By the SightShield team · · 3 min read
The silhouette problem
A camera inside a shop pointing at the glass entrance on a sunny afternoon often shows customers as black shapes against a white glare. A camera in a car porch facing the sunlit gate does the same. The camera cannot expose correctly for both the bright background and the shaded face at once, so it sacrifices the face — the one detail you need. This is called backlight, and it is one of the most common reasons CCTV footage fails to identify people.
What WDR does
Wide dynamic range (WDR) lets a camera show detail in both very bright and very dark parts of the same scene. True WDR cameras capture multiple exposures for each frame — one short for the bright areas and one long for the dark — and combine them, so the face in the doorway and the street outside are both visible.
True WDR vs digital WDR
Spec sheets list WDR in decibels. Higher is better, but compare true WDR figures; “DWDR” on a spec sheet indicates a digital feature only.
| Type | How it works | Result |
|---|---|---|
| True WDR (often 120 dB or more) | Sensor captures multiple exposures and merges them | Faces and background both clear in strong backlight |
| Digital WDR (DWDR) | Software brightens dark areas of a single exposure | Helps slightly; noisy and weak in strong backlight |
| BLC / HLC | Backlight compensation or highlight compensation adjusts exposure for a region | Useful tweak, not a replacement for true WDR |
Where you need true WDR
- Cameras inside glass entrances of shops, showrooms, banks and offices.
- Lobby cameras facing main doors.
- Car porches and garages looking out at a sunny gate.
- Corridors with a window at the end.
- Loading docks looking out through open shutters.
Placement fixes that beat any setting
- Mount the camera to look across the doorway rather than straight at it.
- Place it outside the glass, looking in, so the subject is lit by daylight.
- Raise the camera angle so less bright sky or road is in the frame.
- Add light on the subject’s side — a porch or lobby light reduces the contrast.
- Use a tighter lens so the face fills more of the frame.
A shop example
A mobile shop on Commercial Street had a camera above the counter pointing at the glass door. In the afternoon every customer appeared as a black outline. Moving the camera to the side wall, angled across the doorway, and switching to a 4MP true-WDR model made faces clear at all hours. The change cost one camera and an hour of work.
Tuning WDR on the camera
WDR is often off by default or set to auto. Turn it on for backlit cameras and adjust the level while watching the live image at the brightest time of day. Too much WDR can make images look flat or create halos and motion artefacts, so use only what the scene needs. Revisit the setting in the evening, when the backlight disappears.
WDR and night
At night the problem can reverse: a bright streetlight or vehicle headlights in the frame. WDR helps here too, and colour night vision cameras with good WDR handle mixed lighting better than basic infrared models.
Colour night vision vs infrared →Fixing backlit cameras
If your entrance camera shows silhouettes, we can reposition it, tune WDR or replace it with a true WDR model — often the cheapest way to make an existing system identify people.
CCTV installation and upgrades →Quick answers
What does WDR mean in CCTV?+
Wide dynamic range: the ability to show detail in bright and dark parts of a scene at the same time.
Is DWDR the same as WDR?+
No. DWDR is a digital enhancement of one exposure; true WDR merges multiple exposures and handles strong backlight much better.
What WDR rating should I look for?+
True WDR of around 120 dB or more for cameras facing bright doors and gates.
Why are faces dark on my entrance camera?+
Backlight from the bright door or gate. Turn on WDR, reposition the camera or add light on the subject.
Does WDR help at night?+
Yes, with headlights and streetlights in the frame.