WDR solves the problem of a single frame containing both very bright and very dark areas. Ordinary scenes do not need it; backlit scenes cannot do without it.

• Typical applications: entrances where inside is dark and outside is bright, tunnel portals and car park ramps, bank counters behind glass doors, loading docks, and interiors facing street windows.
• How to judge: if correct exposure by day leaves highlights blown to white or shadows crushed to black, you need WDR. If the scene is evenly lit, you do not.
• Key specifications: look at the dynamic range figure in dB — 120 dB and above is common — and whether true multi-frame capture is used. Cheap 'digital WDR' only stretches gamma and adds visible shadow noise.
• Using it well: enabling WDR introduces some noise and motion smear. At night with limited light, let it switch off automatically or reduce its strength to avoid degrading the image.

Engineering advice: specify WDR models at backlit positions where faces or plates must be legible, and pair them with appropriate illumination and mounting angles. That delivers far more than trying to fix things later with parameters.