Firstly some background. CCTV cameras were originally analogue and cabled using coax cable and were separate systems. In 1996 Axis developed the first IP camera, capable of running over a normal data IP network. Since then many benefits have been developed, one of which is the ability to have cameras with wide dynamic range (WDR), although some analogue cameras were capable of this in a lesser way.

Why do we need it and where do we use it I hear you say? Let’s answer the second question first, we need a WDR camera in areas where there is both a lot of bright light and areas of shadow, for instance in a warehouse where lighting is subdued but, with the opening of a shutter door a large amount of bright light floods in, or in a lobby with a camera facing glass entrance, in this case a person coming in would have his face in shadow, as the camera would set light levels to cope with light through the glass. Example pictures of this can be seen on the Axis website by clicking here.

WDR cameras are able to highlight the shadows and dim down the light such that the final image shows detail in both areas. To do this they use one long exposure and one short exposure before combining to produce the balanced frame with smoothed out light levels. This is all done by the camera before transmission to the recorder.

Many manufacturers now provide WDR cameras, it is up to us installers and indeed consultants to make sure these cameras are used where needed even though they cost a little more.

For a more detailed description of WDR there is an excellent white paper on the Axis website or contact Able for further information.