When part of an image is extremely dark but another part is so bright you can’t see any details, that’s dynamic range—the difference in lighting. Cameras with wide dynamic range (WDR) have special hardware & software that allows them to balance that lighting for one clear image. This makes them ideal for recording areas like store entrances where the contrast between the sunshine outside and the dim lighting inside can be extremely difficult to record.
How Wide Dynamic Range Works?
Cameras have problems with underexposed and overexposed images because they can only accurately record the middle area of light between very dark and very bright. Cameras with WDR technology have advanced sensors that can produce a wider range of lighting, allowing them to record in a higher light depth.
Along with recording a larger range of lighting more accurately, WDR-enhanced cameras have two other ways of balancing light for better images. Tone mapping lets the camera or software automatically brighten dark areas and darken light areas.
Alternatively, the camera will capture several shots of the scene at different exposure levels. This creates overexposed and underexposed identical images, which the camera will combine. It takes the most balanced parts of both images, creating the recorded image you see. This method requires an extremely fast and light-sensitive sensor, however, and is only available on advanced professional cameras.
How Wide Dynamic Range Can Help You
Cameras with wide dynamic range are great for many tricky lighting situations:
Lobbies and showrooms with many windows where the contrast between natural light and indoor light causes bright and dark areas Indoor recording, where the light when a door opens may make the person and their clothing unrecognizable Nighttime recording, where non-IR lighting may overexpose some areas while leaving other areas dark
When considering a camera with WDR, ask yourself two questions:
Is there a way I can balance the light? WDR is only available on professional cameras and may not fit into your budget, so adding or moving lights to balance your images might be a budget-friendly alternativeIs there a different camera location I can use? Doorways and windows may add too much light to a shot, so consider moving a camera you already own to record from a different location or angle before installing a camera with WDR
If it’s not possible to add balanced lighting or move the camera, a professional-level camera with WDR may be right for you. WDR cameras are available from all major surveillance camera brands including Axis, Optica, and Mobotix