By the SightShield team · · 3 min read
The short answer
Most blurry night footage comes from one of five things: infrared light bouncing back into the lens, a dirty dome or spider web, slow shutter speed smearing anything that moves, a lens that goes out of focus under infrared, or simply not enough light for the camera. Most are cheap to fix.
Quick diagnosis
| What you see | Likely cause |
|---|---|
| Foggy white haze across the whole picture | IR reflecting off the dome cover, a nearby wall or the eaves |
| A bright moving blob or streaks | Spider web or insect near the lens |
| Still areas sharp, moving people smeared | Slow shutter / low light |
| Everything soft, day image fine | Focus shift under infrared |
| Grainy, noisy picture | Too little light, gain turned up high |
| Faces white and featureless up close | IR too strong at short range |
IR reflection and haze
At night the camera's infrared LEDs light the scene. If that light hits something close — the dome cover, a wall edge, a ceiling, a sunshade — it bounces straight back into the lens and washes out the picture.
Fixes: clean the dome inside and out; make sure the dome's foam ring or divider sits correctly between the LEDs and the lens; angle the camera so it does not see a nearby wall or ceiling; or move it slightly away from the edge.
Spiders and dust
Infrared light attracts insects, and insects attract spiders. A single web strand in front of the lens shows up as a bright blur at night and can also trigger endless motion alerts. Regular cleaning is the fix. Some installers use insect-repellent wipes on the housing; they help but need repeating.
Motion blur from slow shutter
In low light many cameras slow their shutter to gather more light. Still objects look fine, but people and vehicles smear. In the camera settings you can cap the slowest shutter speed — 1/50 or 1/100 of a second is common for areas where you need to recognise moving people — and add light so the camera is not starved.
Focus shift under infrared
Infrared light focuses at a slightly different point from visible light. Better cameras use IR-corrected lenses to keep focus in both. On cameras with motorised (varifocal) lenses, re-run autofocus at night, or set the focus with IR on so both day and night images stay sharp.
Not enough light
- Check the camera's IR range covers the area you want — a 30 m IR camera will not light a 60 m boundary.
- Add white or infrared lighting to large yards and car parks.
- Consider colour night-vision cameras where some ambient light exists, such as street-lit gates.
- Lower the resolution expectation: a high-megapixel camera with a small sensor may look noisier at night than a lower-resolution camera with a larger sensor.
Simple maintenance prevents most of this
Cleaning domes, clearing webs and checking night images are part of every routine service visit. If your night footage is poor and cleaning has not fixed it, a technician can check angles, settings and lighting on site.
CCTV AMC and repair service →Quick answers
Why is my CCTV clear in the day but blurry at night?+
Usually IR reflection off the dome or a nearby surface, a spider web, slow shutter on moving objects, or focus shift under infrared.
Will a higher megapixel camera fix night blur?+
Not by itself. Night performance depends more on the sensor, lens and lighting than on megapixels.
Does a colour night-vision camera solve blur?+
It helps where there is some ambient light, because the camera gets more light to work with. In total darkness it still needs its own light.