Doorbell 4 pre-roll - unusable quality

Hi, I have just got a brand new Video Doorbell 4 and the pre-roll feature is useless - see shot below:  You could not identify these people if you tried. The video is better (but still not great) after the pre-roll ends. Can anyone advise? ...I am not sure if it is a setting I need to change or whether my unit is defective. Also note when the video triggers (4 seconds in) the people are already in the indented part of the drive - is this the maximum range I can expect (I have it on max sensitivity)? thanks! James.