CCTV FAQ (Frequently Asked Questions)

A WDR camera (Wide Dynamic Range) is used for capturing images of objects surrounded by a strong back light, while still keeping the background visible. WDR technology uses special high-speed CCDs to make two consecutive image scans to one picture. Non-WDR cameras just make one pass. The first scan captures images in the normal light condition. Right after, the camera captures the second image at high speed to capture the images that are in the strong light. The image processor then superimposes the two video images to provide a single picture that can see all areas. A typical use for a WDR camera is capturing scenes indoors that have large windows in the background with lots of sunlight. A WDR camera would enable you to capture both the indoor and outdoor/background scene clearly.

DVR stands for Digital Video Recorder. A Security DVR is capable of taking the video from digital or analog cameras and recording it into a digital format on a hard drive. It can record high quality video, maintenance free, for weeks or even months. An ideal replacement for time lapse VCRs.

PoE makes the powering of CCTV devices easy. You take your camera that accepts power via the Ethernet port, you plug in the RJ45 cable into the port, and you walk away. Inside the leading end you plug in a PoE switch or PoE injector and voila, power is magically delivered to the device along with the data connection. The power is delivered over the pairs inside the network cable and so is the data communicated through the same cable.

The length of the recorded footage on a DVR or NVR is impacted by many variables. Firstly the number of cameras and how they are setup to record can greatly increase or reduce the recording duration. If the cameras are setup to record just on motion detection without audio, you will get most efficiency out of your DVR. Frame Rate also plays a huge role in video storage, a frame rate of 6 frames per second will make recorded video look jumpy, whereas 15 frames per second will smooth out the movement but double the storage space required. Most cctv cameras can record at a maximum of 30 frames per second, you would use this to capture number plates of extremely fast moving vehicles, the storage for video at 30 fps will be considerably higher than 6 and 15 fps video streams.

When it comes down to image quality, digital cameras will always surpass analog cameras. Similar to analog TV’s versus digital TV’s the image clarity and sharpness is much better. In addition, the recording resolution (the amount of information displayed on the screen) is much higher. On the news nearly every day we see terrible CCTV footage, you’re not able to make out the face of a suspect or their number plate or any distinguishable features for that matter. Digital CCTV cameras dramatically improve the ability to recognize detail which can lead to identification and if the suspect is guilty, conviction.