1. Why night footage is weak
A camera without light cannot see. In the dark the sensor receives too little light, so footage becomes noise and shadow. Adding light or infrared illumination changes the situation.
2. IR range
Infrared illumination is invisible to people, and the camera sees it. IR range tells you how far the camera sees at night. The greater the range, the farther it covers in the dark.
3. WDR and contrast
WDR (wide dynamic range) solves a different problem: when part of the scene is bright and part is in shadow. A camera with WDR sees both at once — a face by a window and a corner in shadow.
4. LUX and sensitivity
LUX measures how much light a camera needs for a usable picture. A lower value means better low-light performance. A camera with low LUX sees more before IR must switch on.
5. Why a stronger camera is not enough
A camera with more megapixels still cannot see in the dark without IR or light. The fix is a combination: IR for darkness, WDR for contrast, and a position that uses available light.
6. Where night vision fails
Reflection from glass, a direct light source and rain all weaken night footage. A camera facing a street or shop window needs tuning and often a second camera.
7. Recommendation
Look at IR range and WDR in the spec, not just megapixels. Test the camera at night, not in daytime, before you decide.
RULE OF THUMB: Night footage is tested at night. A camera that sees well by day guarantees nothing after dark.