Yes you do need to be zoomed in to make the plate as large as possible.
But the angle also comes into play. The closer the angle is to 90 degrees, the harder it is to read the plate and the shorter the amount of time a vehicle is in the field of view.
Turn on motion detection on playback and see when BI triggers for motion and for what.
You may need to move you trigger zone towards the left to account for a lag/delay in when BI triggers for motion and take the alert image.
What FPS are you running at?
But the angle also comes into play. The closer the angle is to 90 degrees, the harder it is to read the plate and the shorter the amount of time a vehicle is in the field of view.
Turn on motion detection on playback and see when BI triggers for motion and for what.
You may need to move you trigger zone towards the left to account for a lag/delay in when BI triggers for motion and take the alert image.
What FPS are you running at?