a vari-focal lens. During installation you can zoom in or out to balance area covered with detail captured. The more you zoom in the better the detail, the more you zoom out the less the detail but the wider the area covered. We sell varifocal cameras with 3 main lens ranges : 2.8-12mm, 6-22mm & 5-50mm. The smaller the number the wider the angle of view the larger the number the more telephoto it is. If you are planning a CCTV system get in touch, we can look at your site over the internet whilst discussing your requirements and ensure the correct cameras are used in each location.

Choose the right lens

Increasing the resolution of your cameras can help improve the image quality but unless you first ensure the camera is zoomed in sufficiently you are wasting your time. Merely throwing pixels at a fixed lens wide angle camera is like trying to heat your house with all the doors and windows wide open. Most people think they want a wide angle camera to give the widest coverage. This is the single biggest mistake you can make and yet remarkably most of the cameras for sale in places like Maplins or other national retailers are wide angle.

As you move away from a wide angle camera the pixels spread apart rapidly and little detail is captured. At D1 resolution a 2.8mm 90º angle of view camera can only identify someone about 1.5 metres away. Even at HD 1080P this only increases to about 3 metres.

In this 1080P HD 2.1 megapixel wide angle image we will digitally zoom in to try and show the silver car in more detail. Underneath is a standard D1 resolution 0.4 megapixel camera optically zoomed in during installation. Even though the camera is much lower resolution with only 1/5th of the pixels more detail is captured. This demonstrates the importance of using the correct lens and also shows the dangers of using fixed lens wide angle cameras

HD 1080P 2.0 megapixel wide angle camera

1080P wide angle camera

Digitally zooming in on the 1080P image to try and see the Porsche in detail

1080P zoomed in

 

Standard definition D1, 0.4 megapixel camera optically zoomed in during installation

D1 zoomed in