Most CCTV cameras have a mechanical device operated by a solenoid and a photo-diode that removes the IR-cut filter from the light path after dark so that its IR LED emitters can illuminate the scene with infra-red light. The image will switch from color to Black & White. In the morning when the sun comes up the camera automatically moves the IR-cut filter back into the light path behind the lens to cut the infra-red light and this returns the camera to full normal color. Most dash cams I've seen that have any sort of night vision designed to illuminate the interior of a car at night do not have mechanical IR filters but I don't know for certain about the Blackvue.
ALL digital cameras, whether video or still cameras, DSLRs or smartphones have the IR-cut filter.
If you get anything other than a
magenta cast to the colors from your IR enabled dash cam there is some other explanation, perhaps as an incorrect menu setting or a sensor problem.
If you remove the IR-cut filter from a digital camera your image will look something like this:
If you make an image with the
same camera with an IR-cut filter installed you will see normal colors in the image.
The above IR image without a filter was slightly modified in the camera's color and white balance settings.
Typically, if you simply remove the IR filter and leave the white balance set for normal daylight your image will look like this:
Edit: Please note that after looking at Blackvue's web site, it is not clear whether the camera being discussed here even has IR LED emitters. That may only exist in their Taxi dash cams for interior cabin coverage but not other cams. There is discussion about the DR-900S for example
that states that their cameras use HDR along with boosting ISO gain at night for "night vision". If that is the case, then the colors should not be affected much, if at all, as they would have the required IR-cut filter. So, this whole discussion about IR-cut filters may have nothing to do with this problem.
Hi,
