Why does the preview image in photo mode sometimes display in black and white with YI 4K Action Camera?
Black and white photos may be due to overexposure. This can be common during the day if the shutter is not set to Auto and the EV (exposure value) is too large (i.e. +2.0).
You can resolve this by setting the shutter to automatic and the EV (exposure value) to 0. If the camera preview still does not improve, try restoring to factory settings.