during the dark it's quite bad at detecting, the sensitivity is at high (low, medium, high). During the day it seems to work ok, but the odd time it will miss the movement.
One other thing I have detected is, if I move just in front and the bell icon (motion detected) and recording icon appears on the screen, if I get out of the field of motion detection it continues to record for a few seconds (normal) but if I move back in just after it has stopped recording it will miss me.
Seems weird but may be a timer issue or something, cannot figure it out.