Many nighttime reflection issues that occur are caused by IR reflection. Many of the IR reflection issues are caused by:
Losing contact between the foam gasket ring and dome cover.
Nearby barriers in the environment that reflect IR light.
Dust, wet, moist on the plastic dome cover.
Possible internal damage to the lens, which may need replacement
FOAM GASKET RING PROBLEM
The most severe case of IR Reflection is caused by the foam gasket ring not being firmly pressed against the camera dome. This will create a “halo” effect.
To minimize the chance of IR light reflection into the lens, please make sure that the dome bubble is sitting snug against the foam ring. Please note, that upon good contact with the dome cover, the foam gasket ring will appear to be squashed a little bit.
Image of the Foam Ring
NEARBY OBJECTS AND BARRIERS
Nearby objects and barriers are another possible cause of “Foggy” night images. Figure 5 shows the effect of a small piece of cardboard positioned only 4 inches away from the side of the camera. Even though not visible in the picture (the cardboard is outside of the camera’s field of view), the IR reflection is huge.
To avoid this situation:
Avoid installing the camera in heavily lit or light reflecting areas.
Avoid installing the cameras in tight corners.
Use wall mount brackets to offset the cameras from walls and close surfaces.
Try to rotate the camera as much away from background surfaces as possible.
Make sure plants/vegetation are clear of the near Field of View.
Plants' leaves are highly reflective.
DUST, WET, MOISTURE ON CAMERA COVER
Dirty/moisture dome cameras also cause IR “bleeding” and poor night vision image. Avoid touching the dome during the installation and try to keep the protective film on the dome unit until the very end. Touching the dome cover creates grease stains/spots on the bubble, which create blur. These may not affect the daytime image but will immediately be an issue with nighttime IR images.
Always clean the dome cover with a soft cloth after the installation. Commonly, the domes get covered with dust/dirt, raindrops stains, and cobwebs over time. This will cause the image quality to degrade over a period of time (“foggy condition”). Periodic cleaning of the dome cover may be required to maintain a clear image.
Additionally, fastening the screws to make sure the camera is fully sealed. For moisture climate, you also can put desiccant packets to absorb water inside the dome camera. You should replace any desiccant packets at least once every year. Because they become less effective as time goes by.
For more details on this issue please view the following video: